Patent ID: 7053573
Filing Date: 2006-05-30
Classification: H02P

Abstract:
1. A motor drive apparatus comprising: a charge/discharge reference voltage generation circuit that generates two different charge/discharge reference voltages that define an upper limit and a lower limit of a potential difference which varies continuously according to a rotation speed setting voltage for setting a rotation speed of a motor; a capacitor that is charged and discharged; a charge/discharge circuit that switches charge and discharge of the capacitor so that the capacitor is charged/discharged between the two charge/discharge reference voltages according to a pulse signal which indicates a relative position between a rotor and a stator of the motor; a comparator that compares a charge/discharge voltage of the capacitor with a comparison reference voltage between the two charge/discharge reference voltages, and generates a pulse-delayed signal by continuously delaying the pulse signal according to the rotation speed setting voltage; and a drive circuit that turns on and off a drive transistor for causing a current to flow through a drive coil of the motor, based on the pulse-delayed signal.