Patent ID: 11005400

Abstract:
In order to suppress high-frequency noise in micro-step driving of a stepping motor, a motor control device (100) includes an H bridge circuit (20) and control means for driving a switching element of the H bridge circuit (20) with a PWM signal and for setting a charge mode, a fast attenuation mode, or a slow attenuation mode for a motor coil. In a range from an electrical angle where the reference current value starts descending to an electrical angle of +52°, the control means switches the H bridge circuit (20) every PWM cycle to the charge mode and then to the slow attenuation mode. In a range exceeding +52° and to +90 degrees where the reference current value starts ascending, the control means switches the H bridge circuit (20) every PWM cycle to the charge mode and, if the motor current exceeds the reference current value, then the control means switches it to the fast attenuation mode and further to the slow attenuation mode.