From a Redundant Number System Adder to a Novel 4-2 Compressor

We present a novel 4-2 compressor for designing multi-operand addition circuits. The design is based on a current mode circuit from which the equivalent voltage mode circuit is derived. This circuit can be used to build very fast multi-operand addition structures. We provide a gate level cost and speed comparison between our design and existing 4-2 compressors. Also, we make an analytical comparison of 4-2 compressor/counter addition structures with those produced using Wallace and Dadda trees. We showed that similar cost, our 4-2 compressor achieves up to 33% reduction in delay. Our structure has with more regularity in structure of trees and wires are than Wallace and Dadda trees.