Logic Transformation for Low Power Synthesis

Abstract

In this article we present a new approach to the problem of local logic transformation for reducing power dissipation in logic circuits. The proposed approach overcomes one of the critical limitations common to the previous approaches of local logic transformations for low power, namely, a sequential greedy transformation that identifies signals with high switching activities and then resynthesizes the signals one by one. Instead, we identify a set of signal lines as a group for logic transformation, and determine an order of transformation of the signals with the maximum reduction of power dissipation in the circuit. As a practically feasible solution to this problem, we develop a power model called a finite state input transition (FIT) model, which allows the efficient measurement of the change of power dissipation of the circuit for every possible sequence of logic transformations among the signal lines. Experimental results show that the proposed approach performs an extensive local logic transformation, reducing power consumption by 33% on average without any increase of circuit delay.