High Performance Thermal Solution for High Power eGaN® FET Based Power Converters

Conference: PCIM Europe 2018 - International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management
06/05/2018 - 06/07/2018 at Nürnberg, Deutschland

Proceedings: PCIM Europe 2018

Pages: 7Language: englishTyp: PDF

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de Rooij, Michael; Zhang, Yuanzhe; Reusch, David (Efficient Power Conversion (EPC) Corporation, USA)
Chandrasekaran, Sriram (Raytheon, USA)

Higher power density wafer level chipscale (WLCS) GaN FETs have traditionally relied on cooling from junction-to-board into the PCB. Some work has been published on adding backside cooling using silicon pads or gel based thermal interface materials (TIM) [1, 2, 3]. Past thermal solutions for GaN FETs required careful assembly to minimize mechanical stresses that complicated implementation. This paper explores a thermal cooling method suitable for WLCS GaN FETs that eliminates mechanical stresses during assembly and yields excellent thermal performance using a liquid thermal interface material. A 140 V to 28 V Buck converter, capable of delivering 34 A (1 kW) was designed and built. Tests were performed using forced air cooling on the PCB and repeated with the proposed thermal solution that resulted in more than a four times increase in output current capability compared to a converter without a heatsink.