SOURCE-ELECTRODE DRIVING CONTROL CIRCUIT AND CONTROL METHOD THEREOF

摘要

Disclosed are driving control methods and circuits for quasi-resonant control of a main power switch of a switching power supply. In one embodiment, a driving control circuit can include: (i) a clamp circuit coupled to a gate of the main power switch, where the clamp circuit is configured to clamp a voltage of the gate to a clamping voltage that is greater than a threshold voltage of the main power switch; (ii) a valley voltage detection circuit configured to activate a valley control signal when a drain-source voltage of the main power switch is at a resonance valley level; and (iii) a source voltage control circuit configured to reduce a voltage of a source of the main power switch to turn on the main power switch in response to the valley control signal being activated.

主权项

1. A driving control circuit, comprising:
a) a main power switch having a gate connected to a clamping voltage that is greater than a threshold voltage of said main power switch; b) a valley voltage detection circuit configured to activate a valley control signal when a drain-source voltage of said main power switch is at a resonance valley level; and c) a source voltage control circuit configured to reduce a voltage of a source of said main power switch to turn on said main power switch in response to said valley control signal being activated.