Proximity Optimization for Adaptive Circuit Design

Abstract

The performance growth of conventional VLSI circuits is seriously hampered by various variation effects and the fundamental limit of chip power density. Adaptive circuit design is recognized as a power-efficient approach to tackling the variation challenge. However, it tends to entail large area overhead if not carefully designed. This work studies how to reduce the overhead by forming adaptivity blocks considering both timing and spatial proximity among logic cells. The proximity optimization consists of timing and location aware cell clustering and incremental placement enforcing the clusters. Experiments are performed on the ICCAD 2014 benchmark circuits, which include case of near one million cells. Compared to alternative methods, our approach achieves 1/4 to 3/4 area overhead reduction with an average of 0.6% wirelength overhead, while retains about the same timing yield and power.