Using SAT-based craig interpolation to enlarge clock gating functions

Dynamic power saving is gaining its dominance in modern low power designs, while clock gating, which blocks unnecessary clock switching activities, is one of the most efficient approaches to reduce the dynamic power. In this paper, we exploit the interpolation technique in a SAT-based clock gating algorithm in order to grant a greater flexibility in enlarging the gating capabilities over the original gating candidates. We also developed several techniques to improve the runtime and memory usage of the clock gating algorithm, including a gating capability filter to reduce the number of formal SAT proofs, a dynamic backtracking limit controller to shorten the SAT runs, and a shrinking method to ease the final gate count overhead. The experimental results show that our proposed algorithm can gate up to 2X clock switches with less than 5% area overhead when compared to the state-of-the-art SAT-based clock gating methodology.