Secondary side post regulator of flyback power converter with multile outputs

A secondary side post regulator circuit applied in a flyback power converter with multiple outputs, which has a transformer, a low-voltage output circuit for generating a low output voltage, and a high-voltage output circuit for generating a high output voltage, wherein the low-voltage output circuit has a low-voltage output capacitor and a rectifier unit and is coupled to a first secondary winding of the transformer, and the high-voltage output circuit has a high-voltage output capacitor and a high-voltage output switch and is coupled to a second secondary winding of the transformer, the secondary side post regulator circuit comprising:

• a ramp generator, generating a ramp signal according to a detecting signal from the low-voltage output circuit;
• and
• a comparator, generating an on-time signal to control an on-time of the high-voltage output switch according to the ramp signal and a feedback signal from the high-voltage output circuit to have energy stored in the high-voltage output capacitor transferred to the low-voltage output capacitor through the conducted high-voltage output switch.