Patent ID: 8485166

Claim:
An ignition device for an internal combustion engine comprising: a plasma discharge type spark plug; an ignition coil which supplies a discharge voltage to said spark plug on the basis of an ignition signal; and a power circuit which is connected in parallel to said spark plug, and supplies plasma energy for generating plasma in discharge space of said spark plug at the time of starting of discharge of said spark plug, said power circuit comprising: a DC/DC converter which is connected to DC power, and outputs a DC voltage; a PJ capacitor which is connected to the output side of said DC/DC converter, and charges the plasma energy for generating the plasma in the discharge space of said spark plug; a tank capacitor which is charged by the output of said DC/DC converter, and charges said PJ capacitor at a predetermined time; a voltage limiting circuit in which a plurality of different voltage limiting values for setting a charging voltage of said tank capacitor are set, and which restricts an output voltage of said DC/DC converter to a predetermined value; and a high breakdown voltage switch which is provided between said tank capacitor and said PJ capacitor, and in which ON/OFF control is performed by a driving signal corresponding to an operation state of said internal combustion engine to control a charging time period of said PJ capacitor, said voltage limiting circuit switching set values of the voltage limiting values by a control signal synchronized with the driving signal of said high breakdown voltage switch.