Device for instantaneous protection considered off time of IGCT

摘要

PURPOSE: A transient protection device is provided to protect a device and prevent spreading of the disorder by interrupting a gate drive signal through sensing of signal variation owing to turn-off fail of the device using a monitoring signal for feeding back a drive state for the gate drive signal. CONSTITUTION: In a device for sensing an error of IGCT and protecting the IGCT used as a high-voltage large-volume switching device, a trigger signal generating part(11) generates a trigger signal which is delayed by a predetermined time, compared with a gate drive signal, at falling edge timing of a gate drive on signal. A latch signal generating and error state displaying part(13) judges a state of a monitoring signal of feeding back a driver state for the gate drive signal at a time when the trigger signal is generated, and displays an error state. At the same time, the latch signal generating and error state displaying part(13) interrupts an input of the gate drive signal. The monitoring signal is supplied to the latch signal generating and error state displaying part(13) via an inverter(15).