A New Method for Solving Systems of Nonlinear Equations in Circuit Simulation
James T. Wilkes · 1994
Efficient analog simulation of integrated circuits continues to be an important step in the design of integrated circuits. The heart of this simulation is solving systems of nonlinear equations that are derived from a description of the circuit. Most of the current solvers for these systems are based on Newton-type methods with enhancements for dealing with the convergence problems that these methods are known to encounter. However, current solvers continue to experience convergence difficulties. In this study, we introduce a new technique for dealing with one of the convergence problems that damped Newton methods encounter. The method is motivated by problems in which the convergence of a damped Newton method is initially slow with no evidence of ill-conditioning or singularity. The new method is termed NlEm (en-lem), short for nonlinear elimination. Issues relevant to the implementation of the algorithm in the context of circuit simulation are discussed. This discussion is based on a...