초록 ▼

According to the invention, a primary winding of an ignition coil is coupled with an insulated-gate bipolar transistor (IGBT). The IGBT is controlled by a current restriction circuit, which includes a control transistor for performing the on-off operation of the IGBT such that the IGBT is made condu

According to the invention, a primary winding of an ignition coil is coupled with an insulated-gate bipolar transistor (IGBT). The IGBT is controlled by a current restriction circuit, which includes a control transistor for performing the on-off operation of the IGBT such that the IGBT is made conductive upon occurrence of an ignition control signal, and nonconductive, when a primary current of the ignition coil reaches a certain value depending on a reference voltage determined by a bias circuit. The bias circuit has a condenser, which is charged by a base current of the control transistor to change the base potential of the transistor slowly, when the transistor is made nonconductive.

대표청구항 ▼

[ We claim:] [1.] An ignition apparatus for an internal combustion engine, having:an ignition coil;an insulated-gate bipolar transistor for performing the switching control of a primary current of said ignition coil;an electronic control unit for supplying an ignition control signal to a gate of sai

[ We claim:] [1.] An ignition apparatus for an internal combustion engine, having:an ignition coil;an insulated-gate bipolar transistor for performing the switching control of a primary current of said ignition coil;an electronic control unit for supplying an ignition control signal to a gate of said insulated-gate bipolar transistor to make said transistor carry out the switching operation; andcurrent control means for restricting the ignition control signal in accordance with the primary current of said ignition coil,wherein said current control means comprises:a transistor for rendering said insulated-gate bipolar transistor conductive upon occurrence of the ignition control signal, when said transistor is in a low impedance state, said transistor being changed to a high impedance state, when the primary current of said ignition coil reaches a certain value;a bias circuit for providing a bias voltage to keep a base of said transistor at a predetermined potential, by which said transistor is changed to the low impedance state; anda condenser, which is connected to the base of said transistor and changes the base potential of said transistor with a certain time constant, when said transistor is changed to the high impedance state.