Compact Solid-State Marx Modulator With Fast Switching for Nanosecond Pulse

Abstract

This article describes the compact solid-state Marx modulator (SSMM) with a fast rising time and a short pulsewidth based on the modular structure. By stacking of the TO-263-7 packaged silicon carbide <small>mosfet</small>s having high voltage and fast switching capabilities, the designed circuit consists of three components, including the Marx capacitor, an <small>on</small> switch for applying pulse to the load, and an <small>off</small> switch to pull down the pulse. The <small>off</small> switch connected in parallel with load is chosen as a <small>mosfet</small> instead of a diode that is used in the conventional Marx generator. Because the <small>off</small> switch provides a discharging path for the stored energy on the parasitic capacitance, it is highly related to the fast falling time. In order to provide complementary driving signal and power for <small>on&#x002F;off</small> switches, the simple control algorithm with a minimum component count and a reliable drive circuit against the noise are proposed. In addition, the synchronization of all the gate signals and a compact configuration for minimizing the stray inductance are essential to shorten the rising, falling, and pulsewidth. Based on the proposed circuit, the following specifications of the developed SSMM are achieved: the output voltage of 10 kV, the pulsewidth of less than 50 ns, and the rising and falling times of less than 15 ns.