Switched mode power supply controller and method

摘要

A switched mode power supply has a transformer and a power switch to switch a primary current for operation in a critical conduction mode. The switched mode power supply has a controller which switches off a primary current when a peak current is reached. The primary current is switched on again when a zero current condition in the secondary is detected the first time after the primary current has been switched off and a minimum primary current off time has been reached.