Cascode型GaN功率器件的开关过程及损耗分析

Switching process and loss analysis of Cascode GaN power device

共源共栅级联(Cascode)型氮化镓(GaN)功率器件开关过程较为复杂,其开关过程和功率损耗直接影响器件的设计、应用和分阶段建模.由于器件封装成模块结构,很难对内部器件的开关性能进行分析,因此利用同型号耗尽型GaN管与低压Si MOS管搭建外部级联型GaN功率器件,检测双脉冲开关过程中低压Si MOS管漏极电压,从而分析耗尽型GaN管与低压Si MOS管各自的开关过程,以及各自的寄生参数对整管开关特性的影响.推导了考虑寄生电容影响的GaN功率器件的开关损耗计算模型.采用实际Cascode型GaN功率器件,搭建器件开关特性测试硬件平台,研究不同驱动网络参数对开关特性的影响规律.实验结果验证了本文分析方法的正确性.

The detailed switching process of Cascode GaN power devices is very complicated, the switching process and power loss directly affect the design, application, and modeling in stages of the device. It is difficult to analyze the switching performance of the internal devices because the devices were packaged into modules. Therefore, the same type of depletion GaN transistor and low-voltage Si MOS transistor were used to build external cascaded GaN power devices to detect the drain voltage of low-voltage Si MOS transistor in the process of double pulse switching, so as to analyze switching process of the depletion GaN transistor and low-voltage Si MOS transistors and the influence of their parasitic parameters on the switching characteristics of MOS transistors. The switching loss calculation model of GaN power devices considering the parasitic capacitance was derived. By using the actual Cascode GaN power device, the hardware platform for testing the switching characteristics of the device was built to study the influence of different driving network parameters on the switching characteristics. The experimental results verify the correctness of the analysis method in this paper.