Pi Zero LiPoly – Final

Pi with my LiPoly board

My Pi Zero LiPoly board was working, but not exactly in the way it’s supposed to. Charging was fine. Powering the Pi from the battery, fine. Th problem came on the net MCP_IN, in the schematic below. I was reading voltage at the test point for MCP_IN, JP4.

Schmatic v1.2Either the comparitor wasn’t comparing properly, or the MOSFET wasn’t blocking all current when shut off. Or, something else was wrong.

That “something else” was a pretty rookie mistake. See if you can find it before looking below…

Error in v1.2Long enough. My comparitor was wonky, because it was unpowered, as you can see in the image below. +5 volts doesn’t actually connect to the +V pin on the comparitor chip.

Fixed that and it works exactly as expected now.