DRIVING APPARATUS FOR BRUSH-LESS MOTOR

摘要

A phase difference between a counter-electromotive voltage induced in a driving coil and a voltage which is applied to the driving coil is detected by comparison of a terminal voltage of the driving coil (U0) and a reference voltage (NB), a frequency of a voltage-control oscillator which controls switching of the voltage applied to the driving coil is varied by an output signal made by the comparison, and the phase difference is controlled to be zero thereby.