Generating voltage drop aware current budgets for RC power grids

Abstract

Efficient verification of the chip power distribution network is a critical task in modern chip design. It should be done early in the design process where adjustments can be most easily incorporated. As an alternative to simulation based methods, vectorless verification is a class of techniques that requires user-specified current constraints (budgets), and checks if the corresponding worst-case voltage drops at all grid nodes are below user-specified thresholds. However, obtaining/specifying the current constraints remains a burdensome task for users. Recent literature has addressed the constraints generation problem by proposing the inverse problem: for a given grid, we would like to generate circuit current constraints which, if adhered to by the underlying logic, would guarantee grid safety. In this paper, we adopt the same framework. We develop an efficient algorithm for constraints generation that targets a key grid quality metric namely the uniformity of temperature distribution across the die area.