M. Moghaddam - Dept. of Electrical Engineering Shahed University Tehran – IRAN
M. B. Ghaznavi-Ghoushchi

In this paper the graph energy and electrical power consumption of various parallel prefix adders (PPA) are measured and investigated. By comparison the graph energy of PPAs with their power consumption, a linear relation between them is considered. Moreover, the measurements represent direct relation between arcs number and graph energy in PPA structures. Using these results a new PPA (proposed І) is introduced that it is achieved from Sklansky adder with reduction of graph energy and limiting the recursive stages to maximum 8 steps. A new standard, product of arc numbers and logic depth, is applied to compare the performance of proposed adder І with other PPAs. In addition using even and odd cells in proposed adder І resulted in proposed adder ІІ. All the simulations are done with Hspice and CMOS technology 180nm. Simulation results represent that power-delay-product of our 32-bit proposed adder І and ІІ come with about 17% and 35% improvement compared with Sklansky adder, respectively.

Parallel Prefix Adders, Sklansky Adder, Lowpower, Low-Area, CMOS Circuits, Graph Energy