To provide a motor drive device that can implement soft start control of a motor in a simple and inexpensive circuit configuration even when the motor is released from lock protection and restarted.
A motor drive device 1 includes: a control circuit section 10 for controlling the direction of a driving current Ic for driving a motor 2; a current detection circuit 3 for detecting the driving current Ic; a current limit adjustment circuit 20 for suppressing the rate of increase in the driving current Ic in cooperation with the current detection circuit 3 at a start when the rotating speed of the motor 2 is increased to a stationary rotating speed; and a soft start assist circuit 30 for resetting the current limit adjustment circuit 20 when the motor 2 is locked and disabled from rotating. When the motor 2 is locked, the control circuit section 10 reduces the driving current Ic to lock-protect the motor 2, and when the motor 2 is released from lock protection and restarted, the soft start assist circuit 30 instructs the current limit adjustment circuit 20 to suppress the rate of increase in the driving current Ic.
Miho Takeuchi
Ishikawa Tatsuro
Tsuyoshi Shiraka