Parallel Prefix Adder (PPA) is one of the fastest types of adder that had been created and developed. Some of the common types of parallel prefix adders are Brent-Kung, Kogge-Stone, Han-Carlson and Ladner-Fischer adders. This paper involves an investigation of the performances of these adders in terms of computational delay, interconnect usage and power. The investigation and comparison for all these adders was conducted for 8 bit size. By using the XILINX 14.5 design software, the designs for above mentioned adders were developed. The simulation result produced the vector waveform which then shows the computational delay; interconnect usage and power for the adders. Hence, this project is significant in showing which of these adders being tested perform better in terms of computational delay, interconnect usage and power.
Key words: Low power; parallel prefix adder; carry save adder; ripple carry adder; han-carlson adder
The fundamental operations involved in any Digital systems are addition and multiplication. Addition is an indispensible operation in any Digital, Analog, or Control system. Fast and accurate operation of digital system depends on the performance of adders. The main function of adder is to speed up the addition of partial products generated during multiplication operation. Hence improving the speed by reduction in area is the main area of research in VLSI system design. Over the last decade many types of adder