Method for controlling switching transducer e.g. power converter for, e.g. laptop computer, involves turning OFF main switch, when voltage across auxiliary winding reaches the threshold voltage

摘要

The method involves providing a detection circuit which detects the voltage of an auxiliary winding (32) of the transformer (14), when the main switch (16) is ON. The voltage across the auxiliary winding is compared with a threshold voltage which is set to a value at which the amount of energy transferred per pulse to the secondary side circuit is minimized. The main switch is turned OFF, when the voltage across the auxiliary winding reaches the threshold voltage. The time duration between switching ON and OFF of the switch is set to minimum pulse width of switch. Independent claims are included for the following: (1) switching transducer; and (2) power converter.