MCP73831 not charging
2 years ago I started to design a PCB using a MCP73831T-2ACI/OT and a li-po battery. The battery has a protection circuit. Even though I designed the PCB it is the only time I have worked with a management controller so I still have a lot to learn. Anyway, after some prototypes and testing it was working perfectly. We started a production of 500 PCBs in July last year. In February that we start selling the product but we realized some batteries had already discharged. The issue was that some batteries didn't charge anymore. I measured the voltage of the battery and it was 2.4~2.6V and the output of the protection circuit was 0V. This matches the over-discharge protection of the battery.
A workaround for this was to connect the battery directly to 3V until the voltage was above 2.7V and then we could charge it with the USB normally. Of course our costumers can't do this if they forget to charge the battery after 6 months.
I was wondering if MCP is not charging the battery because it thinks there is no battery attached or something. I attached the specifications of the battery I'm using, the specs of the protection circuit and also the part of the schematic with the MCP73831.
I hope someone could guide me to figure out how to fix this for the next production.
Have a nice day,
post edited by gercer - 2020/03/31 10:29:40