| 摘要 |
<p>The circuit for converting an analog signal into corresponding N-bit digital signal (A/D converter ) of a parallel comparison type comprises a 2<N-M> number of M-bit encoders(6),a single N-bit encoder(8)and error suppression circuits(10),a block indicating signal on a block indicating line belonging to each M-bit encoder serving as an output inhibit signal for one of the other error suppression circuits connected to the M-bit encoder in one lower order (or higher order) with respect to the corresponding M-bit encoder, and the block indicating line of each M-bit encoder being connected to an output terminal of one of the comparators in a lowest order (or highest order) or a few comparators in the comparator group to which the corresponding M-bit encoder is connected. Therefore, if an output signal is generated from the highest comparator (or lowest comparator) in the comparator group whose output terminals are connected to the corresponding M-bit encoder, the transmission of the output signal of the M-bit encoder in one lower order (or higher order) to the N-bit encoder is interrupted by means of the corresponding error suppression circuits when the output signal from the one lower order (or higher order) is generated. The block indicating signal is directly used as the output inhibit signal for the one lower order error suppression signal so that no particular gate circuit is needed, thus reducing the number of transistors. In addition, a small number of comparators are connected to the block indicating line so that the number of transistors is accordingly reduced.</p> |
