A-D converter suitable for fuzzy controller

An analog-to-digital converter, comprising:

• (a) reference voltage generating means for generating a plurality of different analog reference comparison voltages;
• (b) decoder means connected to said reference voltage generating means and including at least one decoder block composed of plural array switches, for decoding a non-linear function coded by an arrangement of array switches to output the analog reference comparison voltages in response to digital signals in accordance with the coded function;
• (c) at least one comparator means connected to said decoder means, for comparing the outputted analog reference comparison voltage with a voltage of an analog input signal to be converted and outputting a reset signal when the analog reference comparison voltage is substantially equal to the analog input signal voltage;
• and
• (d) approximation register means connected to said at least one comparator and to said decoder means, for successively outputting the digital signals to said decoder means to successively output the different analog reference comparison voltages to said comparator in accordance with the non-linear function and for outputting an A-D converted signal in response to the reset signal from said comparator, whereby the digital signals corresponding to the analog signals can be obtained in accordance with the at least one non-linear function by selectively switching the array switches of said decoder means in response to the digital signals outputted from said approximation register means.