Electrothermal failure safety of TIL GTO thyristors

The work presents the main dynamic characteristics testifying to the built-in electrothermal failure-safe features of 4 × 4 mm area TO-220-packed two-interdigitation-level (TIL) GTO thyristors. It is shown that 1) a fairly good and stable current balance between the interdigitated fingers is preserved during both the turn-off and turn-on; 2) the temperature rise in the structure of TIL GTO´s is kept within safe limits under high-voltage/high-current conditions; 3) the final dimensions of the anode current crowding zone are large enough thus limiting the density of power dissipated during transient turn-off. Thanks to these self-protective features, the developed TIL GTO´s possess the highest value of the peak interruptable anode current IATO(60 A) ever reported in the open literature for this class of GTO´s (identical device area and case) and could safely operate at high commutation frequencies under heavy load conditions.