| 摘要 |
PURPOSE:To perform a stable rotation drive operation without using a special position detector by detecting the position by a terminal voltage presented at the input/output terminal of a current to 3-phase coils. CONSTITUTION:The terminal voltages of 3-phase coils 3a-3c of a brushless DC motor is detected by a position detector 11. A switching drive unit 12 having a selective switch and a start accelerator 13 outputs a switching signal of the first drive transistors 4a-4c and the second drie transistors 5a-5c on the basis of the control signal of the detector 11. The supply currents to the coils 3a-3c are detected by a current detector 10, and the composite ratio of the coil terminal voltages in the detector 11 is controlled in response to the output of the detector 10. |
