A motor driving circuit may include a Hall sensor configured to generate a Hall signal according to the position of a rotor of a motor to be driven; a Hall bias circuit; an analog amplifier configured to amplify the Hall signal; an A/D converter configured to convert the Hall signal 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; and a driver circuit configured to drive the motor according to the control signal. The components may be monolithically integrated on a single semiconductor substrate. The amplitude control circuit may include an amplitude correction circuit; and a target amplitude judgment circuit configured to adjust the gain of the analog amplifier.