An improved avalanche triode Marx circuit which solves the second stage switch vulnerability problem
Y. Liao, L. Yu, C. Yao, Shurong Dong, Hu Boxiong · 2024
Pulse generators with high voltage, subnanosecond and high repetition frequency have been used more and more in the fields of biomedicine and ultra wideband radar. Avalanche triode Marx circuit is an important way to generate high voltage subnanosecond pulses. However, the second stage switch is easy to be damaged in practice, which greatly reduces the reliability of the circuit. By analyzing the discharge mechanism, it is found that the damage of the second stage switch is related to the slow conduction speed of the first stage switch. In fact, the first stage was the last switch to be broken by an avalanche, causing the second stage switch, which had already been activated, to undergo a huge electrical stress for a moment. The electrical stress is the passive raising voltage of the second stage switch, which is the direct cause of the easy damage of the second stage switch. An effective Marx circuit of improved avalanche triode is proposed in this paper. The traditional avalanche triode Marx circuit is compared. Finally, stable output with rising edge of 230 ps, amplitude of 1.65 kV and repetition frequency of 100 kHZ is achieved.