A/D converter utilizing successive approximation

DETAILED DESCRIPTION In view of the drawbacks with the prior art, it is an object of the present invention to provide an A/D converter capable of reducing the lowering of the accuracy of A/D conversion.
An A/D converter according to the present invention comprises reference voltage generator means for generating a plurality of reference input voltages from a power supply, a comparator composed of switching means for alternately inputting external analog input voltage and said reference input voltage into said A/D converter and of an amplifier for amplifying said respective input voltages, and control means for controlling said reference voltage generator means and said comparator based upon an output from said comparator, said amplifier circuit of said comparator and said reference voltage generator means sharing a power supply.
The above and other objects, features, and advantages of the invention will become more apparent from the following description when taken in conjunction with the accompanying drawings.