AN ALGORITHM FOR SIMULATING POWER GROUND NETWORKS USING PADE APPROXIMANTS AND ITS SYMBOLIC IMPLEMENTATION/

This paper presents an event-driven algorithm and its symbolic impleme ntation for the analysis of power and ground (P/G) bus networks. The a lgorithm uses frequency-domain techniques and moment matching approach es based on Fade approximants to estimate the transfer function at eac h node in the P/G network, Afterwards, the transient waveforms are ext racted for each node. The process requires repetitive simulation of a linear and time-variant (from one time event to the next) circuit mode l for the P/G network which is the reason a symbolic implementation wa s produced. The P/G network is modeled by a hierarchical combination o f mesh and tree structures that are composed of a collection of RC-pi- segments and pulldown (or pullup) switches. The snitches are symbolica lly represented by Boolean variables and a compiled symbolic code is g enerated only once for each P/G network. The transient waveforms are t hen produced by repetitive evaluation of the symbolic output. The resu lts show that the symbolic implementation is an order of magnitude fas ter, with reasonably good accuracy, than using a traditional analog ci rcuit simulator like SPICE.