Patent ID: 8653774

Claim:
A motor driving circuit comprising: a Hall sensor configured to generate a Hall signal which comprises a first signal and a second signal that are complementary, according to the position of a rotor of a motor to be driven; a Hall bias circuit configured to supply a Hall bias signal to the Hall sensor; an analog amplifier configured to amplify the Hall signal; an A/D converter configured to convert the Hall signal amplified by the analog amplifier into a digital signal; an amplitude control circuit configured to adjust the amplitude of the digital signal; a control signal generating unit configured to generate a control signal to be used to drive the motor, based upon an output of the amplitude control circuit; and a driver circuit configured to drive the motor according to the control signal, wherein the aforementioned components are monolithically integrated on a single semiconductor substrate, and wherein the amplitude control circuit comprises: an amplitude correction circuit configured to stabilize the amplitude of the digital signal; and a target amplitude judgment circuit configured to adjust the gain of the analog amplifier based on the result of comparing the output of the amplitude correction circuit with a reference value.