THE USE OF THYRISTORS AS MAIN SWITCHES IN EML APPLICATIONS

We studied the application of conventional, bipolar thyristors with different ringer gate structures as current switches in EML. The experiments showed that the bipolar thyristors have to own a fine structured gate to be able to switch a high current within a short time (high dI/dt). We succeeded in switching currents of 90 kA with a maximum dI/dt of 550 A/mus and a blocking voltage up to 6.5 kV within 0.26 ms. Furthermore we report on results obtained with serial and parallel configurations of conventional thyristors. If steps are taken to distribute the voltage equally, the devices in series work well. In parallel configurations an equal current distribution can be realized by giving each thyristor its own current source. With such a configuration of four parallel thyristors, we were able to achieve switching currents of 160 kA within 0.25 ms. The blocking voltage was 4.2 kV and dI/dt was 250 A/mus.