Evaluation of Si and SiC SGTOs for High-Action Army Applications

The U.S. Army Research Laboratory has been exploring silicon and silicon carbide supergate turn-off thyristors (SGTOs) for high-power pulse switching required by Army survivability and lethality applications. Silicon SGTOs (3.5 cm²) were pulsed at 5 kA with a half-sine current waveform measuring 1 ms at the base. The recovery time, or Tq , of the devices was evaluated from the point at which the main current pulse fell to zero. Using a driver designed to provide both turn-on and turn-off signals, the Tq was reduced to 10 mus. Smaller silicon carbide SGTOs (0.16 cm²) were similarly evaluated for wide-pulse performance. They were switched several times at a peak current above 300 A, with an unassisted Tq time of 30 mus. This paper provides details of the aforementioned pulse switching as well as a description of continuing evaluations involving parallel devices and larger test beds.