| 摘要 |
<p>An object of the present invention is to suppress surge voltages at the time of current shutoff of a switching device (Q1) for the purpose of protection from overcurrents although the switching device (Q1) is not in an overcurrent state. The control apparatus for a switching device (Q1) of the present invention comprises a current sensor (10), a comparator (501), a timer latch (502), a control circuit (80), and a transistor (95). The current sensor (10) detects the current of a switching device (Q1) and accordingly outputs a detected voltage ES. The comparator (501) outputs a signal when the detected voltage ES is equal to or greater than a reference voltage ER1. When the time duration of the output signal is equal to or greater than a setting time, the timer latch (502) outputs a surge suppression detection signal S3. Based on this surge suppression detection signal S3, the control circuit (80) outputs, to the transistor (95), a driving signal S12 to turn off the switching device (Q1). The reference voltage ER1 is smaller than a reference voltage ER2 used when detecting an overcurrent flowing in the switching device (Q1).
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