Transient analysis of diode switching circuits using asymptotic waveform evaluation

An efficient transient analysis of diode switching circuits using the asymptotic waveform evaluation (AWE) technique is presented. The method accurately simulates the excess carrier redistribution phenomenon in a diode junction using a reduced order model. The diode model is derived by directly solving the carrier continuity equations in an analogous manner to that of the AWE solution to transmission-line equations. The method efficiently calculates the poles and the residues of the diode model by recursively generating the moments of the carrier concentrations. It reduces the computational cost by an order of magnitude over that for Linvill´s multisection model of ladder or lattice networks of many lumped elements used to model carrier diffusion and the recombination process. The pole-residue model is capable of providing an increasingly accurate approximation to the characteristics of a diode under all operating conditions. The diode recovery phenomenon is simulated for illustration, and the improved accuracy is verified by comparisons with results from conventional methods and published works