Circuits and methods to control a current in a coil are disclosed. The circuit and methods provide over-dwell protection and soft shut-down functionality to safely discharge the coil. The safe discharge of the coil is facilitated by a soft-start ramp signal that reduces the coil current gradually by controlling a switching device according. A profile of the soft-start ramp signal over time determines the gradual reduction. The profile of the soft-start ramp signal can be adjusted to set (i) an over-dwell period of the coil current, after which the coil current is shut down, and (ii) a soft shut-down period, over which the coil current is gradually reduced.

Circuits and methods to control a current in a coil are disclosed. The circuit and methods provide over-dwell protection and soft shut-down functionality to safely discharge the coil. The safe discharge of the coil is facilitated by a soft-start ramp signal that reduces the coil current gradually by controlling a switching device according. A profile of the soft-start ramp signal over time determines the gradual reduction. The profile of the soft-start ramp signal can be adjusted to set (i) an over-dwell period of the coil current, after which the coil current is shut down, and (ii) a soft shut-down period, over which the coil current is gradually reduced.

An ignition coil has primary and secondary coils, a coil casing having a casing body, an accommodating part and a high voltage tower shaped part of a cylindrical shape, a resistance member arranged as a movable member in a tower through hole of the high voltage tower, a high voltage cap, and an insulation resin member with which the accommodating part is filled. A proximal end part of the tower through hole has an inner diameter which is greater than an outer diameter of a maximum outer diameter part of the resistance member. A distal end part of the tower through hole has an inner diameter which is less than the outer diameter of the maximum outer diameter part of the resistance member. A vent part is formed, through which the proximal end part of the tower through hole communicates with the distal end part of the tower through hole.

An ignition coil has primary and secondary coils, a coil casing having a casing body, an accommodating part and a high voltage tower shaped part of a cylindrical shape, a resistance member arranged as a movable member in a tower through hole of the high voltage tower, a high voltage cap, and an insulation resin member with which the accommodating part is filled. A proximal end part of the tower through hole has an inner diameter which is greater than an outer diameter of a maximum outer diameter part of the resistance member. A distal end part of the tower through hole has an inner diameter which is less than the outer diameter of the maximum outer diameter part of the resistance member. A vent part is formed, through which the proximal end part of the tower through hole communicates with the distal end part of the tower through hole.

In a general aspect, an ignition circuit can include a control circuit that is coupled with an engine control unit (ECU) to receive a command signal from the ECU. The control circuit can include a multi-pulse generator configured to, in response to the command signal, generate a multi-pulse drive signal. The multi-pulse drive signal can include a first pulse cycle having a first duty cycle, a second pulse cycle having a second duty cycle, and a dwell period during which the multi-pulse drive signal continuously remains at a logic high value. The control circuit can be configured to provide the multi-pulse drive signal to an ignition switch coupled with the control circuit to receive the multi-pulse drive signal.

In a general aspect, an ignition circuit can include a control circuit that is coupled with an engine control unit (ECU) to receive a command signal from the ECU. The control circuit can include a multi-pulse generator configured to, in response to the command signal, generate a multi-pulse drive signal. The multi-pulse drive signal can include a first pulse cycle having a first duty cycle, a second pulse cycle having a second duty cycle, and a dwell period during which the multi-pulse drive signal continuously remains at a logic high value. The control circuit can be configured to provide the multi-pulse drive signal to an ignition switch coupled with the control circuit to receive the multi-pulse drive signal.

Circuits and methods to control a current in a coil are disclosed. The circuit and methods provide over-dwell protection and soft shut-down functionality to safely discharge the coil. The safe discharge of the coil is facilitated by a soft-start ramp signal that reduces the coil current gradually by controlling a switching device according. A profile of the soft-start ramp signal over time determines the gradual reduction. The profile of the soft-start ramp signal can be adjusted to set (i) an over-dwell period of the coil current, after which the coil current is shut down, and (ii) a soft shut-down period, over which the coil current is gradually reduced.

Circuits and methods to control a current in a coil are disclosed. The circuit and methods provide over-dwell protection and soft shut-down functionality to safely discharge the coil. The safe discharge of the coil is facilitated by a soft-start ramp signal that reduces the coil current gradually by controlling a switching device according. A profile of the soft-start ramp signal over time determines the gradual reduction. The profile of the soft-start ramp signal can be adjusted to set (i) an over-dwell period of the coil current, after which the coil current is shut down, and (ii) a soft shut-down period, over which the coil current is gradually reduced.

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.

A semiconductor apparatus can block the voltage from the power source when the voltage from the power source reaches an excessive level, without requiring a larger chip size. Provided is a semiconductor apparatus including a power semiconductor element a gate of which is controlled in response to a control signal, an overvoltage detector configured to detect that a voltage at a collector terminal of the power semiconductor element reaches an overvoltage level, and a block unit configured to, in response to the detection of the overvoltage level, control the gate of the power semiconductor element to transition to an off-voltage. The semiconductor apparatus may further include a reset unit configured to, in response to that the control signal is input that turns on the power semiconductor element, output a reset signal for a predetermined period of time.