Control circuit for ignition coil

An ignition coil control circuit which controls, in accordance with a signal from an ECU, a current flowing to a primary coil of an ignition coil for impressing a high voltage to an ignition plug,

• said ignition coil control circuit comprising:
• a switching circuit for switching the primary coil of said ignition coil;
• a driving circuit for driving said switching circuit;
• a control signal output circuit for generating and outputting a driving control signal to said driving circuit in accordance with the signal from said ECU;
• and
• a current limiting circuit for detecting a value of a current applied to said primary coil by said switching circuit and controlling said switching circuit so as to make said current not larger than a predetermined value,
• wherein said control signal output circuit uses the signal from said ECU as its power source, and said current limiting circuit uses a switching driving signal output from said driving circuit as its power source.