Patent attributes
A control apparatus for a switching device which suppresses surge voltages at the time of current shutoff of a switching device to protect from overcurrents although the switching device is not in an overcurrent state, including a current sensor, a comparator, a timer latch, a control circuit, and a transistor. The current sensor detects the current of a switching device and outputs a detected voltage. The comparator outputs a signal when the detected voltage is equal to or greater than a reference voltage. When the time duration of the output signal is equal to or greater than a setting time, the timer latch outputs a surge suppression detection signal, based on which the control circuit outputs to the transistor a driving signal to turn off the switching device. The reference voltage is smaller than a reference voltage used when detecting an overcurrent flowing in the switching device.
