| 摘要 |
A gate driver for turning on and turning off a power switching device (118) having a capacitive gate control input (162) provides galvanic isolation between low-level control circuitry (122) and the power switching device by means of a transformer (104) having a controlled amount of effective secondary leakage inductance. The secondary (108) of the transformer is connected in series with the gate control input (162) and a first unidirectional conducting device (110). Driver logic on the secondary side of the transformer controls a gate switch which is connected across the gate control input. The gate driver operates in a multiplexed mode: if a voltage pulse is applied across the primary winding (106) of the transformer at a time when the power switching device is off the driver logic will turn the gate switch off, thereby enabling charging of the effective gate capacitance (116) as a means of turning the power switching device on; if a voltage pulse is applied across the primary winding of the transformer at a time when the power switching device is on the driver logic will turn the gate switch on, thereby discharging the effective gate capacitance as a means of turning the power switching device off. |
