| 摘要 |
<p>Provided is a highly safe ignition device for an internal combustion engine whereby overcurrent can be quickly blocked when abnormalities occur in the igniter, preventing abnormal heat generation caused by overcurrent due to short-circuiting between ignition coil windings, etc. When an overcurrent flows from a primary winding (1a) of an ignition coil (1) through a power transistor (31) of an igniter (3), an overcurrent detection comparator (42) in an overcurrent detection means (4) turns on; and when the overcurrent detected state exceeds a permissible time duration, a permissible charge conductance time determination comparator (52) in an overcurrent conduction time observation means (5) turns on, a switching element (6), which is provided to a bypass circuit extending from a safety circuit (13) to GND without passing through the ignition coil (1), is switched from open to closed, the bypass circuit closes, a current exceeding the rated current flows to and fuses the safety circuit (13), and the supply of electricity from a vehicle battery (11) to the ignition coil (1) is inhibited.</p> |
