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A multiplexing drive circuit for an AC ignition system having a common leg that includes two switches coupled in series, and one or more dedicated legs, wherein each leg includes two switches coupled in series. The multiplexing drive circuit also includes a transformer for each of the one or more de

A multiplexing drive circuit for an AC ignition system having a common leg that includes two switches coupled in series, and one or more dedicated legs, wherein each leg includes two switches coupled in series. The multiplexing drive circuit also includes a transformer for each of the one or more dedicated legs, each transformer having a primary winding coupled between one of the one or more dedicated legs and the common leg, and wherein each transformer has a secondary winding coupled in parallel to a spark plug, and a pulse-width modulated (PWM) switch controller configured to operate the common leg and dedicated leg switches to control characteristics of the spark discharge for the spark plug. Wherein the switch controller is capable of real time diagnostic checks by monitoring the time at which a spark discharge event takes place.

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1. An Alternating Current (AC) ignition device, comprising: a switching network configured in a half bridge configuration;an ignition transformer with a primary coil attached as the load of the switching network;a controller configured to control the switching network;a comparator network configured

1. An Alternating Current (AC) ignition device, comprising: a switching network configured in a half bridge configuration;an ignition transformer with a primary coil attached as the load of the switching network;a controller configured to control the switching network;a comparator network configured to compare AC ignition system parameters to reference parameters; where the result of the comparison indicates to the controller how to operate the switching network. 2. The AC ignition device of claim 1, wherein the system parameters and the reference parameters compared in the comparator network are voltages. 3. The AC ignition device of claim 1, wherein the reference parameters are generated by the controller. 4. The AC ignition device of claim 1, wherein the controller is configured to set a commanded value that dictates peak current through the primary coil of the ignition transformer. 5. The AC ignition device of claim 4, wherein the controller is configured to instantaneously change the commanded value. 6. The AC ignition device of claim 1, further comprising a power supply and a current sensor configured between the power supply and the switching network with the current sensor configured to provide a system parameter that correlates to current drawn from the power supply into the switching network. 7. The AC ignition device of claim 6, wherein outputs of the comparator network are inputs into the controller. 8. The AC ignition device of claim 7, wherein the controller monitors a time at which the comparator network determines that current through a primary coil of the ignition transformer has reached low and middle points as dictated by the reference parameters. 9. The AC ignition device of claim 7, wherein the controller monitors a condition where excessive current is drawn from the power supply as compared to the reference parameters. 10. The AC ignition device of claim 1, wherein a secondary coil of the ignition transformer connects to a spark plug, and wherein the controller monitors an amount of time that it takes from the moment the AC ignition device is engaged to when current through the primary coil of the ignition transformer has reached a commanded current level which is then used to correlate to when the spark plug discharges. 11. The AC ignition device of claim 1, wherein the switching network configured in a half bridge configuration comprises switches that are unidirectional with respect to voltage and bidirectional with respect to current. 12. A method for controlling an ignition system, comprising the steps of: measuring system parameters of an initial ignition cycle;comparing the system parameters with reference parameters of the ignition system;changing the operational state of a switching network if the comparison of system parameters to reference parameters shows a peak current has been reached in a load of the switching network; andwherein the step of changing the operational state of the switching network triggers a subsequent current cycle in a load of the switching network. 13. The method of claim 12, further comprising the step of changing the reference parameter that sets a commanded value for peak current in the load of the switching network. 14. The method of claim 12, wherein the reference parameters are ideal voltages corresponding to values for low current in the load of the switching network, a middle current between ideal low current and ideal peak current in the load of the switching network, ideal peak current in the load of the switching network, and an ideal maximum value of current supplied to the switching network; wherein the system parameters are a measured voltage that correspond to current in the load of the switching network and a measured voltage that corresponds to current supplied to the switching network. 15. The method of claim 14, wherein the step of comparing compares the voltage corresponding to ideal peak current in the ignition system to the measured voltage that corresponds to current in the load of the switching network. 16. The method of claim 14, further comprising the step of diagnosing failures in the ignition system. 17. The method of claim 16, wherein the step of diagnosing failures comprises the step of indicating that during the comparing step the measured voltage that corresponds to current supplied to the switching network is greater than the ideal maximum value of current supplied to the switching network. 18. The method of claim 16, wherein the step of comparing further comprises measuring a time it takes from a start of the ignition cycle for the measured voltage that corresponds to current in the load of the switching network to rise from at least one of the ideal low voltage to the ideal middle voltage for the load of the switching network, from the ideal low voltage to the ideal peak voltage for the load of the switching network, or from the ideal middle voltage to the ideal peak voltage for the load of the switching network, and wherein the step of diagnosing comprises the step of indicating that a measured time from the step of measuring happened faster than expected, longer than expected, and/or never happened. 19. The method of claim 14, wherein the load of the switching network is a primary coil of an ignition transformer with a secondary coil attached to a spark plug; wherein the step of comparing further comprises the step of measuring the time it takes from the start of the ignition cycle for the voltage that corresponds to current in the load of the switching network to reach the ideal peak current in the load of the switching network, and storing the measured time. 20. The method of claim 19, further comprising the step of determining the level of erosion of a spark gap of the spark plug. 21. The method of claim 20, wherein the step of determining the level of erosion is done by correlating a measured time from the initial ignition event to a breakdown of the spark gap of the spark plug to reference values for an amount of time it takes to breakdown a representative spark gap of a representative spark plug at various levels of erosion for the representative spark gap. 22. The method of claim 21, wherein the references values are contained in a look-up table. 23. The method of claim 19, wherein the measured time is compared to a predefined period of time, and if the measured time exceeds the predefined period of time a misfire condition has occurred. 24. The method of claim 12, wherein the switching network is a half bridge switching network. 25. The method of claim 12, wherein the ignition system is an Alternating Current (AC) ignition system. 26. The method of claim 25, wherein the switching network of the AC ignition system is a half bridge switching network 27. The method of claim 12, wherein the ignition system is a Direct Current (DC) ignition system. 28. The method of claim 27, wherein the DC ignition system output current is a DC value and the switching network is a MOSFET and diode network.