A High-Voltage Flat-Top Pulse Generator With Sub-Nanosecond Rise Time Based on Avalanche Transistors

Abstract

Avalanche transistor-based (AT-based) Marx circuits have been widely researched in many fields for generating high-voltage nanosecond pulses with high repetition rates. This article introduces a novel circuit design based on ATs that produce square pulses instead of the traditional damped sinusoidal output of Marx circuits. The proposed circuit uses a pulse forming network (PFN) module instead of the capacitor at each stage of the Marx circuit. This generator comprises 20 stages of PFN modules, each containing 11 capacitors and 11 inductors (dimensions of $145\times 90$ mm). It can produce square pulses with a voltage range exceeding 3 kV, a rise time of 860 ps, a pulsewidth of 13.5 ns, and a repetition rate of 15 kHz. It has a maximum peak power of 180 kW and operates on a cable load of $50~\Omega $ . The pulse amplitude could be adjusted from 1860 to 3190 V. Extensive testing to drive the atmospheric pressure plasma jet (APPJ) has been conducted to investigate the performance characteristics of the generator. To facilitate a better comparison of the quality of APPJ in the proposed topology with a conventional AT-based generator, an extra 7.5-kV setup was developed. This article offers new perspectives on the design of AT-based generators.