Patent ID: 7911813
Filing Date: 2011-03-22
Classification: H02M,Y02B

Abstract:
1. A synchronous rectifying circuit for a resonant switching power converter, comprising: a power transistor and a diode, coupled to a transformer and an output of said resonant switching power converter for rectifying; a sense transistor, coupled to said power transistor for generating a mirror current correlated to a current of said power transistor; a controller, generating a driving signal to control said power transistor in response to a switching-current signal; and a current-sense device, coupled to said sense transistor for generating said switching-current signal in response to a switching current of said transformer, wherein said current-sense device is coupled to said sense transistor for generating said switching-current signal in accordance with said mirror current, said controller enables said driving signal to turn on said power transistor once said diode is forwardly biased, and said controller generates a reset signal to disable said driving signal and turn off said power transistor when said switching-current signal is lower than a threshold.