I use this exactly this for D1.
If you can not buy from this source search for “RoHm 0.5A/20V Schottky SOD-323, RB551V-30 TE17” on eBay or Aliexpress.
For C1 I use a 10uF cap size 0805.
I would recommend to first try to build a single cell verson of this driver and than modify another for two cells. Firmware can be a little tricky for two cell drivers.
I have some SD103AWS SOD-323 diodes from another project but i’m going to order these you mentioned .
Just ordered also all the other components including pcb …
Correct. It is for maximum output that is only limited by battery selection and quality of components. If you do not have at least one light with one of these you should try it. The biggest drawback is as the cell fades so does the output whereas the 7135 drivers did not do that until they fell below voltage. Both drivers have their place but for sheer max lumens the new DD drivers cannot be beat
Well, this is good timing. I took a little time off to pursue other things, and not only is there a plethora of new hardware and firmware out there (the 1K limit has finally been breached!), but Wight is back. Welcome back, and THANK YOU for putting us down a fresh path in driver land.
All is right with the world.
PS Ordering Attiny 25s and 85s and can’t wait to see what I can cram in them.
I have another silly question….
Is there any ready-to-flash firmware available in this forum after i build this driver (for attiny13a) ? in about 2 weeks i’ll have all the components needed , so it’s time to search for a good firmware.
For an FET only driver I would start with STAR firmware or one of ToyKeeper's firmwares. You can find them all in ToyKeeper's Repository under JonnyC and ToyKeeper. For ToyKeeper I would start with starry-offtime and with STAR I would start with STAR_off_time. ToyKeeper's BLF A6 is also an excellent firmware, but it is geared towards FET+7135, and while you can convert it to use with FET only I would try some of the others first.
I need your help 0:)
Can i do a zener mod on the driver , so i can use it with mt-g2 ?
can someone describe what diode to take , and if i need to remove something else ?
i have pcbs v044
The second part is picking R1/R2 resistors for a usable voltage divider. Tom E or someone might chime in here with good info for you. The values Matthaus linked to above are not correct for this. Maybe 19.1k and 2.2k with a re-calibration?
Again: recalibrate the LVC I think. ToyKeeper provides a test firmware for doing just that!
FWIW, RMM posted a spreadsheet you can use to experiment with resistor values, with an approximation of how those should appear to the MCU:
So, for example, if you wanted a 3S light… tell it to estimate the values for 3*2.5V and 3*4.4V (7.5V and 13.2V) and adjust the resistors until they produce useful values. You probably want the results to be between 32 at 224, spread across a fairly wide range.
I don’t really know what I’m doing, but I gave it 48000 and 3300 and it produced 3S values from 111 to 196.
Last year I build a light with this driver and zener mod (S8 with XHP50, 2x18350 cells), with the normal 19.1K and 2.2K (I did not realise the problem so never worried about that), and the LVP kicks in at 3.6V/cell (resting voltage after LVP event, under load it must have been quite a bit lower) which is not that great but it is below half drainage so it is usable.
The first part is definitely true! With our current offtime setup there seem to be a lot of factors. I’m sure that there are many which I do not have a good handle on.
It does look like you did some testing which really made resistor selection seem important for the current OTC setup though, check your post #552. Does that still hold water as far as you are concerned?
I saw a few of Sharpie’s posts over in another thread RE: the A6 driver. After filtering out any confusion from those posts… These drivers have never been perfect and we’ve already discussed some of that stuff but it never hurts to rehash it again. It got the wheels turning in my head.
I’m saying this pretty blindly, but maybe a simple way to improve offtime consistency (if/when it’s a problem at least) would be to use a larger cap with a bleeder resistor. Whatever is bleeding through the ATtiny13A is doing so slowly. Moving to a 10uF X5R cap should significantly reduce whatever influence the ATtiny13A has over the cap and allow a bleeder resistor to become the dominant factor.
10uf with a bleeder would be simple enough to test on current boards.
For the record, using 19.1k for R1 and X7R 1uF for OTC is reliable enough for me, even at very high temps. It’s just when you get into TK’s mode reversing that you need the extra accuracy. 22k for R1 did give more issues, for whatever reason.