Patent ID: 9647560
Date: 2017-05-09
CPC Classifications: H02M,Y02B

Claim:
1. A switching power converter comprising: a transformer including a primary winding coupled to an input voltage and a secondary winding coupled to an output of the switching power converter; a power switch coupled to the primary winding of the transformer, current in the primary winding being generated responsive to the power switch being turned on and not generated responsive to the power switch being turned off; a rectifier coupled to the secondary winding of the transformer, the rectifier conducting a rectified current to the output of the switching power converter during off cycles of the power switch; and a detection circuit continuously measuring a voltage across the rectifier outside of a blanking period of the detection circuit, the detection circuit detecting a decrease in the voltage across the rectifier outside of the blanking period and generating one or more current pulses in the secondary winding of the transformer in response to detecting the voltage decrease, wherein the blanking period ends when the voltage across the rectifier reaches a threshold or the blanking period is extended by a predefined amount of time after the voltage across the rectifier reaches the threshold.