Stepper-motor control method

摘要

A device for outputting a suitable rotation torque relative to a load torque or actual torque exerted on a stepper-motor when the stepper-motor is used as a drive of an image processing device. The output torque of the stepper-motor depends on a supply current to the stepper-motor. CPU determines a suitable supply current using a table in ROM so that the stepper-motor is able to rotate at an optimum rotation torque. To this end, CPU sends a particular signal to the motor driver so that an appropriate supply current is supplied to the excitation phases A/B of the stepper-motor. The CPU determines the load torque based on an integrated current fed to the stepper-motor during a particular period. The CPU calculates difference between the load torque and rotation torque and determines the signal to be applied to the motor driver based on the torque difference.