Drive control device for direct current motor, rotation drive system for direct current motor and semiconductor integrated circuit for driving coil

摘要

A dc motor drive system with a PWM control system permits a high-accuracy rotation drive control while detecting the currents flowing into the coils without using shunt resistors. The system drives output MOS transistors by the PWM control to make the currents flow into the coils, and drives to rotate the dc motor. The system includes current sensing MOS transistors having a predetermined size ratio 1/m (M>1) to the output MOS transistors that make the currents flow into the coils. The current sensing MOS transistors are capable of making flow reduced currents proportional to the currents of the output MOS transistors.