Comparative Study of Parallel Prefix Adders Based on Carry Propagation and Sum Propagation

Binary adders are an indispensable part of computing systems. There are different types of adders, they differ in terms of their structure and logic used. All these adders have been designed to achieve faster computation as possible. Parallel prefix adders (PPA) are one of the most efficient adders. In this work, PPAs such us Ladner-Fischer, Kogge-Stone, Brent-Kung, Knowles and Roy-auto synthesis adders were studied and compared in terms of delay, area and power. The adders now existing are using carry propagation (CP) as its fundamental concept to perform addition. Carry is a major problem in most of the adders because of its complexity and cost in the design of fast adders. The feasibility of performing addition without using carry i.e. by sum propagation (SP) concept is also analyzed in this paper.