| 摘要 |
PROBLEM TO BE SOLVED: To reset a stepping motor to an excitation origin through an internal oscillator upon power interruption using charges in a capacitor for smoothing power supply. SOLUTION: If the power supply voltage drops below a predetermined level due to power interruption when a stepping motor M is stopping at a position other than an excitation origin, pulse input from an external oscillator is stopped forcibly by a power supply voltage detecting section 11 and first and second NAND circuits 12, 13. The stepping motor M is reset to an excitation origin by fourth and fifth NAND circuits 18, 20 based on a pulse waveform signal generated from an internal oscillation circuit 16 in the rotational direction determined at a rotational direction switching section 19. |
