IGNITION DEVICE FOR INTERNAL COMBUSTION ENGINE

PURPOSE:To simplify the circuit structure by giving a turn-off command to a switching element when the discharge current flowing from an energy accumulating capacitor via the primary winding of an ignition coil becomes a preset value. CONSTITUTION:When a turn-on command is given to a switching element 31 based on an ignition signal 18, charges of an energy accumulating capacitor 13 charged by a high-voltage generating circuit 12 in advance are discharged to the primary winding 14 of an ignition coil, and a discharge spark with a quick rise is generated on an ignition plug 17 connected to the secondary side 15. The primary current of the ignition coil has an increasing tendency transiently, thus a command to forcibly turn off the switching element 31 is given to it when the current detected by a current detecting circuit 33 is increased to the preset value. The primary current of the ignition coil is then forcibly cut off, the resulting high voltage is generated in the secondary winding 15, and a discharge spark extending the discharge duration is generated succeedingly to the quickly rising discharge spark portion. Reliability can be improved with a simple structure.