Analog to digital converter of the parallel comparison

Claim 1

An analog-to-digital converter of parallel comparison type comprising a plurality of comparator means each producing a binary-code signal of a predetermined level only when an analog input signal applied to said comparator means is between two reference voltages predetermined for said comparator means, said reference voltages being predetermined in a multiplicity of stages corresponding to the quantization of the analog input signals, said reference voltages being applied to respective comparator means being different from one another, and code conversion means for converting parallel binary-code signals obtained from said comparator means into a series of binary-code signals having the number of bits related to the number of quantization levels, said plurality of comparator means including a plurality of differential comparators and a plurality of output transistors each inserted between two adjacent differential comparators, each of said differential comparators including at least two transistors, each of said output transistors having an emitter connected to the collector of one of the two transistors of the first of the adjacent differential comparators and having a base connected to the collector of one of the two transistors of the second of the adjacent differential comparators, said output transistors being turned on and off by the potential differences of the collector outputs of said two differential comparators, thereby forming window type comparison characteristics.