Design consideration for large current GTO

Abstract

Current crowding of a GTO (gate-turn-off) during turn-off operation and operating limits without breakdown were investigated by a current-distribution-measurement method and by computer simulation. It was found that to increase the maximum turn-off current, current crowding is suppressed by a gate structure optimized for the distribution of a steady on-state current. Also, current flowing into a unit GTO is reduced by optimizing the number of unit GTOs so that they are operating in a safe operating area. The characteristics of a 4000 A trial GTO fabricated on the basis of these considerations are reported.<>