Paging Craighb

[Visus]

This new ecig use an invert method of powering up to 20 watts in AC..  I found it to be so badarse but how the heck do they do it without frying your lips.  I looked all over for an inverter for a 3.7v lipo but could not find anything that would fit the small mod,  baller awesome design in very small form..

How do they do it...

If you have the time watch this video:

German engineered Pipeline Pro
It has menu functions up the wazoo, does everything you can imagine wanting control over vaping,  ramp ups,  led brightness, timeouts, etc etc...
Its Badarse.

[CraigHB]

I don't have time to look at the whole video right now, pretty long, but I jumped to the section where he scopes the output. 

If it was actually a DC-AC inverter it would have a symmetric waveform.  Inverters tend to require a good number of components that would be difficult to fit in the limited space availble in an e-cig.  It may be an "inverter like" design that that reduces the component count and results in a lot of positive overshoot.

It looks more like it's using an inverting buck-boost controller of some kind that produces a lot of overshoot on the positive side.  The waveform is unusual, but they may be taking some shortcuts with the design to minimize the footprint. 

Looks like they've simply eliminated the output caps.  Though normally an inverting buck-boost converter would not have that much positive overshoot, even without the output caps which simply smooth the output to DC.  You see a waveform like that when you scope a converter's output behind the caps.

The frequency is low for a traditional converter used in an e-cig.  An inverting buck-boost converter is actually a traditional converter, they're just not normally used for outputs over a Watt or two.  Converters in e-cigs normally run around 500kHz to minimize the amount of inductance required and thereby the size of the inductor.  That one is only running around 200kHz.  They're either using a lot of inductance or they're doing something unusual that results in a lower frequency.

Inverting buck-boost controllers are not that common.  They're used when negative voltages are required, but generally not for higher outputs like you need for an atomizer.  Evidently they found a controller that suits their purposes.  There's a lot of custom chips anymore that we just don't see elsewhere, they could have contracted a chip maker to build something custom to their own specs.

I've not actually seen a traditional power converter that produces a waveform like that so it's something they're doing out of the box.  In any case, anything that can deliver power to the atomizer can do the job, can be any kind of waveform you like.  You only have to provide an indication of RMS output to the user.  That makes the output waveform transparent, unless of course, you start hooking it up to test equipment.  You wouldn't be able to measure output on that with anything but a scope or a DMM capable of measuring DC+AC RMS signals.  Only high end DMMs can do that.

[Visus]

Thanks for the reply

Phil threwdown on the review and it was trial and error to get the waveform he had which he said probably isn't correct but perhaps close..
Whats uber strange about the output he could not use his lazybox he said the inductance was too high on the resistors and it would throw an error code.  He is ordering low inductance resistors specifically for designs of this nature.   

I owned a music studio for 6 years and from my music engineering the waveform looks like they used an effect processor with gate and compression threshold, its wave form looks similar on the board  when throwing some tuned effects on a vox-- made famous phil collins song "in the air tonight"  back then no digital effects, using a compressor. The new digital chips for verb effects are tiny.  Heckuva design I would betcha there's a link there with music tech..   Genius...

He needs that 50k scope Dave from eevblog just tore apart.  MY thoughts run it thru an audio input and look at it on an equalizer monitor and  its repeating, "all your bases belong us" or german made din dadada rfol...   

[CraigHB]

Mr. Busardo is self admitted not very knowledgeable about electronics, but I do have to hand it to him for providing scope data on his reviews.  He was the first to start doing that and it's super valuable info.  It's possible his waveform is mangled because he's using low quality probes, but not likely.  It looks like he's using a Rigol scope and those come with good test leads.  Other than that, waveforms don't lie, they can be offset incorrectly one way or the other, but that's about it. 

Based on what I see in that waveform, I'd say the mod is using a stripped down converter of some sort.  Since an atomizer is purely resistive and does not introduce reactive effects, there's no concern about any kind of non-DC waveform injected to create a power output.  This allows some nifty shortcuts if you're willing to take them (I wouldn't myself).

Assuming this is what the makers of this mod have done, then output would be highly sensitive to parasitic reactance (inductance or capacitance).  Atomizers don't have this electrical characteristic so it's not an issue for normal use (well they do, but it's very small and inconsequential). 

However, parasitic reactance could be an issue for test equipment that may introduce too much of it.  In his case, he may be able to mod his test equipment, but by doing that he may invalidate the measurements.  So I'd say best of luck there, but it's probably not going to be of any help. 

Like I said, the only way to accurately evaluate the output of a waveform like that is to use a scope or a high end DMM.  A frequency analyser can also do the job, but those tend to be cost prohibitive, at least a couple grand for a decent one.

[Visus]

wow
great info I really like tearing mods apart to see how they work
heck i tear everything down build it back up

Some of yall no cheat in school 

Busardo is a dbl e

My brother from another mother is a dbl e iit mit  for the feds
they have the coolest gear, brain no need to work at all

You are correct lol

Its the small size that is blowing me away.. Its the smallest of any "smart vv vw tube mod" and does a heckuva lot brain..    Yeah but smart phones, so I can see how,  but, just wow 
I really like the interface -- German cars are different too mercs use a vacuum to open door locks no rods a freakin $$$$ vacuum,  they think different.