MOTOR AND DISC APPARATUS THEREWITH

摘要

PROBLEM TO BE SOLVED: To provide a disc apparatus and a motor having a small power loss and low level noise and vibration. SOLUTION: A power transistor of a power supply unit 20 forms current paths to the 3-phase coils 12 to 14 while it is conducting high frequency switching. A position detecting unit 31 outputs a position signal corresponding to the rotating position of a rotor 11. A switching control unit 22 generates a switching pulse signal in response to the result of comparison between a current detection signal and a command signal. A power supply control unit 32 determines the power feeding section of the power transistor in response to the position signal of the position detecting unit 31, and controls the power transistor to conduct high frequency ON/OFF switching in response to the switching pulse signal of the switching control unit 22. Moreover, the power transistor is periodically controlled to the OFF state with the predetermined repetition period, and the repetition period of the OFF state is extended when a disc 1 is rotating at a higher speed.