Fast power/ground network optimization based on equivalent circuit modeling

Abstract

This paper presents an efficient algorithm for optimizing the area of power or ground networks in integrated circuits subject to the reliability constraints. Instead of solving the original power/ground networks extracted from circuit layouts as previous methods did, the new method first builds the equivalent models for many series resistors in the original networks, then the sequence of linear programming method is used to solve the simplified networks. The solutions of the original networks then are back solved from the optimized, simplified networks. The new algorithm simply exploits the regularities in the power/ground networks. Experimental results show that the complexities of simplified networks are typically significantly smaller than that of the original circuits, which renders the new algorithm extremely fast. For instance, power/ground networks with more than one million branches can be sized in a few minutes on modern SUN workstations.