Dynamic current localization in power bipolar switches with imperfect interconnections of controlled cells

Abstract

The objective of this paper is to analyze the safe operating area limitation caused by dynamic current localization at the gate turn-off transient of thyristor-like bipolar devices with imperfectly coupled elementary cells. The impact of series gate resistance on switching characteristics is studied by numerical simulation for the typical case of integrated thyristor with external MOS-control. The inequality of gate resistances for different cells is found to cause dangerous current localization and subsequent failure at the turn-off operation. Quantitative thresholds for the onset of current localization are determined and compared for different possible turn-off modes of the device under study.