Battery charging protection circuit

摘要

A battery charging protection circuit for use in a power controller circuit utilizes the base emitter junction of a first NPN bipolar transistor to permit current to flow only from a backup battery input terminal to a power supply voltage output terminal of the power controller circuit. The base emitter junction and base collector junction of a second bipolar transistor are used to permit current to flow only in the direction from the backup battery input terminal to the substrate of the power controller circuit.