Patent ID: 7286376

Claim:
A soft switching power converter, comprising: a transformer; a capacitor, coupled to said transformer for soft switching operation; a first switch, coupled for switching said transformer to transfer energy from an input of said power converter to an output of said power converter; a second switch, coupled for switching energy in said capacitor to said transformer; and a control circuit, coupled to said output of said power converter for generating a first signal and a second signal in response to a feedback signal for regulating an output of said power converter, wherein said first signal and said second signal are coupled for switching said first switch and said second switch, respectively; wherein an on-time of said second signal increases in response to a decrement of said on-time of said first signal in a first range of said feedback signal, a first delay time is generated after said first switch is turned off and before said second signal is enabled, a second delay time is generated after said second switch is turned off and before said first signal is enabled, wherein said second delay time is constant corresponding to said first range of said feedback signal, said second delay time is varied with respect to a second range of said feedback signal, and said second delay time is increased proportionally to a decrement of said feedback signal.