Abstract: A bipolar stepper motor driving device drives a stepper motor including stator coils having plural phases. The bipolar stepper motor driving device includes H-bridge circuits, a current detector, a control circuit, and a re-turning-on instruction unit. The H-bridge circuits are provided correspondingly to the phases of the respective stator coils. The current detector detects current flowing in the stator coils. The control circuit executes drive control of the H-bridge circuits. The re-turning-on instruction unit commands the control circuit to switch into a short-circuited state a stator coil which has shifted from an energized state to an off-state among the stator coils, on a condition that an absolute value of a reverse current detected by the current detector has changed from a value larger than a threshold current value to a value smaller than the threshold current value.

Abstract: A bipolar stepper motor driving device drives a stepper motor including stator coils having plural phases. The bipolar stepper motor driving device includes H-bridge circuits, a current detector, a control circuit, and a re-turning-on instruction unit. The H-bridge circuits are provided correspondingly to the phases of the respective stator coils. The current detector detects current flowing in the stator coils. The control circuit executes drive control of the H-bridge circuits. The re-turning-on instruction unit commands the control circuit to switch into a short-circuited state a stator coil which has shifted from an energized state to an off-state among the stator coils, on a condition that an absolute value of a reverse current detected by the current detector has changed from a value larger than a threshold current value to a value smaller than the threshold current value.