Patent ID: 8537584

Claim:
A circuit comprising: a drain-source voltage comparator, coupled to a rectifier, said drain-source voltage comparator configured to compare the drain-source voltage of said rectifier to a first reference voltage; a blanking time circuit generating a blanking time signal; a light load logic circuit, coupled to said drain-source voltage comparator and said blanking time circuit and generating a load indication signal; a charging circuit comprising a capacitor, charged during a heavy load state of said load indication signal and discharged during a light load state of said load indication signal; a comparator comparing the charging circuit voltage with a second reference voltage; and a monostable trigger with an input coupled to an output of said comparator, and said monostable trigger configured to output a light load control signal to latch off synchronous rectification of said rectifier during synchronous rectification operation of said rectifier, if said load indication signal is a pattern for a predetermined time.