CASCADE A/D CONVERTER

PROBLEM TO BE SOLVED: To provide a cascade A/D converter which can be operated at a high speed. SOLUTION: A cascade A/D converter is provided with comparator 8a-8d converting analog input signals into digital signals, latch circuits 9a-9e holding the outputs of the comparators, D/A converters 10a-10c converting the outputs of the comparators into the analog signals again, and subtracters 11a-11c subtracting the outputs of the D/A converters from the analog signals and outputting them to the comparator of a next stage are cascade-connected for a plurality of stages, and window comparators 50a-50f detecting the change of the codes of the comparators and an error correction circuit 51 removing noise generated in the change point of the code based on the outputs of the window comparators. At least either of switching circuit 60 switching the analog input signal and desired voltage or switching circuits 70a-70c switching the outputs of the subtracters and desired voltage is provided.