Control device for stepping motor and control method for stepping motor

Abstract

A control device for a stepping motor capable of hold control that can smoothly reduce an excitation current at a rotation stopping time of the stepping motor is provided. A control device (10) for a stepping motor (20) causes an excitation current to flow in a plurality of coils to rotate a rotor. The control device (10) includes a driving circuit (40) that applies a driving voltage to the coils, and a control circuit (30) that controls the driving voltage. The control circuit (30) performs hold control to move the rotor to a predetermined stop position by changing a magnitude of the excitation current flowing in the coils so that the magnitude of the excitation current becomes close to a target current value that gradually decreases, in a hold time period at a rotation stopping time of the stepping motor (20). The control circuit (30) sets an operation mode of the driving circuit (40) at an operation mode corresponding to a comparison result of the magnitude of the excitation current and the target current value, of a plurality of operation modes, at each predetermined period in the hold time period. The plurality of operation modes include a charge mode to increase the excitation current and a first attenuation mode to attenuate the excitation current.

Dependencies are inferred from the claim text.