Logic Optimization by Output Phase Assignment in Dynamic Logic Synthesis

        Domino logic is one of the most popular dynamic circuit configurations for implementing high-performance logic designs. Since domino logic is inherently non-inverting, it presents a fundamental constraint of implementing logic functions without any intermediate inversions. Removal of intermediate inverters requires logic duplication for generating both the negative and postive signal phases, which results in significant area overhead. This area overhead can be substantially reduced by selecting an optimal output phase assignment, which results in a minimum logic duplication penalty for obtaining inverter-free logic. In this paper, we present this previously unaddressed problem of output phase assignment for minimum area duplication in dynamic logic synthesis. We give both optimal and heuristic algorithms for minimizing logic duplication.

By: Ruchir Puri, Andrew Bjorksten (IBM Austin) and Thomas E. Rosser (IBM Austin)

Published in: RC20533 in 1996

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