| 摘要 |
<p>The present invention provides a rotation position detecting circuit for a sensor-less motor, and a motor device, which do not use a back electro-motive voltage. A motor (1) is rotated and driven by adding a sensor signal having a high frequency to a sine wave drive signal and a cosine wave drive signal through adders (5S) and (5C), respectively. A sensor signal is extracted and demodulated from a signal flowing in the motor (1) by a band pass filter (9), and this is defined as a rotation position detection signal. In the sensor signal from the band pass filter (9), its current value is changed corresponding to a change of an impedance resulting from a rotation of a magnet of the motor. It is possible to detect the rotation position of a rotor magnet, by detecting the change of the current value. <IMAGE></p> |
