| 摘要 |
PURPOSE:To eliminate Hall elements and miniaturize a device by energizing three-phase-connected coils forcibly to start rotation, and by obtaining driving voltage based on signal for comparing the neutal point voltage and driving voltage of the coils with each other, to drive a motor. CONSTITUTION:With frequency for starting a rotor easily, from a ring counter 18, driving signal is fed to a switching circuit 12 via a switch 19 and a converter 11, and is fed to coils 10U-10W, and the rotor is rotationally started. Along with the rotation, voltage found at the neutral points of the coils is compared with driving voltage by comparators 13U-13W, and by edge detectors 14U-14W, edges are detected, and are turned into clock signals via an OR circuit 15 and a monostable multivibrator, 16, and the input to a D flipflop 17 is provided, and change-over signal is obtained. This signal is fed to the converter 11 via the switch 19 and is turned into the driving signal. |
