Electric power steering apparatus includes a steering torque detection section
for detecting steering torque acting on a steering system, a motor for imparting
steering assist torque to the steering system; a voltage raising circuit including
a switching element to be driven by a voltage-raise controlling PWM signal; and
a motor driving controller for setting a target current to be supplied to the motor
on the basis of at least the detected steering torque, setting a motor-current
controlling duty factor signal on the basis of the target current, operating a
switching circuit on the basis of the duty factor signal to control a motor drive
current, and driving the motor with the controlled current. CPU of the motor driving
controller generates the PWM signal for controlling the voltage raising circuit.
