Quiescent current disconnect system and apparatus for ignition coils of internal combustion engine ignition system

Ignition coil quiescent current disconnect system

• to interrupt current flow through the ignition coil (12) of the ignition system of an internal combustion engine by opening a switch (13) controlling current flow to the ignition coil, comprising
• means (15, 16) generating a speed-control signal (f.sub.e);
• means (22) generating a clock signal (f.sub.o, f.sub.c);
• and a disconnect control stage (20) including
• a counter (30) connected to the speed-related signal (f.sub.e) and the clock signal (f.sub.c) counting out the speed related signal at the clock rate and providing a count signal
• and a logic stage (32) having the count signal from the output of the count decoding stage (31) as well as the speed related signal (f.sub.e) applied thereto and providing a disconnect signal upon logical combination of the speed related and the count signals.