What about TSV521?
Input offset voltage is to high about 800uV. If you want to choose cheaper opamp and want low offset voltage go to Max of 50uV.
Yes but IMO a two stage RC filter is a waste of components, single is enough.
Interesting part, it is indeed faster although I donât think it changes much in our case. But for a 2 channels tint ramping driver, it might help with faster loop response when switching between the two channels (maybe ?).
Itâs cheaper than OPA333 and LTC2066 but not TLV333.
Of the MAX9616-9620 series, MAX9619 is pin for pin compatible with LTC2066 (it has a shutdown pin) and can be used in place of it in Lume1 as a cheaper alternative.
Edit : but OPA/TLV333 can still be used in place, itâll just be always on.
Great, thank you. MAX9619 is not much cheaper , but at least i can get it in my local shop. Now id like to remove one 0603 passive around max9619 to gain space for C11 1206 6.3V 100uF output capacitor ;))
It is not waste. Better to have two stage PWM DAC. You have faster response of DAC and better ripple of DC voltage. Also you have better cutoff frequency. And need just one or two components more.
I think it is fast enough for a flashlight and some ripple is fine for an LED.
About R5 I mentionned before I might have been wrong, it seems that when the cap is in parallel with R4 it makes the output unstable.
When can I buy a FW3A with Lume1?
Serious question. How hard would it be to turn the FET channel into a linearly regulated variant?
Sounds difficult, what functionality are you after ?
Running emitters like quad e21a in 3V or boost HX or even something like a triple 219B, HL2X or Osram white flats. Anything with a turbo amperage more than 5A but not compatible with DD due to very low Vf or otherwise intolerant to overdriving.
For higher current with low Vf LEDs then a 6~8A buck would be preferable, with the low switch limit of this buck-boost IC it barely even boosts anyway. For multi emitters like quad E21A the better option is to wire them in 2S2P and use a boost driver.
I agree on the boost portion of this driver being mostly unnecessary, but I still like that its there. I love that it can drive a UV and Red emitter efficiently. Flexibility in a BLF driver is admirable IMO.
6-8A buck is something I really want to see soon. Convoy and Sofirn has done it, but lack open source FW.
I agree on the boost config for the e21a quads. It makes even more sense when you consider the mcpcb wiring layout for 3V vs 6V. I overall prefer the Lume X1 for my desired applications, but since this one exists for sale already (and specifically for the FW3A), I was tempted to make it work.
I still think that it could make sense to have the 3A buck/boost and then programmable current (a la l4p) linear FET would be the ultimate flex driver. Energy efficient on sustained modes, cost efficient on crazy modes, and suits almost any emitter setup I can think of.
It would require quite a bit of hacking, although maybe not impossible. Here are the issues I can see:
The output of the op-amp needs to be fed into the gate of the FET, maybe doable with soldering of very small wires. You will need to remove the charge pump IC.
The PWM output from the MCU (probably) goes through a voltage divider before the RC filter. This voltage divider divides PWM voltage down to a level that will match measured voltage of sense resistor. This divider is probably optimized so that max PWM (255) equals highest desired output of the switching converter. You would probably need to mess about a little with those resistor values so max PWM equals max current you wish to obtain through the FET. You will loose some resolution of the switch converter but I take it that would be acceptable.
The FET chosen might not be very good choice for linear operation, you have to check that, possibly youâd need to replace it. Note that itâs a dual FET, not a ânormalâ single FET. Itâs dual to prevent boosted current leaking back into the battery when voltage is higher on output side.
And as you probably know already, the software will need to be modified quite a bit.
Edit: The biggest issue is that the FET has to be turned off when using the switching converter. If you feed the output of the op-amp to the FET as well as feedback on the switching converter, you will need to find a way to isolate the op-amp output from FET gate when not using the FET.
Did you request permission from loneoceans to create this driver or is this another copy like what you did with the Tamagotchi driver especially since youâre now putting your own name (âQuadBLFâ) on the driver to make it seem like it is yours again? If you received permission, there is no problem at all and good effort.
I have several resonable questions. lume1 is the open source hardware or only open source firmware at all? Do we need to have special permissions if anyone want to make a copy of lume1 driver if we use original name or if we made some modifications of it?
From post 17 of loneoceans
Closed hardware? Like locked in safe? Schematics is not a hardware, its just instruction how to create a hardware. So thanks to smart guy Loneoceans i learned how to create a specific hardware. The PCB design is mine, i have source code and i can call it as i wish. It would be not nice to use Lume brand as your own, right? This will be just another driver inspired by Lume1, based on TPS63020 controller and open source software.
Open-source hardware (OSH). Lume1 is shared on OSH Park. Any questions? 