PULSE WIDTH MODULATOR FOR DRIVING MOTOR

PURPOSE:To smoothly drive a motor by connecting a series unit of a pair of transistors in parallel with a DC power source, and conducting a transistor of positive or negative side in response to positive or negative of a control signal, thereby reducing the variation in the current of the motor. CONSTITUTION:Comparators 11-14 compare a control signal (a) input to an input terminal 17 or a signal inverted by an inverting amplifier 15 from the control signal (a) with a reference triangular wave signal (b) input to an input terminal 16, and output pulse signals A-D. The signals A-D are supplied through delay circuits 18-21 having prescribed delay times and inverter amplifiers 22- 25 to transistors Tr1-Tr4, respectively. Thus, stable drive control having small variation in the motor current, smooth motor drive and no vibration can be performed.