Integration circuit, decrement circuit, and semiconductor devices

An ignitor comprising a circuit with a millisecond order time constant and with a minimum circuit size and area, which is capable of self-shutdown without leading to erroneous ignition upon detection of an abnormality. An ignitor 1 capable of self-shutdown upon detection of an abnormality comprises an abnormality detection circuit 12 whose rise output is applied to the gate of a self-shutdown MOSFET 33 via an integration circuit 33 comprised of a diode 8 and a capacitor 9. The gate voltage of IGBT 5a, which is a main-current switching device, can be decremented.