Low power stepping motor driver circuit and method

摘要

A stepping motor driver system includes a switching system which sequentially selects windings of a stepper motor in a predetermined pattern to effect stepping of the rotor of the stepping motor from one "hold" position to the next. The stepping motor drive system sequentially connects a high supply voltage to each of the windings to achieve rapid current buildup in the selected windings and to maintain a predetermined average current in the selected windings. An input circuit responsive to a power control signal electrically disconnects the stepping motor windings from the power supply and electrically connects a low current holding current source to the windings so that a low holding current flows through the selected windings, maintaining a "holding" torque on the rotor at a predetermined stepping position thereof. Low power consumption, rapid frictional damping of mechanical oscillation of the rotor, and elimination of audio hum are thereby attained when the rotor is in a hold position.