Gallium nitride high electron mobility transistors (GaN HEMTs) show significant advantages in high frequency and high switching speed applications, which has gathered great interests. Due to the low short-circuit withstand capacity, the short-circuit protection with high response speed is critical for GaN HEMTs. Besides, the high switching speed of GaN HEMTs brings severe interference to protection circuits, which becomes a key obstacle for ultrafast short-circuit protection. This article analyzes the interference mechanism of dv/dt noise on the desaturation short-circuit protection circuits in detail. According to the noise propagation model, an improved protection circuit is proposed, in which a discharging capacitor is employed to enhance the noise immunity behavior. In addition, optimization methods of the key parameters are presented, which allow the designers to evaluate the noise immunity of the protection circuits with different parameters during the design processes. The experimental results show that the response time of the protection circuit is within 110 ns. Without the proposed methods, the noise introduced by a low dv/dt of 2.5 V/ns will generate false-trigger protection actions. The improved protection circuit can survive under the dv/dt up to 84 V/ns, which verifies the validity of the proposed optimization methods.

中文翻译：

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一种具有强抗扰度的 GaN HEMT 短路保护电路


氮化镓高电子迁移率晶体管（GaN HEMT）在高频和高开关速度应用中显示出显着的优势，引起了人们的极大兴趣。由于GaN HEMT的短路承受能力较低，因此高响应速度的短路保护对于GaN HEMT至关重要。此外，GaN HEMT的高开关速度给保护电路带来了严重干扰，成为超快短路保护的关键障碍。本文详细分析了dv/dt噪声对退饱和短路保护电路的干扰机制。根据噪声传播模型，提出了一种改进的保护电路，其中采用放电电容器来增强抗噪声性能。此外，还提出了关键参数的优化方法，使设计人员能够在设计过程中评估不同参数的保护电路的抗噪声能力。实验结果表明，保护电路的响应时间在110 ns以内。如果没有所提出的方法，2.5 V/ns 的低 dv/dt 引入的噪声将产生误触发保护动作。改进后的保护电路能够承受高达84 V/ns的dv/dt，这验证了所提出的优化方法的有效性。