The bipolar transistor and GTO thyristor in a high power, high frequency cascode switch configuration

A bipolar transistor has been operated in the snubberless cascode or emitter switch configuration up to power levels of 180 kVA at a switching frequency of 50 kHz. There are no fundamental limitations in extending this rating. The transistor has been reliably operated with the V/sub cex/ rating. Storage times have been reduced by a factor of 10, while current fall time is maintained under 100 ns up to current levels of 300 A. The drive circuitry is shown and discussed in depth. Results are shown for tail voltages of 500 V to 700 V and collector currents of 30 A to 300 A. The gate-turn-off (GTO) thyristor cascode or cathode switch has achieved current fall times of under 150 ns and storage times under 500 ns at current levels in excess of 300 A. The switch has been tested up to 200 A on a 600 V DC rail.<>