Recharging of the gate charge of a transistor

摘要

Power switches operate with reduced power consumption. A circuit controls a power switch via its gate having a gate capacitor. The circuit comprises an on-control switch coupling the gate of the power switch with a charge supply to provide a gate charge to the gate capacitor of the power switch, thereby putting the power switch to the on-state; a transformer and an off-control switch coupling the gate of the power switch with ground via a primary winding of the transformer to discharge the gate capacitor of the power switch, thereby causing a discharge current through the primary winding and thereby putting the power switch to the off-state; wherein a secondary winding is coupled to the charge supply, such that a current, which is induced in the secondary winding, recharges the charge supply.

主权项

1. A circuit configured to control a first power switch via a gate of the first power switch; wherein the gate of the first power switch comprises a gate capacitor; the circuit comprising
a first on-control switch configured to couple the gate of the first power switch with a charge supply to provide a gate charge to the gate capacitor of the first power switch, thereby putting the first power switch to the on-state; a transformer comprising a primary winding and a secondary winding which are electromagnetically coupled; and a first off-control switch configured to couple the gate of the first power switch with ground via the primary winding of the transformer to discharge the gate capacitor of the first power switch, thereby causing a discharge current through the primary winding and thereby putting the first power switch to the off-state; wherein the secondary winding is coupled to the charge supply, such that a current, which is induced in the secondary winding by the discharge current in the primary winding, recharges the charge supply.