| 摘要 |
A circuit for the commutated turn-off of latched power switching devices, such as of the insulated-gate transistor/insulated-gate rectifier type, monitors the gate drive voltage and a load-current-related parameter (e.g. the collector/anode voltage) of the at least one power switching device connecting a load to a source. Comparator outputs provide logic signals indicating whether the at least one switching device has latched or has turned off in normal manner, responsive to cessation of gate drive. Circuitry for providing a cyclic gate drive signal is enabled whenever a latched condition is detected. The cyclic signals occur until the latched device is actually turned off, at a driven-unlatching current typically one-half the device latching current and typically at least an order of magnitude greater than the current at which the device will undergo self-unlatching turn-off. |
