Non-quasi-static model of transient processes in a forwardbiased p–n-junction

Abstract: A voltage surge at the beginning of the transient characteristic for a forward-biased p–n-junction is demonstrated, which occurs due to the dependence of the series loss resistance on the diffusion charge. It is shown that modern SPICE models of a p–n-junction do not allow one to describe this surge due to the fact that the series resistance is assumed to be independent of the charge, and the accumulated diffusion charge is calculated in the quasi-static approximation. A non-quasi-static model of transient processes in a forward-biased p–n-junction is proposed, which correctly describes the overshoot in the direct recovery transient response. The proposed model includes only common quasistatic elements of computer-aided design systems, which makes it available for implementation at the user level.

Keywords: p–n-junction, direct recovery, series loss resistance, diffusion charge, non-quasi-static model