Hi
I'm using the following circuit to charge a single LIPO cell. VIN is 5V. The Mosfet is there to stop the load drawing current while the battery is charging but I don't think it's relevant. My problem is that the LED does not light. The STAT pin remains at about 4V, unless it's disconnected, in which case it's at about 1V. Even when the battery is fully charged to 4.2V the STAT pin does not change. The battery does however charge as expected.
Weirdly, I had this exact circuit made up by a company in China a while back, and the modules from them do work. If I swap round the MCP73831 between the two sets of boards, the China module no longer works and the one I'm making does. It seems unlikely but the only thing I can think is that my batch of chips is different from the ones the Chinese people used, and that mine are faulty. Any other ideas?

I'm using the following circuit to charge a single LIPO cell. VIN is 5V. The Mosfet is there to stop the load drawing current while the battery is charging but I don't think it's relevant. My problem is that the LED does not light. The STAT pin remains at about 4V, unless it's disconnected, in which case it's at about 1V. Even when the battery is fully charged to 4.2V the STAT pin does not change. The battery does however charge as expected.
Weirdly, I had this exact circuit made up by a company in China a while back, and the modules from them do work. If I swap round the MCP73831 between the two sets of boards, the China module no longer works and the one I'm making does. It seems unlikely but the only thing I can think is that my batch of chips is different from the ones the Chinese people used, and that mine are faulty. Any other ideas?

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