Patent ID: 9214870
Filing Date: 2015-12-15
Classification: H02M,Y02B

Abstract:
1. A synchronous rectifier circuit having a synchronous rectification element, and a synchronous rectification control circuit for turning on/off said synchronous rectification element according to the current flowing through the synchronous rectification element, the synchronous rectifier circuit, comprising: a current detection circuit, having a transformer, the transformer having a primary side wiring connected in parallel with said synchronous rectification element and a secondary side wiring connected across a phase adjustment capacitor phase-adjusting the voltage across said phase adjustment capacitor to be in phase with the current flowing through said synchronous rectification element, for detecting the current flowing through said synchronous rectification element as a synchronized voltage waveform, wherein when the differential voltage between the saturation voltage of said synchronous rectification element and the voltage detected by said current detection circuit decreases to the turn-on threshold voltage during an off-period of said synchronous rectification element, said synchronous rectification control circuit turns on said synchronous rectification element, and when said differential voltage increases to the turn-off threshold voltage during an on- period of said synchronous rectification element, said synchronous rectification control circuit turns off said synchronous rectification element.