A novel design of multiplex differential voltage comparators(MDVC) is presented for reducing current and power dissipation. According to the special properties of relational operation and logical operation, parts of the comparators are redundant in some instances, and thus can be turned off. By selecting and switching the current routes, several effective differential pairs are biased by a single tail current stage-by-stage and the redundant comparators are turned off by cutting their tail currents. As a result, the quiescent current and power consumption are greatly decreased. The switching of current is achieved by the input differential pair transistors themselves and hence no extra switches are required. When a MDVC is used in a flash analog-to-digital converter(ADC), its current dissipation is much lower than that of the conventional comparators. This architecture can also be used in window-comparators, maximum or minimum comparators, and comparators for logical operations. The power dissipation in all these cases could be reduced significantly.
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