A synchronous rectification circuit for power converters operable under fixed and/or variable frequencies where no current sense circuit or phase-lock circuit are needed is provided. It has a power switch coupled to a transformer for the rectification. A signal-generation circuit is used for generating a control signal in response to a magnetized voltage of the transformer, a demagnetized voltage of the transformer, and a magnetization period of the transformer. The control signal is coupled to turn on the power switch. The enable period of the control signal is correlated to a demagnetization period of the transformer.
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation application of patent application Ser. No. 11/464,078, filed on Aug. 11, 2006, which is now allowed. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
