Differential switch circuit

摘要

A differential switch circuit having an input circuit being responsive to an input signal for providing switch instructions corresponding to the level of the input signal, a bias circuit coupled to the input circuit for generating bias signals respectively corresponding to the switch instructions, and a differential transistor circuit coupled to the bias circuit for providing a plurality of outputs in accordance with the potential of each of the bias signals. The input circuit includes comparators which respond to three levels of the input signal and provide the switch instructions in a manner so that the switch instructions respectively correspond to the levels of the input signal. The bias circuit includes three bias sources. Each of the bias sources generates one of the bias signals according to the switch instructions. The differential transistor circuit includes a current source and three switch transistors each of which emitter is coupled to the current source, each of which base receives one of the bias signals, and each of which collector provides one of the outputs.