A method for reducing the pin count of an integrated ignition coil

摘要

In a first preferred embodiment, the present feature of the invention multiplexes both the ionization and driver current feedback signals into one signal, thus reducing cost and making coil packaging easier. The multiplexed signal first outputs the ionization detection signal and then replaces the ionization signal with the charge current feedback signal when the charge command V_in is enabled. In other words, the multiplexed feedback signal outputs the ionization feedback signal and switches to the charge current feedback signal when the charge command V_in is active. In a second preferred embodiment, the present feature of the invention comprises a method and apparatus to multiplex the ignition driver gate signal with both the ignition coil charge current feedback signal and the ionization signal, thus reducing the package pin count by two.