Dynamic on-Resistance in GaN-on-Si HEMTs: Origins, Dependencies, and Future Characterization Frameworks
Dynamic on-Resistance in GaN-on-Si HEMTs: Origins, Dependencies, and Future Characterization Frameworks
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DOI：
10.1109/tpel.2019.2955656
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发表时间：
2020-06
影响因子：
6.7
通讯作者：
G. Zulauf;M. Guacci;J. Kolar
中科院分区：
文献类型：
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作者：
G. Zulauf;M. Guacci;J. Kolar
氮化镓高电子迁移率晶体管（GaN HEMT）表现出动态导通电阻（d${R_{\text{on}}}$），其中导通后立即的导通电阻高于相同结温下的直流值。最近大量文献报道了 d${R_{\text{on}}}$，其中一些文献发表的传导损耗增加了八倍，而另一些文献则发现该问题不存在。这种变化很大程度上归因于标准化双脉冲测试（DPT）方法，该方法没有指定阻断时间，并且会忽略多个开关周期累积的任何影响。由于没有一致的测量结果，设计人员无法准确估计采用 GaN HEMT 的转换器的传导损耗。我们讨论了电荷捕获的根本原因，以找到对 d${R_{\text{on}}}$ 的关键影响，并表明 DPT 技术给出了无效的结果。我们的测量验证了每个操作参数必须独立控制，并且只有稳态 d${R_{\text{on}}}$ 测量才能预测原位性能。对于本文中测试的商用 GaN HEMT，最坏情况下的 d${R_{\text{on}}}$ 比相同温度下的直流电阻高出近两倍，这证实了准确的 d${R_{\text{on}}}$ 表征对于预测转换器特性仍然至关重要。最后，我们为 GaN HEMT 制造商提供了报告框架以及估算 GaN HEMT 转换器传导损耗的方法。
Gallium nitride high-electron-mobility transistors (GaN HEMTs) exhibit dynamic on-resistance (d${R_{\text{on}}}$), where the on-resistance immediately after turn-on is higher than the dc value at the same junction temperature. A proliferation of recent literature reports d${R_{\text{on}}}$, with some publishing an eight times increase in conduction losses and others finding that the problem is nonexistent. This variation can be largely attributed to the standardized double-pulse-test (DPT) method, which does not specify the blocking time and will ignore any effects that accumulate over multiple switching cycles. With no consistent measurements, designers are left without an accurate conduction loss estimate in converters with GaN HEMTs. We discuss the underlying causes of charge trapping to find the key influences over d${R_{\text{on}}}$, and show that the DPT technique gives invalid results. Our measurements validate that each operating parameter must be independently controlled and that only steady-state d${R_{\text{on}}}$ measurements will predict in situ performance. For the commercial GaN HEMT tested in this letter, the worst-case d${R_{\text{on}}}$ is nearly two times higher than the dc resistance at the same temperature, confirming that accurate d${R_{\text{on}}}$ characterization remains critical to predicting converter characteristics. Finally, we provide a reporting framework for GaN HEMT manufacturers and methods to estimate conduction losses in converters with GaN HEMTs.