Semiconductor Components Industries, LLC

Hirotada Honma

Qingquan Tang

Hajime Takahashi

Mitchell Henry

An ignition system may include an igniter circuit to control the current in a coil supplied by a battery based on an input signal from an engine control unit. To prevent overheating, the igniter circuit may be configured to shut down the current in the coil when the input signal is held high for an over dwell period. The disclosed igniter circuit is configured with circuitry to automatically adjust the over dwell period used based on a condition of the battery to prevent overheating without prematurely shutting down. The automatic adjustment includes indirectly monitoring the battery condition based on a current or a voltage of a switching device coupled to the coil.

Igniter circuit having an adjustable over dwell time

In an implementation, a method of operating an ignition circuit can include enabling a charge path control circuit and a switch circuit to charge a primary winding of an ignition coil of the ignition circuit until a threshold current is reached in the primary winding. After reaching the threshold current in the primary winding, the method can include maintaining a current in the primary winding of the ignition coil in correspondence with a current limit by alternatively activating and deactivating the charge path control circuit complementary to alternative activation and deactivation of a circulating-current path control circuit. During the maintaining the current in the primary winding, the method can include initiating a spark in a spark plug included in the ignition circuit, the initiating the spark including controlling an amount of energy delivered from the primary winding to a secondary winding of the ignition coil.

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Kita-ku, Japan

Hirotada Honma