Various embodiments of the present technology comprise a method and apparatus for a current circuit. According to various embodiments, the current circuit may be utilized for current detection or current limiting. The current circuit may be configured to compensate for a base current, making detection of an input current more accurate.

A system for interrupting ignition is disclosed. Specific implementations of ignition interrupters may include a first conductive tab configured to couple to a spark plug; a second conductive tab configured to couple to a spark plug wire; a first tab holder coupled with the first conductive tab; a second tab holder coupled with the second conductive tab, where the second conductive tab overlaps with the first conductive tab; a sled positioned perpendicularly to a plane of the first conductive tab and the second conductive tab, the sled coupled between the first conductive tab and the second conductive tab; a first spring coupled to the sled; and a second spring coupled to the sled; where the sled may be configured to move to an open position in the gap between the first conductive tab and the second conductive tab, decompressing the first spring and the second spring.

A system for interrupting ignition is disclosed. Specific implementations of ignition interrupters may include a first conductive tab configured to couple to a spark plug; a second conductive tab configured to couple to a spark plug wire; a first tab holder coupled with the first conductive tab; a second tab holder coupled with the second conductive tab, where the second conductive tab overlaps with the first conductive tab; a sled positioned perpendicularly to a plane of the first conductive tab and the second conductive tab, the sled coupled between the first conductive tab and the second conductive tab; a first spring coupled to the sled; and a second spring coupled to the sled; where the sled may be configured to move to an open position in the gap between the first conductive tab and the second conductive tab, decompressing the first spring and the second spring.

An ignition device for generating a spark discharge at a spark plug based on a first voltage from a first supply and a second voltage from a second supply. The second voltage is higher than the first voltage. In the ignition device, a primary coil includes a center tap, a first terminal on a ground side of the center tap, and a second terminal on a first-supply side of the center tap, and a secondary coil is electromagnetically coupled to the primary coil and electrically connected to the spark plug. A first switch is configured to make or break an electrical connection between the first terminal and ground, a second switch is configured to make or break an electrical connection between the second supply and the center tap, and a third switch is configured to pass or interrupt a current from the second terminal to the first supply. A controller is configured to control an on/off state of each of the first to third switches.

An ignition device for generating a spark discharge at a spark plug based on a first voltage from a first supply and a second voltage from a second supply. The second voltage is higher than the first voltage. In the ignition device, a primary coil includes a center tap, a first terminal on a ground side of the center tap, and a second terminal on a first-supply side of the center tap, and a secondary coil is electromagnetically coupled to the primary coil and electrically connected to the spark plug. A first switch is configured to make or break an electrical connection between the first terminal and ground, a second switch is configured to make or break an electrical connection between the second supply and the center tap, and a third switch is configured to pass or interrupt a current from the second terminal to the first supply. A controller is configured to control an on/off state of each of the first to third switches.

A multi-charge ignition system including a spark plug control unit adapted to control at least two coil stages so as to successively energise and de-energise the coil stages to provide a current to a spark plug, the two stages including a first transformer including a first primary winding inductively coupled to a first secondary winding a second transformer including a second primary winding inductively coupled to a second secondary winding. A first switch is located between the high end side of the first primary winding and the high end side of the second primary winding, and a second switch is located between the low side of the first primary winding and high side of the second primary winding.

A multi-charge ignition system including a spark plug control unit adapted to control at least two coil stages so as to successively energise and de-energise the coil stages to provide a current to a spark plug, the two stages including a first transformer including a first primary winding inductively coupled to a first secondary winding a second transformer including a second primary winding inductively coupled to a second secondary winding. A first switch is located between the high end side of the first primary winding and the high end side of the second primary winding, and a second switch is located between the low side of the first primary winding and high side of the second primary winding.

A circuit and method for gradually reducing a coil current during a shutdown period is disclosed. The circuit and method include a controller that is configured in a control loop with a current sensor that measures the current in the coil and a transistor that can be controller to limit the current in the coil. The open-loop gain of the controller is determined by a resistance of a variable feedback resistor, and the resistance of the variable feedback resistor is reduced during the shutdown period as the coil current becomes small. The reduction of the resistance maintains a suitable phase margin by lowering the open loop gain of the circuit for low coil currents. Thus, during shutdown, the circuit provides control accuracy for high coil currents and control stability for low coil currents.

A circuit and method for gradually reducing a coil current during a shutdown period is disclosed. The circuit and method include a controller that is configured in a control loop with a current sensor that measures the current in the coil and a transistor that can be controller to limit the current in the coil. The open-loop gain of the controller is determined by a resistance of a variable feedback resistor, and the resistance of the variable feedback resistor is reduced during the shutdown period as the coil current becomes small. The reduction of the resistance maintains a suitable phase margin by lowering the open loop gain of the circuit for low coil currents. Thus, during shutdown, the circuit provides control accuracy for high coil currents and control stability for low coil currents.

An ignition exciter high frequency switching converter, ignition assembly, and method of operating the same, include a high frequency switching converter operably by way of a control circuit having a timing mechanism, to operate the high frequency switching converter in discontinuous conduction mode to charge a tank capacitor for igniting an igniter.