Effects of gate current on conduction modulation in pulsed power thyristors

Texas Tech, in conjunction with PTS Company, has studied some of the device parameters of PTS's Pulse Power Thyristors(PPT), especially thePPT5325. The objective of this work was to establish the di/dt, turn-on, and reverse recovery characteristics of the PPT with varying gate drive current and anode voltage and are more specifically stated below:

1. Determine if varying gate current will improve turn-on times,
2. Determine if pulling charge from the gate will improve turn-off times and lower reverse voltages,
3. Determine the reverse recovery times,
4. Determine if the reverse recovery times can be improved by removing excess charge carriers, or plasma, from the gate with varying gate voltage,
5. Compare the PPT5325 with other pulsed power thyristors. The PPT was tested using a constant current gate drive circuit having a rise time of approximately 250ns, pulse width of lOus, and a maximum of 500A. A capacitive discharge circuit was used with anode-cathode voltages varying from OV to 1.2kV. The anode circuit is also capable of reapplying a reverse anode voltage at a specified time. This paper describes the necessary methods in designing these test circuits to obtain the device characteristics just explained.