Modular High-Voltage Switch with fast Rise Time

Summary

For an experimental setup for the treatment of biological cells by Pulsed Electric Fields a modular semiconductor-based closing switch has been developed. The switch consists of separate modules, which can be assembled according to the requirements of the experiment. The modules have been designed for use in a closing switch for a Blumlein-type pulse generator to deliver a pulse voltage of up to 9.6 kV into a 100 Ohm load with a pulse length between 10 ns and 50 ns. Each module is equipped with two MOSFETs in parallel configuration. For switching a higher voltage the modules are stacked. MOSFET drivers, control circuitry, and an auxiliary power supply are part of each module. The control circuitry enables a synchronized switching of the modules of a stack within 1 ns. The modular MOSFET switch has been set up and tested in different configurations: With one stack of 12 stages pulses with a fixed pulse length of 50 ns at a pulse amplitude of up to 9.6 kV have been generated. A pulsed current of 190 A at a rise time of 8 ns has been achieved. Two stacks of seven stages each have been used for control of the pulse length and pulse polarity of the Blumlein type pulse generator. The switches are closed with a defined delay time. The generation of pulses of both polarities with pulse lengths between 10 ns and 50 ns has been demonstrated. One stack of six stages has been operated at a repetition rate of 150 kHz at 4 kV charging voltage with resonant charging. The paper describes briefly the design of the modules and presents measurement results on the operation of the modular switch.

Additional informations

Authors

Sack Martin, Mueller Georg