Electronic ignition system

An ignition system for a spark-ignition internal combustion engine having a direct current potential source and an ignition coil having at least a primary winding coupled to said direct current potential source, said ignition system comprising:

• a solid-state switching device connected in series with said ignition coil primary winding, said solid-state switching device having a conductive state permitting current flow through said ignition coil primary winding and having a nonconductive state preventing current flow through said ignition coil primary winding;
• means for generating a periodic electrical signal in timed relation to operation of said engine, said electrical signal having a period equal to the ignition cycle of said engine;
• a first capacitor for storing electrical charge;
• a first constant current source coupled to said first capacitor;
• a constant current drain coupled to said first capacitor;
• circuit means for supplying electrical charge at a constant rate to said first capacitor from said constant current source for a predetermined fractional portion of said electrical signal, said circuit means for charging said first capacitor being coupled to said circuit means for generating said electrical signal;
• circuit means for discharging said first capacitor through said constant current drain during each period of said electrical signal and after the end of said predetermined fractional portion of said electrical signal during which said first capacitor is charged, said first capacitor being discharged through said constant current drain until the charge on said first capacitor has decreased to a predetermined level;
• circuit means for placing said solid-state switching device in its conductive state when said first capacitor has discharged to said predetermined level;
• and
• circuit means for placing said solid-state switching device in its nonconductive state at a predetermined point in said electrical signal.