Synchronous rectification controlling circuit and synchronous rectification controlling method

Abstract

In one embodiment, a synchronous rectification circuit can include: (i) a sampling circuit configured to sample a voltage across first and second power terminals of a synchronous rectifier, and to generate a first sampling voltage; (ii) an enable controlling circuit configured to delay the first sampling voltage, and to generate a second sampling voltage, and to activate a ramp voltage when the first sampling voltage is higher than the second sampling voltage; (iii) the enable controlling circuit being configured to generate an enable controlling signal in response to a comparison of the ramp voltage against a reference voltage that represents a predetermined light load condition; and (iv) a driving circuit configured to activate a driving signal to turn on the synchronous rectifier when the enable controlling signal and a synchronous rectification open signal are active.

Dependencies are inferred from the claim text.