| 摘要 |
PURPOSE:To reduce the required number of input signals, by constituting a selector with a ternary signal decoding means which varies a first signal being varied to ternary values to binary values, and a means which outputs selectively the decoding signal on one side of the above means and a second signal by the decoding signal on the other side of the above means. CONSTITUTION:The titled selector is constituted of a ternary signal decoding part 11 and a selective output part 12, and the decoding part 11 is constituted of current mirror parts 21 and 22, and a decoding signal generating part 23. A first signal C with the ternary values is generated by adding signals A and B on the gates of transistors 71 and 72 respectively, and is inputted to the above current mirror parts. A first output line of the mirror part 21 is connected to a third output line of the mirror part 22, and the sizes of the capacity of current inflow and outflow are compared, and a signal E with binary values corresponding to the size is generated. Similarly, a second output line of the mirror part 21 is connected to a fourth output line of the mirror part 22, and a signal F with the binary values is generated. Therefore, the signals E and F with binary values can be generated corresponding to the states of the signal C. The signals E and F are outputted as the decoding signals G and H via the decoding signal generating part 23. To the selective output part 12, the signals G and H and a signal D from an input terminal 2 are inputted, and the decoding signal G or the signal D is selected and outputted corresponding to the state of the signal H.
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