Comparative Analysis of High Speed Carry Skip Adders

In this paper we compared a high speed carry skip adders by considering parameters such as area, LUT’S, delay, power. When compared to conventional CSKA and other adders. Here in this project in first stage CSKA designed by using multiplexer as skip logic so by using this speed gets increased by skipping of carry. so here area gets increased so to reduce area another hybrid variable latency carry skip adder(Brent-kung adder) is designed .here power utilization also gets decreased, speed gets increased, but some delay is produced here to overcome that we followed a another method called Kogge-Stone adder here so it reduces the critical path delay. In Kogge-stone adder power is highly consumed due to more no of wiring connections so another adder was designed to reduce power consumption which is Sklansky adder which reduces power Consumption. This is done in Xilinx ISE 14.7 and power was analyzed using Xilinx power analyzer.

Delay Efficient 32-Bit Carry-Skip Adder

The design of a 32-bit carry-skip adder to achieve minimum delay is presented in this paper. A fast carry look-ahead logic using group generate and group propagate functions is used to speed up the performance of multiple stages of ripple carry adders. The group generate and group propagate functions are generated in parallel with the carry generation for each block. The optimum block sizes are decided by considering the critical path into account. The new architecture delivers the sum and carry outputs in lesser unit delays than existing carry-skip adders. The adder is implemented in 0.25 m CMOS technology at 3.3 V. The critical delay for the proposed adder is 3.4 nanoseconds. The simulation results show that the proposed adder is 18 faster than the current fastest carry-skip adder.