Abstract
This paper describes a high voltage switch with MOSFETs connected in series employing a novel driving method in which the turn-on of the master stage by the input signal simultaneously puts other stages in conduction. Stages comected in series except for the master one are driven using the displacement current which flows just when the master stage is turned on. The displacement current can simultaneously drives those stage because the current flows in series through those stages. Hence, the fast switching speed can be obtained even with many stages connected in series. A prototype high voltage switch has been built and its characteristics has been investigated. We found that the parasitic capacitances between the stages and the ground position make the switching characteristics worse and that optimizing the circuit condition makes fast switching possible even with the parasitic capacitances. We have showed that the rise time is almost constant even with the increase in the series number, and that the rise time of 22ns in obtained with 10 MOSFETs' stage in series under an output power condition of 8kV and 120A.
