A high power cascode switch for rapid and efficient energy transfer at high repetition rates

Rapid pulsing from high voltage, high current pulsed power supplies is challenging for a number of reasons, chief among them is the lack of solid state switches capable of switching desired voltage and current with sufficiently fast turn on and turn off times. To address this issue, a switching system composed of power MOSFETs arranged in a cascode configuration has been developed. This system is capable of switching 500 V at 1 kA with turn on time less than 10 ns and a maximum di/dt of 1×10¹⁰ A/s. It has been used as the primary switch in multiple pulse generators and has operated at pulsed repetition rates as high as 100 kHz. In these initial tests, repetition rate was limited only by the charging circuitry. Given sufficiently robust charging, this design is capable of operating at repetition rates as high as 1 MHz in an architecture that produces 10 kV, 5 ns pulses. The first prototype of this system has been completed and characterized; the results from measurements designed to extract time resolved switch parasitics are reported. In light of the successful implementation of this prototype, design of the next iteration of this modular cascade switch is planning stages. Emphasis is placed on usability, with the intention of producing a fully shielded “black box” that is easily integrated into the front end switching system of existing pulsed power supplies.