Freewheeling diode for a GTO thyristor

摘要

In freewheeling diodes loaded with direct voltage which are connected in antiparallel with GTO thyristors in static converters, spontaneous failures due to loss of the blocking capability occur even when the diodes are operated distinctly below the rated blocking voltage. These failures, which are presumably attributable to cosmic radiation, can be reduced considerably when the doping and the thickness of the centre zone are selected in such a manner that when the maximum blocking capability is reached, the field strength at the nn<+> junction is at least 0.2-times the field strength at the pn junction. <IMAGE>