IGNITION DEVICE FOR INTERNAL COMBUSTION ENGINE

It is an object of the present invention to provide an ignition system for an internal combustion engine which accomplishes a stable current blocking operation of an ignition coil. A main IGBT (110) controls to conduct or block a primary current flowing through the ignition coil in response to an input ignition control signal to generate a high voltage on the secondary side of the ignition coil. The main IGBT (110) and a current limiter circuit (150) are integrated in a monolithic silicon substrate of an insulating gate bipolar power transistor. The main IGBT has a collector and a gate connected through a depletion IGBT (152) forming part of a constant current circuit, and a resistor (R4). When a voltage generated across the resistor (R4) becomes equal to or higher than a zener voltage, a zener diode (ZD2) leads this current to an emitter of the main IGBT.