Patent ID: 7007683

Claim:
An internal combustion engine ignition apparatus, comprising: an ignition coil having a primary coil and a secondary coil; and a switching circuit which interrupts a current of the primary coil of the ignition coil on the basis of an ignition signal voltage to generate a high voltage for ignition in the secondary coil of the ignition coil, wherein the ignition signal voltage is a pulse-like voltage including a rising portion and a falling portion, the switching circuit has no power supply terminal connected to a battery and includes an output terminal connected to the primary coil of the ignition coil, an input terminal for receiving the ignition signal voltage, and a reference potential terminal, the switching circuit includes a switching element which is connected between the output terminal and the reference potential terminal, applies a current to the primary coil of the ignition coil in an on state, and interrupts the current of the primary coil when an of f state is caused, a drive resistor for the switching element, a current supply circuit which is connected between the input terminal and the reference potential terminal and supplies a driving current to the drive resistor, and a waveform shaping circuit which controls the driving current from the current supply circuit to the drive resistor, brings the switching element into the on state on the basis of supply start of the driving current, and brings the switching element into the off state on the basis of supply interruption of the driving current, and the waveform shaping circuit includes a comparison signal generation circuit for generating a comparison signal on the basis of the ignition signal voltage, and a reference signal generation circuit for generating a reference signal on the basis of the ignition signal voltage, starts to supply the driving current to the drive resistor when the comparison signal becomes larger than the reference signal in the rising portion of the ignition signal voltage, and interrupts the driving current when the comparison signal becomes smaller than the reference signal in the falling portion of the ignition signal voltage.