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The avalanche transistor-based Marx circuit has great advantages in generating high-voltage nanosecond pulses. The introduction of auxiliary triggering topology (ATT) can reduce the damage probability of transistors in M × N-stage Marx bank circuits (MBCs). However, as the number of modified stages increases, the output voltage drops significantly, which makes it not achievable to adopt ATT at each stage. The transistors in nonmodified stages still have a certain failure rate when operating at a high repetition rate. Moreover, the previous ATT is only applicable in the negative polarity MBC. In this article, an improved ATT is proposed to solve the above problems. First, its operating principle is analyzed, and the feasibility of its application in both negative and positive MBCs is verified by simulations. Then, the effects of the improved ATT on M × N-stage MBCs are experimentally studied, and the results show that the improved ATT can be used in all stages of MBC without reducing the output voltage. It can also reduce the minimum operating voltage of transistors and widen the regulating range of output voltage. In addition, it can improve the synchronous conduction of parallel-connected transistors. Finally, two nanosecond pulse generators with positive and negative polarity, respectively, are developed and used to drive the atmospheric pressure plasma jet. The amplitude of output voltage can be adjusted in the range of 5–10 kV, measuring at the open end of a coaxial cable with 75 Ω impedance, and the maximum repetition rate is up to 7 kHz. [ABSTRACT FROM AUTHOR]

Avalanche transistor (AT)-based repetitive nanosecond pulse generators with high amplitude, fast rise time, narrow pulse width, and low jitter have been widely developed and applied in numerous fields. However, relatively little research has been carried out on the positive nanosecond pulse generation with high flexibility in a wide range of output voltage amplitude. In this article, a novel AT-based Marx circuit (MC) topology adopting base-triggering method is proposed to avoid the formation of current filamentation inside the transistors and resolve the contradiction between high-voltage output and high repetition rate operation. A $6\times 10$ -stage MC prototype is implemented with optimized parameters to validate the feasibility of the proposed topology. The conduction processes of transistors show that, with the injection of additional base current, the switched-ON modes are transformed, which contributes to reliable conduction of transistors even without sufficient overvoltage ramp. With the adoption of inner triggering loops, the minimum working voltage of the prototype is extended to 1150 V. The operation characteristics of the generator in the whole operation range are investigated in depth. Experimental results illustrate that, at the 75- $\Omega $ match-ended coaxial cable, the prototype is capable of generating positive pulses with an adjustable voltage amplitude in the range of 6.50 to 12.39 kV, a basically consistent rise time of 3.6 ns and pulse width of 19.5 ns. Over 107 successive pulses are generated at a maximum repetition rate of 1 kHz without any device failure. [ABSTRACT FROM AUTHOR]

Avalanche transistor-based Marx bank circuit (MBC) is widely used to generate nanosecond pulses with high amplitude, high repetition rate, fast rise time, and low jitter. Recently, the problem that avalanche transistors in the first several stages of $M \times N$ -stage MBC fail frequently has been alleviated by adopting auxiliary triggering topology (ATT). However, the reasons for improvement and the optimal design method have not been fully understood. In this article, a flexible $4\,\,\times10$ -stage MBC is developed to further investigate the output characteristics under different modified stages, capacitors, and loads through both experiments and simulations. The results show that on the one hand, adopting ATT will cause energy loss of the main capacitors to auxiliary triggering capacitors, which can decrease the output voltage; and on the other hand, transistors operating in the auxiliary triggering switching-ON mode have lower residual voltage than in the lower overvoltage switching-ON mode, which can increase the output voltage. This implies that there exists an optimal value of modified stages, which is 5 for the $4\,\,\times10$ -stage MBC. Besides, by adopting ATT, the waveform of output pulse changes, and the rising edge becomes faster. Finally, a repetitive nanosecond pulse generator is developed based on the optimized parameters, which can produce pulses with an amplitude of 9.04 kV, a rise time of 3.4 ns, a pulse width of 18.8 ns, and a maximum repetition rate of 1 kHz at the 75- $\Omega $ open-ended cable. Also, the feasibility of this modified MBC is validated by the preliminary experiments of driving atmospheric pressure plasma jet (APPJ). [ABSTRACT FROM AUTHOR]