Patent ID: 6809939
Filing Date: 2004-10-26
Classification: H02M,Y02B

Abstract:
A synchronous rectifying control circuit of a flyback switching power supply connected to a secondary side of a transformer in said flyback switching power supply, said circuit at least comprising:a plurality of sets of power source ends arranged at an output end of a secondary side coil of said transformer and having a first power source output end and a secondary power source output end; a plurality of rectifying circuits connected with said secondary power source output end of said power source ends and used to rectify a voltage waveform between said first power source output end of said power source ends and a reference potential end; a set of induction ends arranged at the output end of said secondary said coil of said transformer and having a first induction end and a second induction end, said second induction end being said reference potential end, said first induction end being connected to a rectifying diode, which is used to rectify said first induction end and said reference potential end to form a detection end having a waveform with the same phase as said power source ends; and a synchronous control circuit connected to said first power source output of said power source ends and said detection end and having a synchronous input end and a control end, said synchronous input end being used for input of a synchronous signal, said control end being connected to said rectifying circuits and used to control synchronously said rectifying circuits to generate a uniform rectifying response period.