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:
.
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.
How would charging with the main power circuit work exactly ? Changing from battery in/LED out, to USB in/battery out ?
For the software sources follow the link to Gchart Anduril2 branch.
For the schematic here it is for the LIN16 that Gchart built :
Not very different from the schematic I posted in the attiny1-series thread, just with the PWM/LDO stuff removed : LDO, Vbatt divider, LDO input cap, capacitor for the PWM low pass filter. I added a reverse polarity protection PFET, it’s better to not have a diode drop for driving the HDR FET and it gives more accurate Vbatt readings.
Compared to the Noctigon linear driver I didn’t put a gate source resistor for Q1, it only seems to decrease the output current accuracy, and for the same reason I decreased the value of the Vsense-/in- resistor, it was quite off with the 10k value, with flicker on the 2 lowest levels.
For the Kicad sources, I’ll have to look up how to share a project with custom libraries, it seems… not straightforward.
True the shortage is annoying, I wanted to try to develop a powerfull 1S to 1S buck-boost driver but the parts aren’t in stock :cry:
Hmm, I’m not able to find them in large capacitance, also they’re quite expensive 
, too bad, it would have been interesting to try.
Edit : wrong schematic
I would like to buy a DACFreeman driver for my FWAA…
If thefreeman or gchart wants to sell me one…
Please PM me your paypal, and name your price…
Im in USA
+1
I hear you, there are still a few things I need to address.
- make adjustments to the ramp
- tweak the thermal regulation because the light steps down (relatively) too fast and too much, it just gets warmish.
- I need to wait till the 17 Nov to see if Mouser receive new stock of the buck converter, I only have 5 left and preferably I’d like to keep them for my projects. Digikey does have ”factory stock” but they don’t charge VAT so it’s problematic for me (large custom clearance fees).
- test the USB to serial adapters I should receive in a few days, I would prefer that users are able to flash their drivers with future updates and tweaks. The best would be that Sofirn sells one ready to use (with pogo pins), I think I saw Gchart mention that they would sell one along with the SP10S Pro?
- probably should make an interest thread at some point, ideally I would make a small batch, more than 2 but max 10, or something like that.
- oh and think about the price
A beer 
:person_facepalming: