Ultra-fast generator for impact ionization triggering

Abstract

In recent years, it has been discovered that thyristors triggered in impact ionization mode find their dI/dt capability boosted by up to three orders of magnitude. This innovative triggering requires applying an important overvoltage on the anode-cathode of the thyristor with a slew rate > 1 kV/ns. Compact pulse generators based on commercial off the shelf components (COTS) would allow the spread of this technology into numerous applications, including fast kicker generators for particle accelerators.Our approach for such a compact pulse generator begins with a HV SiC MOS with an ultra-fast super-boosting gate driver. Super boosting in the gate of a 1.7 kV rated SiC MOS allows to reduce its rise time by a factor of ≈ 30 (datasheet tr = 20 ns vs. measured tr < 680 ps), resulting in an output voltage slew rate > 1 kV/ns and an amplitude > 1 kV.Next, additional boosting is obtained by a Marx generator with D2PAK thyristors, reaching an output voltage slew rate > 16 kV/ns. Finally, creating sufficient current necessary for the triggering of a big thyristor presents a new challenge. In this paper, we present an upgraded board design with a higher current output capacity.