| 摘要 |
PURPOSE:To realize the decrease in power consumption necessary for a brushless motor, to improve temperature characteristics, and to reduce cost by using a magnetoresistance effect element as a magnetoelectric transducer to detect magnetic poles of a rotor magnet. CONSTITUTION:This is a magnetic pole detector which controls energization of a magnetoelectric transducer 20 which detects magnetic poles of a rotor magnet 7 and drive coils on the basis of detection signals of this magnetoelectric transducer. The magnetoelectric transducer 20 is provided with at least first and second current paths made of a ferromagnetic substance having magnetoresistance effect: these are arranged at right angles with each other and connected in series, where an output terminal is provided at their node; and the first and second current paths are arranged close to the rotor magnet 7. This design can much increase impedance, but decrease power consumption as a brushless motor, so that the variation in the number of rotation due to ambient temperature decreases because of a low coefficient of temperature. |
