Breaktru Forum
eCigarette Forum => Modding => Topic started by: Dznutz on July 13, 2012, 12:29:26 AM
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SO my question is how do you come up with the formula to choose what mosfet to use with a tact switch?
Should it support 0-5? 0-10?
I have a 12v 50ma and looking to fire the evercool and ptn04050c mods.
Sorry I have been searching and reading and all I run into is you should use one but the question is which one?
Thanks in advance all you electronics guru's.
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Generally, you want low RDS(on) and with a single battery, low VGS(th). That's "on resistance" and "gate-source threshold voltage". I wouldn't go below a VGSS of 12V and VDSS 20V though you could get away with lower (those are maximums for gate-source and drain-source voltages). The ones with lower maximums are more susceptable to damage. MOSFETs can get damaged easily by over-voltage. Just touching one without grounding yourself first can fry it. You can get ones that are ESD protected, but selection is limited.
Here's the one I like to use. It's a P-channel which means it's a high side switch;
http://www.fairchildsemi.com/pf/FD/FDS6576.html
You can use an N-channel, but you have to be careful with ground offsets since it's a low side switch (all grounds have to be connected to the MOSFET, not the battery). I don't have an N-channel recommendation off-hand since I tend to use high side switches for this kind of thing. High side switches are just easier.
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for a n chanel irlu3114 is what i use and i think breaktru does aswell cheers jimmy
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Thank you guys for all the info =)
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Ok one more question
Are the one listed above ok for just a standard 3.7 mod?
That should b the ? on this and thank you in advance.
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The P-channel I linked to is good for a single cell. For the N-channel mentioned, VGS(th) is a bit high for a single cell. This (http://www.fairchildsemi.com/pf/FD/FDD3706.html) would probably be a better one.
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Thank you Craig
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Hi Craig or any one else :D
My next question is from the information found on fairchild's site they say to use a 4.7? resistor on the gate for ringing purposes. Is this true? I have seen several schematics for mosfets where people are talking about using 10k from gate to ground to prevent damage. again is that true?
Is a resistor from gate to source needed as well? if so how do I determine which resistor is needed? Sorry to be a pain just really trying to learn with out being more confused when I started :yes"
Thank you in advance
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The "ringing" only happens at high frequency like when using the MOSFET in a switching regulator. In that case, a 2 to 5 Ohm resistor in series with the gate dampens the ringing to keep if from causing undesirable effects. The need for a damping resistor depends on various design and component characteristics. With a good driver and a MOSFET with low gate charge, it's usually not necessary. It's called ringing because the voltage curve appears on an oscilloscope just like the sound waves of a bell ringing. A damping resistor is never required for a user power switch.
For an N-channel switch, you need a "pull down " resistor on the gate. Pull down only means the resistor connects the gate to ground. For a P-channel switch, you need a "pull up" resistor that connects the gate to input voltage. This resistor is always necessary for a power switch and good values range from 4.7K to 47K Ohms. 10K is a typical value.
For ESD protection (damage from static), Zener diodes are used, not resistors.
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For an N-channel switch, you need a "pull down " resistor on the gate. Pull down only means the resistor connects the gate to ground. For a P-channel switch, you need a "pull up" resistor that connects the gate to input voltage. This resistor is always necessary for a power switch and good values range from 4.7K to 47K Ohms. 10K is a typical value.
Ok I am getting it now. How do I determine the pull down/up resistor value? and esd in not needed to power a switch correct?
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There's no formula required for that. 10k is a good value for a pull up or pull down resistor. It's just a matter of how much current you want to flow. More current provides better resistance to noise and less current provides lower power consumption. It can also be depend on minimums and maximums for the tactile switch.
ESD protection is only required if you are using the MOSFET for a touch switch, but it's still not a bad idea to add it even with a tactile switch. There are MOSFETs available with protection built-in, but selection is limited. You can simply add a Zener diode with a reverse breakdown voltage lower than the maximum gate-source voltage of the MOSFET. Connect it from gate to source with the polarity bar on the high side. That would be on the gate for an N-channel and on the source for a P-channel.
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(http://i45.tinypic.com/34y9nyv.jpg)
Does this work for the mosfet with a tact switch?
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Does this work for the mosfet with a tact switch?
DZ, it's not correct. The 3101 is an N-Channel. There are several schematics in the modding forums. Just substitute the finger for a tact.
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This is how it should be wired. Note the part numbers
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Nice and clear, Dave - nice!
The pics of p & n together is very useful.
I think one of the most irritating "parts" to selecting the components is: we read the forums and take notes - parts and values - and then wander over to digikey & mouser and discover they don't list the same info in the same way. In fact, their parametric/search stuff often ignores things we care about! (Having to DL every bloody datasheet to look for several comparable values is a royal pita ;-)
I was going to mention that many "finger" posts were for touch-switches, (and added that 10-100Mohm resistor).
Again, Nice!
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Yes thank you Break, I did wire it the other way, just wondered if the way I posted would work. From tiral and heat , I figured no it wont.
Thank you for confirming it.
Thank you also for the P channel post as well.
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This is how it should be wired. Note the part numbers
Got a couple of irl3103 should i just remove the tact switch and follow the diagram if i want to use it as a touch sensor switch? Or i have to wire it differently?
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Got a couple of irl3103 should i just remove the tact switch and follow the diagram if i want to use it as a touch sensor switch? Or i have to wire it differently?
Same wiring. Just bump up the resistor between G and S. Start at 1M. I have gone as high as 100M ohm.
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This is how it should be wired. Note the part numbers
yeah thanks Dave very nice and clear You Rock! :beer-toast:
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Same wiring. Just bump up the resistor between G and S. Start at 1M. I have gone as high as 100M ohm.
Yeah seems like the 2M is not working for me. I'll try to buy some higher value resistors. :)
Btw, i have to put a 1k resistor in G to touch pad yeah?
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sorry i can't start new thread...
Iam searching for a fuse smd are these ok ? http://www.ebay.com/itm/10Pcs-Littelfuse-SMD-0603-5A-5-Amp-Fast-Fuse-467-0467005-NRHF-/221010323199?pt=LH_DefaultDomain_0&hash=item33753de6ff
which ressetable fuse has the lower resistance ?
Also iam searching for a current sensor smd , a charge pump for high side n-mosfet switch and an inductor smd for step circuit do you know something good ?
What extra hardware except from an mcu i need to drived an oled like this ?
http://us112401600.trustpass.alibaba.com/product/120752718-103326398/Santek_0_69_OLED.html
for n-mosfet i want something to step the gate voltage higher that drain voltage to use n-mosfet as high side switch
thanks.
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sorry i can't start new thread...
Iam searching for a fuse smd are these ok ? http://www.ebay.com/itm/10Pcs-Littelfuse-SMD-0603-5A-5-Amp-Fast-Fuse-467-0467005-NRHF-/221010323199?pt=LH_DefaultDomain_0&hash=item33753de6ff
which ressetable fuse has the lower resistance ?
Also iam searching for a current sensor smd , a charge pump for high side n-mosfet switch and an inductor smd for step circuit do you know something good ?
What extra hardware except from an mcu i need to drived an oled like this ?
http://us112401600.trustpass.alibaba.com/product/120752718-103326398/Santek_0_69_OLED.html
for n-mosfet i want something to step the gate voltage higher that drain voltage to use n-mosfet as high side switch
thanks.
Your questions are above my pay grade but when I am looking for parts like the smd fuses, I'll go to a parts distributer site like Mouser, Digikey, etc. You have the option to search for a part. The results are shown with the parts specifications. You can refine the search by selecting say the lowest resistance, smd, or what ever... like here: Mouser (http://www.mouser.com/Search/Refine.aspx?N=254138)
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thank you i know mouser but iam searching for tested components...
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Mouser probably has the best parametric search for finding parts. It's the first place I look when putting together a new design. They even show parts they have on the books but dont stock. If you find something you like, you can try findchips.com or another vendor to locate stock.
The best SMD fuses are the Littelfuse LoRho (http://www.littelfuse.com/~/media/Files/Littelfuse/Technical%20Resources/Documents/Data%20Sheets/Littelfuse_Resettable_PTCs_LoRho_Datasheet.pdf). They have by far the lowest resistance and they're small. I ran two the 1210L350SL in parallel for an incredible 4m Ohms insertion resistance, that's measured. Though you should use the bigger 1812s if you have room. The smaller ones wear out faster. If they trip too many times, the resistance goes up. The bigger ones don't have that problem.
There's only one single chip current sensor I've seen that will work well for an e-cig mod. Dave uses it, maybe he can give you a link. I use a current sense resistor and differential op-amp circuit myself. It's kind of a pain though, has to be calibrated for each build. It's good becuase I can set the upper limit to get the best resolution. Current range is hard wired with the single chip solution.
I can't help you much with a charge pump. I always use MOSFETs with low enough VGS(th) that I don't need to use one. It's kind of an archaic way to go with the wide range of logic level P-channel MOSFETs now. In any case, you should be able to find one that suits your needs. It's a pretty standard part.
That OLED looks like a run of the mill COG unit. All you need is an MCU to drive it. Probably just has an I2C interface, power, ground, and reset connection.
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i am searching for a current sensor
See: Current Sensor (http://breaktru.com/smf/index.php/topic,575.msg3838.html#msg3838)
and check the 2 posts below it.
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I can't help you much with a charge pump. I always use MOSFETs with low enough VGS(th) that I don't need to use one. It's kind of an archaic way to go with the wide range of logic level P-channel MOSFETs now. In any case, you should be able to find one that suits your needs. It's a pretty standard part.
low VGS(th) doesn't help if you want to use n-mosfet as high side switch for low side helps.
To use it as high side Vg must be higher than Vd to force n-mosfet go to saturation.
Because i have some mosfets with ultra low RDSon and low VGS (2.5V) i want something like charge pump to use as high side switch.
For low side works fine without extra components but i want high side switch.
For mcu i have some tqfp atmega chips (its easy to solder this chips without expensive equipment) i will program it in c with avr-gcc compiler.
Here i have found some p-mosfets with very low RDSon http://www.aosmd.com/products/mosfets/p-channel
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There can be good reasons to use an N-channel for a high side switch, for example if you have a lot of stock already of a certain part or if you need absolute minimum on resistance, but it's not something people do typically anymore. There was a time where P-channel MOSFETs were considerably more expensive than N-channel MOSFETs and did not have the performance specs to operate efficiently with lower voltages. That's just not the case anymore. So given the option, there's really no reason to increase your part count using an N-channel.
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The only MOSFET I could get locally has negative voltage values on the data sheet. Would the switch work with a NPN 3904 transistor instead of the MOSFET? Or is 2.5 amps (my max vaping amperage) too much for the transistor.
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Note, that you have to choose your VGS(th) as low as possible. I already had few transistors which theoretically should do the job - but couldn't fully open the gate. Make it around 2V. Some 3V do work, too.
As for the N-channel transistor, see my old circuit:
(http://img824.imageshack.us/img824/2429/hvmosfetswitchschemat.png)
From globally available ones you can get for example IRLR8743PbF.
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The only MOSFET I could get locally has negative voltage values on the data sheet. Would the switch work with a NPN 3904 transistor instead of the MOSFET? Or is 2.5 amps (my max vaping amperage) too much for the transistor.
A 2N-3904 has a Continuous Collector Current of only 200ma
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You can use a bipolar transistor if you want, but MOSFETs make better switches since bipolar transistors tend to be more lossy. For example, a bipolar transistor with a VSAT of 200mV will lose 1/2 Watt at 2.5 Amps. A MOSFET with an RDS(on) of 15 mOhms will lose 1/10 Watt at 2.5 Amps. Also, you need a bias resistor for a bipolar transistor and it has to be properly selected to ensure the transistor is fully saturated under all conditions without overloading the base-emitter junction.
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The mosfet the guy at the electronics store recommended is the IRFU9110, data sheet here http://html.alldatasheet.com/html-pdf/181384/IRF/IRFU9110PBF/58/1/IRFU9110PBF.html VGSth min -2.0. I am a little confused with the negative values on the sheet, all the other ones I looked at had positive values. Looking at the diagram from earlier posts, the resistor goes from gate to source? Thanks for all the help.
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The mosfet the guy at the electronics store recommended is the IRFU9110, data sheet here http://html.alldatasheet.com/html-pdf/181384/IRF/IRFU9110PBF/58/1/IRFU9110PBF.html VGSth min -2.0. I am a little confused with the negative values on the sheet, all the other ones I looked at had positive values. Looking at the diagram from earlier posts, the resistor goes from gate to source? Thanks for all the help.
That mosfet is a P-Channel. It has a high RDS(on) of 1.2 ohms.
Yes the resistor goes from Gate to Source like: See Circuits (http://breaktru.com/smf/index.php/topic,215.msg1550.html#msg1550)
Not sure why neg V. Maybe Craig could answer that?
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P-channels use negative values because N-channels are the positive convention. To turn the transistor on, Vgate is less than Vsource so VGS is negative.
Also when used as a switch, P-channels are wired differently than N-channels. A P-channel switches from the high side. An N-channel switches from the low side. High side switches are easier to implement, but N-channel MOSFETs are generally cheaper and perform better, specifically, they have lower gate charge (they're faster) and they have lower RDS(on) (not as lossy).
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Thank you Craig for your expertise :thumbsup:
I was puzzled w/ the Neg V because I looked at some P-Ch datasheets and some showed Neg and some Pos :Thinking:
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Thanks for the help. I have ordered the IRL 3103 as pictured in the diagram. That way I know it will work correctly. You guys are the best.
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Ok I have a strange one today. I went to wire in a STD30PF03LT4 & tact switch into a 3.7mod and its always firing. No biggie grabbed another one from the tape and same thing?!?! After 5 of them I'm baffled. I have used some from the same tape and they worked fine. Wired exactly as break's post earlier.
Any ideas what could be causing this?
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Ok I have a strange one today. I went to wire in a STD30PF03LT4 & tact switch into a 3.7mod and its always firing. No biggie grabbed another one from the tape and same thing?!?! After 5 of them I'm baffled. I have used some from the same tape and they worked fine. Wired exactly as break's post earlier.
Any ideas what could be causing this?
What size resistor did you use.
Too low won't turn on or won't turn on fully
Too high won't turn off
The resistor I showed was for using finger touch. Lower ohms is required for using a tact switch
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I used 15k. Same as I always use. I have tried 20k and no res and its always on.
I checked and the ohm @ 14.7
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This may sound stupid but are you using a N/O tact sw?
Another thing... did you try it with a load (atty)
Are you powering a PTN04050c with it and breaking the positive to board.
I know that you said you have done this before with this Mosfet but did you double check your wiring?
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This may sound stupid but are you using a N/O tact sw?
Another thing... did you try it with a load (atty)
Are you powering a PTN04050c with it and breaking the positive to board.
I know that you said you have done this before with this Mosfet but did you double check your wiring?
Yes N/O switch, yes on the load (carto 1.7) and no it's just a 3.7 mod. Last week I did a 4050 with a mosfit from the same tape. That's what has me baffled
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There's not much to go wrong there. The only thing I can think of is if you're using N-channel wiring for that P-channel MOSFET or if you're confusing the terminals.
A rather remote possibility is ESD damage. That one has no protection so it's going to be vulnerable until it's installed in a circuit. You should use a ground strap when handling unprotected MOSFETs. I've burned a few that way myself. They're really delicate, doesn't even take a static shock you can feel. Though, I doubt you would burn five of them in a row handling them unless the whole tape got zapped somehow.
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when using a tactile switch as the power switch on a 04050 chip, is it essential to use a mosfet, or can you get away with out using one at all?
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when using a tactile switch as the power switch on a 04050 chip, is it essential to use a mosfet, or can you get away with out using one at all?
Look at the amperage rating on the tact switch and then look at the amperage of the 04050 input... This should answer your question
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Look at the amperage rating on the tact switch and then look at the amperage of the 04050 input... This should answer your question
found the amperage rating for the switch, but reading the pdf for the 04050, i must be missing it but cant find a minimum input amperage, i am such a noob when it comes to this lol :)
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@rhay, if you go back a few posts in the ".44 mini Booster Box Mod Variable Voltage" thread, wreck did a calculation for fuses using this chip.
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thanks, found it, i guess i will have to use a mosfet with the tactile switch. :)
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thanks, found it, i guess i will have to use a mosfet with the tactile switch. :)
Exactly :laughing:
I'm not trying to be a smart ass. I'm just trying to point out that reading datasheets or spec listing can help us immensely.
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Always read the data sheets. You can be surprised at the level of general application information in them sometimes. For more complex parts, they often give you a typical application you can use as a Chinese blueprint.
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Hi guys
Thanks for all the info in this thread.
Question about using a p channel
I want to make an unregulated parallel 18650 "mech" box
Can someone point me to a MOSFET that can handle high currents and work for 4v?
I don't know where to start and I would love to build something that can sub ohm with a tact switch.
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Charlie,
You can use a STD30PF03L. It comes in a DPAK or IPAK footprint. Your choice of physical size.
See the P-Ch diagram in Reply #13 (http://breaktru.com/smf/index.php/topic,616.msg5417.html#msg5417) in this thread.
Here are P-Ch Mosfets with lower internal resistance: FDD3706/FDU3706 (lowest resistance) and FDS6576
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Thanks Bteaktru
I am excited to make something with this
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Where would someone put a zener to cut the votlage of when it reached 3. volts or so?
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You can use a STD30PF03L. It comes in a DPAK or IPAK footprint. Your choice of physical size.
See the P-Ch diagram in Reply #13 (http://breaktru.com/smf/index.php/topic,616.msg5417.html#msg5417) in this thread.
Here are P-Ch Mosfets with lower internal resistance: FDD3706/FDU3706 (lowest resistance) and FDS6576
Unfortunately the ones hot off the press only come in the newer surface mount packages. You need to mount those on a host board. Not a big deal to make a host board and mount the part, but not as simple as soldering wires to pins.
The latest models with the lowest on resistance are not being made available in the the leaded packages. You can still find parts in leaded packages that work well enough, but if you want the best performance possible, you have to go with one of the newer packages. They all go by different names from different makers, for example Vishay calls them PowerPAK SO-8, Fairchild calls them PQFN 5x6 8L, and TI calls them Q5 or Q5A.
Here's an example; http://www.vishay.com/docs/62860/si7157dp.pdf
You can also find some nice power FETs in a 3x3mm DFN type package, but those are a bit hard to work with since they're pretty small. Though they're good if you want to absolutely minimize the footprint.
Here's an example; http://www.vishay.com/docs/62909/si7655adn.pdf
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Ok I got a few mosfets mc7805ct will this work to wire in my tact switch I can't figure out if it's a p or n channel
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The MC7805CT is a Voltage Regulator w/ a 5V output. Not a Mosfet
http://www.lmgtfy.com/?q=MC7805CT (http://www.lmgtfy.com/?q=MC7805CT)
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Pretty much all electronics vendors provide links to data sheets with their parts listings. When you have questions about a part, just post a link to the data sheet and someone here can answer them for you. Don't really know how you got from a MOSFET to a regulator, you probably got the part number wrong.
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Apologies for reviving an old thread. Is there someone who can help with the above post? Im also i terested on doing one of this mosfet / tact switches that can go sub ohm on a 3.7v/4.2v input. Can anybody help?
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No such thing as an old thread/topic if it is relevant.
See Reply #13
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Break as always you and the vets are an awesome wealth of knowledge. Appreciate it. I just bought a who,e bunch of the irl 1303 it should be here on monday!!
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Hi
Is it possible to use a Zenner Diode with the N CH Mosfett to provide a low voltage cut off? As im planning on using 2 Lipo packs in parallel probably go with something like this http://uk.mouser.com/ProductDetail/NXP-Semiconductors/NZX3V3C133/?qs=sGAEpiMZZMtQ8nqTKtFS%2fISyHb0gtGyWnMdca58vn6A%3d .
Placing the Diode in the circuit as shown on the attachment? I assume this would prevent the on signal to the mosfet?
Thanks
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I sometimes get asked technical questions in PM where I feel my answers could be a general benefit to others. Don't really understand why people feel they need to contact me in PM for technical info, kind of the point of the forum, but that's what they do sometimes.
In any case, I got a series of questions about using a MOSFET and I thought I would post my answers in the event they can be generally helpful. This was the newest applicable thread so I'm posting in this one. Here's the exchange;
I got into modding and been working on a dual 26650 mech box mod I finally learned enough from reading about all the things you've done to put a n channel mosfet in my mod but the voltage drop seems a little much I'm using the irlu3114 with a 10k resistor the vgs is 1v to 2.5v is it possible the gates not opening all the way or can I run the mosfets in parallel.
In general, you need to ensure the voltage between the gate pin and source is equal to or greater than a value specified in the part's data sheet;
http://www.mouser.com/ds/2/200/international%20rectifier_irlr3114zpbf-342321.pdf
If you look on page 2 of that data sheet, you'll see the RDS(on) value specified at 4.5V. So to get a resistance of 5.2 mOhms, you need at least 4.5V between the gate and source pin. If you go lower than that, "on state" transistor resistance goes up quickly.
When using a single cell (or parallel cells), you need a transistor that is specified at 2.5V. The IRLR3114 is specified at 4.5V. Here's an example;
http://www.fairchildsemi.com/ds/FD/FDD3706.pdf
Also, you need to ensure you're using the correct polarity. If you want to switch the high side (positive), you need a P-channel MOSFET. If you want to switch the low side (negative), you need an N-channel MOSFET.
An N-channel requires a pull-down resistor between gate and source. Pull-down simply means the resistor is connected to battery negative along with the transistors's source pin. The other side of the resistor is connected to the switch and the transistors's gate pin. The opposite side of the switch is connected to battery positive.
A P-channel requires a pull-up resistor between gate and source. Pull-up simply means the resistor is connected to battery positive along with the transistor's source pin. The other side of the resistor is connected to the switch and the transistors's gate pin. The opposite side of the switch is connected to battery negative.
would you know of a n channel mosfet that can handle around 100a or at least 75a that would be good.
You need to go to a leadless package if you want a small MOSFET able to handle high currents while also driven by a single cell or a set of parallel cells. They don't have leads so you have to make a little host board for one. Here's an example;
http://www.vishay.com/docs/64815/sir404dp.pdf
100A is a lofty requirement. You won't find a 2.5V specified MOSFET with a current rating that high. The one above would be about the best you can do in terms of a 2.5V specified part. You can find ones in a small leadless package 100A and over, but they're 4.5V or 10V specified. Though I don't really understand the need for such a high current rating. A 60A MOSFET should be more than enough for anything you could do with an e-cig.
and where can I learn about host boards
A host board is nothing special. It's just a small PCB that allows you to tie wires to a component that does not have leads. You can simply get some FR4 copper clad off eBay and cut out a small piece with a metal saw or Dremel tool. Then you can probably just cut the pads for the MOSFET with the Dremel tool as well. It's only 3 pads. Then you can reflow solder the part to the board.
If you want to etch your host boards, there are a ton of articles on the net about making your own PCBs. Do a search on "PCB toner transfer method". Also search on "toaster oven reflow soldering". There's tons of articles on that as well.
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Very good Craig. That should help a lot of folks.
If I said it once, I said it 100 times to members who PM me on questions as well. Please post it so others can benefit as well.
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Hi
Is it possible to use a Zenner Diode with the N CH Mosfett to provide a low voltage cut off? As im planning on using 2 Lipo packs in parallel probably go with something like this http://uk.mouser.com/ProductDetail/NXP-Semiconductors/NZX3V3C133/?qs=sGAEpiMZZMtQ8nqTKtFS%2fISyHb0gtGyWnMdca58vn6A%3d .
Placing the Diode in the circuit as shown on the attachment? I assume this would prevent the on signal to the mosfet?
Thanks
I am wondering this as well. I have ordered some 3.0v zener diodes.
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I have a couple of irlb3034 from previous project (airsoft mosfet) will i be able to use those and wire them same as irl 3103? Like the diagram on reply #13?
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The 3034 should work fine as it is also an N-ch mosfet and with lower resistance than the 3103
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thanks banshee, how much of an amp draw does the "mosfet switch" would allow? im planning to use it in an un regulated box, that will mostlikely do sub ohm.
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Here is the datasheet for it: irlb3034 (http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CB8QFjAA&url=http%3A%2F%2Fwww.irf.com%2Fproduct-info%2Fdatasheets%2Fdata%2Firlb3034pbf.pdf&ei=oEjiU4yiEsqnyATc4YG4Ag&usg=AFQjCNEGjFxdKwlb1jWnouWklY6wpU99Gw&bvm=bv.72197243,d.aWw&cad=rja)
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This is how it should be wired. Note the part numbers
I have a couple of question about the master switch and the resistor. Im doing this on a duel 18650 with an std30pf03l mosfet. Is the 15k the same on a duel battery and how much current does the master on/off need to carry?
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The 15K should work fine with 2 series or parallel 18650s if using it with a tact switch. If using it as a touch, then 100meg maybe in order.
You won't be switching the on/off under load which can cause arcing and be detrimental to the switch contacts.
A 3A @ 125V on/off which equates to 375W. If using 8.4v with 2 series batts the switch should be able to handle 44.64A at 8.4v
See THIS (http://breaktru.com/smf/index.php/topic,162.msg13234.html#msg13234) for switch amps/volts.
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For parallel cells, there's no difference, you can think of them as one bigger cell. For series cells, voltage is doubled so current for a given resistance is also doubled. There may be considerations there, but the 15k resistor will work fine with either battery configuration.
In reviewing this thread to answer that, I noticed an unanswered question;
You can not simply use a Zener diode on the gate pin of a MOSFET to provide a low voltage cut-out. This is actually the third time I've seen this idea, don't understand why people keep coming up with it.
You have to provide a digital voltage level to the MOSFET gate, either on or off. A Zener diode is an analog part that is not able to generate a digital voltage level. It ramps current up and down with voltage. Using one in a divider on the MOSFET gate will put the transistor in its active region.
The active region of a transistor is where it behaves more like a variable resistor than a switch. Remember the primary function of a transistor is to provide a variable current source. Though MOSFETs are designed to be used as a switch, they still have this active region where they behave like a traditional transistor.
It's possible to use a Zener with an array or transistors to generate a digital signal. You can use a comparator chip to do that more simply. The most simple way is with a voltage detector which is a chip designed exactly for that purpose.
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Thanks. Its just a simple parallel box. Just wanted to make sure. I actually have a bunch of 20 and 30amp round switches from the car stereo linear actuator days. Im pretty sure they would handle almost anything I would throw at it but the mosfet sounds a lot safer than just hoping the switch doesn't stick
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After reading for the last few days, Im now hooked. Would you tell me if all this works together for a duel 18650 box.
Already ordered a crap load of tact switches
low voltage cut-NCP300HSN30T1G
mosfet-STD30PF03LT4
fuse- assume 2 for each batt-30R300UPR or 16R300GU
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This is how it should be wired. Note the part numbers
http://breaktru.com/smf/index.php?action=dlattach;topic=616.0;attach=1366;image
Would this be wired the same way if replacing the tact with a standard N/O Switch?
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The switch used in the diagram is already an NO (normally open) momentary switch. A momentary NO switch operates the same electrically whether that's a tactile or a high current switch.
You can use any type of switch you like there. However, the primary advantage of using a transistor is it allows a small current to control a big current. With a transistor you can use a small low current switch. With the inclusion of the transistor it still consumes much less space than a switch able to handle high currents directly.
Also, a transistor is more reliable than a switch and with careful selection can waste less power. Transistors capable of supporting as much as 50A current are still relatively small. There's the wear on a tactile that has to be considered, but generally tactiles have much higher cycle life than heavy switches.
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The drawing was great and all but it didn't have fuses or the low voltage cut. (are the ones I listed ok and which do you like better) I was making sure I didn't order a bunch of stuff that didn't work together.
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I assume you mean two parallel cells when you say "dual 18650 box". The parts you listed will work for a single cell or dual parallel cells. Though they will work, you can make a better selection on the fuses and MOSFET.
You can select a MOSFET in a similar package with a lower gate-source threshold. That will provide lower "on" resistance. It wastes less power and reduces voltage loss in the transistor.
You do have to be picky with MOSFETs. They can vary quite a bit in terms of "on" resistance and threshold voltage. There's actually good reasons why that's the case, has to do with speed and voltage tolerance. Speed matters for certain applications, but not for a user on/off switch. Voltage is low with a single cell or parallel cells so a higher gate-source or drain-source voltage tolerance is not required.
There's a few ways to spot those low threshold voltage MOSFETs. First, they often have an RDS(on) specification for 2.5V at the top of the data sheet. Another way to spot them is they'll have a maximal gate-source tolerance of 12V or less stated in the absolute maximums. Finally, you can look at the gate-source threshold listed in the data sheet, it will have a minumum less than than .8V and a maximum not greater than 1.5V.
You can use two 3A hold fuses on each or cell or one 6A hold fuse on each cell. You'll get lower resistance with four 3A fuses in total, but that may or may not be better in terms of the fit inside the enclosure and of course there's more parts. Your call on that.
You can find fuses with lower resistance than the ones you listed. You want to look for the lowest resistance available with the required hold/trip currents.
There's a also a matter of the fuse's physical size. The higher the voltage and current tolerance, the bigger they are. You can reduce size by looking at ones with a lower voltage tolerance. The lowest they go is typically 6V and a Li-Ion cell is only 4.2V so just look for the smallest ones with the lowest resistance.
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Thank you. Well back to the drawing board, back to mouser anyway
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Inside
(http://i.imgur.com/YTeg2BC.jpg)
Battery voltage
(http://i.imgur.com/DXi462O.jpg)
Firing 0.61 ohm coil
(http://i.imgur.com/YjjJaGr.jpg)
* 2 x MOSFETS - http://www.mouser.com/ProductDetail/International-Rectifier/IRLB3034PBF/?qs=sGAEpiMZZMshyDBzk1%2fWi5%252bqVgN3%252bWS8iNZUeqPPDAc%3d (lay on top of each other, solder leads together to parallel)
* 2 x 15 Amp Fuses - http://www.mouser.com/ProductDetail/TE-Connectivity-Raychem/MHP-TA15-9-85/?qs=sGAEpiMZZMsxR%252bBXi4wRULUWu%252b0%2fKKWjHla6GdFh6iY%3d
* 2 x 18650 Holders - http://www.mouser.com/Search/ProductDetail.aspx?R=1043virtualkey53400000virtualkey534-1043 (each sanded to about 18.5mm in width)
* 1K Ohm 1/4 Watt Resistor - http://www.mouser.com/Search/ProductDetail.aspx?R=MFR-25FRF52-15Kvirtualkey57620000virtualkey603-MFR-25FRF5215K
* Hammond 1590GBK Enclosure - http://www.mouser.com/ProductDetail/Hammond/1590GBK/?qs=%2fha2pyFaduiJ5sxgvcfZdIk1sIy4rFZea7BKawP8o84%3d
* Tactile - http://www.ebay.com/itm/281341680838
* Blue LED .28 Voltmeter - http://www.ebay.com/itm/350926594725
* Tint For Voltmeter - http://www.amazon.com/gp/product/B00CCSD5U0/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1 (3 layers used)
* FDV Spring Loaded 510 - http://fatdaddyvapes.com/shop.html
* 14, 18, 24 Gauge Wire
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Nice job david :rockin smiley:
Very neat work. Looks very professional :beer-toast:
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Diagram
(http://i.imgur.com/CY0yYwJ.png)
Inside
(http://i.imgur.com/YTeg2BC.jpg)
Battery voltage
(http://i.imgur.com/DXi462O.jpg)
Firing 0.61 ohm coil
(http://i.imgur.com/YjjJaGr.jpg)
* 2 x MOSFETS - http://www.mouser.com/ProductDetail/International-Rectifier/IRLB3034PBF/?qs=sGAEpiMZZMshyDBzk1%2fWi5%252bqVgN3%252bWS8iNZUeqPPDAc%3d (lay on top of each other, solder leads together to parallel)
* 2 x 15 Amp Fuses - http://www.mouser.com/ProductDetail/TE-Connectivity-Raychem/MHP-TA15-9-85/?qs=sGAEpiMZZMsxR%252bBXi4wRULUWu%252b0%2fKKWjHla6GdFh6iY%3d
* 2 x 18650 Holders - http://www.mouser.com/Search/ProductDetail.aspx?R=1043virtualkey53400000virtualkey534-1043 (each sanded to about 18.5mm in width)
* 1K Ohm 1/4 Watt Resistor - http://www.mouser.com/Search/ProductDetail.aspx?R=MFR-25FRF52-15Kvirtualkey57620000virtualkey603-MFR-25FRF5215K
* Hammond 1590GBK Enclosure - http://www.mouser.com/ProductDetail/Hammond/1590GBK/?qs=%2fha2pyFaduiJ5sxgvcfZdIk1sIy4rFZea7BKawP8o84%3d
* Tactile - http://www.ebay.com/itm/281341680838
* Blue LED .28 Voltmeter - http://www.ebay.com/itm/350926594725
* Tint For Voltmeter - http://www.amazon.com/gp/product/B00CCSD5U0/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1 (3 layers used)
* FDV Spring Loaded 510 - http://fatdaddyvapes.com/shop.html
* 14, 18, 24 Gauge Wire
Pardon my ignorance but why did u stack 2 mosfets on this mod?
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Lower resistance, less voltage drop
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It's not a problem to parallel MOSFETs. There are some derating issues that have to be considered in some cases, but nothing significant for a simple power switch. The derating issues only become significant in rectification applications where you rely on the transistor's body diode.
That's a 4.5V specified MOSFET so it's going to have higher resistance at the voltages you see with a single cell or parallel cells. "On" resistance is about five times greater at 3V gate-source voltage than it is at 4.5V gate-source voltage. If you look at figure 3 in the part's data sheet you can see that.
You could actually do better with a single 2.5V specified MOSFET than two 4.5V specified MOSFETs in parallel. However, it's hard to find the 2.5V specified ones in a leaded package. They're almost strictly found in a leadless package. That being the case, using two of those in parallel may be the best you can do in a leaded package. Of course for series cells it's not an issue since gate-source voltages are double.
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Is this a 2.5v? Fig. 6 of the .pdf correct?
http://www.mouser.com/ProductDetail/NXP-Semiconductors/PSMN1R1-30PL127/?qs=sGAEpiMZZMshyDBzk1%2fWi%252bFHavO7hMd5kNDjFjgQRzM%3d
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No, that one is not a 2.5V specified part. Even though it says logic level, that term can be interpreted loosely. For modern electronics, logic level means a 3.3V supply which calls for a 2.5V specified MOSFET. Older electronics used a 5V supply so a 4.5V specified MOSFET could be called logic level back then.
If you look at figure 7, you'll see that the "on" resistance curve doesn't flatten out until about 4V which is typical for a 4.5V specified MOSFET. You can see on page 5 that the gate source threshold is 1.3 to 2.2V which is also typical for a 4.5V specified MOSFET. 2.5V specified parts have a threshold that ranges typically from .6 to 1.5V.
The best graph to look at for behavior with respect to gate-source voltage is the one shown in figure 7. Most of the newer parts have that chart, but for some reason the older data sheets don't always show that. The Infineon part mentioned before does not have that chart in its data sheet. In that case, the chart shown in figure 6 can give you an idea, but it's not going to define "on" resistance specifically. Figure 6 shows the transfer characteristic which is how the part reacts to a VGS pulse with no resistance in series with the drain and source.
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PSMN1R9-40PLQ
http://www.mouser.com/ds/2/302/PSMN1R9-40PL-355172.pdf
http://www.mouser.com/Search/ProductDetail.aspx?qs=5XOdhvmYM0MZtKYUGpYp1Q%3d%3d
(http://i.imgur.com/w9RevAx.jpg)
Edit: blue values and red lines added by me
(http://i.imgur.com/SG29mxi.png)
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That's a good one, you can see the curve is pretty much in the flats at 3.0V which would be a typical minimum for a single cell. Though it's a 4.5V specified part, it has a curve that gets in just under the wire for a single cell. Typically, the 4.5V specified parts don't get into the flat part until about 4V, but that one has a curve more to the left than most for some reason. That chart is the one that matters so whatever that one says is what goes.
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Incredibly helpful. Thank you!
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Ok guys, I know this has been went through but cut me some slack. Will this be ok or do you have some better suggestions for a duel parallel 18650 box.
mosfet: STD30PF03LT4
Fuse:16R600GU (2)
LVC: NCP300HSN30T1G
Res:MF1/4 CCT52R1502F
and FR4 board
I have 125w 3v on/off and tact switches
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Fuses could be lower resistance. Example:
- http://www.mouser.com/ProductDetail/TE-Connectivity-Raychem/MHP-TA6-9-85/?qs=sGAEpiMZZMsxR%252bBXi4wRULUWu%252b0%2fKKWjBWiAigcFBno%3d
- http://www.mouser.com/ProductDetail/TE-Connectivity-Raychem/RGEF600K-AP/?qs=sGAEpiMZZMsxR%252bBXi4wRUPvXk7Yvu5NnmoOdNchDqMo%3d
Mosfet should have a lower Rds On & Vgs th. Example:
- http://www.mouser.com/ProductDetail/Vishay-Siliconix/SI7157DP-T1-GE3/?qs=sGAEpiMZZMshyDBzk1%2fWiwR5CZlvOXdbnme3vGBIvNgPnnBXp6tncw%3d%3d
For a 15k 1/4 watt resistor, I've used this:
- http://www.mouser.com/ProductDetail/KOA-Speer/MF1-4DCT52R1502F/?qs=sGAEpiMZZMu61qfTUdNhG%2fDQawzJ6c7P6ZlqRHSMJdY%3d
Same resistor you were looking at, but typed the part number in incorrectly.
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I actually looked at that mosfet but to be honest Im not sure I even know how to mount it, let alone wire it. Im not new to electronics but I am new to this. My background was in car audio. Its way more forgiving. I am dam... and determined to learn everything I can. I do thank all of you for being patient
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Check out this n-channel mosfet and diagram instead:
http://www.mouser.com/Search/ProductDetail.aspx?qs=5XOdhvmYM0MZtKYUGpYp1Q%3d%3d
(http://i.imgur.com/5G1s12V.png)
Instead of the 2x15 amp fuses, you can use 2x6 amp. The device will be limited to 12 amps when using two batteries in parallel, 6 with a single battery.
You can use 18 gauge wire instead of 14 from the fuses to 510 & source pin to batt negative.
Also 20 gauge instead of 18 from each battery to fuse,
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Those SMD parts can be a bit intimidating I'll admit, but once you've actually done one, you'll be surprised that you were concerned about working with them. The steps required are not difficult, just more involved than soldering a wire to a lead and heat-shrinking it.
Just two steps really, make a small PCB with 3 pads and reflow solder the part in a frying pan or toaster oven. You need a few tools and supplies, but nothing major, some solder paste, some copper clad, and you need some number drills to make mount holes for your wires. You can cut your pads in the copper clad with a Dremel which you probably have already if you're making your own enclosures.
It that's all too much, there's a couple leaded TO-220 parts that have been mentioned on the forum that have pretty good specs for a single or parallel cells. However, I have yet to see a leaded P-channel part with specs as good as the SMD P-channel parts. If you go with one of those few leaded N-channel parts, you should be able to do just about as well as you can with an SMD part.
ex. http://www.mouser.com/Search/ProductDetail.aspx?qs=5XOdhvmYM0MZtKYUGpYp1Q%3d%3d
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Well, if Im going to learn it then I might as well learn it right. Hopefully there are a few videos on the subject. The good part is that Im not in any hurry to do this. Guess I might better order a few extra parts.
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when running mosfets parallel would that require 2 15K resistors or just the one mounted to the top mosfet?
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Just need one pull-up (PMOS) or pull-down (NMOS) resistor for the both of them. You can use the same value as you would for a single MOSFET.
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Ordered some psmn1r9-40pl. Going to make one based on the circuit david linked and one driven with a LTC1157. See what works best.
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Craig, do you have a recommendation for an smd p-chan?
I have mf1/4dct52r1502f resistors
ncp300hsnt1g low voltage cutoff
rgef600k-ap fuses
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If you're going to use a high side NMOS driver, you can use any MOSFET really. The driver will provide a 5.4V gate-source voltage so you don't need a low threshold voltage. Go for the lowest on resistance. This one is better; http://www.nxp.com/documents/data_sheet/PSMN1R1-30PL.pdf
The best P-channel I've come across for use as a user power switch is this one; http://www.vishay.com/docs/62860/si7157dp.pdf
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when running mosfets parallel would that require 2 15K resistors or just the one mounted to the top mosfet?
(http://i.imgur.com/u2WkM4x.jpg)
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Spent too much on shipping in the last few days. I will try that one next time. Thanks for all the help.
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If you're going to use a high side NMOS driver, you can use any MOSFET really. The driver will provide a 5.4V gate-source voltage so you don't need a low threshold voltage. Go for the lowest on resistance. This one is better; http://www.nxp.com/documents/data_sheet/PSMN1R1-30PL.pdf
The best P-channel I've come across for use as a user power switch is this one; http://www.vishay.com/docs/62860/si7157dp.pdf
Thank you. Its the smd route. Hard to believe something this small can power a mechanical mod.
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It comes down to how much heat the part produces. At 20A with 2 mOhms on-state resistance for that PMOS I mentioned, the transistor has to dissipate 800mW which isn't all that much for a part that size. Consider those little through hole resistors can handle 250mW. Also, you're not powering an atomizer continuously so there's less heating anyway.
The ratings you see in the data sheet are for a part mounted on a 1 inch square pad of 2 oz. copper where a lot of heat can be transferred through that big drain pad.
The mechanical switches with high ratings probably have more resistance than that transistor does. They make more heat, but they're also a lot more massive so they can handle more heat before they get noticeably warm.
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(http://i.imgur.com/bi0z3Gc.jpg)
(http://i.imgur.com/hn3MJPC.jpg)
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Nice work David. Very neat and orderly :rockin smiley:
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^ This mofo showing off with that purdy wire dip and neatly routed
awesome david
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David: have you thought about putting the polarity labels on the batteries as well. I usually have to check the batts polarity more than once before inserting into the sled. Especially with flat top batts.
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Good idea, i'll see what I can come up with
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Good idea, i'll see what I can come up with
David, where did those battery decals come from?
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David, where did those battery decals come from?
http://breaktru.com/smf/index.php/topic,1344.msg16503.html#msg16503
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Got all these parts and Im I didn't make a mistake. How are 4-3amp hold fuses going to work in a parallel 18650 un-regulated box. Mabye Im thinking of this wrong but as soon as It gets hit with a sub ohm load wont they be exceeded?
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Four fuses with 3A hold in parallel will provide a 12A hold and typically a 24A trip. Usually the trip current is double the hold current, but not always, depends on the fuse. You can draw up to 24A without the fuses tripping, though they may trip a little lower if there's any pre-heating and there's some derating there. For sure you should be able to pull 20A without issue. That will get you down to about 200m Ohms. That's quite low, but if you are compelled to run an atomizer lower than that, you'll need fuses with a higher rating.
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Thank you Craig. Guess Im over thinking things. Thank you guys for bearing with a novice.
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Welcome, enjoy your mod :)
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Input voltage (4.2-3.0) doubled and outputted (8.4-6.0) to drive mosfet gate
http://www.mouser.com/ProductDetail/Analog-Devices/ADM660ANZ/?qs=sGAEpiMZZMtitjHzVIkrqYThiPHWFX9aAfsE1NTyhUU%3d
(http://i.imgur.com/sl5gEyJ.png)
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Got something up and running. Thanks for all the help. I will post pics when I figure out how to close the lid.
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What minimum wattage rating should we use for the 10k/15k resistor across mosfet gate and source? Tempted to sandwich an SMD resistor between the leads to tighten up real estate.
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You can do that, probably go as small as 0402 (1005 metric) if you want to, probably an 0603 (1608 metric) will fit nicely.
In some cases N-channel MOSFETs provide advantages over a P-channel, mainly high speed switching, but for a user power switch, you can find PMOS parts with similarly low on-state resistance eliminating the need for a voltage doubler. The other option is to simply put the NMOS on the low side. Either will eliminate the need for that part.
Though if you want to use a high side NMOS for whatever reason, that's how to do it. You can alternately use a high side NMOS driver which is a chip specifically designed for driving a high side NMOS switch. Here's an example; http://www.linear.com/product/LTC1981
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http://www.mouser.com/ProductDetail/Analog-Devices/ADM660ANZ/?qs=sGAEpiMZZMtitjHzVIkrqYThiPHWFX9aAfsE1NTyhUU%3d
(http://i.imgur.com/sl5gEyJ.png)
What exactly is the charge pump doing in that config and why connected to batt positive on gnd.
My thoughts were it stops vdrop but then I looked at how its wired and I figure it wouldn't do that. Maybe it does..
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The input voltage is being doubled to drive the mosfet gate.
Normally connected, it inverts the input voltage. When wired as shown, basically backwards, it will work as a voltage doubler.
http://www.mouser.com/ds/2/609/ADM660_8660-243873.pdf
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Thanks
Page 8 Fig:8
What exactly is it doing that you cannot with just wiring off the batts?
Its benefit? Does it open and close the fet better etc., reliability?
Yes I know drive a higher rds but with the fets Craig Break and you have posted and their low rds and ohms, is it that bigger a benefit?
Uber curious cause that looks hecka cool but ups the parts count.. :thumbsup:
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Mosfets with a higher Vgs Th (and hopefully lower Rds On) could be used. Did a quick search and this looks like it would work nicely: http://www.mouser.com/ProductDetail/International-Rectifier/IRFB7430PBF/?qs=sGAEpiMZZMshyDBzk1%2fWi5hvHeWgOih0blGzR0OIw98%3d Pg 1 Figure 1 in the data sheet
another: http://www.mouser.com/ProductDetail/International-Rectifier/AUIRFB8409/?qs=sGAEpiMZZMshyDBzk1%2fWi7r8jvGh7mrdq5g7UCjvCmQ%3d Pg 6 Fig 16
You're certainly correct, some of the mosfets posted here seem to have a low enough Vgs Th and Rds On that the charge pump wouldn't really be needed.
longwhiteclouds recently put together a mod with a PSMN1R9-40PLQ and had very good results:
"I'm getting 0.27 volt drop on a 0.3ohm coil with a little li-po charged to 3.8v"
http://www.reddit.com/r/OpenPV/comments/2fyjfu/whats_everyone_thoughts_on_this_mosfet_as_an/ckdzsof
With two parallel IRLB3034PBFs and two fully charged VTC4s, I was getting a 0.2 ohm coil dropping 0.3v, 0.6 ohm dropping 0.1v and 1.3 ohm dropping 0.05v.
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Woot click in brain when read your post and then the data
Rds On (Max) @ Id, Vgs 1.7 mOhm @ 25A, 10V
So the closer to 10v the better -- awesome understood
That mech is badarse ;hubba; and safe and should become a standard, no more stories of bad haps but darwin will still hand his beer to his buddy
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http://imgur.com/Ih6yoFk
http://imgur.com/Cbwz8Dj
http://imgur.com/fIFLetV
http://imgur.com/fJsTza0
I keep snapping legs of my mosfets trying to shoehorn them into a 1590g case with batteries so I made this while I wait for some prototype circuit board to arrive to do it properly(er).
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I keep snapping legs of my mosfets trying to shoehorn them into a 1590g case with batteries so I made this while I wait for some prototype circuit board to arrive to do it properly(er).
Hold the leg with a long nose pliers as close to the body as possible before bending, keeping the leg at the base straight so it looks like this.....
(http://www.miataforumz.com/attachments/how-40/1780-megasquirt-diypnp-how-step-step-instructions-dsc_0847-jpg?dateline=1316371330)
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Is there any way to determine the wattage requirement for the 10-15k resistor that goes between S and G on a mosfet? I've got some SMD resistors that would fit nicely between the legs, but I'm not sure if they'd do the trick or not.
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Yes, you can. Divide battery voltage by the resistance to get current. Square it and multiply by resistance. Or, you can square voltage and divide by resistance. It's going to be a small number so you'll find that you can use pretty much any wattage rating you want. Like I said, even the tiny 0402 parts with a 1/16W rating will be okay. It's probably an 0805 that fits well, those are 1/8W. The 0603 size is 1/10W.
BTW, that particular charge pump has an unusual wiring when configured as a doubler. I thought it was hooked up wrong at first, but then looked at the data sheet and saw it was right. It's designed mainly to be used as an inverter, but can be configured as a doubler by using a different wiring scheme. That's probably why the wiring looked strange to you Visus.
It's generally easier to find low on-state N-channels than P-channels, especially in the leaded packages. A doubler allows you to use one of those on the high side. However, you can simply wire the part on the low side without the need for a voltage doubler. In some cases, it can be handy to have your switch on the high side, but generally it's a moot point for a mod that does not incorporate a lot of electronics.
You're not gaining anything in gate-source voltage with a doubler. A higher gate-source voltage is better for lower on-state resistance, but the gate-source voltage is equivalent when using a doubler on the high side versus using the switch on the low side. There's nothing gained there. However, you can use a tripler which will provide in increase in gate-source voltage for a high side NMOS such as the high side NMOS driver I linked to before.
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Hi guys
Question about using a p channel
Wouldn't a N channel be better? (lower rds on)
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Thanks again Craig. I will give that a try next time. Still not quite sure about this high side low side stuff. If the fet is opening/closing the negative feed it is low side?
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Yes, you can. Divide battery voltage by the resistance to get current. Square it and multiply by resistance. Or, you can square voltage and divide by resistance. It's going to be a small number so you'll find that you can use pretty much any wattage rating you want. Like I said, even the tiny 0402 parts with a 1/16W rating will be okay. It's probably an 0805 that fits well, those are 1/8W. The 0603 size is 1/10W.
Sorry I didn't realize this was in reply to my post on the other thread. Brain didn't process. As it happens the 0805 SMD resistors i bought were 1/2W, and fit perfectly between G and S on the PMOSii I'm using. Thank you for clarifying though, as always I really appreciate you taking the time to respond!
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If the fet is opening/closing the negative feed it is low side?
Low side is negative, high side is positive.
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Input voltage (4.2-3.0) doubled and outputted (8.4-6.0) to drive mosfet gate
http://www.mouser.com/ProductDetail/Analog-Devices/ADM660ANZ/?qs=sGAEpiMZZMtitjHzVIkrqYThiPHWFX9aAfsE1NTyhUU%3d
(http://i.imgur.com/sl5gEyJ.png)
Perfboard - http://www.mouser.com/Search/ProductDetail.aspx?R=PR2H1virtualkey57130000virtualkey854-PR2H1
Caps - http://www.mouser.com/ProductDetail/TDK/FK24X5R1C106K/?qs=sGAEpiMZZMt3KoXD5rJ2N48tYEMqcp4xjy22eXGkXaI%3d
(http://i.imgur.com/4LZpR4T.jpg)
(http://i.imgur.com/62xYhjo.jpg)
(http://i.imgur.com/Q6OZTuh.jpg)
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Alright, so after referencing this page for the past few days and trying to get my head wrapped around the different specifications that MOSFETs have, I think I may have what I need to build the parallel box mod I want. I just need to know if either of these chips will be able to handle what I have in mind. They both should have a good turn on voltage threshold for single/parallel cells and a good drain-source voltage as well. My goal is to pretty much do whatever build I want on this box i.e. all the way down to below 100milliohms if need be (.1ohm).
https://www.fairchildsemi.com/pf/FD/FDD3706.html (https://www.fairchildsemi.com/pf/FD/FDD3706.html)
This one is only rated for 50a and seems to only be available in SMD, but could I run 3 in parallel for a total of 150a capacity? What ill effects would I see with 3 in parallel? What about 2 in parallel?
http://www.mouser.com/Search/ProductDetail.aspx?qs=5XOdhvmYM0MZtKYUGpYp1Q%3d%3d (http://www.mouser.com/Search/ProductDetail.aspx?qs=5XOdhvmYM0MZtKYUGpYp1Q%3d%3d)
This one is rated at 150a. That is pretty much what I was looking for, but are there any downsides to using this chip?
ADDITIONALLY, these can be secured to the metal casing directly since they are N-channel mosfets, correct? Shouldn't that help with heat dispensation and therefore further reinforce the current ratings published?
Thanks a bunch!
- MrFrizzy
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Both of those have good "on-state resistance versus gate-source voltage" charts for a single cell or parallel cells. The Fairchild part has a lower threshold, though the NXP part is probably better. It has lower on-state resistance and it has a maximum gate-source voltage of 20V versus 12V for the Fairchild part. The NXP part would be better for either single or series cells. Even though the Fairchild part has a lower threshold, you'll get considerably lower on-state resistance with the NXP part even as low as 3V gate-source voltage.
You can mount the tab to chassis ground and it will improve heat dissipation and the ability of the part to handle high currents. If the chassis is a thermally efficient metal, it will make a large difference there. It looks like the tab is electrically isolated for that NXP part.
You can parallel MOSFETs, but going with three of them brings rise to some derating issues. Mainly it increases the amount of power required to transition the MOSFETs on and off. If you are powering the gates through a low impedance source (like a tactile switch), it should not be an issue in terms of speed, but the current spikes can overload a tactile and burn out the contacts.
There's a lot of capacitance with three gates in parallel. There's a rush of current that runs in and and out of the gates when the MOSFETs are turned on and off. Specifically, each of those NXP parts has 120nC total gate charge. Three would make that 360nC which at 3V, is like a 100nF capacitor. That can be a bit much for a tactile switch, they're not really rated for current spikes like that.
With such a low on-state of those NXP parts, you're getting switch resistance under an mOhm with two in parallel. That's low enough to handle 40A without any issue. In fact, if bolted to the chassis, two of them won't even warm up at currents quite a bit higher than that.
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That is exactly what I was looking to find out! I figured the tactile switch would have some troubles with paralleled MOSFETs in the long run, but I think I can make a larger momentary switch work in the looks department.
Another thing that I was looking at was the possibility to run USB charging boards in parallel. The one I had in mind was this (http://www.icstation.com/product_info.php?products_id=2514#.VCr6ONXF958). It uses the TP4056 chip. Could I use 1 usb port and create jumpers to tie the two boards together via the "In+" and "In-" holes? OR, is there another chip I can be looking at that has a higher charging current?
I have found these two pages, Linear Technology (http://www.linear.com/parametric/Battery_Charger_IC#!1806_Li-Ion!1033_>=5!1069_Linear|Switching|Shunt!chem_Li-Ion!vmax_5!icharge_!bat_bat) & Texas Instruments (http://www.ti.com/lsds/ti/power-management/battery-charger-solutions-products.page#p238max=5;18&p338=Li-Ion&o4=ACTIVE&p1313=4.2&p1153max=2;1.5), that have many charging ICs that potentially will work. I also found this (http://www.tpmicro.com/goods.php?id=52) chip from TP Micro that sounds like it will do the trick as well. I'm not sure if I am missing anything or if there is anything in particular to look for, but I would appreciate all the help I can get!
Thanks!
- MrFrizzy
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There's two areas where charging rates are limited not including the maximal rate the batteries can tolerate. First is the power connector and supply, secondly is the charger controller chip.
There's a good amount of power that a linear charger controller has to dissipate. They work pretty much the same as a linear regulator with current limiting. Like any linear regulator, it has to dissipate the difference in output voltage minus the difference in input voltage times output current. That being the case, that little chip has to dissipate a worst case of 5V input minus 3V output (lowest battery voltage) times the charging rate. So with a 1A rate, that can be as high as 2W, a lot for a small linear regulator.
You can get around that limitation by using a charger controller that employs a DC-DC converter. Those conserve power aside from a small loss usually under 10%. In that case, the charger controller can put out much higher currents. There are charger controllers like that, not a wide range of them, but they are available. They tend to be costly in both price and part count. They reguire a larger PCB and have a larger number of supporting parts.
The other limitation is the supply and connector. USB mini-B and micro connectors are limited in the amount of current they can handle. You can remove that limitation by using a barrel type DC power connector. The larger ones like the 5.5x2.1mm are rated for up to 6A. Of course you also need an adapter that can support the current demand, not going to be a USB adapter since those typically don't go above 1A. You can find them up to 2A, but you don't want to run one close to its limit if you can avoid it.
It should be possible to parallel USB charger controllers, though it would be a rather odd thing to do. Odd as it is, I can't think of any reason why it would cause any functional issues. You would need a separate connector and adapter for each charger or it defeats the purpose due to the limitation of the USB connector. If you try to run 2A or more through a single connector, it will fail at some point, possibly not immediately, but it will fail.
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How would I go about making an 8.4v REGULATED box mod? ie 8.4v whatever the charge in the battery?
Bob
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How would I go about making an 8.4v REGULATED box mod? ie 8.4v whatever the charge in the battery?
Bob
That'd be two freshly charged lipos (4.2v + 4.2v = 8.4v) in series, but you'll get a nominal voltage of about 7.4v out of that, as lipos tend to stay around 3.6-3.7v for most of their usable charge.
If you want to keep it at 8.4v all the time, you'd have to use a booster board to force the voltage to stay around 8.4v and be regulated.
Or... and I kind of doubt anyone would recommend this, you could use a buck board and three lipos in series to regulate a nominal 11.1v down to 8.4v... tricky and potentially lethal.
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There's two areas where charging rates are limited not including the maximal rate the batteries can tolerate. First is the power connector and supply, secondly is the charger controller chip.
There's a good amount of power that a linear charger controller has to dissipate. They work pretty much the same as a linear regulator with current limiting. Like any linear regulator, it has to dissipate the difference in output voltage minus the difference in input voltage times output current. That being the case, that little chip has to dissipate a worst case of 5V input minus 3V output (lowest battery voltage) times the charging rate. So with a 1A rate, that can be as high as 2W, a lot for a small linear regulator.
You can get around that limitation by using a charger controller that employs a DC-DC converter. Those conserve power aside from a small loss usually under 10%. In that case, the charger controller can put out much higher currents. There are charger controllers like that, not a wide range of them, but they are available. They tend to be costly in both price and part count. They reguire a larger PCB and have a larger number of supporting parts.
The other limitation is the supply and connector. USB mini-B and micro connectors are limited in the amount of current they can handle. You can remove that limitation by using a barrel type DC power connector. The larger ones like the 5.5x2.1mm are rated for up to 6A. Of course you also need an adapter that can support the current demand, not going to be a USB adapter since those typically don't go above 1A. You can find them up to 2A, but you don't want to run one close to its limit if you can avoid it.
It should be possible to parallel USB charger controllers, though it would be a rather odd thing to do. Odd as it is, I can't think of any reason why it would cause any functional issues. You would need a separate connector and adapter for each charger or it defeats the purpose due to the limitation of the USB connector. If you try to run 2A or more through a single connector, it will fail at some point, possibly not immediately, but it will fail.
It won't run at 2a, I read that they will actually put out about 850ma each so only around 1700ma total. My phone charger is rated at 1.8a and I haven't had any issues yet so i'm not too worried about burning things up. I think i'll give it a go and find out what happens, or purchase some of those chips and make a single board for the pair. The less ghetto looking I can make the box the better. :yes"
You have been a great help Craig! Thanks! :beer-toast:
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Sorry if this as already been posted but I was on break.
Here is plans for a unregulated 18650 box to give a little more details (http://alturl.com/wm2u8). Hope it helps. I know they sell them but they have the best diagram I have seen so far in regards to wiring.
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Sorry if this as already been posted but I was on break.
Here is plans for a unregulated 18650 box to give a little more details (http://alturl.com/wm2u8). Hope it helps. I know they sell them but they have the best diagram I have seen so far in regards to wiring.
FYI - That link seems to be dead.
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How would I go about making an 8.4v REGULATED box mod? ie 8.4v whatever the charge in the battery?
If you want to keep it at 8.4v all the time, you'd have to use a booster board to force the voltage to stay around 8.4v and be regulated.
There are no off-the-shelf boost modules I'm aware of capable of putting out 8.4 Volts at the currents required to power an atomizer. So it's not really practical unless you are comfortable in designing your own boost converter. There may be controller chips available with the required input and output range, but DC-DC converter design is quite tricky. Not something to try without some formal knowledge of electrical design.
Or... and I kind of doubt anyone would recommend this, you could use a buck board and three lipos in series to regulate a nominal 11.1v down to 8.4v... tricky and potentially lethal.
Actually, that would be my recommendation, use a buck module with 3 Series cells. You can use whatever 3.7V cells you like provided they have the required drain limit. Doesn't have to be a 3S LiPo. The high drain LiPos can be hazardous if used without any protection. However when protected, they're really no more hazardous than any other high drain Li-Ion battery. The main problem with them is they are vulnerable to physical damage and can ignite quite violently when punctured. You need to enclose them in a way that protects them physically.
There is some protection a buck module offers for over-current and short circuit, though it's never a bad idea to add a fuse inline for backup. Most converter modules require some kind of reverse polarity protection so if using removable cells, you need that at least.
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I was gonna suggest the 04050c but at 8.4v your double the bat so it should be fine up to at least 4amps but
being rated at 2.5A it won't be within specs.
It regulates up to 15v with a hack 24v and using in my own part theory of reduced voltage @3.8-6.2v and higher current its working a treat here mine is stable at 7 amps with 18ga wiring with 22ga it was not.. This all depends on battery used. It' will short/handle over 150Amps lol, it is not short circuited protected so its one to be careful with.. Its almost impossible for us to hurt it but shorting it and your batts may not be..
Badarse and hugely overlooked but oh well . lol
Fingers crossed over here but yeah its a nice booster but way way out of spec. I have used it for a year now and still going great..
Check out Xomby post
Its tiny mon
(https://lh3.googleusercontent.com/-IOf-AOLlSZQ/VC4CulguzhI/AAAAAAAAAOM/ac2zP528cQk/w320-h240-no/14%2B-%2B1)
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Oh okay, I thought that one topped out at 6V, according to the data sheet anyway. If it can put out 8.4V without dying, then yes, it can be used for that.
In any case, the series battery configuration will deliver the maximal current the module is rated for which can be as high 20A, higher in terms of burst limits. The big advantage with the booster is it's single cell and a lot smaller, but greatly more limited in output current.
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Here's a 50watt booster
you can run with series batts
lil biggums and gets warm @50 watts but if you wood mod it it will be probably be manageable..
https://www.youtube.com/watch?v=wJU7AJgERG8
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Oh okay, I thought that one topped out at 6V, according to the data sheet anyway. If it can put out 8.4V without dying, then yes, it can be used for that.
In any case, the series battery configuration will deliver the maximal current the module is rated for which can be as high 20A, higher in terms of burst limits. The big advantage with the booster is it's single cell and a lot smaller, but greatly more limited in output current.
Theres a guy on ecf says he blew out resistors on it but I have not. I wonder if he made a wiring mistake or such he blew them twice.
He was not using a pot and has it set for 4.8v.. I think he may have shorted it out too many times, he uses ss mesh builds on raidy's original genesis and that design is a short prone.. Meh' he post on here too, but I have not seen em in a while..
Its trustworthy using Breaks build but at 8.4v not sure how many amps/watts it can handle there..
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Here's a 50watt booster you can run with series batts lil biggums and gets warm @50 watts but if you wood mod it it will be probably be manageable.
That's like the crappiest converter you could build;
It's asynchronous (uses a diode rectifier)
It has a 65 mOhm internal switch (way too high resistance)
It's current mode (less efficient)
It uses bulk capacitors (takes up way too much space)
It's built on a perf board (maximally lame)
Everything opposite of what I would do in building a converter. I'm amazed he even got it to work.
Though I've got to hand it to that guy, he makes the most complicated things sound simple. He did it that way to show a booster in the most simple way possible so I understand the motivation, but not good for anything but a paper weight after being used as an educational tool.
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That's like the crappiest converter you could build;
It's asynchronous (uses a diode rectifier)
It has a 65 mOhm internal switch (way too high resistance)
It's current mode (less efficient)
It uses bulk capacitors (takes up way too much space)
It's built on a perf board (maximally lame)
Everything opposite of what I would do in building a converter. I'm amazed he even got it to work.
Though I've got to hand it to that guy, he makes the most complicated things sound simple. He did it that way to show a booster in the most simple way possible so I understand the motivation, but not good for anything but a paper weight after being used as an educational tool.
:laughing2: :thumbsup:
But the internet said,
Ok another day spreading misinformation, I am getting good at that . :yes"
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I use the following as benchtop power supplies for testing:
1.23v to 30v buck @ 3A max
http://www.amazon.com/gp/product/B009HPB1OI/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
3.5v-35v boost @ 6A max (with on-board voltmeter)
http://www.amazon.com/VvW-Adjustable-Regulated-Converter-Voltmeter/dp/B00IOMST5O/ref=sr_1_6?s=electronics&ie=UTF8&qid=1412361364&sr=1-6
4v-30v boost @ 5A max (no voltmeter)
http://www.amazon.com/VvW-RRLM2587-3-5-30V-Converter-Regulator/dp/B00IOMSTOK/ref=sr_1_29?s=electronics&ie=UTF8&qid=1412361472&sr=1-29
as far as I can tell, they're all pretty accurrate, and i really haven't had any issues with them (using one as a power supply for a 12V PWM controlled fan, as supply for both the fan and the 556-based PWM circuit)
Potentially quickie mod boards...
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My new 5000mAh beast. Thanks for all the help everyone. Without Craigs wisdom and Davids parts lists it wouldn't have been possible.
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Potentially quickie mod boards...
Possibly, but you have to be suspect of any converter that requires a heat sink. The whole idea of using a converter is to conserve power improving run times and generating less heat that can make a mod uncomfortable in the hand. A really good converter with high efficiency has no need of heat sinks since it shouldn't get that hot in the first place. Heat sinks allow crappy converters to put out the power good ones can without them.
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I advise going with a mech switch and bypassing all of this irrelevant nonsense imo....lol but .............if you must craig is the man ;hubba;
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Very true, all this stuff is moot if you use a wholly mechanical mod, but then there's the dreaded battery fade. It's less of a problem than it used to be, but it's still there. Of course things like battery fuel gauges and power meters are kind of a critical feature, they're not necessities, but they help a lot.
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Very true, all this stuff is moot if you use a wholly mechanical mod, but then there's the dreaded battery fade. It's less of a problem than it used to be, but it's still there. Of course things like battery fuel gauges and power meters are kind of a critical feature, they're not necessities, but they help a lot.
if truth be told..........there is plenty of battery fade on regulated mods too and when I build the coils right, battery fade is what I enjoy :wave:
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My new 5000mAh beast. Thanks for all the help everyone. Without Craigs wisdom and Davids parts lists it wouldn't have been possible.
Now that's a spiffy mod! doubles as a USB power bank too?
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if truth be told..........there is plenty of battery fade on regulated mods too and when I build the coils right, battery fade is what I enjoy :wave:
Something is wrong with your mod builds. Only when at specified on data sheet range tolerances ie: close to needing charge..
They are guaranteed/warrantied to not do that.
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Something is wrong with your mod builds. Only when at specified on data sheet range tolerances ie: close to needing charge..
They are guaranteed/warrantied to not do that.
If your batt's are fading quickly, then you really want to keep a better eye on how far you let them drain before recharging... I'll bet you're over-discharging them, and killing them early.
Note* this INCLUDES temporary over-drainage from pulling too much current at or near the low capacity level of the battery. Common with regulated mods, and depending on your atty setup, mechanicals as well.
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Now that's a spiffy mod! doubles as a USB power bank too?
Thanks. That was the plan but I somehow managed to wire it up so the usb out only works when the button is pressed. Wasn't really a feature I wanted, just happened to be the charge board I had on hand.
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if truth be told..........there is plenty of battery fade on regulated mods too
Well it depends. The mods I build have zero battery fade by design. The mod will flag a low battery when battery voltage is too low to provide the desired output. However with mods that don't have that ability, like ones that are simply regulated, you can get battery fade if battery voltage falls below what the regulator requires to provide a selected output.
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Yeah mine stay rock solid until sag.
Maybe coil break in fsor is having IDK thats strange.
It does happen on mods like an ego twist but thats only because it has those tiny 30ga wires put better wires on it and it goes all the way to cutoff..
Wow I remember reading up on how the ego twist was revolutionary for power and size. :laughing2:
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FYI - That link seems to be dead.
Odd. Seems to be working for me. Here is the direct link to the plans http://www.smalllinks.com/3ZR0
This is a window that shows the set up for the unregulated mods. I don't know what the watts are on the MOSFET but I do see that there is a 15k resistor being used.
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Odd. Seems to be working for me. Here is the direct link to the plans http://www.smalllinks.com/3ZR0
This is a window that shows the set up for the unregulated mods. I don't know what the watts are on the MOSFET but I do see that there is a 15k resistor being used.
You posted it was the best diagram ever.
I think xomby was saying no to the death of no.
well I am saying it, that link is dead to me :thankyou:
Have you seen the mech and fet recommended diagrams in this post? :laughing2:
Come on man/maa'm thats like a kindergarten mech compared to this post of mechs..
Also in this post you will know what fet/fets you are using and why it makes your mech one of the most badarse/safest mechs ever.
Not ragging on awesome everything in one place link but whoa awesome is in this thread.
Basic mechs so july of 2014 :thumbsdwn2:
My opinion and being silly bout my opinion..
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You posted it was the best diagram ever.
I think xomby was saying no to the death of no.
well I am saying it, that link is dead to me :thankyou:
Have you seen the mech and fet recommended diagrams in this post? :laughing2:
Come on man/maa'm thats like a kindergarten mech compared to this post of mechs..
Also in this post you will know what fet/fets you are using and why it makes your mech one of the most badarse/safest mechs ever.
Not ragging on awesome everything in one place link but whoa awesome is in this thread.
Basic mechs so july of 2014 :thumbsdwn2:
My opinion and being silly bout my opinion..
Visus, there's a thousand and one ways to wire up a mod. Some are arguably 'better' than others, but try to reign in the put-downs. Everyone has different levels of skill/learning and tools/ability to create a mod, and we ALL started knowing diddly squat at some point. Maybe he/she's after something specific, or maybe they just want to know if a design like this would work at all.
As an aside, once you start throwing switches and mosfets into the mix, it's no longer a "mech" mod. Strictly speaking, using wires or anything other than a screw and spring as a "switch" precludes a mod from being a "mech mod". We're talking about box-mods here. PV, still, if you like. But not "mech".
The second link did work... google image result.
This looks like an unregulated 3.7v mod with a... N-chan? Besides the fact that they don't list the part# for the mosfet, so you don't really know what you're getting. Unless the n-chan's properties make it to cutoff at around 3.1v, there's no low-voltage reference, so you could kill your batteries if you run them down too low.
The wiring diagram looks proper, although Craig or BT could take a quick look and verify.
Other than the mystery mosfet, it's a decent design for a simple unregulated mod. The fact that it includes fuses is a plus. The fact that the diagram is easy to read is a plus. But lack of details on the mosfet is a big red FAIL.
I included the diagram here because it's clean and pretty. @Reckful -- This would work with any sized battery, not just 18650.
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Visus, there's a thousand and one ways to wire up a mod. Some are arguably 'better' than others, but try to reign in the put-downs. Everyone has different levels of skill/learning and tools/ability to create a mod, and we ALL started knowing diddly squat at some point. Maybe he/she's after something specific, or maybe they just want to know if a design like this would work at all.
As an aside, once you start throwing switches and mosfets into the mix, it's no longer a "mech" mod. Strictly speaking, using wires or anything other than a screw and spring as a "switch" precludes a mod from being a "mech mod". We're talking about box-mods here. PV, still, if you like. But not "mech".
The second link did work... google image result.
This looks like an unregulated 3.7v mod with a... N-chan? Besides the fact that they don't list the part# for the mosfet, so you don't really know what you're getting. Unless the n-chan's properties make it to cutoff at around 3.1v, there's no low-voltage reference, so you could kill your batteries if you run them down too low.
The wiring diagram looks proper, although Craig or BT could take a quick look and verify.
Other than the mystery mosfet, it's a decent design for a simple unregulated mod. The fact that it includes fuses is a plus. The fact that the diagram is easy to read is a plus. But lack of details on the mosfet is a big red FAIL.
I included the diagram here because it's clean and pretty. @Reckful -- This would work with any sized battery, not just 18650.
Lol Xomby ya read this post that same diagram is in this post. I was not putting it down jack
its not a basic mech its very and awesome but as I said it's right here with whats what added.
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The reason I posted it once more Virus was because some one added that it was a dead link, that was all but back on topic. Thanks for clearing that up a little bit more for me since I seemed to not have added the additional information XombyCraft.
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it's all good
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The reason I posted it once more My master ViSus was because some one added that it was a dead link, that was all but back on topic. Thanks
Fixt it for ya :thumbsup:
was just being silly about it that mech with parts is in this post but the guy who runs that site also has a video on youtube showing you how to wire it, dont know if you know that, he makes some good vids on how to wire a dna and okr..
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http://www.mouser.com/Search/ProductDetail.aspx?qs=l%252bcklhsjygejnWlO5Xf07A%3d%3d
What about this p-chnl.
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Not going to work well other than with series cells. The gate-source threshold is too high for a single cell or parallel cells. That one doesn't show an "on-state resistance versus gate-source voltage" chart, seems most of those older style MOSFETs do not. Looking at the transfer characteristics that are provided, it will barely turn on and probably burn up if battery voltage gets down to 3V. Even at 3.7V on-state resistance will be too high.
This one would be a lot better for a single cell; https://www.fairchildsemi.com/datasheets/ND/NDP6020P.pdf That's the best through hole type PMOS I can see for a single cell with a quick look at the Mouser listings.
The Vishay Si7157DP is the absolute best PMOS I've found for use with a single cell, but it's the more modern SMD type so you have to mount it on a host board.
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Ok Craig, I need some expert help. Duel 18650 in parallel capable of sub ohming. I have 10-SI7175DP mosfets and 10-NCP300HSN30T1G low voltage cutoffs. I have all the switches. (more than one box). Im having issues finding fuses that aren't the size of a truck. If Im thinking of this right that's 4 fuses around 7- 10amps each with a hold current around 4 - 7amps or so. That would be 16-28amps hold and around 40amp trip correct? That's if you ever maxed it out. I think I have thought about this so much I have confused myself
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Yeah it's easy to get confused by too many specs, happens to me too sometimes.
The problem with high currents is you can get to a point where any combination of PTC fuses just won't be able to do the job. If you're running parallel 18650s and looking for a maximum over 40A, you need to run close to the trip current otherwise it will take so much current to trip the fuses, they aren't going to do much good in terms of protection.
That being the case, you probably should run two 4 or 5A hold fuses on each cell and just take what you get in terms of maximal current demand. You're probably not going to be able to guarantee a 40A load. At a nominal 3.7V, you're looking at an atomizer resistance of less than 100 mohms. 200 mOhms is probably practical in terms of the lowest you would go and a quad set of 4A hold fuses can support that no problem. A set like that will also provide a low enough trip current the fuses will actually protect the batteries and circuit if a short or reverse polarity condition occurs.
This one is going to be the smallest best PTC fuse, four of them will get you up to 36A;
http://www.digikey.com/product-detail/en/1210L450SLWR/F5790CT-ND/3661932
Once again it's the SMD type so you need to use a host board. It's possible to solder wires to them directly, but I wouldn't recommend it.
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Honestly its very doubtful it will ever see anywhere close to that. Those fuses will work out well with the smd mosfets. Seems like Im going to be doing some dremel work. If I can get it right everything should fit on one small board. Thanks Craig
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On fusing I thought this was cool, using a rated 40-50amp fuse utilizing a blade fuse..
POST #6
http://www.e-cigarette-forum.com/forum/modder-accessories-supplier-forum/524238-pdib-library-tech-specs-info.html
Just another way to it. If you don't short or batts old and do not make a 30A+ runway to the other you wont need it anyway lol..
They do sell resettable blade fuses @ 40A-50A and they would be about the same size as a smd build, tad bigger
http://www.optifuse.com/cirbreakType1.php#
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I have a crap load of those type and circuit breakers to. ( I owned a custom car stereo shop). I had actually thought of trying one just to see how well it would work. In theory it should work as well as any other type fuse.
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Not theory, actuality, they will work just fine..
No auto reset, fuse needs replacing only bummer in a small space..
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Those fuses can do the job for high currents if you don't mind replacing them. It's actually pretty rare that you run into an issue so it may be practical. I haven't seen an over-current issue in quite some time myself. All of my mods use non-removable cells so I don't know how often you would run into the reverse polarity situation.
There are some issues in using those blade fuses. They do have a little more resistance than a good set of PTC fuses. Also, they are slow blow and intended for automotive applications where the power supply has a much higher maximal current and voltage. They mainly protect wiring and not electronics. There's a big difference in maximal current output comparing a car battery to a small Li-Ion battery.
For example, a 30A blade fuse takes about 10 seconds to blow with a 50A fault current. That may not provide the protection required for some electronics. You'd have to check the charts with any blade fuse to make sure the fuse will actually protect the circuit. Here's an example;
http://www.littelfuse.com/~/media/automotive/datasheets/fuses/passenger-car-and-commercial-vehicle/blade-fuses/littelfuse_atof_datasheet.pdf
There's lots of other single use fuse types you can use. For example ceramic fast-blo fuses are often used in multi-meters to protect the ammeters in them. That might be a better option in terms of protection.
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TBH as you can buy those fuses at almost every convenience store (7-11, Quick check, Wawa if you prefer), why spend more on PTCs that take up more room? nothing superior if it "just works".
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But lack of details on the mosfet is a big red FAIL.
I have been playing around with this for some time trying to find out which one would be good for a mosfet switch. I was thinking that a n-channel mosfet, located here (40V 195A 375W) (http://www.digikey.com/product-detail/en/IRLB3034PBF/IRLB3034PBF-ND/2096638) should be good enough.
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Quick question. Can I solder to the body on this N channel? I'm having trouble fitting 16 gauge wires to two pins so close together. I think I saw somewhere that the body connects to drain but I can't find it now.
http://www.mouser.com/Search/m_ProductDetail.aspx?NXP%2fPSMN1R9-40PLQ%2f&qs=%2fha2pyFadugYxVTQgB%2f3OeNXtkh0yKvRPw%2fvPX4XdvRJ7e%252b6ibP%2f%2fA%3d%3d
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Do a continuity check but on the data sheet it appears its just the mounting body.
http://www.nxp.com/documents/data_sheet/PSMN1R9-40PL.pdf
You do know you can make the legs wider by bending them very wide with two needle nose one to hold stability off the body and the other to shape....
should gavel you plenty room..
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Bending the legs was going to be my next step, I already put one on the board and snipped the legs though. Good plan breaking out the multimeter though, thanks I will try that..
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how would someone add a voltmeter to a mosfet build, i want the voltmeter to display when i fire the mod/
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(http://i.imgur.com/bUdCZBX.png)
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Nice work on the drawing David
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Nice
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Allrighty, Im stuck. So i built the okr..and the raptor 120 and i wanted to build a mosfet mech box. so i gets me to looking around and reading and it seems everybody was using the irlb3034 n-fet for it. so went looking for diagram..found said diegram and compared it to others...yep..its for an n-fet build...not a p-fet. I say to myself..this looking ALOT eaisier than stuffing a raptor in a 1590g box..(yeash!) so i go order...and since i proatice good ordering ..i ordered ten of em..it was cheaper by over a buck..wait a week..and bamp! there here . I go to build it all..lay it out with everything...solder it up little heatshrink..and looks good and clean.
So why wont it vape? heres the diagram i used
http://vapingunderground.com/attachments/dual-parallel-n-channel-mosfet-box-mod-jpg.5577/
I went back and checked it all..tested the volts...it was 3.3 under load...and the mosfet got REALLY hot...the hotter it got the more it vaped...so i unhooked it to try to figure it out..iv changed out for another (couple) fets and thay all do the same thing..mosfet got really hot.. with barly any vape.
so, in short..im stuck.
btw..did read all over these forums for answers befor i posted and couldnt find any answers..
so any thoughts?
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Allrighty, Im stuck. So i built the okr..and the raptor 120 and i wanted to build a mosfet mech box. so i gets me to looking around and reading and it seems everybody was using the irlb3034 n-fet for it. so went looking for diagram..found said diegram and compared it to others...yep..its for an n-fet build...not a p-fet. I say to myself..this looking ALOT eaisier than stuffing a raptor in a 1590g box..(yeash!) so i go order...and since i proatice good ordering ..i ordered ten of em..it was cheaper by over a buck..wait a week..and bamp! there here . I go to build it all..lay it out with everything...solder it up little heatshrink..and looks good and clean.
So why wont it vape? heres the diagram i used
http://vapingunderground.com/attachments/dual-parallel-n-channel-mosfet-box-mod-jpg.5577/
I went back and checked it all..tested the volts...it was 3.3 under load...and the mosfet got REALLY hot...the hotter it got the more it vaped...so i unhooked it to try to figure it out..iv changed out for another (couple) fets and thay all do the same thing..mosfet got really hot.. with barly any vape.
so, in short..im stuck.
btw..did read all over these forums for answers befor i posted and couldnt find any answers..
so any thoughts?
Sorry but the link to your diagram requires membership to that forum so I can't see your diagram.
You mentioned that you soldered it up to the little heatsink. Is that the base heatsink on the mosfet? I believe that the base is the same as the "D" Drain pin.
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grrrr, i still dont know what i did wrong, but i took everything apart and started from scratch. I used davids diagram from the post up above and made sure it was all good solder connections. I must of had a bad one because it vaped like it was suposed to. :rockin smiley: i get a .4v drop under load with a .10 coil. the only heat issues are from the atty lol. to avoid blowing up the my battiries im using one of the new 26650 batteries that "say" it has a 75amp pulse limit. so far so good. now i just have to try my cutting skills out for the voltmeter. As allways, ty all for paving the way, couldnt of done any of it without this forum. :thankyou:
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I'm happy to hear that you got it working Rigure :applaude:
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I used davids diagram
i get a .4v drop under load with a .10 coil.
You should be using coils with a resistance of 0.14 ohms or higher if you used my drawing.
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just wondering why people use 2 mosfet? thanks
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Lower Rds On
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Lower Rds On
so in other word it can handle lower resistance? like lower than 0.10?
thanks
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well, in the end,yeah. But it's to lower loss in the mod. putting in parallel conductors (in this case the fets) half's the resistance, therefore less voltage drop in the series.
ETA: Just looked closer at your question. I haven't looked at this circuit, so can't tell you what load it will drive. but it will have less loss, everything else equal, with parallel fets.
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(http://i.imgur.com/BlxpECg.jpg)
(http://i.imgur.com/H3EVcfu.jpg)
(http://i.imgur.com/y61j8DW.jpg)
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Nice work David :rockin smiley:
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Thanks!
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Yes can ask u breakthou about mosfet that had been at and looking data sheet or is this the wrong place too be post about them
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Can you rephrase the question modfo. Sorry, I'm not understanding it.
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I didn't want too post on something in the wrong place but looking at a few different mosfets but one of them TP4056 for building a battery charger if I was going too build one
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I would call the TP4056 a Battery Charger Controller IC rather than a Mosfet.
I think you should start a new topic for it.
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Hi all,
Mast (a modder from Plumes of Hazard) is releasing a mosfet box that has a 5 click on/off function, which is something i've not seen before and think is pretty cool.
I was wondering if anyone had any idea how to achieve this?
Cheers
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I believe some modders are using the ego board from FT for that 5x click on/off function.
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http://www.mouser.com/ProductDetail/Vishay-Semiconductors/SUP75P03-07-E3/?qs=sGAEpiMZZMtp5ziQ9mm%252bAr%252bCSjsN5ZoY
http://www.mouser.com/ProductDetail/International-Rectifier/IRF4905PBF/?qs=sGAEpiMZZMvsw8vHdI9Fup5iKG09kH7G
I have two mods that will be really difficult to use n-channel. Can either of these be used? I need to use this type if possible. I could parallel two if need be
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I believe some modders are using the ego board from FT for that 5x click on/off function.
Wow I did not see this post Mamu I was happy cause came into mind virginally because a question on ecf about having a puff meter, using those boards lol NICE.. Dangit made like 4 orders from ft since Dec lol ....
I even clicked in here looking for davids post on the charge pump firing the fet didn't even see it scared:..
It is really cool...
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I have two mods that will be really difficult to use n-channel. Can either of these be used? I need to use this type if possible. I could parallel two if need be
The Vishay part has lower on-state resistance so that would be a better part to use. However, the threshold voltage on either part would be too high for a single cell. Would work well with series cells though. If you plan to run high outputs upwards of 50W then you might want to parallel a couple of MOSFETs, otherwise it should not be necessary.
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I didn't even see the 4.5v.
Why do some have neg numbers such as this one? http://www.mouser.com/ProductDetail/IXYS/IXTP44P15T/?qs=sGAEpiMZZMshyDBzk1%2fWi2Lis36WbXR%252bdOL7vJS80To%3d
I am truly trying to learn what to look for.
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I even clicked in here looking for davids post on the charge pump firing the fet didn't even see it scared:..
It is really cool...
(http://i.imgur.com/yxkzbUw.png)
(http://i.imgur.com/kiJ3W4u.jpg)
http://www.mouser.com/ProductDetail/Analog-Devices/ADM660ANZ/?qs=sGAEpiMZZMtitjHzVIkrqYThiPHWFX9aAfsE1NTyhUU%3d
http://www.mouser.com/ProductDetail/TDK/FK24X5R1C106K/?qs=sGAEpiMZZMt3KoXD5rJ2N48tYEMqcp4xjy22eXGkXaI%3d
http://www.mouser.com/Search/ProductDetail.aspx?R=PR2H1virtualkey57130000virtualkey854-PR2H1
http://www.reddit.com/r/OpenPV/comments/2fz267/mosfet_and_charge_pump_doubles_voltage_to_gate/cke5d7u
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Why do some have neg numbers such as this one?
It's just nomenclature. The N-channel parts are considered to be positive current flow from drain to source. Since current flows source to drain in a P-channel, it's negative. Also, gate voltage minus source voltage is positive to turn on an N-channel. Gate voltage minus source voltage is negative to turn on a P-channel. Sometimes you see the minus sign in the specs and sometimes it's taken for granted and left out.
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So I gave up and just went with the trusty 3034. How could you incorporate a on/off switch to shut off power so it wont fire? Where could it be placed so that it doesn't get the current flow from the batteries? Its a simple duel 26650 box with a 3034 n-channel but it will be driven hard
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The Gate of the N-FET is low current, so put the master switch in line with the Gate. It won't disconnect power but will prevent the atty from firing.
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So I gave up and just went with the trusty 3034. How could you incorporate a on/off switch to shut off power so it wont fire? Where could it be placed so that it doesn't get the current flow from the batteries? Its a simple duel 26650 box with a 3034 n-channel but it will be driven hard
dc99 awesome! look forward to seeing the box! :beer-toast: :thumbsup: :wave:
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Thanks Mamu. Its really more of a "I don't want it to accidentally fire thing" so that should work fine. Its was either that or use another mosfet along with the switch.
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Triple parallel mosfets and gate driver. Anyone have any thoughts on this? Is there is simple minimal component solution for low voltage cutoff (~3v) that could be added?
(http://i.imgur.com/XIP1axM.png)
Minus the charge pump, I made this pcb layout last night in Diptrace. First time using pcb software... I'm sure the design is far from perfect. I was planning on laying solder on top of the high current traces.
(http://i.imgur.com/0YK8ffV.png)
(http://i.imgur.com/EbR4NBJ.png)
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With gate driver
(http://i.imgur.com/mEkId6R.png)
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Nice pcb
Cannot beat adding in an ego board it will eliminate your on/off sw and give ya shutdown...
Already know they are highly efficient and will keep at ~4.2v until 3.5ish maybe longer since minimal load..
Only a buck too lol.. Put some pins on it place it one ur pcb easy cheesy..
IMO best thing since sliced bread for our mods..
http://www.fasttech.com/product/2137901
Check out discussions and that 1A charge board I really want one of those
(http://i00.i.aliimg.com/photo/v0/60154951586_1/e_vaporizer_box_mod_420mAh_700mAh_1000mAh.jpg)
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Nice pcb
Cannot beat adding in an ego board it will eliminate your on/off sw and give ya shutdown...
Already know they are highly efficient and will keep at ~4.2v until 3.5ish maybe longer since minimal load..
Only a buck too lol.. Put some pins on it place it one ur pcb easy cheesy..
IMO best thing since sliced bread for our mods..
http://www.fasttech.com/product/2137901
Check out discussions and that 1A charge board I really want one of those
(http://i00.i.aliimg.com/photo/v0/60154951586_1/e_vaporizer_box_mod_420mAh_700mAh_1000mAh.jpg)
http://cnmmtech.en.made-in-china.com/
Heres a place you can get them. Look around, there are quite a few you only have to get 20. A friend on another site ordered a 100 of the 1000ma charging boards
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Thanks DC was being cheap
order 5 testers
waiting for fasttech free shipping and no translating ish
Wonder how warm they get @1A
I found ego boards for 8-15 cents from a manufacturer
I dug deep
http://translate.google.com/translate?hl=en&sl=zh-CN&u=http://product.dzsc.com/product/infomation/997260/201311201466546.html&prev=search
:laughing:
:thumbsup:
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Is there is simple minimal component solution for low voltage cutoff (~3v) that could be added?
Easiest thing to do is add a voltage detector inline with the gate signal. Take a look at the TPS3700; http://www.ti.com/product/TPS3700
I was planning on laying solder on top of the high current traces.
Solder actually has about a tenth the conductivity of copper. It's fine for joints where there's only a thin layer of solder between copper connections but not so great for beefing up current paths. It's better to add solder mask over the trace then solder a solid copper wire along the length of it.
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Thanks for the help. Much appreciated.
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I'm looking at the MAX8212 since the schematic seems quite simple.
http://www.maximintegrated.com/en/products/power/supervisors-voltage-monitors-sequencers/MAX8212.html
http://datasheets.maximintegrated.com/en/ds/MAX8211-MAX8212.pdf
I would like to wire it as shown in figure 5, vin from the ADM660 voltage doubler and resistors selected for over voltage detection of 6v. (R1=1Mohm, R2=4.22Mohm)
Would the output from the ADM660 be noisy? Should I select and use an R3 resistor for hysteresis with the MAX8212?
(http://i.imgur.com/Oy3FEMA.png)
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The loading on the detector from the MOSFET gate array is highly capacitive. Loads that are capacitive result in large current spikes until terminal voltage is achieved. The detector is not designed to drive loads like that as it has a maximal current loading of 7mA. Also the output impedance of the detector is rather high so it can result in large on-off transition times for the MOSFET array. MOSFETs can generate a lot of heat if they switch too slowly. Based on your use of an array, that's something you're trying to minimize.
What you could do is use a complimentary MOSFET pair to isolate the detector from the load. Small power MOSFETs in a SOT23 package are a dime a dozen and fairly easy to work with. Alternately you can use a MOSFET driver. They can be found with built-in doublers and high impedance control inputs that would eliminate these issues in using a stand-alone doubler.
Your R1 and R2 values are quite high. Most modern chips have very high impedance inputs so it's not an issue to go with inline resistance as high as a meg, but 5meg is pushing it. Also it makes things highly susceptible to noise and there will be a good amount from the doubler. I would suggest a total inline resistance no greater than a meg. I would take those resistance values down a decade (divide by 10).
I would suggest a 1uF MLCC cap as close as possible to the power and ground pins for both the doubler and detector. Most chips are sensitive to supply voltage quality and the caps filter some of the noise.
Your schematic shows 10uF electrolytics on the oscillator and output caps for the doubler. MLCC caps actually do a better job as they have the lowest ESR. A 4.7uF MLCC cap will offer better performance than a 10uF electrolytic cap and will occupy much less space. They can be found in leaded packages if you are planning on free wiring your circuit.
I would actually do what you're trying to do quite differently. I would put the detector right off the battery controlling a MOSFET driver. Ideally you want the detector right off the battery. Doublers typically have a lot of output ripple and as you are sensing voltage after the doubler, you can run into issues with false detection due to ripple voltage. I'd also filter the detection input some amount to provide some noise immunity. The trigger switch I would put in series with the detector control output. That's assuming positive logic (active low or low for battery below threshold). I would use the TPS3700 which provides both and wire the active low output.
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3 smd mosfets, resistor and fuses. Connections for gate disconnect on-off switch, fire switch, voltmeter, 510 and batteries.
https://oshpark.com/shared_projects/TbLFzpbz
(http://i.imgur.com/dRFS0W5.png)
(http://i.imgur.com/3qQT9SD.png)
(http://i.imgur.com/RFdnMkz.png)
(http://i.imgur.com/sVeS5UU.png)
https://www.youtube.com/watch?v=gWls2Lj7EpY
https://www.youtube.com/watch?v=qTBFmfro9WA
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Nice work David. Congrats :beer-toast:
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Very nice work David.
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What wattage are ya testing @. Definitely awesome.. :thumbsup:
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Yes, very neat David.
Have you measured it's voltage drop?
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Thanks.
Coil is 0.2 ohms. Batteries were close to full charge. Battery sag and voltage drop was around .45-.6 volts. My excessively long wires and not soldering the wires to the battery contacts accounted for some of that I would imagine.
Did a 3rd test fire video with a 0.16 ohm coil. Melted the insulator on a TOBH clone... oops... but the board stayed pretty cool.
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Very Cool! Can you make me one? :beer-toast:
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Very Cool! Can you make me one? :beer-toast:
He says as many as you like lol
https://oshpark.com/shared_projects/TbLFzpbz
Thanks David
What fet are you using? I tried typing in the numbers on em but no luck..
Duh' found it, very thorough helps us there lol
https://uk.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=20a3a44206
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He says as many as you like lol
https://oshpark.com/shared_projects/TbLFzpbz
Thanks David
What fet are you using? I tried typing in the numbers on em but no luck..
Duh' found it, very thorough helps us there lol
https://uk.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=20a3a44206
So he owns OSH or just rents there? :popcorn:
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So he owns OSH or just rents there? :popcorn:
That would be sweet if he did own it maybe IDK. Hook us up Davids I see lots of projexts ;hubba;
No you can buy 3 for $4.80; or you were serious asking for a freebie? if so, me too, send me one too. :thumbsup:
I didn't know if you did not see you can buy it at bottom of page, internet post seems as if ya didn't see that..
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That would be sweet if he did own it maybe IDK. Hook us up Davids I see lots of projexts ;hubba;
No you can buy 3 for $4.80; or you were serious asking for a freebie? if so, me too, send me one too. :thumbsup:
I didn't know if you did not see you can buy it at bottom of page, internet post seems as if ya didn't see that..
Not asking for freebies unless he wants to give me one to test or something. I am not seeing where to buy them. Can you link that for me please? cant_believe:
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That would be sweet if he did own it maybe IDK. Hook us up Davids I see lots of projexts ;hubba;
No you can buy 3 for $4.80; or you were serious asking for a freebie? if so, me too, send me one too. :thumbsup:
I didn't know if you did not see you can buy it at bottom of page, internet post seems as if ya didn't see that..
why is this thing double posting sheet? fainting:
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Break will clean the dbl posts up if he sees this, it has happened before, his forum is broken, someone must have loaded the best ejuice recipe in history of juice making.. :laughing:
-------------------------
Its on the bottom of the page left side, "Order Now" but first register an account.
heres the link for both
Register page:
https://oshpark.com/users/sign_up
Buy TriParaMos v1.0:
https://oshpark.com/shared_projects/TbLFzpbz/order
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Break will clean the dbl posts up if he sees this, it has happened before, his forum is broken, someone must have loaded the best ejuice recipe in history of juice making.. :laughing:
-------------------------
Its on the bottom of the page left side, "Order Now" but first register an account.
heres the link for both
Register page:
https://oshpark.com/users/sign_up
Buy TriParaMos v1.0:
https://oshpark.com/shared_projects/TbLFzpbz/order
Thanks Visus! I have them in my cart and have registered an account. Have to run now back to check out later. I like the mouser parts list to go with the board too very cool and conv! :beer-toast:
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Question, can I use other N chan mosfets on this board?
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boards ordered just need to know if I can use mosfets I already have or not?
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Question, can I use other N chan mosfets on this board?
That's a common footprint for MOSFETs. It's based on a SO-8 layout. Lots of SMD MOSFETs use it. It goes by different names by different makers. Vishay calls it PowerPAK SO-8, Ti calls it VSON-8. Basically if you can fit an SO-8 package the leadless versions will fit as well.
The one he's selected is a good one, though if you plan to run down to 3V input, you're taking it right to the edge of the gate-source voltage versus on-state resistance curve. For better performance at minimal input voltages you may want to select a transistor with a curve a little more to the left.
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Craig
Need help on this selection of MOSFET.. I know you have listed a ti fet b4³ but its buried somewhere..
Also on the ego boards using, they are usually pwm so using a cap/res as a low pass filter to keep the the MOSFET open what would be a good shot in the dark without a scope to use as a cap and resistor.. Im searching for a calculator after I type this I know it's probably one out here lol.. Im guessing 33.3hz like every other board out of China at that time then.. Im gonna try it.
http://www.ti.com/lit/ds/symlink/csd13202q2.pdf
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That's a common footprint for MOSFETs. It's based on a SO-8 layout. Lots of SMD MOSFETs use it. It goes by different names by different makers. Vishay calls it PowerPAK SO-8, Ti calls it VSON-8. Basically if you can fit an SO-8 package the leadless versions will fit as well.
The one he's selected is a good one, though if you plan to run down to 3V input, you're taking it right to the edge of the gate-source voltage versus on-state resistance curve. For better performance at minimal input voltages you may want to select a transistor with a curve a little more to the left.
Craig would IRL3103STRL N Chan 30V 64Amps work? Thanks Craig You Rock!
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Hey fsors thanks for being interested in the mosfet board. Best of luck getting everything assembled and working once you get the boards.
IRL3103STRL is a different package D2PAK/TO-263 it's larger and won't fit on the pads. Also, RDS ON is fairly high. I would use a mosfet with RDS ON of 2 milliohms or less.
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Hey fsors thanks for being interested in the mosfet board. Best of luck getting everything assembled and working once you get the boards.
IRL3103STRL is a different package D2PAK/TO-263 it's larger and won't fit on the pads for the mosfets. Also, RDS ON is fairly high. I would use a mosfet with RDS ON of 2 milliohms or less.
Thanks david4500, I will get the ones you have linked to the boards then unless Craig or someone thinks there is a better option. Really excited to build this. How did you solder the mosfets and fuses to the board?
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I would use a mosfet with RDS ON of 2 milliohms or less.
When/if I build a box mod I am going to use ur whole setup, ordering things from ti soon so wanted to try their mosfets, the one I choose has about 7.5mohms at 7.4v its not as important on reg but every bit does count. You did heckuva research finding that fet it's lower than most I have found lil low on the amp side but three get ya 75A and uber low mohms so ya definitely the one...
I get confused looking at specs on fets but this one seems stout and I can try a sample..
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With a soldering station by hand. Hakko 888D with the stock chisel tip. Had it around 650F (maybe lower) most of the time. Bumped up to around 700F by some of the thicker traces. I watched a few video on youtube about hand soldering surface mount components. Basically, I got a bit of solder on the tip of the iron then tinned one pad for a component. Then applied flux (I used chip-quik smd291) to all of the pads for a part. Placed the part with tweezers, aligned as needed. Used a toothpick to keep the in place, then soldered the tab to the pad that was tinned. With the part tacked in place, carefully solder the remaining tabs or pins.
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Visus, what project are you planning to work on if not a box mod?
TI might have some mosfets suitable for the pcb. I think they'd have to be reflow soldered since the tabs are all underneath the case.
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With a soldering station by hand. Hakko 888D with the stock chisel tip. Had it around 650F (maybe lower) most of the time. Bumped up to around 700F by some of the thicker traces. I watched a few video on youtube about hand soldering surface mount components. Basically, I got a bit of solder on the tip of the iron then tinned one pad for a component. Then applied flux (I used chip-quik smd291) to all of the pads for a part. Placed the part with tweezers, aligned as needed. Used a toothpick to keep the in place, then soldered the tab to the pad that was tinned. With the part tacked in place, carefully solder the remaining tabs or pins.
Fantastic david4500! I have a VV soldering iron and will give it a go when all the parts come in. This will go in a Box Mod of some sort. What are you putting yours in? Thanks for your help!!! :thankyou:
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I have some 1590Bs laying around, I'll make two mods with those. Should be plenty of room for everything. Could probably fit into a 1590G.
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very cool, I was thinking about the same enclosures. I look forward to seeing some pics when you finish yours david4500 and hope you will post a few.
Thanks david4500! :beer-toast:
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Need help on this selection of MOSFET.. I know you have listed a ti fet b4³ but its buried somewhere..
http://www.ti.com/lit/ds/symlink/csd13202q2.pdf
Also on the ego boards using, they are usually pwm so using a cap/res as a low pass filter to keep the the MOSFET open what would be a good shot in the dark without a scope to use as a cap and resistor.. Im searching for a calculator after I type this I know it's probably one out here lol.. Im guessing 33.3hz like every other board out of China at that time then.. Im gonna try it.
I'm not sure what you plan to use that MOSFET for, but that's 2x2mm package, it's very small and hard to solder by hand without at least 10x magnification. I'm kind of confused on what you want you are asking. If you can be more specific I can probably recommend something.
Are you looking to filter the PWM signal completely or just filter any noise out of it? Normally you arrive on values for resistance and capacitance in a low pass filter by looking at the time constant. It's simply 1/RC. That specifies the period of the frequency reduced in magnitude by -6dB (reduced by half). Typically you want your time constant no greater than one tenth the period of the frequency you want to allow and 10 times the period you want to block. So if you want 33Hz to pass you need a time constant 3mS or less. If you want to block 33Hz, then you need a time constant 300mS or greater.
You decide on a value for R then set C based on that. Depending on loading, you may be limited in how high you can go with resistance. Obviously, the higher the resistance the smaller capacitance value you can use. If resistance is low due to loading requirements, capacitance values can get quite high.
Oh btw if you're not already aware, period and frequency are just two ways of saying the same thing. Period is 1/frequency and frequency is 1/period. Scientific calculators a have in inverse button to quickly do that and the one on mine is quite worn, use it a lot.
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Visus, what project are you planning to work on if not a box mod?
TI might have some mosfets suitable for the pcb. I think they'd have to be reflow soldered since the tabs are all underneath the case.
I have some plastic cases I posted a while back in parts, been procrastinating filling them.
08100's with 18650 finally
I have been loyal to 14500's and still are but cannot beat the runtime of 18650's using a subtank so I may as well build it.
I also want to build a mcu mod and a box mod for my son and for that I would use your board..
Yeah really really tiny, I came up with a really cool method of soldering by tinning the wires positioning on top of the pads and sorta wave soldering to them makes a really solid connection and can use 18ga. drain pretinned that area is 1mm 18 ga is ~1.5mm using tape to help mask .. It also acts as a rudimentary heatsink.. Really tiny use of space so its a win win for aa box mod.. Ya wouldn't even know its there lol.. I got really good at soldering 0402 items and
I actually like that style better than leads style for ghetto wire no board.. I am testing/trying, it may not be doable without a board and reflow but why not try lol.. They have other 3x3mm and 5mm MOSFETs I also will try..
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Lol I was answering Davids question, sorta answered your first part lol.
I squint really good lol with a 100 watt fluro lighting it up..
Want a good 2s fet from ti n chan but also wanna play with the tiny stuff rfol..
pls recommend one thats definitely doable wired ..
Ego
Really just want to filter the noise out, Zander gave it a go and could not get his fet to open.. I know some ego boards are cv --no worries there, but if the one I get is pwm, I figured a low pass filter, lil knowledge from google search was easy enough but no-- you say I need to ~know what ~frq it is, so how to filter the signal to open the fet without knowing, that would be a better question...
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Craig would IRL3103STRL N Chan 30V 64Amps work? Thanks Craig You Rock!
Thanks and you're welcome. David4500 already answered your question, but any MOSFET in an SO-8 or compatible leadless package will fit on that layout.
In looking for something with a curve "a little more to the left", narrow your parmetric search to parts that have a maximal gate-source voltage tolerance of 12V over the more typical 20V. That's the way it works with MOSFETs, the lower the maximal VGS the further to the left the curve is. Though the tradeoff there is tolerance to abuse so it's better to use a 12V tolerant part than an 8V tolerant part, the 12V part is a little tougher.
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Thanks and you're welcome. David4500 already answered your question, but any MOSFET in an SO-8 or compatible leadless package will fit on that layout.
In looking for something with a curve "a little more to the left", narrow your parmetric search to parts that have a maximal gate-source voltage tolerance of 12V over the more typical 20V. That's the way it works with MOSFETs, the lower the maximal VGS the further to the left the curve is. Though the tradeoff there is tolerance to abuse so it's better to use a 12V tolerant part than an 8V tolerant part, the 12V part is a little tougher.
Thanks Craig! Any recommendations on a specific mosfet from you for this board would be highly valuable to me and very much appreciated. Another question, is do I need to use 3 mosfets on the board? Thanks in advance Craig! You Rock! :yes"
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Lol I was answering Davids question, sorta answered your first part lol.I squint really good lol with a 100 watt fluro lighting it up..Want a good 2s fet from ti n chan but also wanna play with the tiny stuff rfol..pls recommend one thats definitely doable wired ..
TI does make some really nice N-channel MOSFETs. Mostly they're the 5x6mm leadless packages, but there's a number of smaller ones too. Weird though, they have few P-channel ones. They do make one really nice PMOS in a 3x3mm package, but that's the only noteworthy one they make. In any case, the small stuff is do-able by hand, I use parts like that all the time. Though it's taken me a lot of soldering practice and skill to get there. Preferably you can use a hot air station or even frying pan or toater oven reflow. Mainly the trick is being able to see what you're doing. I use a 10x stereo microscope, but there's options there as well.
Ego
Really just want to filter the noise out, Zander gave it a go and could not get his fet to open.. I know some ego boards are cv --no worries there, but if the one I get is pwm, I figured a low pass filter, lil knowledge from google search was easy enough but no-- you say I need to ~know what ~frq it is, so how to filter the signal to open the fet without knowing, that would be a better question...
I know there's a schematic posted for the eGo board around here somewhere, but I don't feel like taking the time to look for it. An ideal time constant to allow 33Hz and block higher frequencies would be 3mS. If this on a gate drive you can't put too much resistance inline or you'll slow down the switching speed of the MOSFET too much causing it to overheat. In the extreme like 10K Ohms the MOSFET won't even turn on at all.
With the limitation on resistance you'll end up with a large capacitance to make your filter ideal since the bandpass frequency is so low. What you'll have to do is use the highest resistance you can get away with and the largest capacitance you can comfortably put on the PCB. Probably like 100 Ohms and 10uF which gives you a time constant of 1mS. That's pretty close to the ideal 3mS. That should filter most of the electrical noise you may run into. 100 Ohms might still be too high, probably 50 Ohms would be better dropping the time constant to 500uS. It will still catch a lot of the noise since it tends to be higher frequency stuff anyway.
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Thanks and you're welcome. David4500 already answered your question, but any MOSFET in an SO-8 or compatible leadless package will fit on that layout.
In looking for something with a curve "a little more to the left", narrow your parmetric search to parts that have a maximal gate-source voltage tolerance of 12V over the more typical 20V. That's the way it works with MOSFETs, the lower the maximal VGS the further to the left the curve is. Though the tradeoff there is tolerance to abuse so it's better to use a 12V tolerant part than an 8V tolerant part, the 12V part is a little tougher.
Woot answered my question too
I was unsure of my choices because of the 12v 20v etc I can read the bar graphs but still shaky legs lol..
Its why mostly everybody just goes with 3034 so many variables assumed when selecting a fet.. But its a good fet...
I cancelled my ego purchase lol.. Not even gonna mess around with it until I build the box mod an I can use my sons ego board, also check it to know what its doing.
Thanks Craig Never mind the ego part I will ask ya later Im more than sure when then...
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We keep posting at the same times lol
Thank ya very much, theres actually a spot open on the ego board for a resistor and a capacitor on the output so it would be an easy task too.. :thumbsup:
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Oh, I have to add a correction, the time constant is simply RC not 1/RC, spaced out on that, the step response for a low pass filter is Vin times one minus the natural log of -t/RC so I thought 1/RC for some reason. It's actually still meaningful, it's just the time constant in terms of frequency not period.
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Thanks Craig! Any recommendations on a specific mosfet from you for this board would be highly valuable to me and very much appreciated. Another question, is do I need to use 3 mosfets on the board?
Well, here's a couple NMOS with a low threshold and low on-state resistance;
http://www.ti.com/lit/ds/symlink/csd17312q5.pdf
http://www.vishay.com/docs/64815/sir404dp.pdf
Those are leadless SO-8 packages. They can actually be soldered by hand, I do them all the time, just use a lot of flux under the pads to make sure you get good flow and plenty of heat on the iron, 650F will do with 63/37 solder. Otherwise you can reflow them with a hot air pencil or even in a frying pan or toaster oven.
There may be some regular S0-8 ones worthy of looking at, but I usually don't bother with them because all the best ones are coming out in those leadless packages.
You could probably run just one if you wanted, but the idea is to lower on-state resistance. There's really nothing to be gained by running fewer MOSFETs except cost of parts, but just two will still halve the on-state resistance and be plenty low enough for all but the highest outputs.
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Well, here's a couple NMOS with a low threshold and low on-state resistance;
http://www.ti.com/lit/ds/symlink/csd17312q5.pdf
http://www.vishay.com/docs/64815/sir404dp.pdf
Those are leadless SO-8 packages. They can actually be soldered by hand, I do them all the time, just use a lot of flux under the pads to make sure you get good flow and plenty of heat on the iron, 650F will do with 63/37 solder. Otherwise you can reflow them with a hot air pencil or even in a frying pan or toaster oven.
There may be some regular S0-8 ones worthy of looking at, but I usually don't bother with them because all the best ones are coming out in those leadless packages.
You could probably run just one if you wanted, but the idea is to lower on-state resistance. There's really nothing to be gained by running fewer MOSFETs except cost of parts, but just two will still halve the on-state resistance and be plenty low enough for all but the highest outputs.
Thanks Craig! I have booked those for tomorrow. The ti looks particularly interesting. Thank You for sharing your knowledge and kindness! :thankyou:
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I actually like the Vishay one better. Though the on-state resistance is a little higher, it has 12V tolerance on Vgs and it has a very left curve that is well into the flats at 3V. Also, the Vishay package has tits on the leads making it easier to solder. The TI package is ground flat on the lead sides.
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I actually like the Vishay one better. Though the on-state resistance is a little higher, it has 12V tolerance on Vgs and it has a very left curve that is well into the flats at 3V. Also, the Vishay package has tits on the leads making it easier to solder. The TI package is ground flat on the lead sides.
Well that makes me like it best then too! What resistor would it take? Should I use 3 of these fets? Thanks Craig! :thankyou:
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The short answer is a single resistor between 4.7k and 47k should be fine. I'd probably use a single 10k pull-down resistor on those three MOSFETs.
Here's the long answer. The pull down resistance is not particularly critical, nor it is critical to pull each gate down individually with three separate resistors. It's fine to tie the gates together and pull them down with one resistor.
One consideration for pull down (or up) resistors and MOSFETs is the gate-source leakage. Typically it's in the nano-Amps. If you go high enough, and I mean really high like 10meg, the leakage can cause a voltage drop high enough to partially turn on the MOSFET.
Another consderation is noise sensitivity. When resistances are high enough, voltages can be picked up from currents running on the board and even from EMI radiated by the power grid or radio. For things sensitive to only a volt or two it can cause problems. Again this only for really high resistances over several mega-Ohms.
Finally there's the turn off and turn on times for the MOSFET. When pulling the gate up, resistance is only limited by the source (the battery) and current paths which is quite low, but when the gate is pulled down, charge stored in the transistor's gate-source junction has to dissipate through the pull-down resistor. For high resistances and/or MOSFETs with high gate charge, that can cause the MOSFET to shut down slowly generating unnecessary heat and power loss. Again this is going to be for higher resistances, probably above 100k, but it also depends on gate charge. With the three MOSFETs in parallel you are tripling the gate charge.
You may want to limit the current that flows by using a higher resistance, but typically for a device that draws as much power as an atomizer, there's not much concern over power consumption in peripheral circuitry. Using a milli-Amp to drive the MOSFET is not a concern. Though for some battery powered devices other than e-cigs it can be.
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Thanks for all the wisdom Craig.
That Vishay mosfet looks interesting. Think I'll give it a try with my next parts order.
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No on-board fuses this time.
https://oshpark.com/shared_projects/PqyAD9aT
(http://i.imgur.com/vt8pvuk.png)
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The short answer is a single resistor between 4.7k and 47k should be fine. I'd probably use a single 10k pull-down resistor on those three MOSFETs.
Here's the long answer. The pull down resistance is not particularly critical, nor it is critical to pull each gate down individually with three separate resistors. It's fine to tie the gates together and pull them down with one resistor.
One consideration for pull down (or up) resistors and MOSFETs is the gate-source leakage. Typically it's in the nano-Amps. If you go high enough, and I mean really high like 10meg, the leakage can cause a voltage drop high enough to partially turn on the MOSFET.
Another consderation is noise sensitivity. When resistances are high enough, voltages can be picked up from currents running on the board and even from EMI radiated by the power grid or radio. For things sensitive to only a volt or two it can cause problems. Again this only for really high resistances over several mega-Ohms.
Finally there's the turn off and turn on times for the MOSFET. When pulling the gate up, resistance is only limited by the source (the battery) and current paths which is quite low, but when the gate is pulled down, charge stored in the transistor's gate-source junction has to dissipate through the pull-down resistor. For high resistances and/or MOSFETs with high gate charge, that can cause the MOSFET to shut down slowly generating unnecessary heat and power loss. Again this is going to be for higher resistances, probably above 100k, but it also depends on gate charge. With the three MOSFETs in parallel you are tripling the gate charge.
You may want to limit the current that flows by using a higher resistance, but typically for a device that draws as much power as an atomizer, there's not much concern over power consumption in peripheral circuitry. Using a milli-Amp to drive the MOSFET is not a concern. Though for some battery powered devices other than e-cigs it can be.
Thanks Craig You are a asset to the community and are a Master with a wealth of knowledge! So if I tied them I can pull them down with a 15K that's cool! I will go that way. Do I have to use fuses on this board?........I probably will use the fuses anyway since there are spots for them but just want to know if it's by-passable? :thankyou:
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No on-board fuses this time.
https://oshpark.com/shared_projects/PqyAD9aT
(http://i.imgur.com/vt8pvuk.png)
david4500 those look cool too and I might have to order some after the first set gets done which I just got an email about. They say they will be back from the printer around March 13th. Look forward to building with them. :thankyou:
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Do I have to use fuses on this board?
It's never a bad idea to use fuses, but they do introduce additional power loss. For parallel removable cells it's rather sketchy to run without some kind of reverse polarity or charge mismatch protection. For anything powered by a Li-Ion battery there really has to be some kind of protection from excessive currents. They're just too hazardous otherwise.
I don't use fuses myself, but cells are permanently installed and an MCU monitors current and temperature so the system knows if there's a problem. Even then it would not be a bad idea to add fuses as a backup, I don't because I'm covered and I don't want to introduce the power loss.
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Quick question, is the heavy solder enough?
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Do I have to use fuses on this board?........I probably will use the fuses anyway since there are spots for them but just want to know if it's by-passable? :thankyou:
(https://644db4de3505c40a0444-327723bce298e3ff5813fb42baeefbaa.ssl.cf1.rackcdn.com/uploads/project/top_image/TbLFzpbz/i.png)
Yeah I would use them since there is room on-board. Use the new fuse free board if you wish to not to use them or have them off-board.
But if the fuses were to be omitted, run a wire from 510+ or battery+ and connect to "510+" on the board.
If the on-off switch was going to be omitted as well, connect that wire to "SW1-" instead of "510+".
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Craig I found something of interest and wanna know why you two EE's agree to disagree, are mosfets that much better now, more closely matched? The post is from 2011 and thats huge past days for todays electronics, that is mindboggling cool..
Heres your quote:
Here's the long answer. The pull down resistance is not particularly critical, nor it is critical to pull each gate down individually with three separate resistors. It's fine to tie the gates together and pull them down with one resistor.
Heres the post of interest of this.. It also confirms your post about MOSFET choices further to the left on the graph as heat rises RDson grows so ya..
MOSFET RDS(on) has a positive temperature coefficient - the warmer it gets, the higher the RDS(on) gets. If you connect two MOSFETs in parallel with similar characteristics (i.e. the same part number from the same manufacturer), drive them identically, and don't have huge asymmetry in your PCB layout, the MOSFETs will indeed share current quite nicely. Always make sure each MOSFET has an independent resistor in series with each gate (never parallel gates without resistors) as gates tied directly together can weirdly interact with each other - even a few ohms is better than nothing.
http://electronics.stackexchange.com/questions/16882/dissipating-1w-on-a-to-220-without-heatsink
I would tell guy my instructor said its not critical but I have read where you also said the same in a post but that was for pwm circuit .... So ya why agree to disagree..
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(https://644db4de3505c40a0444-327723bce298e3ff5813fb42baeefbaa.ssl.cf1.rackcdn.com/uploads/project/top_image/TbLFzpbz/i.png)
Yeah I would use them since there is room on-board. Use the new fuse free board if you wish to not to use them or have them off-board.
But if the fuses were to be omitted, run a wire from 510+ or battery+ and connect to "510+" on the board.
If the on-off switch was going to be omitted as well, connect that wire to "SW1-" instead of "510+".
Thanks david4500! I like these kind of options! :yes" :thankyou:
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Craig I found something of interest and wanna know why you two EE's agree to disagree,
You can model the gate source connection with a capacitor and resistor in series. For matched parts, gate charge is similar enough that gates will charge equally and MOSFETs will turn on equally. In that case it's two of the same resistors and two of the same capacitors in parallel. Currents will equally flow between them. For non-matched parts, tying gates together could result in one part carrying the bulk of the load during on-off switching. That can be a problem in terms of unequal loading and asymmetric heating.
Furthermore, a user on-off switch is not the typical application for a Power MOSFET. They're actually used for all kinds of different switching applications and that can have a big impact on design considerations and part selection. For higher speed stuff like PWM or even converter switches, it's not uncommon to parallel MOSFETs to obtain higher current ratings. Motor controllers are a good example. High output ones can have tens of MOSFETs running in parallel. Equal loading of the gate-source junction is critical. Even variations between parts coming off the same line can be an issue. However, for a user on-off switch, this does not become much of a consideration since the speeds are pretty slow, unless you plan to cycle the switch as fast as humanly possible.
Hope that addresses your confusion.
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Thanks,
Wasn't confused, I woulda argued with guy in class per se' but needed my argument. :thumbsup:
Past few days I've crammed enough in my head to explode on some breadboards lol
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Well, eh, question then. Hopefully that made plain sense to you, basically the lower the switching frequency the less of a concern there is. A user on-off switch is about as low a frequency as you can get. And I can relate to exploding head syndrome, get it sometimes myself. Problem is the more you know the more you realize you still need to learn and then when you want to try some new circuit you try to understand it all in one sitting. I call it burning brain cells. Programming actually gets me worse than circuit design.
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Well, eh, question then. Hopefully that made plain sense to you, basically the lower the switching frequency the less of a concern there is. A user on-off switch is about as low a frequency as you can get. And I can relate to exploding head syndrome, get it sometimes myself. Problem is the more you know the more you realize you still need to learn and then when you want to try some new circuit you try to understand it all in one sitting. I call it burning brain cells. Programming actually gets me worse than circuit design.
Lol ya its awesome learn mosfets, controllers, computer, and control everything lol...
They are producing new items that change the way it was done/did daily. I love it, efficiency is awesome. Example: If Tesla home batteries are as amazing as posted many things are going to change.. But whoa the future incoming faster than the economy can handle so ya, you engineers rolling hot in the brain cells..
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In a spacious 1590B
(http://i.imgur.com/Xh1jwzE.jpg)
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Very tidy.
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Wow that looks good
love ur switch choices the led in em is baller
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http://www.mouser.com/ProductDetail/STMicroelectronics/STD100N10F7/?qs=sGAEpiMZZMvMXeU%252bpcMAVNQG84RiK2Um
Any reason this wont work? Its available in almost every package
Im still looking for the elusive p-chn that is easy to work with. http://www.mouser.com/ProductDetail/Infineon-Technologies/IPD042P03L3-G/?qs=sGAEpiMZZMvplms98TlKY8VID4ASP18oAUQnIRM03p0%3d
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For the nfet, the rds on is too high. You'll want around 2 milliohms. Vgs th is also slightly high, 4.5v. You want it to be less than 2.5-3v. If for any the smd pcbs, of the packages shown in the data sheet they are all too large.
I think Craig has posted some well suited pfets in the past if you look through his posts.
Got the quad board today:
(http://i.imgur.com/PtI31GK.png)
When soldering the drain tabs on the back, I didn't realize the solder was flowing though the vias to the other side.
(http://i.imgur.com/trxLZMe.jpg)
(http://i.imgur.com/8UyxwOj.jpg)
(http://i.imgur.com/2ZUG7Ea.jpg)
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Very cool david, will the solder flow through mess with anything? scared:
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david do you think I can get one of these boards in this size package?
(http://i1250.photobucket.com/albums/hh529/fsors/VG%20BOX/1_zps6nmacevb.jpg) (http://s1250.photobucket.com/user/fsors/media/VG%20BOX/1_zps6nmacevb.jpg.html)
(http://i1250.photobucket.com/albums/hh529/fsors/VG%20BOX/3_zpswf8vvmc7.jpg) (http://s1250.photobucket.com/user/fsors/media/VG%20BOX/3_zpswf8vvmc7.jpg.html)
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I think Craig has posted some well suited pfets in the past if you look through his posts.
I'll save you the trouble of searching, this one is the best PMOS I've come across for a single cell or parallel cells;
http://www.vishay.com/docs/62860/si7157dp.pdf
I've mentioned that part a few times already on the forum here. I use this part myself and I've measured 2 mOhms at nominal voltage for a single battery. This one has lowest on-state resistance and lowest gate-source threshold of any PMOS I've come across. Granted you might be able to find a PMOS with lower on-state resistance and higher gate-source threshold, but it's doubtful.
Not that it matters for a user on-off switch, but FYI, notice the incredibly high gate charge on that PMOS. You really couldn't use it for much else besides a user on-off switch, or something that runs at a very low frequency like a 33Hz PWM driver. The gate charge on that one is like a 1uF capacitor which is a huge amount of capacitance for a MOSFET gate. It has a very large gate junction, probably covers the entire channel.
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Very cool david, will the solder flow through mess with anything? scared:
Something to be aware of... just be little less generous with the solder than I was. I kept feeding solder not realizing it was going through to the other side. I can clean up the blobs with some solder wick if I wanted.
david do you think I can get one of these boards in this size package?
TriParaMos in a Hammond 1590G:
(http://i.imgur.com/TJkNYnp.png)
TriParaMos-NF (no fuses)
In a 1590G:
(http://i.imgur.com/TZcCOOr.png)
(http://i.imgur.com/kmSAMLv.png)
1590P:
(http://i.imgur.com/BCtzZKQ.png)
1590A:
(http://i.imgur.com/hv05KSE.png)
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Awesome david Many mounting options really look forward to getting the boards. :thankyou: :beer-toast:
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I can clean up the blobs with some solder wick if I wanted.
I use the hell out of that solder wick. I wouldn't be able to do any PCB work without it. I usually keep a couple rolls of the #1, #2, & #3 sizes on hand. It's a crisis if I run out.
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Question, could I use the boards David designed for the SI7157DP? I worked on a board for two days and decided Im not smart enough to design boards.
I was going to post a picture of how far I got and ask for help but
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I think all the boards he's posted switch the low side requiring an NMOS. The SI7157DP is a PMOS so you need a board designed for a high side switch.
What software were you using to design a PCB that you had too much trouble with? There's other free PCB design programs that are easier to use, KiCad is one, gEDA is another.
Eagle is one of the hardest programs to learn to use, it does things in a way that's not similar to other computer programs. The reason is that it started out as a DOS command line program. They never totally redesigned the program for Windows, only added buttons and menus in the graphical interface to automate the scripts the old DOS program used. You can actually still use all the original DOS commands in the command line box.
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ExpressPCB, My biggest problem is that I really don't understand what is required and Im not ashamed to admit it. The board design stuff is driving me nuts. Not like theres anything out there that's really a lot of help. Its not that I cant put the parts in the design, its more of how big a pad to use and such. If there anything that will help Im up for learning. I just cant figure out how because everything Ive seen either assumes your an engineer or a genius
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Right there with ya dc99 I loaded up PCB for linux played with it for a few hours and watched few vids on yt.
im linux savvy to advanced level but whoa that thing is stupid hard...
It takes 20 operations just to do simple task such as use the library and make your own files for layers, it is a rudimentary pcb designer thats made for the people who made it. lol
Any suggestions for linux Craig?
Checking the other two compatibility now..
Woot Kicad good to go for fedora .. going to give it a whirl..
Its called electronic lab for linux but its kicad with add ons
Anyone else with linux its in yum dir
# yum groupinstall 'Electronic Lab'
It supposedly has everything in library (userloaded) to design and simulate anything up to date 2015 in electronics to micro-nano particle research
Exactly what I was looking for an extensive library
Thanks Craig
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Welcome, gEDA was originally written for Linux, but now has Windows ports for some of the components. KiCad is highly regarded. I believe it runs natively on Linux though there is a full Windows version as well.
@dc99, most PCB software provides a WYSIWYG interface meaning you can put up a "snap to" grid that reflects actual measurements. I use an inexpensive digital micrometer I got off eBay and it's surprisingly accurate. I'll measure my parts then base my PCB drawings directly off those measurements. It's something I do quite often.
For example, you can measure the thickness of a wire or component lead to determine the size hole you need. I usually make the pad wall equal to the hole size so the overall pad diameter is three times the hole diameter. You'll want to add a little to the hole diameter for production tolerance.
Generally it's better to use parts drawn yourself than rely on canned libraries. They can have inaccuracies or fail to meet needs for the type of soldering you do.
If you're using ExpressPCB software it's going to be somewhat limited, though it's very easy to use. You'll do better if you invest the time to learn a general PCB design tool i.e. Eagle, KiCad, gEDA. ExpressPCB is a proprietary program not able to output the standard Gerber and Excellon plot files used by most PCB fabs. It's also limited in output options for printing templates and making your own PCBs.
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Oh, @Visus, if you're talking about circuit simulators, there are some free PCB design packages that include them. One is Design Spark from RS Electronics (I believe they own Farnell) and another is MultiSIM Blue from Mouser. I haven't tried the simulators on those so I don't know how well they work. Personally, I use OrCAD PSpice which is not a free program, it's a professional package and expensive, I managed to get a license for it from an engineer buddy. I also use LTSpice which is very good for what it's designed to do, mainly analog stuff. That one is free.
In terms of circuit simulators native to Linux, I'd have to look them up. I have used Linux in the past, but typically I run everything on Windows. Linux gets too time consuming to configure, though it does work a lot better than Windows once you get it set up.
It is handy to have everything in one suite, but for example I don't care for OrCAD's PCB design software, but the simulator is good. Sometimes it's better to pick and choose components than use a single suite.
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Woot already drew my 1st schematic input symbols and library components, footprinted, and populated a pcb, moving along nicely. My brain is tired now lol.. Its an awesome program really well done, quite easy for a noob compared to the other program.
Doing a course from contextual electronics on kicad called, "getting to blinky" using a 7555 to blink a led.
I had no idea it would draw the connections and vias even insert proper package dimensions on its own after the schematic was made and/or added library symbol parts that usually have a similar footprint in the cvpcb program. I was doing it arse backwards just wanted to define layer, draw pads, and connect the lines.. I found it impossible to do lol..
Awesome I figure in a few weeks ill have plans for synthetic food made from excrement -- no really someone in Japan actually designed a food machine that makes synthetic meat from excrement.. It's not that far fetched if you think about what fertlizes plants and then we eat the plants, the cows, pig, goat, sheep, etc. eat the plants ewwww...lol A lot fish only eat other fish lol.. Hmn Jesus was on to something there, but stones in glass house, he intelligently called us a bunch of neanderthal nasty eating crap mofo's in a way... :laughing2: He was/is wayyy too smart lol..
Woot Thanks again, Love this stuff..
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Downloaded KiCad. Seems way easier. Im still a little dumb at it but I think I can figure this one out. Thanks Craig.
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Hey dc, if kicad doesn't work out for you check out Diptrace. I downloaded multiple pcb programs and was clueless. Wasn't until diptrace I was able to jump right in and start making boards. The only thing I had to look up in the tutorial was how to make a custom pattern/footprint.
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Dc your gonna love it, I already have a knack for it. Just watch and follow along with a yt tutorial on it and it's easy.
This guy takes ya along to build a blinking led and when ya get done with that.
https://www.youtube.com/user/contextualelectronic
Go to Nicholas next, Nicholas will simplify what Contextual made ya do from scratch.
It makes it click in the head fast.
https://www.youtube.com/channel/UCctMiEpCvXzipAYyB-RjmYg
For really cool 1st time review use from an engineers point of view. Dave from EEVblog reviews the program,
he actually had a tough time with it and then boom he had it down in basically 3 hours... Powerful package was his impression and that was from 2012 they have refined it, so it's even better today.
https://www.youtube.com/watch?v=bg0sEjD7R6M
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Craig the electronic suite actually comes with maybe a hacked similar program called gnuspice and three other simulators, it was a 4gb download, it was huge almost 7gb total install, took forever. It loaded many programs along with Kicad.. I probably will never use most of them; even chemistry and petri dish electrical simulations.. That area of building for me is a good ways down the road, if lol...
Today I did learn I could just draw a simple pcb and no need for schematic if I did not want to use one, woot.. Had to learn to use the editors properly and I have those semi- down now...
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Yes there's two ways to go about it. You can start with a schematic and have the program "rubber band" a board for you. Then you can manually draw out the traces or use the autorouter. That aspect of a PCB program is one that comes under a lot of criticism. Some autorouters can do a good job for you and others fall down on the job. The quality of a PCB suite's autorouter is usually a big point in terms of how well software scores in a review.
The other way to go is to start with a blank board and add your own components and your own connections. I tend to jump right to the board for most stuff, though for large designs, doing it the automated way can save a lot of time. It just depends on what you feel more comfortable with. Either way works. In the professional world it's typically done in an automated fashion because of the big reduction in the time it takes to lay out a board. For hobby stuff it's your time and up to you how you use it.
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Craig the electronic suite actually comes with maybe a hacked similar program called gnuspice and three other simulators, it was a 4gb download, it was huge almost 7gb total install, took forever. It loaded many programs along with Kicad.. I probably will never use most of them; even chemistry and petri dish electrical simulations.. That area of building for me is a good ways down the road, if lol...
Yeah that's the thing with Linux, you can probably find ten different programs for any one thing you're trying to do. Though the one issue wth open source stuff is there's no real assurance of any quality, the software can be the best thing since sliced bread or a total POS. You sometimes have to kiss a few frogs, I've had that happen before with open source stuff. In any case, if you find a good circuit simulator for Linux, then great. For most of the stuff I do as a hobbyist, LTSpice is a very good simulator and it's free so I just use that. For things LTSpice can't do, I use OrCAD PSpice which is not that often.
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Is the TPS3700DDCR suitable for a low voltage shut-off on an unregulated box? I remember a wiring diagram somewhere on here but I cant find it.
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That's a super handy part, just used it in a non-ecig application to detect a low battery for a 2S powered device (two cells in series). Works great and has a really wide detection range, you could use it to detect a low battery on 12S if you wanted, though it has a limit of 18V on the power supply. You can use it on 1S as it has a detection threshold down to 400mV and a minimal supply voltage of 1.8V.
There's a typical application circuit in the part's data sheet you can reference on how to wire it. Pretty simple really, just a voltage divider on the detection pin and a power supply. You can select outputs of active low (low when below threshold voltage) or active high (high when below threshold voltage) which is another super handy thing about that part. Those are open drain outputs so you need a pull-up resistor on them which works out perfect since you would likely be using the output to turn a MOSFET on and off. Open drain means the output pin behaves like a switch.
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Just got an email that my boards are on the way! :)
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Ok Craig, Ive been working on a board. May get done by next century. Haha. Anyway, I put two SI7157DP on it so far. No way that should get exceeded. What value resister would you suggest?
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Probably a 10k Ohm should do fine, just tie the gates together and use one pull-up on it. That's a pretty good part, use it myself. With a single cell or parallel cells that will get you down to 1 mOhm with the two in parallel. So with a 5W tolerance for the part, you're looking at comfortably driving a load up to 50 Amps on each MOSFET for a total of 100 Amps.
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Just got an email that my boards are on the way! :)
I've been really happy with the service from Osh Park. I'm only a couple states away from where they ship (Oregon) so I usually get them within 3 mailing days of the email notice.
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I've been really happy with the service from Osh Park. I'm only a couple states away from where they ship (Oregon) so I usually get them within 3 mailing days of the email notice.
That's awesome! I need to get the mosfets ordered now. Look forward to building with the boards!
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mofets, fuses and resistors on order! :rockin smiley:
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Got the boards today and they look fantastic. The other stuff should be in on wednesday so next weekend is the plan. :rockin smiley: :thumbsup: :laughing2:
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Good luck with the board fsors.
http://www.vishay.com/docs/64815/sir404dp.pdf
I wanted to try that mosfet, but mouser doesn't have them in stock. I found one similar enough:
http://www.mouser.com/ProductDetail/Vishay-Semiconductors/SIR800DP-T1-GE3/?qs=sGAEpiMZZMshyDBzk1%2fWi0mX49X1Ojk8bkorZS29FXY%3d
(http://i.imgur.com/S4YZoFG.png)
(http://i.imgur.com/agO7wUg.png)
For this first version of the board, the holes for 24 gauge were perfect. Holes for 16 gauge were alright, a little tight. The vias on the drain pad were too large, too many and were sucking up the solder. The exposed copper for the drain on the back of the board cold be covered with solder resist. I've made a revision to the pcb to address those slight issues https://oshpark.com/profiles/david4500
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Good luck with the board fsors.
I wanted to try that mosfet, but mouser doesn't have them in stock. I found one similar enough:
http://www.mouser.com/ProductDetail/Vishay-Semiconductors/SIR800DP-T1-GE3/?qs=sGAEpiMZZMshyDBzk1%2fWi0mX49X1Ojk8bkorZS29FXY%3d
(http://i.imgur.com/S4YZoFG.png)
(http://i.imgur.com/agO7wUg.png)
For this first version of the board, the holes for 24 gauge were perfect. Holes for 16 gauge were alright, a little tight. The vias on the drain pad were too large, too many and were sucking up the solder. The exposed copper for the drain on the back of the board cold be covered with solder resist. I've made a revision to the pcb to address those slight issues https://oshpark.com/profiles/david4500
I assume you are referring to the boards in my possession now? How would I cover it?
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Another nice board David. Man, if you would have just did that one for the 7157 p-chn you would have saved me a couple of weeks and a bunch of headaches.
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I assume you are referring to the boards in my possession now? How would I cover it?
Just pointing out somethings that could be refined & improved upon on the first version. Functionally they should be just fine. You'll be (hopefully) insulating the whole board fully anyways after soldering and connecting the wires. Heat shrink, epoxy, hot glue, whatever.
Another nice board David. Man, if you would have just did that one for the 7157 p-chn you would have saved me a couple of weeks and a bunch of headaches.
Thanks. Seems like the nfets and usually superior so I haven't even thought about messing with those really. I'd love to see your board. I'm sure your hard work really paid off.
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In some cases I think it would just be easier to use the p-chn. Don't hold your breath, Im still learning all this and it will take a while. Knowing what you want and how to turn it into a board are totally different things. Mabye not to you guys and gals but to me learning the software and knowing what to put where and how to isn't easy. Its ok though. I will learn it and not bug you guys.
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In some cases I think it would just be easier to use the p-chn. Don't hold your breath, Im still learning all this and it will take a while. Knowing what you want and how to turn it into a board are totally different things. Mabye not to you guys and gals but to me learning the software and knowing what to put where and how to isn't easy. Its ok though. I will learn it and not bug you guys.
p channel is good when you are using the body of the mod as the neg part of the circ :popcorn: :yes" :beer-toast:
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Just pointing out somethings that could be refined & improved upon on the first version. Functionally they should be just fine. You'll be (hopefully) insulating the whole board fully anyways after soldering and connecting the wires. Heat shrink, epoxy, hot glue, whatever.
Thanks. Seems like the nfets and usually superior so I haven't even thought about messing with those really. I'd love to see your board. I'm sure your hard work really paid off.
sweet will insulate as norm when there is a chance of shorts :thankyou: :yes" ;cheers;
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I found my diagram for this one: NCP300HSN30T1G, Does this one wire the same: TPS3700DDCR. As you may have noticed Im not an engineer and I know you guys get tired of answering dumb questions but I at least want to learn
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Glad this thread is still alive and kicking :D and so many great things have been updated in it.
fsors you old dog, how you doing?
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Hey David4500 I did order a few of your boards, my hope is they fit better and slimmer in this 3 x 18650 mod I made, the 3034's are tight with that voltmeter in there :D
(http://i.imgur.com/hSFybei.jpg)
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Wow nice looking mod. I'd imagine they'll fit for you. Check out the dimensions listed on oshpark. I'm working on a dual mosfet board right now that will be even smaller.
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Glad this thread is still alive and kicking :D and so many great things have been updated in it.
fsors you old dog, how you doing?
Yes the old dog is still kicking and I'm well too :laughing2: How are you dz? :wave: Nice looking triple ya got there.
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https://oshpark.com/shared_projects/qV9Nc7Rm
(http://i.imgur.com/oiuatRr.png)
https://oshpark.com/shared_projects/Rjc2gpVf
(http://i.imgur.com/xqUj8ME.png)
Size comparison next to a TO-220 mosfet
(http://i.imgur.com/IkJsCrg.png)
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Still learning a lot here and have already started my own mod from info here as well as ecf. I am very interested in the Para board but correct me if I'm wrong but aren't the only features that are missing is a 200 ohm pot and a couple of fuses?
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Yes the old dog is still kicking and I'm well too :laughing2: How are you dz? :wave: Nice looking triple ya got there.
Good man, not really doing anything these days, thank gawd. I have been playing in CAD for sometime and the triple is one of my creations, I made it so that top plate can be switched out and you can do either mech like that, blank, DNA40 and OKR with a master on/off and pot, things get a little tight under there with the depth of the volt meter. Here are a few of my creations and always playing and putting more out https://www.shapeways.com/shops/xmods
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Wow nice looking mod. I'd imagine they'll fit for you. Check out the dimensions listed on oshpark. I'm working on a dual mosfet board right now that will be even smaller.
I think they will work perfect under there. I did have one question, I see SW +- is that just a standard slide switch for off on?
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Good man, not really doing anything these days, thank gawd. I have been playing in CAD for sometime and the triple is one of my creations, I made it so that top plate can be switched out and you can do either mech like that, blank, DNA40 and OKR with a master on/off and pot, things get a little tight under there with the depth of the volt meter. Here are a few of my creations and always playing and putting more out https://www.shapeways.com/shops/xmods
Nice 3D Printing! I really need a 3D Box for a sx350 chip that I have. I want one that's the size
of a GBox with a mount built in for the chip, an on off switch mounting bracket built in, a hole for the screen, holes for the 510 and switch mounting on top like in my mod posted above in this thread, the dual 18650 batt sled built in non removable, holes to drop in mags and no usb charge hole as I want the batteries to be removable. It would also be cool if I could have my logo on the box as well. :yes" Glad you are still creating as I love your work! :thumbsup:
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I think they will work perfect under there. I did have one question, I see SW +- is that just a standard slide switch for off on?
Correct.
I like to use these latching pushbuttons
http://www.digikey.com/product-detail/en/GPTS203211B/CW181-ND/3190590
http://www.digikey.com/product-detail/en/GPTS203212B/CW182-ND/3190592
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Still learning a lot here and have already started my own mod from info here as well as ecf. I am very interested in the Para board but correct me if I'm wrong but aren't the only features that are missing is a 200 ohm pot and a couple of fuses?
I have boards with fuses or you can add fuses externally.
If you'd like to add a pot, you'd need additional components to make a pwm circuit. I have a board for that also and there are several others on oshpark as well.
http://breaktru.com/smf/index.php/topic,1505.0.html
http://breaktru.com/smf/index.php/topic,1496.0.html
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Nice 3D Printing! I really need a 3D Box for a sx350 chip that I have. I want one that's the size
of a GBox with a mount built in for the chip, an on off switch mounting bracket built in, a hole for the screen, holes for the 510 and switch mounting on top like in my mod posted above in this thread, the dual 18650 batt sled built in non removable, holes to drop in mags and no usb charge hole as I want the batteries to be removable. It would also be cool if I could have my logo on the box as well. :yes" Glad you are still creating as I love your work! :thumbsup:
DZ....You still here buddy? :wave:
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Indeed I am, daughter had surgery the other day so its been a lot of babying her lol
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Nice 3D Printing! I really need a 3D Box for a sx350 chip that I have. I want one that's the size
of a GBox with a mount built in for the chip, an on off switch mounting bracket built in, a hole for the screen, holes for the 510 and switch mounting on top like in my mod posted above in this thread, the dual 18650 batt sled built in non removable, holes to drop in mags and no usb charge hole as I want the batteries to be removable. It would also be cool if I could have my logo on the box as well. :yes" Glad you are still creating as I love your work! :thumbsup:
I can try but the dang thing on the back of the chip (brain farting atm so cant remember what its called) is huge, I have seen some cut the silicone from the screen and lay the board flat on top of the battery sleds to make that work, sadly I think everything will be close to a b size :(
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@david4500 what I am looking for in a board would be something I can go from parallel to series in and use say the SX mini chip that can be ran in series or parallel. So the question is can your series to parallel board you have up do that or is it over kill? So in other words just a switcher from one to the other but built for the job and not using these underrated rocker switches I see so many using .
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That board is an unregulated voltage mosfet mod that can be switched from parallel to series. It's wasn't meant to be a stand alone board just to switch the battery configuration. I followed a schematic which was posted on BoxModders facebook group (https://www.facebook.com/groups/boxmodders/625920007520019/?comment_id=626301614148525&offset=250&total_comments=295)
When I posted the board on BoxModders (https://www.facebook.com/groups/boxmodders/permalink/681090085336344/) there was one guy who was highly skeptical of the circuit. You may want to read through the posts there.
Take a look at the schematic... You might be able to make the board work for your intent. Instead of a momentary push button (fire switch) you could wire in an on-off instead. Only switch the orientation of the batteries with that switch in the off position. Don't connect anything to the voltmeter pads. The 510+ connection on the board, you could connect that to positive battery wire on the sx board. The 510- connection, connect that to the negative battery connection on the board.
As stated on the Oshpark page, that board is currently untested. According to the creator of the schematic, he has breadboarded the circuit and it functioned. I have the pcb and parts ordered and will find out for myself soon. If everything looks like it checks out to you, give the board a try if you like. I can't say with any certainty that the board works for it's intended purpose, or for what you have in mind.
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I can try but the dang thing on the back of the chip (brain farting atm so cant remember what its called) is huge, I have seen some cut the silicone from the screen and lay the board flat on top of the battery sleds to make that work, sadly I think everything will be close to a b size :(
Oh Bummer :( I think the part you are thinking of that is big is the Inductor.
(http://img.fazendomedia.com/nimg/b0/50/64ad92e2baf7fe9033330b963d33-600x600-0/wire_wound_chip_common_mode_choke_coil_inductor_for_computer_flatting_machine.jpg)
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The good news is my other parts to go on the boards came in! :thumbsup: :yes" :thumbsup:
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There you go fsors :D thats what its called lol
david4500 I do have the board on order already, the question now is, if left in the on position will it drain battery even if not in use. Nonetheless I will test both mech and SX functions when all parts arrive :D
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There will be some idle drain but it should be minimal.
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The triple fet board with no fuses
(http://i.imgur.com/GR1gobk.jpg)
(http://i.imgur.com/YqzN4cb.png)
(http://i.imgur.com/b7RACbe.png)
(http://i.imgur.com/X53HyHo.png)
(http://i.imgur.com/Ikq8CJ1.png)
(http://i.imgur.com/3aqADb3.png)
(http://i.imgur.com/WegPjZU.png)
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Congrats David :rockin smiley: Nice work
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Awesome Work David!!! :thumbsup: In my favorite GBox Too! :thumbsup:
;cheers;
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Thanks fellas!
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Loooks good David freaked_out:
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David, Where do you get the positive/negative stickers? They look cool and I would like to get some. :thankyou:
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http://breaktru.com/smf/index.php/topic,1344.msg16503.html#msg16503
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http://breaktru.com/smf/index.php/topic,1344.msg16503.html#msg16503
Wow Thanks So Much David You Rock! What do you print them on? Paper? Stickers? Card Stock?
:thankyou: :yes" :thankyou:
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The battery labels are great David. I've used them when you first posted them back in August 2014 :thumbsup:
I print mine on the portion of my DVD labels I don't use as shown on the attached............
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Nice! Glad people are using them.
Sucks when I see shitty mods on facebook or ebay with them... or vape shops selling the stickers for $5... oh well.
I took the files for the 4x6 prints and had them printed online on walmart's site. When I did it, they had a deal for your first prints. On matte photo paper, I think I got 50 for $2. I just cut them out and use a bit of epoxy. Stickers would be nice but likely more expensive.
Here's an 8.5 x 11 print also: https://www.dropbox.com/s/c6qvkynzd8b7of0/keystone%20labels%208.5%20x%2011%20print.png?dl=0
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Nice! Glad people are using them.
Sucks when I see shitty mods on facebook or ebay with them... or vape shops selling the stickers for $5... oh well.
I took the files for the 4x6 prints and had them printed online on walmart's site. When I did it, they had a deal for your first prints. On matte photo paper, I think I got 50 for $2. I just cut them out and use a bit of epoxy. Stickers would be nice but likely more expensive.
Here's an 8.5 x 11 print also: https://www.dropbox.com/s/c6qvkynzd8b7of0/keystone%20labels%208.5%20x%2011%20print.png?dl=0
Awesome David I am going to try that. Love the look! :thumbsup: :thankyou: :thumbsup:
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New member here.... I love this thread.
I'm so inspired by these projects!
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New member here.... I love this thread.
I'm so inspired by these projects!
Welcome aboard :-)
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For the nfet, the rds on is too high. You'll want around 2 milliohms. Vgs th is also slightly high, 4.5v. You want it to be less than 2.5-3v. If for any the smd pcbs, of the packages shown in the data sheet they are all too large.
I think Craig has posted some well suited pfets in the past if you look through his posts.
Got the quad board today:
(http://i.imgur.com/PtI31GK.png)
When soldering the drain tabs on the back, I didn't realize the solder was flowing though the vias to the other side.
(http://i.imgur.com/trxLZMe.jpg)
(http://i.imgur.com/8UyxwOj.jpg)
(http://i.imgur.com/2ZUG7Ea.jpg)
Those look awesome.
Can you give me a little more insight into the charge pump used (ADM660ARZ) on the "GD" tri/quad boards when compared to the TriParaMos 1.1?
Looks like both designs use the same mosfet (PSMN1R1-25YLC,115)...
Does the charge pump essentially lower the resistance though the mosfet, what's the idea behind the boards with and without it? (just trying to understand the design side)
Just curious but how much current have you tried passing through those things? Does the PCB generate any current limitations when compared to a TO-220 package size mosfet?
I was going to start my first project using the TO-220 sized package but I might abandon that all together since the PCB based stuff has really peaked my interest. You have so many boards and very interesting designs... not sure which ones I want to start with and play / test, but I am thinking the fused TriParaMos 1.1 is a good way to start. I don't do much surface mount work, mostly though hole stuff with my Arduino... should be interesting / challenging.
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A charge pump is a type of DC-DC converter that uses capacitance instead of inductance to control output voltage. They are limited in output power compared to an inductive converter because of the difference between an inductor and a capacitor. To try to use terms simple as possible, it's the difference between current flowing through a wire coil and charge building up on a set of plates. Current flowing through a wire coil is going to be much less limited in terms of power. The advantage is charge pumps are simple devices and easy to employ.
The charge pump simply boosts voltage so the MOSFET can be driven with a higher voltage than what's available from the battery. This puts the MOSFET in a lower resistance on-state and removes the requirement to use MOSFETs with extra low gate-source threshold. It really frees up the range of MOSFETs that can be used, but also adds more parts. Kind of a 6 of one half dozen of the other situation.
For any current path the limitation is going to be heat. If the current paths on PCB heat up to much that can be a problem as much as MOSFETs overheating themselves. The current paths he's using on the PCB are pretty ample so I imagine the MOSFET would overheat before the PCB traces would. Can't say for sure without torture testing it, but the current tolerances are so high it would not be easy to build a test rig for that, and who wants to burn perfectly good parts anyway.
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Kind of a 6 of one half dozen of the other situation.
and who wants to burn perfectly good parts anyway.
Talking my lingo Craig ;bow; and I might be able to open the mouser box of goodies this weekend who knows? scared: might need your :help:
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A charge pump is a type of DC-DC converter that uses capacitance instead of inductance to control output voltage. They are limited in output power compared to an inductive converter because of the difference between an inductor and a capacitor. To try to use terms simple as possible, it's the difference between current flowing through a wire coil and charge building up on a set of plates. Current flowing through a wire coil is going to be much less limited in terms of power. The advantage is charge pumps are simple devices and easy to employ.
The charge pump simply boosts voltage so the MOSFET can be driven with a higher voltage than what's available from the battery. This puts the MOSFET in a lower resistance on-state and removes the requirement to use MOSFETs with extra low gate-source threshold. It really frees up the range of MOSFETs that can be used, but also adds more parts. Kind of a 6 of one half dozen of the other situation.
For any current path the limitation is going to be heat. If the current paths on PCB heat up to much that can be a problem as much as MOSFETs overheating themselves. The current paths he's using on the PCB are pretty ample so I imagine the MOSFET would overheat before the PCB traces would. Can't say for sure without torture testing it, but the current tolerances are so high it would not be easy to build a test rig for that, and who wants to burn perfectly good parts anyway.
Thanks for taking the time to explain that.
I can see how it can be a benefit, or a necessity depending on which MOSFET is used, and I can see how it opens doors to other options which have a higher Rds On.
I guess my real question was in regards to the parts lists between the two projects listed under the OSH Park for David4500. I’m still learning here, so please excuse me if this is an elementary question, but two boards use the same (PSMN1R1-25YLC,115) MOSFET, one with the charge pump and one without. At least that’s what he selection in both the parts list/project carts on mouser. I understand I can use whatever I want within the same package size, but I just want to compare the two boards using the same MOSFET.
http://www.mouser.com/Search/ProductDetail.aspx?R=PSMN1R1-25YLC%2c115virtualkey66800000virtualkey771-PSMN1R125YLC115
The PSMN1R1-25YLC,115 shows an Rds On of 4.5v, does that mean when using a single cell that the MOSFET is in an active state and its acting as a variable resistor?
Based on the spec sheet chart Figure 7, it looks like the fet is right on the curve? So as the charge drops low, or if there is a great deal of voltage drop across the coil, the fet resistance will shoot up to an unsafe zone?
Am I reading the spec sheet correctly?
If not using a charge pump, you basically want as low as a resistance as possible for drain-source on-state resistance correct? So if one fet is 1.5mOhms and the other is 2.0mOhms at the same voltage, than the lower resistance 1.5mOhms selection would be better?
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For any MOSFET used as a switch you want the on-state to be in the flat part of the curve. As the consideration is "gate-source voltage versus on-state resistance" the gate-source threshold and on-state resistance stated in the data sheet determine the shape of the curve. You always want an on-state resistance as low as possible and you always want the applied gate-source voltage to put the transistor in the flat part of the curve.
You may wonder why MOSFETs vary so much in these specifications. There is a reason for it. There are trade-offs with respect to the speed and cost of a MOSFET. Some applications may require a fast switch and the trade-off there comes in on-state resistance. For some applications on-state resistance is not as important. It becomes of great importance when dealing with higher currents. Some applications may require higher voltage tolerance and the trade-off there comes in higher gate-source threshold.
There's also the advancement of tech. Transistors improve over time getting faster with lower on-state resistance. Parts become more available at wider ends of the spectrum such as transistors with very low gate-source threshold. The through-hole parts are pretty much obsolete in terms of new parts which don't come in through-hole packages. Though through-hole parts are handy for free wiring stuff, they are limited in performance.
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(http://i1250.photobucket.com/albums/hh529/fsors/VG%20BOX/003_zpsbbcxkcq8.jpg) (http://s1250.photobucket.com/user/fsors/media/VG%20BOX/003_zpsbbcxkcq8.jpg.html)
(http://i1250.photobucket.com/albums/hh529/fsors/VG%20BOX/002_zpssebmcpeg.jpg) (http://s1250.photobucket.com/user/fsors/media/VG%20BOX/002_zpssebmcpeg.jpg.html)
(http://i1250.photobucket.com/albums/hh529/fsors/VG%20BOX/001_zpsqerjkde5.jpg) (http://s1250.photobucket.com/user/fsors/media/VG%20BOX/001_zpsqerjkde5.jpg.html)
Just want to say Thanks to David for Great Markers! :thankyou: :yes" :beer-toast:
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Looks good! Which mosfet did you decide on?
Got some new boards assembled:
(http://i.imgur.com/GIX60de.png)
(http://i.imgur.com/ec9I0xy.png)
https://www.youtube.com/watch?v=L8r2rlZ2G8Y
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Love those boards David, now I just wish I could get it to work right. Iv been thru two of then and thay seem to get really HOT. here's some pic, if you spot anything, let me know.
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Hmm... what resistance coil were you firing? Is it the v1.3 version of the board? Any boards earlier had errors and won't function properly.
Looks like you may have not have used flux while soldering. I would recommend that to ensure proper flow and resulting solder joints. I used MG Chemicals 8341 paste flux.
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Ah, no wonder...I got the v2 board befor the added resister for series.... oh, and a .5 ohm coil build.
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I have the radio shack brand, but I did use for each joint, just not alot of it.so you seen the version 2 board is not functional?
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Ok... on that board, it still should function ok, it's just that a pull down resistor was recommended to be added to the series link mosfet to discharge to gate while in series and idle. Don't think that's the cause of the heat issue.
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Can I ad a resister to the circuit on the series mosfet? Like a thru hole one?
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With a 0.5 ohm coil, the mosfets shouldn't be dissipating very much heat.
8.4v with a 0.5 ohm coil would be 16.8 ohms.
http://www.wolframalpha.com/input/?i=8.4%2F0.5%3DCurrent (http://www.wolframalpha.com/input/?i=8.4%2F0.5%3DCurrent)
For single mosfet with an RDS ON of .001 ohms and seeing current of 16.8 ohms, it only 0.28 ohms
http://www.wolframalpha.com/input/?i=Power%3D%2816.8^2%29*.001 (http://www.wolframalpha.com/input/?i=Power%3D%2816.8^2%29*.001)
Here is a screenshot of the most recent board in Diptrace:
(http://i.imgur.com/TEhF7vn.png)
One end of the resistor is connected to a trace leading to the Bat2- pad. The other end is connected to a trace leading to the series link mosfet gate by why of a via (red highlighted hole on left). Along that same trace, the via on the right connects to the lower middle pad of the slide switch. The vias aren't pads... but maybe you could manage to solder a through hole resistor to one of them and the Bat2- pad.
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Thanks david, I'll try that in the morning.
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Hi everyone, this is my first post here in this forum, but have been lurking a long time. Some very interesting stuff discussed here! I have been thinking of drawing up a simple mosfet board for a wooden mod I have, and have had various pcb's made for guitar effects pedals (very low current devices) at a hobby level in the past. So thought I would try a pcb for my mod, but this high current stuff seems to be a totally different ball game!
I have a question regarding the current carrying capacity of copper traces. According to online calculators, if I use a trace from say the drain of a PSMN1R1-25YL and its 200 mil wide and say 100mil long (to get to the atty negative pad) and I'm using 1 oz copper, that trace will only handle 13.4A for a 30 degrees C temp rise. I used this calc (but the several ones I used to cross-check each other were similar)
http://circuitcalculator.com/wordpress/2006/01/31/pcb-trace-width-calculator/
Yet the resistance for the track is given as 0.2 milliohms. Given such low resistance, how can it only be rated to take 13.4A? And with a 30 degree C (86F) temperature increase? Does the intermittent use factor help us, given that we can't vape continually?
You can see the resistance is negligible, am I missing something? 2 oz copper is considerably more expensive :(
I have another question regarding the use of the MHP-TA15-9-77 as a resettable fuse. It looks to me that its actually a temperature cut-off device designed to be installed in a lipo battery pack, so it can sense temperature and cut the power if the temp reaches 77 degrees C. Am I missing something here too?
Any input appreciated guys.
BTW for those that just can't wrap their head around the pcb layout softwares available (like me), I eventually found a quick and easy one that got me going. You don't need a schematic to make it work, you can just draw the pcb, and easy to learn. Its called Sprint Layout and I use version 5.0, I don't like the later one. Its not free, it was about $50 when I got it years ago, but they have a free trial version that will let you see if you like it or not.
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I have another question regarding the use of the MHP-TA15-9-77 as a resettable fuse. It looks to me that its actually a temperature cut-off device designed to be installed in a lipo battery pack, so it can sense temperature and cut the power if the temp reaches 77 degrees C. Am I missing something here too?
Any input appreciated guys.
I just took a look at the spec sheet and you seem to be on point...
http://www.mouser.com/ds/2/418/NG_DS_DS28403_A-109895.pdf
I am a bit new at this too but the spec sheet would lead me to believe the same thing. The vendor website does show a Hold/Trip current values for amperage but its design application for LiPoly packs does make a lot of sense too.
http://www.mouser.com/ProductDetail/TE-Connectivity-Raychem/MHP-TA15-9-77/?qs=1vPsWa5aeatw7frgf8Ap9Q%3D%3D
I am going to order these anyways and test them out… I’ll put a current clamp meter which can record peak valves in line and create an intentional short just to see what it does.
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Exceeding the current hold of 15 amps, the temp of the fuse will rise along with the resistance of the fuse. If it reaches the thermal cutoff, the fuses will fully trip and cutoff the flow of current. Removing the over current, the fuse will cool off and return to its normal state.
On the data sheet, check out page 2, under "design concept" which detail how the fuses function.
This data sheet from TE will have charts showing the relationship between current and temp with the different value thermal fuses: http://www.te.com/content/dam/te/global/english/products/Circuit-Protection/knowledge-center/documents/mhp-devices.pdf
Using two of those 15 amp fuses in parallel, with a mosfet, and installed in a mod, I've intentionally shorted the 510 with a piece of metal. The fuses functioned exactly as them should. The current flow was stop quite quickly. Once the fault was removed, the fuses were slightly more resistive but settled back to normal once cooling off.
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Thanks David,
It appears that it functions for our purpose then, maybe the bimetal strip heats up anyway with the high current and breaks the circuit.
From this datasheet, (http://www.te.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Data+Sheet%7FDS28403%7FA%7Fpdf%7FEnglish%7FENG_DS_DS28403_A.pdf%7FRF3035-000) it clearly states "During an abnormal event, the device reacts to the rise in cell temperature causing the bimetal contact to open at the specified temperature". Hence the reason for my question. It looks like a good alternative to polyfuses and one-shot fuses, and they are cheap, I'll get a couple and test them. I might get a MHP-TA15-9-72 to compare to the MHP-TA15-9-77 as well.
Are you using 1 oz copper on your boards David, or 2 oz? Have you ever felt the large copper areas at the drains and sources getting warm during your testing?
Actually I just realized I have some 1 oz copper-clad board here somewhere, maybe I should cut a small piece off, solder a wire on each end and run some current through it, to see if my intended track width and length will handle the intended current.
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1oz on Oshpark. I'd have to get them somewhere else for 2oz. I just tin the exposed traces or copper fills and it's worked out.
None of the boards or mosfets have been excessively warm after firing. One with 3 parallel mosfets I fired a 0.2 ohm coil for 4 minutes straight. There was a slight temp increase on the board, that was it. No where near hot or burning. I'll get an infrared temperature gun so I can get some actual temp readings.
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Sounds like the 1 oz copper has it all running sweet if it only gets a bit warm after 4 mins firing 0.2 ohms. Very nice.
On second thoughts, you are spreading the power between 3 mosfets, each is only taking 1/3 the power, and there would be more copper for the three compared to just one. Also, I stumbled across a PSMN1Rsomething datasheet suggesting 2 oz copper, but that is for a single mosfet at max power with a 1" square of copper on the pcb to act as a heatsink. I'm gonna have to be careful because I only want to use one mosfet, due to not much room in there. Thanks for your comments, very much appreciated.
(http://i.imgur.com/agO7wUg.png)
Nice board you did there.
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The power dissipation for 3 in parallel is dramatically lower than for a single.
Say the current draw is 30 amps and the RDS ON of the mosfet is 0.0015 ohms (1.5 millohms)
Current^2 * Resistance = Power
30^2 * 0.0015 = 1.35 watts
http://www.wolframalpha.com/input/?i=30^2*0.0015%3DPower (http://www.wolframalpha.com/input/?i=30^2*0.0015%3DPower)
With the multiple mosfets in parallel, the current and RDS ON would be fractionally split. 1/3 in this example, so 10 amps and 0.0005 ohms.
10^2 * 0.0005 = 0.05 watts per mosfet
http://www.wolframalpha.com/input/?i=10^2*0.0005%3DPower (http://www.wolframalpha.com/input/?i=10^2*0.0005%3DPower)
Enormous difference right...? 0.15w vs 1.35w, 9 times lower
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Looks good! Which mosfet did you decide on?
Got some new boards assembled:
(http://i.imgur.com/GIX60de.png)
(http://i.imgur.com/ec9I0xy.png)
https://www.youtube.com/watch?v=L8r2rlZ2G8Y
Hey Looks good! For the box posted above I use the 3034 but the ones I am about to make will use the same as yours with the boards mosfets x 3 and fuses. Thanks for the Markers too they are fantastic! :thankyou: ;hubba; :wave:
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(http://i.imgur.com/QxDdrU0.png)
(http://i.imgur.com/IM3aMfw.png)
(http://i.imgur.com/PZxb241.png)
(http://i.imgur.com/eu6ny7m.png)
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David, is that a micro on this board? If it is, what is it doing? Intriguing...I am dabbling with an Atmel micro much the same size.
(http://i.imgur.com/8UyxwOj.jpg)
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That's the Quad Mosfet board...
I think the part you are referring to is the ADM660ARZ charge pump which doubles the voltage to the gate of the mosfet.
http://www.mouser.com/ProductDetail/Analog-Devices/ADM660ARZ/?qs=BpaRKvA4VqGx3CPq2l2ChQ%3D%3D
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David, did you pull the board with the fuses?
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David, did you pull the board with the fuses?
If a link here is dead, the board was revised and the old version was deleted.
This should be what you're looking for: https://oshpark.com/shared_projects/o7NrTQMe
Check out the project page for the others: https://oshpark.com/profiles/david4500
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Thanks. Im giving up learning the software for now.
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Were you trying to make a board with a p-channel and voltage detector?
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Originally yes. The board you have is perfect for the box Im doing now. Neg. is fine for this one. Plus I like the fuses.
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Were you trying to make a board with a p-channel and voltage detector?
Schematic only at the moment.
Thanks Craig for the part recommendations throughout this thread.
Pfets: SI7157DP-T1-GE3
Voltage Detector: TPS3700
Low voltage cutoff ~3v
It's quite possible I've fucked something up, but this is what I have so far.
(http://i.imgur.com/7SutUfi.png)
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You really didn't have to work on this. It is appreciated though. I may just have to contract you with my ideas. Haha.
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David, I have a quick question. On all of your boards with solder points for the vm, How much space saving could be accomplished if it were just combined with atomizer + & - ? I know it probably would be very little if at all but just throwing that out there.
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The voltmeter pads are usually put in an area where there just so happens to be space. Space isn't made for them. So removing them, there would just be empty space.
Thanks for that thought though. I'll certainly consider that on future boards if space is at a minimum.
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My Mouser order came in (easy to run up a tab over there) yesterday and I couldn't wait to get the iron fired up... Just sharing.
My first board (thanks David4500) for sharing your project.
My only concern is the tinning of the traces for the MOSFETs... not sure if I need to lay on some more solder to make it a bit thicker... any suggestions? (see Picture 2)
I also whipped up a test bed with a 510 connection using some banana jacks... it also doubles as a ohm meter breakout adapter for a DMM. Added a little push button switch to it as well to make REL/Zeroing out the lead resistance easier.
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Nice! Looks like you've got plenty of solder on the traces. I think I fired that board for 4 minutes continuous and it barely even rose in temperature.
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I ordered enough of that board to keep me busy for a while.
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Nice! Looks like you've got plenty of solder on the traces. I think I fired that board for 4 minutes continuous and it barely even rose in temperature.
Good to know... I wanted to test this extensively but I started thinking about each individual MOSFET... is there a way to test each one to make sure none of them were damaged from soldering/heat/or ESD?
I am very excited to get this thing into a box... it will be my FIRST DIY mod.
I was thinking of going with 3 x 18650 and hopefully cram it all into a 1590B, but not sure how I should do that since each fuse on this board was supposed to have its own dedicated connection to the positive on each cell. I was thinking of just making the bridge/parallel connection at the battery sled level and then both fuses would give me a combined 30A hold / 60A trip for the entire bank of batteries.
I might be better off just using 2 x 18650 in a 1590G.
Another thing I noticed was my DMM picking up 0.0407v @ the 510 connection at rest... im guessing there is some voltage leakage / idle drain?
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Emex gr8 job bu I think your resistor is 1k not 10k 1002 is usually 1k 1003 is 10k may be wrong but on my 4 digit smd's thats how it is..
If so it wouldn't possibly shut the mosfets down and you get the leaks?
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Im ordering your 555 board David as soon as ya say its golden which I may have missed the post, but if its golden ya-- gonna poss. put it in a aa 2s box mod, it will fit perfectly per specs and look awesome.. :thumbsup:
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Another thing I noticed was my DMM picking up 0.0407v @ the 510 connection at rest... im guessing there is some voltage leakage / idle drain?
What's the voltage on the gates at rest?
Emex gr8 job bu I think your resistor is 1k not 10k 1002 is usually 1k 1003 is 10k may be wrong but on my 4 digit smd's thats how it is..
I'm pretty sure 1002 is 100 with 2 extra zeros = 10k
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What's the voltage on the gates at rest?
I'm pretty sure 1002 is 100 with 2 extra zeros = 10k
It is,
:thumbsup:
I was confused on the 3 digit to 4 digit smd resistor values but, "I'm pretty sure 1002 is 100 with 2 extra zeros = 10k;" made logic in my brain so off the top of memory it will be correct.. ... :laughing:
http://www.hobby-hour.com/electronics/smdcalc.php
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What's the voltage on the gates at rest?
Battery / Input Voltage = 4.17v
Gate @ Rest = 4.17v (measured from battery Positive to Gate)
510 @ Rest = 0.0488v (with minor fluctuations)
510 @ fire (no atty / load) = 4.17v
Is that normal?
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Battery / Input Voltage = 4.17v
Gate @ Rest = 4.17v (measured from battery Positive to Gate)
510 @ Rest = 0.0488v (with minor fluctuations)
510 @ fire (no atty / load) = 4.17v
Is that normal?
I don't think so, otherwise you would be pulling near 50mA of current from the battery all the time with a 1 ohm coil. I have one mod with a mosfet in it and it doesn't have any voltage at all when off, its 0.000V across the coil. Your circuit board looks like a clean build too. No idea on how to check each individual mosfet at this stage. If I think of something I'll let you know.
On another point, these mosfet-switched devices have no reverse-polarity protection. If the battery is put in backwards it appears the body diode conducts and fires the atty, with the 0.7V approx diode drop. Is there anything else to be aware of? Is there an easy reverse-polarity protection circuit for a mosfet?
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Im ordering your 555 board David as soon as ya say its golden which I may have missed the post, but if its golden ya-- gonna poss. put it in a aa 2s box mod, it will fit perfectly per specs and look awesome.. :thumbsup:
I had some issues on the first version.
Mainly the pfet pads for gate and source were reverse of what they should have been. Diodes were in the wrong direction causing the duty cycle to increase when turning counterclockwise instead of clockwise.
Fixed those issues, most recent update: https://oshpark.com/shared_projects/4JRetcg2
Can't say 100% everything is perfect at the moment, although it should be. Should be getting the boards from Oshpark tomorrow and will test to confirm.
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510 @ Rest = 0.0488v (with minor fluctuations)
Should be from drain current leakage. Pretty sure I've had a similar reading on every mosfet mod I've made.
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Man... cramming the fused TriParaMos into a 1590G is proving to be a challenge...
I feel like I should just use the 1590B and call it a day.
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Man... cramming the fused TriParaMos into a 1590G is proving to be a challenge...
I feel like I should just use the 1590B and call it a day.
Not sure of the exact issue but if it's clearance along side the battery holder, try one of the 3d printed dual 18650 holders. Or if using a keystone or mpd holder, modify to minimal width about 37mm.
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I tested the MHP-TA15-9-77 today, it looks really good, much to my surprise.
It will hold 15A no worries.
At 22A goes open in around 7 secs.
28A 5 secs.
43A maybe 1 sec.
47A maybe half a second if that.
It resets pretty quick and the resistance at 10A flow was measured around 2.25 milliohms, (22.5mV AC on Fluke187), at 5.5A it was about 1.9 milliohms (10.5mV AC).
The testing was done with a high current transformer from a circuit breaker test set, fed with a variac, so AC, but I think the results should be OK and in the ballpark.
So now David, you can say "I told you so" :)
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Schematic only at the moment.
Thanks Craig for the part recommendations throughout this thread.
Pfets: SI7157DP-T1-GE3
Voltage Detector: TPS3700
Low voltage cutoff ~3v
It's quite possible I've fucked something up, but this is what I have so far.
(http://i.imgur.com/7SutUfi.png)
Assembled (used a 30K instead of a 15K for the pullup res)
(http://i.imgur.com/g97AWvx.png)
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Looks good. I really like those PMOS from Vishay, pretty much my go to P-channel for switching power on and off. I've measured 2 mOhms with those at 3.7V, can't do much better than that (using voltage over current measurement). The TPS3700 is a great detector. I used it in my last project (non-ecig) and it works flawlessly, simple and easy to wire as well.
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Wicked cool David. Time to order some more boards.
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Thanks Craig. Really appreciate all of your help especially in this thread as well as the rest of the forum.
Thank you also dc. You considering making a similar board was what helped push me to make the board. Hope they work out well for you if you get some from Oshpark.
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Im sure this board will work as good as your others. Ive been using your board with the fuses on it. It has worked great. Perfect in a G-box with a printed sled
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(http://i.imgur.com/AV1nCHg.png)
(http://i.imgur.com/Osm3wnR.png)
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Hi guys,
I've been running several unregulated single 3.7v IMR (20-30AMP max discharge) cell BF mods for while now with a single PSMN1R2-25YLC, is there anything better recently released in the SMD descrete 5x5x1.1mm package?
I ask only because i plan to make a few mods for friends and although I have had zero issues running 0.6Ohm coils I want to know why I should run more than one, incidentally they will be protected with MHP-TA15-9-77 , 15amp resetables between the battery negative and the source on the mosfet so will be tripping at around 60Watts assuming a 0.26Ohm coil and 4v.
Just because I haven't had issues doesn't mean others wont when a few are in the wild. I have though as stated had ultra reliable performance from the PSMN1R2-25YLC and they seem very resilient to slightly longer than ideal soldering periods.
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I've got a board on eBay with a PSMN0R9-25 and 15K pulldown resistor already soldered on. It also has holes large enough for 14awg stranded wire for the Source/Drain high current lines and made with 2oz copper to reduce losses. I got reports of people using it at 0.08 ohms without it warming up at all.
qty 1 - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=261960134586
qty 5 with wire & heatshrink - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=252096055090
There are other listings including a qty 10.
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Very nice work DIYFL, thanks for sharing 8)
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Very nice Diyfl. I'm glad you and David4500 are doing those boards for the modders. I had one built a while back at oshpark but never got around to making it into a small package. Also if you're still around David, I have built and used 2 of your dualparamos minis and they are flawless.
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I'm sure David4500 will see it. He's the one that invited me here and we've been sharing ideas and possible designs.
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I'm getting back into playing with cads oft and diptrace and I wanna try to replicate your 2 boards but try to add in some form of modular design possibly adding pin header so you could kinda make it like a plug and play upgrade. Unregulated with plug n play pwm.
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The key requirements I had for my board was as small as possible and 14 awg stranded for the high current wiring, and then I managed to squeeze in space for a through hole resistor for people that want to light an LED while vaping without having yet another dangling part.
A side effect of a clean through hole design, those people really needing high performance can parallel the MOSFET's just by stacking them.
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Hey fellas! Yeah I still lurk around here from time to time... been a bit quiet lately... But anyways, TJ glad you like the boards. Making your own is much more satisfying, good luck.
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Where can i purchase your PWM PCB David4500 ?