Efficient steady state simulation of nonlinear integrated circuits

We implemented a modification technique named Newton-Powell, in the harmonic balance based circuit simulator SPECTRE, in order to improve the numerical efficiency of nonlinear circuit analysis. In this paper we discuss some aspect of the algorithm implementation, and we evaluate the Newton-Powell method in terms of efficiency and convergence properties. The method is compared with the well known Samanskii simplification technique and experimental data are reported, demonstrating that Newton-Powell method exhibits better performances, especially in case of strongly nonlinear circuits. The advantages of the concurrent use of Newton-Powell and Samanskii techniques are also investigated.