A High Speed Wallace Tree Multiplier Using Modified Booth Algorithm for Fast Arithmetic Circuits

Abstract

A Wallace tree multiplier using modified booth algorithm is proposed in this paper. It is an improved version of tree based Wallace tree multiplier (1) architecture. This paper aims at additional reduction of latency and power consumption of the Wallace tree multiplier. This is accomplished by the use of booth algorithm, 5:2, 4:2, and 3:2 compressor adders. An efficient VerilogHDL code has been written, successfully simulated and synthesized for Xilinx FPGA vertex-6 low power (Xc6vlx75tl-1Lff484) device, using Xilinx 12.2 ISE and XST. The result shows that the proposed architecture is around 67% faster than the existing Wallace-tree multiplier. I. INTRODUCTION A multitude of various multiplier architectures have been published in the literature, during the past few decades. The multiplier is one of the key hardware blocks in most of the digital and high performance systems such as digital signal processors and microprocessors. With the recent advances in technology, many researchers have worked on the design of increasingly more efficient multipliers. They aim at offering higher speed and lower power consumption even while occupying reduced silicon area. This makes them compatible for various complex and portable VLSI circuit implementations. However, the fact remains that the area and speed are two conflicting performance constraints. Hence, innovating increased speed always results in larger area. In this paper, we arrive at a better trade-off between the two, by realizing a marginally increased speed performance through a small rise in the number of transistors. The new architecture enhances the speed performance of the widely acknowledged Wallace tree multiplier. The structural optimization is performed on the conventional Wallace multiplier, in such a way that the latency of the total circuit reduces considerably. The Wallace tree basically multiplies two unsigned integers. The conventional Wallace tree multiplier architecture comprises of an AND array for computing the partial products, a carry save adder for adding the partial products so obtained and a carry propagate adder in the final stage of addition. In the proposed architecture, partial product generation and reduction is accomplished by the use of booth algorithm, 3:2, and 4:2, 5:2 compressor structures.