DRIVING CIRCUIT FOR STEPPING MOTOR

摘要

PURPOSE:To improve the driving circuit for driving a stepping motor used in printers, copying machines and the like. CONSTITUTION:A pseudo-sine-wave generating circuit 11 generates a digital signal DD on the basis of a control command CK. D/A converters 12A and 12B convert the digital signal DD from the digital form into the analog form and generate a sine-wave shaped reference voltage Vref. A constant-voltage generating circuit 13 generates a constant voltage Vs, which is to become the reference voltage in the digital/analog conversion of the D/A converters 12A and 12B. Comparators CP 11 and CP 12 compare the reference voltage Vref and phase currents Ia and Ib flowing through a stepping motor 15 and generate PWM control signals PW 11 and PW 12. These parts are provided.