| 摘要 |
PCT No. PCT/DE97/00927 Sec. 371 Date Nov. 20, 1998 Sec. 102(e) Date Nov. 20, 1998 PCT Filed May 7, 1997 PCT Pub. No. WO97/44827 PCT Pub. Date Nov. 27, 1997Given too great a dU/dt load of a thyristor, this can trigger in uncontrolled fashion in the region of the cathode surface. Since the plasma only propagates poorly there and the current density consequently reaches critical values very quickly, there is the risk of destruction of the thyristor due to local overheating. The proposed thyristor has a centrally placed BOD structure and a plurality of auxiliary thyristors (1.-5. AG) annularly surrounding the BOD structure. The resistance of the cathode-side base (8) is locally increased under the emitter region (11) allocated to the innermost auxiliary thyristor (1. AG). Since the width (L) and the sheet resistivity of this annular zone (15) critically influences the dU/dt loadability of the first auxiliary thyristor (1. AG), a suitable dimensioning of these parameters assures that the central thyristor region comprises the smallest dU/dt sensitivity of the system and, accordingly, it also ignites first given upward transgression of a critical value of the voltage steepness.
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