| 摘要 |
PURPOSE:To stabilize the drive of a motor early when starting it up, by detecting the relative positional relation between the stator coils and the rotor magnet through the counter-electromotive force produced in the stator coils, and outputting patterns for stator coil excitation according to the resultant position signal. CONSTITUTION:A position detecting circuit 3 detects the position of a rotor magnet through the counter-electromotive force produced in the phase M coil 7 and phase S coil in a motor when driving the motor. The resultant position signal is fed to a signal switching circuit 5 and therefrom to a logical operation circuit 4. The logical operation circuit 4 processes the signal and supplies any of transistors Tr1-Tr4 of phase S or M with a base signal. Since no counter- electromotive force is generated in the coils when starting up the motor, a starting circuit 2 feeds the signal switching circuit 5 with a synchronizing signal for starting up the motor, and thus forcedly starts the rotor. This enables the miniaturization of motors and cost reduction. |
