Control device for stepping motor and control method for stepping motor

A control device for a stepping motor, the control device configured to apply an excitation current to multiple coils to rotate a rotor, the control device comprising:

• a drive unit configured to apply a drive voltage to the coils;
• and
• a control unit configured to control the drive voltage applied by the drive unit,
• wherein the control unit includes an activation control unit configured to perform, during a hold period of an activation period of the stepping motor, an activation control which gradually increases a magnitude of the excitation current flowing in the coils such that the rotor moves to a predetermined initial position, and
• wherein the stop control unit is configured to perform the activation control such that a variation amount of the excitation current per unit time becomes a predetermined threshold value for the activation period or less, and that a value of the excitation current at an end of the hold period of the activation period becomes larger than 30% of the value of the excitation current applied after the end of the hold period of the activation period.

A control method for a stepping motor, which applies an excitation current to multiple coils to rotate a rotor, the control method comprising:

• controlling a drive voltage applied to the coils during a normal driving period of the stepping motor;
• and
• performing, during a hold period of a stop period of the stepping motor, a stop control which gradually decreases a magnitude of an excitation current flowing in the coils such that the rotor moves to a predetermined stop position,
• wherein the stop control is performed such that a variation amount of the excitation current per unit time becomes a predetermined threshold value for the stop period or less.

A control method for a stepping motor, which applies an excitation current to multiple coils to rotate a rotor, the control method comprising:

• controlling a drive voltage applied to the coils during a normal driving of the stepping motor;
• and
• performing, during a hold period of an activation period of the stepping motor, an activation control which gradually increases a magnitude of the excitation current flowing in the coils such that the rotor moves to a predetermined initial position,
• wherein the activation control is performed such that a variation amount of the excitation current per unit time becomes a predetermined threshold value for the activation period or less, and that a value of the excitation current at an end of the hold period of the activation period becomes larger than 30% of the value of the excitation current applied after the end of the hold period of the activation period.