Control circuit with fast dynamic response for power converters

摘要

A control circuit of a power converter is provided. It comprises a voltage detection circuit detecting a reflected signal for generating a voltage-loop signal. A current detection circuit detects a current of a transformer for generating a current-loop signal. An oscillator generates an oscillation signal in accordance with an output load of the power converter. A PWM circuit generates a switching signal according to the voltage-loop signal, the current-loop signal and the oscillation signal for regulating an output of the power converter. A load detection circuit receives a detection signal through an signal-transfer device for increasing a switching frequency of the switching signal. The detection signal is generated once the output is lower than a low-voltage threshold. The oscillation signal determines the switching frequency of the switching signal. The control circuit reduces the voltage drop of the output when the output load is changed.

主权项

1. A control circuit of a power converter, comprising:
a voltage detection circuit coupled to detect a reflected signal for generating a voltage-loop signal; a current detection circuit coupled to detect a current of a transformer of the power converter for generating a current-loop signal; an oscillator generating an oscillation signal in accordance with an output load of the power converter; a PWM circuit generating a switching signal according to the voltage-loop signal, the current-loop signal and the oscillation signal for regulating an output of the power converter; and a load detection circuit coupled to receive a detection signal from an opto-coupler for increasing a switching frequency of the switching signal; wherein the detection signal is generated once the output of the power converter is lower than a low-voltage threshold; the oscillation signal is coupled to determine the switching frequency of the switching signal; the switching signal is used for switching the transformer through a transistor.