Patent ID: 11936287
Assignee: MINMAX TECHNOLOGY CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 0:
1. A self-driven active clamp circuit applied to a flyback converter having a transformer and a switch, the self-driven active clamp circuit comprising:
a clamp switch connected between a first capacitor and a second capacitor in series, wherein another terminal of the first capacitor is connected to a first terminal of a primary-side winding of the transformer, and another terminal of the second capacitor is connected to a second terminal of the primary-side winding of the transformer and the switch of the flyback converter;
a resistor, wherein a terminal of the resistor is connected to a control terminal of the clamp switch, and another terminal of the resistor is connected to the second terminal of the primary-side winding of the transformer and the switch of the flyback converter; and
a diode, wherein an anode of the diode is connected to the control terminal of the clamp switch, and a cathode of the diode is connected to the second terminal of the primary-side winding of the transformer and the switch of the flyback converter;
wherein the clamp switch is a metal-oxide-semiconductor field-effect transistor having a gate as the control terminal, a drain connected to the first capacitor, and a source connected to the second capacitor;
wherein a parasitic capacitance exists between the gate and the source of the clamp switch, and the parasitic capacitance is discharged via the diode;
wherein a driving voltage for the gate of the clamp switch is obtained on the second capacitor according to voltage division by the first capacitor and the second capacitor while the primary-side winding is discharging.