Patent ID: 7352595

Claim:
A primary-side controlled switching regulator, comprising: a transformer, for transferring the energy from a primary-side to a secondary side of the transformer; a switching device, for switching the transformer; a control circuit, coupled to the transformer for generating a switching signal to switch the switching device and to regulate the output of the switching regulator; wherein the control circuit including: a first circuit, coupled to the transformer for generating a first signal and a timing signal by measuring a reflected signal of the transformer, and wherein the timing signal represents a discharge time of the transformer; a second circuit and a third circuit producing a second signal by integrating a current signal with the timing signal, and wherein the current signal represents a primary-side switching current of the transformer; a first error amplifier, having a first reference signal for generating a first feedback signal in response to the first signal; and wherein the first reference signal is increased in response to the increase of the second signal; a second error amplifier, having a second reference signal for generating a second feedback signal in response to the second signal; and a switching control circuit, generating the switching signal in response to the first feedback signal and the second feedback signal.