CONTROL CIRCUIT AND METHOD, AND POWER SUPPLY

摘要

A control circuit and method, and a power supply device. The control circuit includes: an acquisition module (10), which is used for acquiring a voltage signal generated by reverse surge current when the reverse surge current occurs at the primary side of a switching power supply circuit of a synchronous rectifier circuit; a holding module (11), which is used for outputting a first control signal continuously during a first preset period when the voltage signal is higher than a first preset voltage threshold; a control module (12), which is used for controlling the secondary side switching tube of the switching power supply circuit of the synchronous rectifier circuit to be switched off according to the first control signal. The control circuit and method, and the power supply device can restrain the reverse surge current in the switching power supply circuit of the synchronous rectifier circuit effectively, so that the security of the power supply device is improved.