| 摘要 |
<p>PURPOSE:To improve responsibility for driving an electric motor by insertedly providing a feedback circuit to input an electric current detecting signal of the electric motor for encouraging steering force to an error amplifier with an amplifier in which both an offset voltage and an input bias current are small. CONSTITUTION:An output signal of a torque sensor TS to detect the torque of a column shaft provided with a steering shaft is converted into a digital signal through an amplifier 1 and an A/D converter 2, and then inputted to the one input terminal of an error amplifier 5. An error signal between the digital signal and an electric current detecting signal of an electric motor inputted to the other input terminal of the error amplifier 5 is fed to an electric motor driving circuit 6 to control each of transistors T1-T4 for controlling the driving of an electric motor 7. In this case, an electric circuit between an input current detecting resistance R0 and the error amplifier 5 is insertedly provided with a smoothing filter 5 and an amplifier 11 for which one being small in both an offset voltage and an input bias current shall be used.</p> |
