Originally Posted by bogbeagle
What would be the ignition coil in that circuit?
It is the labeled component at the right end of the drawing next to the spark plug. The coil is the largest part inside the module. But in this case it is pretty small though. The higher the driving voltage you can use to drive the coil with means you can make the ignition coil ever smaller and smaller. It has its roots in how the Coil on Plug (COP) ignition systems work in the modern automobile engine. They literally put a small coil right on top of each spark plug and use a microprocessor to control each one, thus eliminating a distributor and providing for custom tuning and timing on a cylinder to cylinder basis.
Yeah they usually parallel the signal wires from the timing hall effect sensor. But some modules could run a separate line off the microprocessor output pin driving the high voltage circuit too.