| 摘要 |
<P>PROBLEM TO BE SOLVED: To properly obtain a binarized signal which indicates a rotational position of a rotor, to reduce the unevenness of the rotation of a motor, and to improve the efficiency of the motor. <P>SOLUTION: A motor drive circuit comprises: a hysteresis comparator which binarizes a positional detection signal of a sine waveform outputted from a magnetism detection element for detecting the rotational position of the rotor of the motor, and generates the binarized signal of a rectangular waveform which forms a prescribed cycle every time the rotor rotates one round; a reference time signal generation circuit which divides the binarized signal outputted from the hysteresis comparator by using a dividing number corresponding to the prescribed cycle, and generates a reference time signal which changes in level within the prescribed cycle at equal intervals; a synchronization circuit which synchronizes a level change of the binarized signal outputted from the hysteresis comparator with a level change of the reference time signal outputted form the reference time signal generation circuit; and a drive circuit which generates an energizing signal for energizing a drive coil of the motor on the basis of the binarized signal outputted from the synchronization circuit. <P>COPYRIGHT: (C)2009,JPO&INPIT |
