Patent ID: 9035582
Filing Date: 2015-05-19
Classification: H02P

Abstract:
1. A motor driving apparatus, comprising an automatic gain control circuit on a signal path for transmitting a rotor-position detecting signal, wherein the automatic gain control circuit comprises: a difference amplifier, for differential amplifying a differential input signal to generate an amplified hall current signal; a current mirror section, for generating a monitoring current signal equivalent to the amplified hall current signal; a full wave rectifier, for full wave rectifying the monitoring current signal to generate a rectified monitoring current signal; a feedback control portion, for monitoring an accumulated rectified monitoring current signal to decide a gain of the difference amplifier, the accumulated rectified monitoring current signal is obtained by adding the rectified monitoring current signal of three phases comprising a first phase, a second phase, and a third phase; and a current/voltage conversion portion, for generating a sine wave voltage signal from the amplified hall current signal, wherein the automatic gain control circuit outputs the sine wave voltage signal as an output signal.