ANALOG-TO-DIGITAL CONVERTER

PURPOSE: To reduce the power consumption with use of a small hardware quantity and also to improve the output characteristic by providing a return processing part which outputs the higher order bits of a digital signal and an interpolation processing part which outputs the lower order bits of the digital signal. CONSTITUTION: An analog-to-digital converter includes a return processing part 10 which outputs hither 3 bits of a digital signal of 6 bits obtained by conversion of input analog signals Vin+ and Vin-, and an interpolation processing part 20 which outputs lower 3 bits of the digital signal. The part 20 includes a sine wave generation circuit 2 which generates four sine waves S0, S1, S2 and S3 whose phases are successively shifted by π/4 and a comparator group 40 which includes plural double input comparators. These comparators perform the interpolation to omit a resistance string and an emitter-follower buffer that drives the resistance string in a conventional converter. Therefore, both hardware quantity and power consumption can be reduced.