Precise identification of the worst-case voltage drop conditions in power grid verification

Identifying worst-case voltage drop conditions in every module supplied by the power grid is a crucial problem in modern IC design. In this paper we develop a novel methodology for power grid verification which is based on accurately constructing the space of current variations of the supplied modules and locating its precise points that yield the worst-case voltage drop conditions. The construction of the current space is performed via plain simulation and statistical extrapolation using results from extreme value theory. The method overcomes limitations of past methods which either relied on loosely bounding the worst-case voltage drop, or abstracted the current space in a vague and incomplete set of bound-type constraints. Experimental results verify the potential of the proposed method to identify worst-case conditions and demonstrate the pessimism inherent in previous bound-type approaches. Copyright 2006 ACM