A METHOD OF CONTROL FOR SYNCHRONOUS RECTIFIERS

摘要

The present application relates to the field of switching power supplies and in particular to switching power supplies in which a primary side is isolated from the secondary side and in which a synchronous rectifier on the secondary side is controlled from the primary side. The application provides a method for minimising body diode conduction losses.

主权项

1. A method of controlling a synchronous rectifier in a switching power supply that includes an inductive element, the method comprising:
operating the synchronous rectifier to turn on at a first time position and to turn off at a second time position in a first switching cycle of the switching power supply; obtaining a first measurement from an auxiliary winding of the inductive element at a time position after the second time position; and adjusting the second time position in a second switching cycle subsequent to the first switching cycle based on a first value derived from the obtained measurement, wherein the first value is the obtained first measurement less a second value.