Patent ID: 8385087

Claim:
A system for controlling a DC/DC forward converter having a transformer with primary and secondary windings, a reset switch, and a first switch coupled to the primary winding of the transformer, the system comprising: a PWM control circuit responsive to an output signal of the converter for producing a PWM signal to control switching of the reset switch and the first switch, a period of the PWM signal including an on-time interval for enabling transfer of power via the transformer when the first switch is on, and a reset time interval for enabling reset of the transformer when the reset switch is on, a maximum value of the on-time interval being pre-set to provide sufficient time for the reset, the reset switch being turned off when the PWM signal goes from a first level to a second level, a first delay period being set between time when the reset switch turns off and time when the first switch turns on; and a first delay control circuit for reducing the first delay period when the on-time interval approaches the maximum value.