Maximum power estimation for CMOS circuits using deterministic and statistic approaches

Excessive instantaneous power consumption in VLSI circuits may reduce the reliability and performance of VLSI chips. Hence, to synthesize circuits with high reliability, it is essential to efficiently obtain a precise estimation of the maximum power dissipation. However, due to the inherent input-pattern dependence of the problem, it is intractable to conduct an exhaustive search for circuits with a large number of primary inputs. Hence, the practical approach is to generate a tight lower bound and an upper bound for maximum power dissipation within a reasonable amount of CPU time. In this paper, instead of using the traditional simulation-based techniques, we propose a novel approach to obtain a lower bound of the maximum power consumption using Automatic Test Generation (ATG) technique. Experiments with MCNC and ISCAS-85 benchmark circuits show that our approach generates the lower bound with the quality which cannot be achieved using simulation-based techniques. In addition, a Monte Carlo based technique to estimate maximum power dissipation is described. It not only serves as a comparison version for our ATG approach, but also generates a metric to measure the quality of a lower bound from a statistical point of view.