Patent ID: 6898497

Claim:
An electric power steering apparatus comprising: a steering torque detection section for detecting steering torque acting on a steering system of a vehicle and generating a steering torque signal indicative of the detected steering torque; a motor for imparting steering assist torque to the steering system; a motor driving controller for setting a target current to be supplied to said motor on the basis of at least the steering torque signal, 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 said motor with the controlled motor drive current, said motor driving controller including a control section having a motor drive circuit for driving the motor with the controlled motor drive current; and a voltage raising circuit for raising a voltage to a given level to be supplied to the motor drive circuit, the voltage raising circuit including a switching element to be driven by a voltage-raise controlling PWM signal, wherein the control section of the motor drive controller further includes a CPU, said CPU generating the voltage-raise controlling PWM signal for controlling said voltage raising circuit, and wherein said CPU of said motor driving controller includes data conversion means for, on the basis of a voltage signal output by and fed back from said voltage raising circuit, generating the voltage-raise controlling PWM signal for controlling said voltage raising circuit.