This is what I call breakthrough tech! Great work.
Are there any functional shortcomings to the 17mm driver which the 20mm driver doesn’t have? It looks like you have to use smaller spring to save space - don’t know how that affects function.
This is what we have been needing for a long time. If it can handle 20W long term that is perfect for most edc style lights and a turbo burst of say 30W would be perfect.
I assume that it could be tweaked to boost up to 12V for an XHP35 correct?
= “For programmability, I decided to go for an Atmel ATtiny84A instead of an Attiny85 due to the fact that it came in a very small 3x3mm QFN package, has EEPROM for storage of memory modes, allows me to use the hobbyist-friendly Arduino environment for sharing / open-source, and comes with a lot more GPIO for additional features.”
I hope not! It shares basically the same schematic except for a few components which are smaller / more power dense, but otherwise will have all the same features. I don't see how using a slightly smaller spring would affect the function, but to test this out, I've also ordered a Convoy S2+ host to build this driver into a real flashlight to see how it does in real life.
That's correct. I plan to make 2 versions on the bench to test - a 6V 3A nominal one hooked up to a 144M/XHP50, and a 12V 1.5A nominal one hooked up to a XHP35, and see how much I can push them. The difference between 12V and 6V versions would be modifying a few of the component values for better efficiency at the desired output voltages.
Yes I will be uploading all the schematics and firmware to my webpage soon so anyone can modify it to suit their needs or contribute to make it better! I'm not the best designer or firmware writer and I'm sure there are lots of folks here who are far better than myself! :)
I kind of doubt it will be able to handle 3A at 12V but 2A might be possible depending on the exact efficiency involved. Although 2A is about perfect for an xhp35 for longer term use, over that and you get quickly diminishing returns. Although a turbo mode of 2.5A for ~45 seconds or so could be possible.
If one of these could be made in 36mm and be programmed to do 1s —> 12v@1-1.5A for E-switches then this would be awesome as a TN4A driver with the carrier modified to run 1s4p.
Would love to play with one of these when they are working. What boost IC are you using? From the pictures in the GXB20 post it looks like possibly TPS61088?
TPS61088? The official datasheet lists 12.6V as maximum output voltage, with 13.2V output overvoltage protection. That is pretty limited for XHP35 handling, though it may suffice for just 1.5A of output.