| 摘要 |
PURPOSE:To suppress noise and vibration by a constitution wherein a stepping motor is driven by preset number of pulses with a small drive current in order to check the operation thereof and the drive current is increased when a decision is made that the stepping motor has stepped out. CONSTITUTION:Selection can be made from a plurality of reference voltages VREF by modifying a set signal and drive current is increased sequentially by modifying the reference voltage VREF so that a stepping motor is operated by a number of pulses preset based on the drive current at that time. Normal operation is checked every time when the operation of the stepping motor ends and a decision is made whether the stepping motor has stepped out based on the check results. If a decision is made that the stepping motor has not stepped out, the drive current is increased. Since a correct drive current is fed, noise and vibration can be suppressed. |
