Design and analysis of a novel fast adder using logical effort method

Abstract

Addition, as one of the fundamental math operations, is applied widely in Very-large-scale integration systems and digital signal processing, such that the computational speed of a system depends mainly on the computational speed of its adders. There are various types of digital adders based on different methods. A novel adder is proposed which performs addition based on a path with a fewer number of levels, and, hence, with higher computational speed and lower power consumption. The goal and innovation is to design a structured fast adder that has a block that can be expanded to higher bits, and in this design, the calculation speed and power consumption of the proposed circuit are optimal. Each proposed adder circuit has several levels, and the formulae of each level are stated. Each level of the circuit is designed with a number of multiplexers and OR gates. The performance of the proposed adder has been investigated and evaluated in two parts of mathematical calculations and simulation, and it has also been compared with other existing fast adders, such as ripple carry adder, carry skip adder, carry select adder, carry look ahead adder and prefix kogge-stone in cases of 8, 16, 32 and 64 bits. The results show that the proposed collector has a good performance compared to other adders-based power consumption, power delay product and delay area product metrics.