I removed from lume1 useless external sensor. Internal 1634 temp sensors works fine same like in attiny85. Led4power have nice MCPCB with termistor pad.
Would there be an advantage in using 3 terminal MLCCs? I think the frequency in these applications is probably too low to matter, but curious if it could make a difference in noise.
So… DAC control ended up being easier than I expected. No changes to the base Anduril(2) code needed. Even using the new Dynamic PWM logic to switch between VREFs to gain even more fine-tune control at lower ranges 
Board design courtesy of thefreeman
Still need to do some config fine-tuning, but overall this works really well! Nice design, thefreeman!
I’m excited. I really need to get the equipment to flash these…
So integrated DAC port can be used for boost drivers right?
Yeah, I don’t think there’s any reason why it couldn’t be used. I’m not an electronics expert, though. But you can use it as input to one leg of the op-amp, assuming you’re using one to adjust the feedback voltage for the boost controller.
Glad that the driver works, and thank you so much for implementing DAC support.
Sure, I haven’t received the boost driver boards but here is a buck driver :
Same size as last time (18mm clearance) and one sided thanks to the lower component count, though I’m getting more current than I should on the bottom of the high power range, still haven’t figured out why but is probably unrelated to the DAC control.
I bought a few CH340N USB boards to try that, very cheap, and also a few CH340N chips to use on your USB to pogo pin flasher.
I didn’t know about those, it seems that it reduces their ESL, but why would that reduce acoustic noise ? Or because they have solder points in the middle and would make the board vibrate less ?
This development is really fascinating to follow.
Mechanical dampening would be better I imagined. But I was thinking that the 90° offset of the conducting paths might have negative interference or something. I don’t know, truly… just thinking out loud
Yesterday I made a buck driver for the FWAA and installed it this morning :
I still haven’t received my gold plated brass buttons so it’s a 10mm2 (D~3.5mm) wire for now, not ideal due to the inevitable oxydation.
I sliced the 219Cs for better tint and throw.
The beam while still very floody is much more usable now, the tint is also much better, I used a lens from kaidomain instead of the original one which increased the duv quite a bit, their AR coated lenses are still purple reflecting, but don’t worsen the tint significantly, less than +0.0005 duv.
Compared with before :
Especially as soon as the FET turns on (lv4) the duv increases a lot, it’s actually very easy to see when ramping up from the 7135 to FET, I didn’t know 219Cs behaved like that, at higher duty cycle the duv comes down.
Thanks to Sunnysunsun for his FWAA’s measurements with which I could design the board before receiving the light.
Ideally I should have made some runtime measurements or at least sustained output to compare with the high efficiency buck driver, but… I was feeling lazy 
(and well, with the LEDs sliced it wouldn’t have worked), I should really do it at some point because while it seems it heats much less at given output, we can’t know for real without a proper comparison.
Ah I also designed a RGB aux board (hence the RGB pads) but still haven’t ordered it…
1 Thank
Very cool!
Since I recently got the Opple Light Master, I used it to look at my FWAA:
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Yay!… I hope you (and or thefreeman) will
get an Opple
and post flicker results
Im wondering if the DAC approach will get rid of those pulses, shown on the bottom right side of the pic.
There is no PWM dimming in my drivers, only analog dimming, prior to the DAC control a filtered PWM signal was used to set the current, so there was in theory a small ripple at the output (not pulses!), in practice the loop isn’t very fast and the ripple was mostly smoothed out.
With the DAC the digital level is properly converted to a voltage and then to current, not ripple from there.
With a DC-DC converter there is always an output ripple though, since the TPS62867 switches at 2.4MHz there is a 2.4MHz ripple, of very low amplitude thanks to the output capacitors, 600kHz for the MP3431 (boost).
The switching frequency does decrease at low output, down to 30kHz for the MP3431 in ultrasonic mode, and ugh, around 60Hz at 5uA for the TPS62867 in my buck driver, but I have decided to not use the 1st level of the low power and high power range because the output can be unstable and flicker (for a different reason), so with a minimum of ~20uA, the min frequency is about150Hz, but contrary to the TPS61288 boost driver the output capacitors don’t discharge a lot even at this low frequency, and I don’t notice any flicker, that said I added a 70uA load to prevent the frequency from dropping below 500Hz to be safe.
About the Opple, I have an oscilloscope so I can just look at the output current waveform, that said I should buy a fast photodiode to directly measure from the light, that would be more practical in many cases.
Thanks, the DAC control is really great for making small drivers thanks to the lower component count.
I actually do have an Opple and I love it. I’ll let you guess which one is top and which one is bottom… Sofirn IF22A (typical FET+1 Anduril) vs thefreeman’s LIN16 driver with DAC control in a Sofirn SC31 Pro body. I really don’t think labels are necessary 
yay!
thank you :+1:
I recognize the FWAA pulses in your top pic
nice to see the HUGE improvement with thefreeman’s driver…
you guys are doing great things!
Yeah, and the small noise we see is likely from the device, the driver being linear it should be smooth as !@#$ :sunglasses:
jon_slider : no need to quote full images, it clutters the thread. (Edit : thank for resizing)
some lights produce smoother readings, for example my AAA Tool:
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Yup, that’s just the switching regulator frequency of a boost converter. When done properly, that’s how buck/boost drivers should look.
Is that new version of linear HDR driver with DAC control.
Great news gchart about DAC control. The next step will be to implement truly CC/CV or PD emulation protocols in future. Also why not to use buck converter or linear converter as charger when the light is not used. In that case we will have great pocket DC power supply and will have few components needed for additional charger. I really enjoy with that project. I hope thefreeman that project to be truly Open hardware and Open software with full schematics and Kicad source. Please don’t make it like most of loneoceans projects which are partial open source with software and not hardware. I really want to help to design as I can. Big problem now with that kind of projects and prototyping is semiconductors shortage and availability of MCU and most DC/DC converters.