SYNCHRONOUS RECTIFIER CONTROLLER FOR OFFLINE POWER CONVERTER AND OFFLINE POWER CONVERTER AND METHOD THEREFOR

摘要

The present invention relates to a synchronous rectifier (SR) controller for an offline power converter and an offline power converter and a method therefor. The SR controller comprises: a controller having an input adapted to be coupled to a drain of an SR transistor, and an output for providing a drive signal in response thereto; a gate driver having an input coupled to the output of the controller, and an output adapted to be coupled to a gate of the SR transistor for providing a gate signal thereto; a first transistor having a drain coupled to the gate terminal, a gate, and a source coupled to ground; and a protection circuit having an input coupled to the drain terminal, and an output coupled to the gate of the first transistor. The protection circuit is responsive to a voltage on the drain terminal exceeding a first voltage, and provides a voltage exceeding a turn-on voltage and less than an overvoltage of the first transistor to the gate of the first transistor.