JPS5638995A - Method and device for driving step motor - Google Patents

Abstract

PURPOSE:To remove the vibration of the step motor, by generating from an input pulse signal a pulse whose period is smaller than that of the input pulse signal and by generating analogue signal currents of different phases from the latter pulse signal to drive the step motor. CONSTITUTION:Pulses P are applied to the forward rotation input of a counter 11 cleared. The output of the counter 11 increases gradually until the number of the pulses P reaches 2<8>. After the number of the pulses P exceeds 2<8>, the output decreases gradually. When the number of the pulses has become 2<8>X2, the output becomes zero. The output of a transfer circuit 12, which reproduces th output of the counter 11 as it is, is changed into driving signals A, -A by a conversion circuit 21. The output of a transfer puase shifting circuit 13 increases gradually until the number of the phlses P becomes 2<7>. After the number exceeds 2<7>, the output of the circuit 13 decreases gradually. When the number has become 2<7>X2, the output of the circuit 13 becomes zero. The output of the circuit 13 is changed into driving signals B, -B by another conversion circuit 22. The energizing of windings of phases A, -A, B, -B is controlled by phase driving transistors 31-34 supplied with the driving signals A, -A, B, -B.