Symbolic synthesis of clock-gating logic for power optimization of synchronous controllers

Abstract

Recent results have shown that dynamic power management is effective in reducing the total power consumption of sequential circuits. In this paper, we propose a bottom-up approach for the automatic extraction and synthesis of dynamic power management circuitry starting from structural logic-level specifications. Our techniques leverage the compact BDD-based representation of Boolean and pseudo-Boolean functions to detect idle conditions where the clock can be stopped without compromising functional correctness. Moreover, symbolic techniques allow accurate probabilistic computations; in particular, they enable the use of non-equiprobable primary input distributions, a key step in the construction of models that match the behavior of real hardware devices with a high degree of fidelity. The results are encouraging, since power savings of up to 34% have been obtained on standard benchmark circuits.