Patent ID: 8387580

Claim:
A plasma ignition device for an internal combustion engine, comprising: an ignition plug for the internal combustion engine; an ignition circuit that is connected in parallel to said ignition plug, and applies a high voltage to said ignition plug to start discharge; and a power supply circuit that is connected in parallel to said ignition plug, comprising a battery section that generates a plasma current for supplying an electric energy to a discharge space of said ignition plug having impedance reduced by discharge start, and a charging section that charges said battery section with a voltage boosted by a booster circuit, wherein said power supply circuit comprises: a voltage limit control section that stops a boosting operation of said booster circuit when a voltage of said charging section is equal to or higher than a first reference voltage for high-voltage abnormality detection as a result of comparison with the first reference voltage; a low-voltage abnormality detection control section that detects an abnormal voltage of said charging section by comparison with a second reference voltage for low-voltage abnormality detection for detecting ground to conduct a given control on said power supply circuit; and a control limiter section that invalidates the given control of said low-voltage abnormality detection control section until said charging section is sufficiently charged.