0 Members and 23 Guests are viewing this topic.
Sounds like a case where you got hit with the parasitic effect of breadboarding. The feedback circuits can be sensitive to that. Good to hear you got it worked out though.I agree the data sheet is sketchy on that part. Knowing the function of the sense pads and that they are internally connected would have been nice information to have. For my own circuits, I'll often pass on parts that don't have a comprehensive data sheet. Big ding on that one.
Craig said he will sell you his for like 10 bucks in a deleted post but I was upset so he sold it to me for 15 lol...
I don't have an electronics background so I learn as I go and good datasheets help me a lot there.
What I'm torqued about though (with myself) is I never once considered it might be the breadboard causing issues and I should have as I've ran down that road before. I especially didn't realize the feedback loop would be affected by it. First time I've worked with Sense and a feedback loop.
I have a Fluke.Funny story with how I got it. A good forum friend sent it to me a few years back when I posted pics of testing something (can't recall what I was testing now) with my cheapie Radio Shack multimeter. Said a modder needs a good DMM and he felt sorry for me with using a Radio Shack one. lol.
I am very new to modding. I have only built a DNA 30 and an Altoids can PV from a vamo pcb. I ordered on of these chips and got it in today. Before I start on this I don’t know if I fully understand your wiring diagram Mamu. I see that there is a 20K Ohm resistor on connections 1 and 2. Do I need to connect these two areas? This will be my first undertaking with a chip like this so any advice would be very appreciated.
I've always experienced problems w/ breadboards so I usually solder most everything. If I'm testing part values that may need to be changed, I solder on alligator clips.
Am curious now if I tied Sense directly at the converter instead of directly at the load, but aint gonna mess with it anymore.
Thank you Mamu for taking the time to make a wiring diagram for this chip. It helps people like me learn a new skill. https://www.dropbox.com/s/bzdfp16y1qdxb58/2014-05-14%2019.46.56.jpghttps://www.dropbox.com/s/0h7w1weicimmr47/0514140024.jpghttps://www.dropbox.com/s/4in9zv57j8m4zb4/0514140033.jpghttps://www.dropbox.com/s/sxcgxjuk4invznl/2014-05-13%2022.12.45.jpg
For situations where noise or voltage spikes are involved, I can't recommend highly enough a decent oscilloscope. T-Equipment.net has a nice Rigol DSO (digital storage scope) for $329. If that's not do-able, even an old analog scope can cover you there and you can find decent ones on eBay for less than $100.]
and aslo have you tried this chip? http://in.mouser.com/ProductDetail/GE-Critical-Power/NSR040A0X43Z/?qs=sGAEpiMZZMt6Q9lZSPl3RZ%252b%252bVUVDyW2OaruvwtMC5Tg%3d
thank you so much manu for your reply..i just ordered 5 pcs of the chips..hehehe ive been waiting for the NSR020A0X43Z for a while..and im done.lol do you think you can push this chip to 6v?.and aslo have you tried this chip? http://in.mouser.com/ProductDetail/GE-Critical-Power/NSR040A0X43Z/?qs=sGAEpiMZZMt6Q9lZSPl3RZ%252b%252bVUVDyW2OaruvwtMC5Tg%3d
It would be at your option to push it to 6v. I usually stay within specs.I've not tried the 40A module, but I think someone on ECF posted about using it. I think 20A is way plenty for me.
Craig, how many channels do you suggest for our modding purposes?
I have a very limited modding budget. I've been looking at this DSO HERE, what are your thoughts on this one?
Thanks Craig! I appreciate your time, expertise, and most of all patience with a noobe! Just a few months ago I MIGHT have been able to pick a DSO out of a line up of parts, but I would not have been able to tell you what it did....LOL. Thank you VERY much!!
Mamu! You are wonderful for helping us out. I built my first mod today using this write up. Trying to stuff it all into a 1590g Hammond box is proving to challenging Lol. A couple questions though. Why are you adding caps to the in/out? The spec sheet says they are not required and when I was test firing mine today it seemed to work fine without them. Just don't want to leave them out if they are crucial pieces.Holy Vape @ 5.5 volts on a .45 ohm fogger v4!!!! As fantastic a wicking design the fogger v4 is, it never had a chance at keeping up with 70 watts Lol.
All models are tested and specified with external 188?F ceramic output capacitors and a 44 ?F external input capacitor. All capacitors are low ESR types. These capacitors are necessary to accommodate our test equipment and may not be required to achieve specified performance in your applications. However, Murata Power Solutions recommends installation of these capacitors.
I like to have at least an input cap on these converters to help buffer the shock/stress on the batts and module from frequent and repeated firing. I think it gives increased stability and longevity to both the batts and the converter. We fire these converters sometimes up to a hundred times a day each and every day.
Got the OKL2-T/20-W12 in yesterday and got it breadboarded this morning. So far, so good with testing (i.e., it's doing what it's suppose to ). Size comparison with the Naos Raptor 20A 120W board...Min output voltage (I'm using a 1K ohm POT + 1.43K ohm resister - for a lower min voltage (~3.0v), switch to a 1.5K ohm POT)...Max output voltage...Testing the P-FET for reverse polarity... good to go with protection...Wiring guide...External parts that I have breadboarded with the OKL (all bought at mouser.com unless otherwise indicated):20K ohm resistor (CMF5520K000FKEK)1.43K ohm resistor (RN60D1431FB14)2x 22uF input caps in parallel (C3225X5R1C226K250AA)4x 47uF 16v output caps in parallel (GRM32ER61C476ME15L)1K ohm POT (PT10MH01-102A2020) (use 1.5K ohm POT for min voltage at ~3v)2x 10A fuses in parallel (RGEF1000)P-FET (SUP75P03-07-E3)1S-6S voltage reader (ebay)3-pos slide switch (1103M2S3CQE2)
can someone explain how mamu decided 20k ohm
Was wondering if a 22k ohm would work instead of a 20k
The low voltage detector IC for UVLO is too teeny tiny for me to work with. I ordered 3 different ones and they are all too tiny I can't even mount them on a stripboard as the pins are too close together, so they require a proper PCB to mount on.
The low voltage detector IC for UVLO is too teeny tiny for me to work with. I ordered 3 different ones and they are all too tiny I can't even mount them on a stripboard as the pins are too close together, so they require a proper PCB to mount on. I'm doing the next best thing then and installing a low voltage indicator with the OKL2-T20.I'm using the LTC1440 to monitor batt voltage - it has an ultralow 4uA standby current.I wired it for a 6.2v low voltage indicator. If the batt's voltage is >6.2v, the red LED does not light. When the batt's voltage is at or less than 6.2v, the red LED lights telling me it's time to charge the batts. The red LED has a sharp 6.2v turn on - no tweens and no dimming. Here's a link to the datasheet: http://cds.linear.com/docs/en/datasheet/144012fd.pdfHere's the schematic...Here's what it looks like breadboarded... the voltage is set at 6.2V on my DC power supply, the red LED lights...Here's what it looks like with everything tucked under the IC...Here's the parts list... you could use 1% resistors if you choose, but I used 5% without issue (maybe I was lucky? )...
hi mamu just wondering why do you need this for? if probely stupid question but im to lazy to make calculation right now..so if your battry gets to lower than 6.2 how many volts left in your battery each?(single bat)
I know, Craig - I really should learn to do it. It would be great to have a tiny board and have all smt parts and then just run the wires. It's even easier since oshpark.com will make the PCB for you based on your design and the prices they charge aren't bad - just need to upload your design file and there ya go.lol Visus - I really did try to work with the voltage detector, but with pins 1,2,3 less than a half mm apart, it was too difficult. And there aren't any in a bigger size at the cutoff volts I need - lol I spent a few hours looking.And this is how tiny it is... don't drop one, you'll never find it
This is how imagined it should be wired:
It's even easier since oshpark.com will make the PCB for you based on your design and the prices they charge aren't bad - just need to upload your design file and there ya go.
The LTc sizing is how I imaged it in my head from doobe's drawing that is uber tiny and to think it cut volts loaded