Patent ID: 8130131

Claim:
An interpolating A/D converter comprising: an analog signal input circuit that receives an analog signal from outside; a reference voltage generation circuit that includes a resistor ladder connected between a maximum reference voltage and a minimum reference voltage and generates reference voltages different from one another; an amplifier group that receives the analog signal and the reference voltages, or a first input signal and a second input signal generated based on the analog signal and the reference voltages; and an interpolation circuit that interpolates output signals from the amplifier group and outputs an interpolation signal, wherein the amplifier group includes a plurality of amplifiers that amplify a differential voltage when a differential voltage between the analog signal and the reference voltages or between the first input signal and the second input signal is smaller than a specified value, and the current flow of which is stopped when the differential voltage is larger than the specified value, and the interpolation circuit includes a plurality of resistors that are connected in series between the adjacent amplifiers.