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.
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.
We’re probably talking about mid 2023 now… there’s a limit to waiting.
If there is enough interest I could redo a FWAA/1AA and 18mm clearance buck driver with the MP2145, it’s not as good as the TPS62867 though, a bit larger and a bit higher Rdson FETs hence the efficiency at high output will be a little lower, relatively, in absolute it should still be very good. Unfortunately It’s also more expensive…
Thanks for schematic. For charging I mean from USB to battery yes. Also there are exist some reverse buck-boost DC/DC converters which can be used for charging and output but not the same time. Constant voltage it is possible with second DAC channel and additional opamp, but sorry I thought in my previous post that Attiny1616 can support more from one DAC channel output but it didn’t. Also there is advantage with second DAC channel because we can to adjust output voltage of DC/DC converter without need to recalculate and adjust voltage divider for different LED with different Vf. For more powerful buck-boost converter which controller you mean for that?
Wow two years for restock Maybe with sacrifice of efficiency MP2145 is better choice also it is in stock for now. Anyway it is better from linear current driver. The biggest problem now are also missing in stock of any kind of MCU from Attiny series. About buck converter it comes to my mind Sofirn SP35. It is interesting which buck converter they used, maybe from some chinese manufacturer.
I think I’ll prefer using a dedicated chip, I’d rather not have to restrict myself to use a BB with reverse capability.
LM34936/LM5176 controller, there is another one from Analog, but while both can convert single cell input voltage they require a >8V bias, I haven’t found a BB controller or powerfull converter that can be powered with single li-ion. 8V is not cool because that’s out of reach of small doubler charge pumps, need to use a boost converter to power the BB controller lol, though there are small micropower ones.
The reason I was thinking about it is because somebody I know was working on a high CRI high current 3V LED, but the project was abandoned due to the very high cost of high CRI phosphors, so I lost a bit of interest on this BB driver.
Yeah the efficiency should still be quite fine, it was actually my first choice before finding the TPS62867, which is very recent (DS March 2021), it’s just that the latter is truly excellent, should’ve bought more of them :cry:
I just hope that with the longer minimum ON time it doesn’t make noise at low output in PFM.
For the 1616 I’m good, I stocked a decent amount.
By the way you were talking about using I2C, there is an I2C equivalent of the TPS62867, the TPS62869, but it’s limited to 3.3V, which for many LEDs is not high enough. Digikey has it in stock.
I thinking as you. Time ago I had same idea as you for powerful Buck-boost but with LM25118 or LM5175. That’s are previous BB controllers before new one LM5176. LM25118 is asynchronous converter. You right they will need additional boost converter for bias voltage. These days I owned Q8 from friend. I really like it but the driver is sucks without any sort of stabilization. This type of big multi emitter flashlight can benefit from powerful BB. For small one it’s pointless anyway.
I think to design PCB for it maybe with linear driver based on code of Emisar D4 with 1634. I don’t need HR like in your design. Maybe simpler one channel is also good choice. Also I like to use Attiny 1616 and DAC. That’s is big step ahead compared to pwm DAC. Also with integrated DAC we can choose different internal reference voltages. I need to see if gchart is used that in him code. With that it is also possible to achieve good resolution of current control.
Yes he did, he used the dynamic PWM code TK recently implemented to switch the VREF between 2.5V and 0.55V giving a dimming range of 1:1159 with the 8bits DAC.
Thanks for the info. I can order from them via their distributor in my country. About replacement for opamp do you know that NCS333A. It seem to be direct replacement of OPA333 and are cheaper. Specs are almost as OPA333. But they are also out of stock for now.
Yeah the specs look good, there is also the MCP6V66.
Note that I don’t use the OPA333, but its low cost identical equivalent the TLV333, in stock at Mouser and Farnell right now.
, too bad, it would have been interesting to try.
:person_facepalming:
