Multiplexed single wire control and diagnosis of an electrical object

摘要

An ignition coil assembly for providing ignition energy to a spark plug in accordance with a dwell pulse and transmitting diagnostic data related to an ignition event occurring after the dwell pulse. The assembly has an ignition coil with a spark plug terminal adapted to mate with the spark plug, and a transistor for conducting current flow through the primary winding of the ignition coil. The current flow is in accordance with the dwell pulse, which arrives over a signal line. A diagnostic block receives at least one electrical signal from the ignition coil and derives diagnostic data therefrom for transmitting over the same signal line in the absence of the dwell pulse.