how does the M5SticC-Plus2 charge its battery?

[wjcarpenter]

I am curious about this. I see from the documentation that the P2 removed the AXP192 power management chip that previous sticks have. (And also, alas, the APIs for knowing if the device is plugged in and whether it's charging, but that's not my question.)

My question is, how is the charging of the battery managed? I tried figuring it out from the schematic on that documentation page, but I came away still wondering. I figured out from noodling around that the measurement of the battery voltage still works on the P2, so I guess that's part of it. But managing the charging of a lithium ion battery seems kind of complicated.

Is the P2 going to catch fire in my hand someday? :-)

[felmue]

Hello @wjcarpenter

the battery charging IC is TP4057 and battery voltage is measured via R40 / R41 into GPI38. See second page of the schematics here.

Thanks
Felix

[wjcarpenter]

@felmue Thanks! Foolish me didn't even notice there were additional schematic pages on that documentation page.