Nonlinear block-type leapfrog scheme for the fast simulation of multiconductor transmission lines with nonlinear drivers and terminations

This paper describes a fast transient simulation technique based on a block-type leapfrog scheme for general nonlinear circuits. In existing leapfrog-based techniques, there is a restriction on dealing with nonlinear elements in the circuit. On the other hand, the block-type leapfrog scheme is suitable for the simulation of tightly coupled networks such as the equivalent circuit of multiconductor transmission lines (MTLs). In this work, we extend the block-type leapfrog scheme to incorporate generalized nonlinear elements, which have two or more terminals such as MOSFETs. The proposed method partitions the circuit into some kinds of local blocks, and locally dense and nonlinear calculations are effectively confined within each relatively-small block. Example simulations of MTLs with nonlinear drivers and terminations show that the leapfrog-based nonlinear solver is much more efficient than HSPICE.