Patent ID: 8310847
Filing Date: 2012-11-13
Classification: H02M

Abstract:
1. A flyback power converter with multiple outputs comprising: a transformer, having a primary winding, a first secondary winding, and a second secondary winding; a primary side circuit, having a main switch coupled to the primary winding; a low-voltage output circuit, which is coupled to the first secondary winding, having a low-voltage output capacitor and a rectifier unit to generate a low output voltage; a high-voltage output circuit, which is coupled to the second secondary winding, having a high-voltage output switch and a high-voltage output capacitor to generate a high output voltage; and a secondary side post regulator circuit, adjusting an on-time of the high-voltage output switch according to a feedback signal responsive to the high output voltage to have energy stored in the high-voltage capacitor transferred to the low-voltage output capacitor for reducing a level of the high output voltage; wherein the secondary side post regulator circuit limits a maximum on-time of the high-voltage output switch according to a detecting signal from the low-voltage output circuit, the detecting signal corresponding to a conducting condition of the rectifier unit and thereby conduction of the high-voltage output switch being only within a time interval during conduction of the rectifier unit.