Seriously! Even 2A requires pulling close to 5A from a 1.5V cell and gets worse with sag and voltage drop.
You’re project is a really good one and ambitious enough on its own. There’s been plenty of clamor for a programmable 1-3V input boost driver and some fringe work has been done but no concerted effort in terms of breaking down the existing PIC mcu versions and coming up with attiny footprint versions.
Very interesting. 
You’ll sell many times more than 200, plenty of people on here will want them and not just one each. Then you have all the trader’s as well, they’ll definitely want them.
Definitely want one, my XHP50 C8 only has 700mAh.
Yeah, I admit to being crazy. But then, a lot of the best inventions were ‘crazy’ for their time. Don’t let any of this crazy talk distract you (theomajigga) from what you’re already doing, though. 
Good!!!
I will keep this thread.
Well that is where I got the s 3.6mm number for trace width! On the 1oz that is typical of these little board fab companies its an 8mm trace width. 
just silly. This is probably why not a lot of high amp boards are made. I am going to work on a two board with pin header for an attiny. YAY!
An update to my latest rev: I got it in the mail, I am going to try and populate one, but I am nervous that there are VIAs that are too close to the GP, the good thing is that it will show itself right away, the bad thing is a hot/cold cycle I don’t know if these chips were designed to take…
Thanks theomajigga. What makes your PCB different from the FET [People are pushing 15-20 amps with these] & MTN Buck Drivers [can handle up to 5.5 amps]. Both 17mm layouts.
Those drivers are essentially direct drive, so not 6V. There aren’t step up FETs or many different controllers for that matter.
An idea I’ve been toying with is using my driver to boost to 6V and then putting a few 7185s together for a CC package. I need to research this a bit more, that would SURELY be a 2 piece board. The heat is going to be the killer at this point.
EDIT: I forgot to preface this by saying that this is exciting work so far. Thanks for showing it off!
Wait, you showed a tailcap draw of 4.2A earlier. I don’t think we’re looking at 97 efficiency here… more like 65% efficiency, right?
Here are my assumptions:
Output = 1.5A @ 6.4v = 9.6W
Input = 4.2A @ 3.5v = 14.7W~
Efficiency = 9.6W / 14.7W = 0.65 = 65%
I take it that this design is CV then?
IIRC that’s the direction Lamdba went with the boost driver for VaraPower lights. It was a fairly different situation, but my understanding was that the driver worked well and provided a lot of power. If you are interested I think that the best information on that driver is available over here, starting with post #20.
It helps me! Thanks for posting the link, but don’t forget to include the post # since BLF’s forum software doesn’t behave nicely with direct links depending on your “view” settings. FWIW that’s Post #1616 over there.
is this the driver that fits the TF F13 ?
or is that the same concept but different diameter ?
This is excellent! Just what I have been looking for.
Excellent work!
Very interesting.
Such a driver would be most handy. MT-G2 is such a nice LED, but needing 2 x Li-ion to run it makes it less useful for anything EDC sized.
Hmmm MIA for over 2 weeks? Maybe he got erased for such a highly advanced driver, mysteriously vanished? Now you see him….now you don’t ?
Well, hop'n he's bizy working on those heat issues. From the OP, he's got a ways to go, but definitely on the right track. Hoping this works out.
I have to admit after seeing claimed 97% efficiency every other posts just looked like a blur. I’ll have to play skeptics too, that’s just way beyond what I can believe.
But if the OP is reading and really working on this, don’t let our skepticism get to you, keep up the good work.
I had offered to send him some LED parts for testing, but never heard back after initial contact. Hmm.
KD one is interesting, but it's big, specs are vague, and thinking there's some gotcha's with battery and LED configurations. It may be 3V-9V input and require at least 2 cells in series in order to support the 6V LED's, for example. I doubt it's doing boost and buck in that size and price.