Patent ID: 11909325
Assignee: CHENGDU MONOLITHIC POWER SYSTEMS CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 2:
3. The drain-source threshold setting circuit of claim 1, further comprising:
a second comparator, configured to receive a turn-on threshold and the drain-source voltage, and to provide a counting signal based on a comparison result of the turn-on threshold and the drain-source voltage; and
a counting circuit, configured to receive the counting signal and a primary switch state indicating signal indicating an on state of a primary switch of a synchronous rectification circuit, and to provide a threshold regulating signal based on the counting signal and the primary switch state indicating signal; wherein
the discharging circuit further receives the threshold regulating signal, and discharges the capacitor based on the drain-source voltage, the dynamic drain-source voltage threshold and the threshold regulating signal; and wherein
the counting signal becomes valid every time the drain-source voltage decreases to the turn-on threshold, and the counting circuit counts every time the counting signal becomes valid, and the threshold regulating signal controls the discharging circuit to discharge the capacitor when the counting circuit counts to a preset number.