Patent ID: 11909325
Assignee: CHENGDU MONOLITHIC POWER SYSTEMS CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 4:
5. A synchronous rectifier control circuit, used with a synchronous rectification circuit having a primary switch and a synchronous rectifier, comprising:
a drain-source threshold setting circuit, configured to receive a drain-source voltage across the synchronous rectifier, and to provide a dynamic drain-source voltage threshold based on the drain-source voltage;
a primary switch detecting circuit, configured to receive the drain-source voltage and the dynamic drain-source voltage threshold, and to provide a primary switch state indicating signal based on a comparison result of the drain-source voltage and the dynamic drain-source voltage threshold; and
an on-control circuit, configured to receive the primary switch state indicating signal, the drain-source voltage and a turn-on threshold, on the premise that the primary switch state indicating signal indicates an on state of the primary switch, the on-control circuit provides a synchronous on signal to turn on the synchronous rectifier when the drain-source voltage decreases to the turn-on threshold.