Patent ID: 7483281

Claim:
A control circuit, for a multi-channel power converter, the multi-channel power converter comprising a first transformer controlled by a first switching signal to produce a first output of the power converter; a second transformer controlled by a second switching signal to produce a second output of the power converter; and the control circuit coupled to the first and second outputs of the power converter to generate the first switching signal and the second switching signal in response to a first feedback signal and a second feedback signal respectively; wherein the first feedback signal and the second feedback signal are produced in accordance with the first and second outputs of the power converter, the control circuit comprising: a modulation circuit, for generating a modulation signal and a burst signal in response to the first feedback signal and the second feedback signal, wherein the burst signal is enabled when the modulation signal is lower than a threshold; an input terminal, for receiving an input signal, wherein the second switching signal is enabled when the input signal is enabled; and an oscillation circuit, coupled to the modulation circuit, for generating an oscillation signal in accordance with the modulation signal, wherein the oscillation signal is utilized to control a switching frequency of the first switching signal and a switching frequency of the second switching signal, wherein the switching frequency of the first switching signal and the second switching signal is modulated in response to the modulation signal when the input signal is enabled and the switching frequency of the first switching signal is modulated in response to the modulation signal and the burst signal once the input signal is disabled.