JPS57173562A - Ignition device - Google Patents

Abstract

PURPOSE:To perform high accurate control, by generating a pulse-like signal of interval in accordance with speed, comparing a voltage level of saw tooth wave with reference voltage at rise-up and fall-down of said pulse-like signal and adjusting the slope of said voltage level. CONSTITUTION:At rapid acceleration, the interval of a pulse signal from a detector part 2 is rapidly narrowed. At this time, a saw tooth wave at an end A is detected by a comparator unit 23A and comparator 32 for whether it reaches reference signal V2 or not at fall-down of the pulse, in accordance with the detection, a capacitor 35 in a voltage memory unit 21 is charged or discharged. While at pulse rise-up time through an inverter 65, comparison is performed with reference voltage V1 by a comparator unit 23B and comparator 61 to charge or discharge the capacitor 35. Further input to the comparator unit 23B is held by a differentiating circuit 62 and flip flop 63 from V1 to V2. Accordingly, voltage at an end B of the voltage memory unit 21 is corrected at each rise-up and fall-down of the pulse signal, then ignition timing can be highly accurately controlled.