Patent ID: 10038387

Abstract:
A control circuit of a flyback power converter according to the present invention comprises a low-side transistor, an active-clamper, a high-side drive circuit, and a controller. The low-side transistor is coupled to switch a transformer. The active-clamper is coupled in parallel with the transformer. The high-side drive circuit is coupled to drive the active-clamper. The controller generates a switching signal and an active-clamp signal. The switching signal is coupled to drive the low-side transistor. The switching signal is generated in accordance with a feedback signal for regulating an output voltage of the flyback power converter. The active-clamp signal is coupled to control the high-side drive circuit and the active-clamper. The active-clamp signal is generated in response to a predicted time of the transformer. The predicted time is determined in accordance with an input voltage, the output voltage and an on time of the switching signal.