| 摘要 |
<p>A device for driving a brushless motor without a position detector for detecting the position of the movable member of a motor. The drive device comprises a phase control loop in which current is supplied to motor drive coils (1, 2, 3) based on an output of a voltage controlled oscillator (40), a phase difference between the current waveform being supplied and the counter-electromotive force of the motor drive coils is detected by a phase error detector (20) during a period where the current is not flowing, the detected phase error signal is amplified by an error amplifier (30) and is input to the voltage controlled oscillator (40) to control the output of the voltage controlled oscillator (40); oscillation frequency initializing means (70); and a drive transistor stop circuit (80).</p> |
