Continuing the discussion from Recommendations for simple lipo chargers?, since this really takes that thread into a direction that has nothing to do with lipo charging:
So, I’ve managed to remake a board with only the MAX77960 circuit, and I have that working properly. I also connected that board’s ground & MAX77960 output to the other board with the microcontroller, and it’s able to provide power to the “rest of the board, but off-board”.
I then tried using my hot air gun to make the MAX77960 circuit on the board that was receiving power. This, unfortunately, only half-worked: the uC is able to successfully communicate with and program the MAX77960, but the MAX77960 doesn’t do its buck/boost power thing. Instead of seeing the switching waveform on the inductor (which I see on the working circuit), it just hangs out around at a constant ~0.9V.
Could it be that my lack of ESD safety is damaging the switcher circuit but not the I2C comms? Or could excessive heat from my newbie reflow technique be destroying the switcher but not the I2C comms? The MAX77960’s LDO is functioning, too, and the I2C status reports things are working.
How do you approach distinguishing between:
- My circuits interact such that they work fine separately, but together they don’t
- I’ve partially destroyed ICs due to heat
- I’ve partially destroyed ICs due to ESD
Thanks for your advice!