US Patent 7312733 Semiconductor apparatus with an analog-to-digital converter and amplifier

A semiconductor apparatus includes an amplifying unit, a bias controlling unit, an AD converting unit and a controlling unit. The amplifying unit is configured to amplify an input signal to output an amplified signal. The bias controlling unit is configured to generate a bias voltage to be applied to the input signal. The AD converting unit is configured to AD-convert the amplified signal into an output signal. The controlling unit is configured to output a control signal to the bias controlling unit. The controlling unit outputs the control signal when an output value indicated by the output signal is equal to a predetermined value. The bias controlling unit changes the bias voltage in response to the control signal.