A 20-kV fast-rise-time all-solid-state Marx generator based on a compact passive composite magnetic isolation drive.

Abstract

All-solid-state Marx generators have shown broad application prospects in fields such as dielectric barrier discharge, biomedical engineering, and environmental treatment. When pursuing nanosecond-scale fast-front pulses, the extremely high voltage change rate (dv/dt) can readily induce Miller false turn-on in switching devices. Meanwhile, conventional isolated driving schemes with robust noise immunity typically rely on bulky independent power supplies, which severely limit the development of highly compact pulsed power systems. To address these challenges, this paper proposes a compact composite magnetic isolation drive circuit that eliminates the need for an independent high-voltage isolated power supply. The proposed topology integrates a passive negative-voltage bootstrap network with an active Miller clamp (AMC) branch. Through the establishment of a transient mathematical model and ablation experiments, the synergistic immunity mechanism of the composite drive is revealed: the steady-state negative bias generated by bootstrapping, together with the low-impedance discharge path provided by the AMC, physically blocks the path through which high-frequency displacement currents could otherwise elevate the gate potential. Quantitative parasitic parameter scanning shows that even with a severe gate stray inductance of 50 nH, the proposed scheme maintains the transient gate voltage within the safe operating area of the device. Based on the above investigation, a 20-stage SSMG experimental prototype was developed. Experimental results demonstrate that the system operates stably under a wide load range (2-20 kΩ) at a repetition frequency of 1 kHz, successfully outputting fast-front high-voltage pulse sequences with an amplitude of 20 kV and a rise time of 22.9 ns.