JPS55122180A - Driving circuit for pulse motor of timepiece - Google Patents

Abstract

PURPOSE:To provide a driving circuit which has a smiple construction, a compensation effect and low power consumption, by detecting abnormality at prescribed timing in terms of the induced voltage of a pulse motor driving coil and by producing required driving pulses when the abnormality occurs. CONSTITUTION:When a step-like load or the like is applied to a pulse motor 114, the amplitude of the induced voltage of a driving coil 118 decreases and its phase deviates. At that time, an abnormality detection voltage based on the sum of the induced voltage and a reference voltage from a reference signal generator 113 cannot set reset the FF of a detection circuit 112 and a prescribed gate of a wave form conversion circuit 109 is opened by the set output of the FF. The sampling of the induced voltage of the coil 118 by circuits 113, 112 is performed through a sampling pulse generation circuit 111 coupled to the conversion circuit 109 to supply the coil 118 with driving pulses of delayed phase and different wave form in comparison with stationary driving pulses at required timing when there is abnormality. Since the detection circuit which does not need a counter or the like is used, the constitution is simplified. This results in providing a driving circuit which has a compensation effect against any load and does not consume needless power.