HarleyQuin, that’s a pretty clear pic. Looks like they’ve bumped down from R150 to R120 for a small increase in output? Probably just whatever was cheapest at the time but R12 is the right component since FT lists it as an 800mA driver.
HarleyQuin and I recently talked about what the two “extra” resistors are doing in there. I noted that they were not part of the application circuit and HQ pointed out that they are present on the working design sold by FT. The resistors in question are the two 0603 seen in post #57. According to HarleyQuin’s circuit the 33k one connects gate to GND (through Rsense) and the 150k one connects Vout/Vcc to GND directly. The 33k one seems to be a pulldown resistor for the transistor, but the 150k one… no idea really.
The following is probably another case of “whatever is cheapest” but I noticed that on one of the no-MCU versions FT sells there is clearly an R150 for sense and an R150 connecting LED- across where the missing transistor is. It’s hard to see on the other no-MCU listing, but I think that one shows a zero-ohm jumper. Again, I seriously doubt that any of that is relevant.
FWIW what both no-MCU examples do show is that these two resistors are not populated (333/33k and 18D/150k) when the MCU/transistor is not populated! Maybe the 150k is a bleeder to help ensure clean mode changes? This is something that RMM just pointed out in another thread when the topic of using an LDO in a clicky came up. I feel decently confident on that now, that’s probably what we are looking at.
Come to think of it, does HQ’s recent pic showing the FT board with MCU removed show that the MCU ground is on the sense side of Rsense? (eg both the pulldown and MCU GND are not connected directly to GND?) Is there any significance to that?