A Simple, Compact, and Power-Efficient Current-Mode Decimal Adder Circuit

Abstract

A size and power efficient current-mode decimal adder is proposed in this paper. The proposed adder does not use binary coded decimal (BCD) number system for processing the decimal data like other decimal adders. Instead, it processes the decimal data as the actual decimal inputs. The proposed adder can be used as a decimal half adder as well as a decimal full adder. The adder is based on simple decimal arithmetic that we use in our daily life. The proposed adder has been simulated in 90 nm technology with a supply voltage of 0.4 V and unit current step of 0.3 µA. The proposed adder occupies an area of only 3 µm² and consumes only 7.52 µW power. This adder is suitable for commercial and financial applications which spend most of their time in decimal computations. For future applications, parallel decimal arithmetic will be more attractive to achieve the output with fewer computations compared to binary and BCD arithmetic.

Keywords: Multi-valued logic, current-mode circuits, decimal adder, arithmetic units