A high current, high dI/dt, light activated thyristor

Solid-state switches are necessary for pulsed power systems which require long life, high reliability and high repeatability. However, state-of-the-art electrically gated thyristors cannot achieve the dI/dt rating necessary for the most advanced pulsed power systems. Optical activation of the thyristor can be utilized to drastically increase the dI/dt rating and thus the area of the switch is determined only by the temperature rise. The authors present experimental results of a novel optical activation technique which can be used to efficiently couple light into a large area thyristor. Using this technique, a single 6 kV, 77 mm thyristor conducted 111 kA with a 10-90% rise-time of 1.3 μs and a pulse width of ∼6 μs. The circuit limited dI/dt was 85 kA/μs. In addition, two switches were operated in series to hold-off 12 kV and, when activated, conducted 108 kA with a 1.3 μs risetime and a pulse width of ∼6 μs.