IC output circuit based on a pulse width modulating system

摘要

A current path for a discharge current leading from ground to a motor is provided when a pulse width modulation (PWM) control is OFF, with a parasitic diode between a P type substrate of an NPN transistor and an N type collector region. A diode with a cathode and an anode connected to a base and an emitter of an NPN transistor is also provided, so that when the PWM control is OFF, a base current is conducted by the diode to the NPN transistor, whereby a current flows from the emitter of the NPN transistor to the collector, providing a current path for the discharge current from the motor to a power terminal.