Towards Highly-Integrated High-Voltage Multi-MHz GaN-on-Si Power ICs and Modules

Konferenz: PCIM Europe 2018 - International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management
05.06.2018 - 07.06.2018 in Nürnberg, Deutschland

Tagungsband: PCIM Europe 2018

Seiten: 8Sprache: EnglischTyp: PDF

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Moench, Stefan (Fraunhofer Institute for Applied Solid State Physics (IAF), 79108 Freiburg, Germany & Robert Bosch GmbH (CR/APJ3), 71272 Renningen, Germany)
Reiner, Richard; Weiss, Beatrix; Waltereit, Patrick; Quay, Ruediger; Ambacher, Oliver (Fraunhofer Institute for Applied Solid State Physics (IAF), 79108 Freiburg, Germany)
Kaden, Thomas (Robert Bosch GmbH (CR/APJ3), 71272 Renningen, Germany)
Kallfass, Ingmar (Institute of Robust Power Semiconductor Systems, University of Stuttgart, 70569 Stuttgart, Germany)

This work investigates how integration of half-bridge transistors, drivers and freewheeling-diodes on a conductive Si-substrate influences DC-DC converter performance. Based on a lateral 600 V GaNtechnology, a 300-150V, 750W buck converter is built. Conventional separate substrate-to-source terminations of the high-side and low-side devices resulted in 97.3% maximum efficiency. A common semi-floating substrate termination as applicable to monolithic ICs reduced the maximum efficiency to 96.8%, but improved no-load losses. Capacitance measurements which include the substrate as terminal explain two opposite effects resulting from the common substrate: Increased Miller capacitance slows down hard-switching turn-on transitions; reduced effective switch-node capacitance speeds up resonant transitions. Operating the integrated GaN driver with external Si-CMOS pre-driver in burst operation up to 40MHz at 350 V shows potential for multi-MHz applications. While monolithic integration is beneficial to reduced parasitic inductances and assembly effort, a differentiated analysis considering different switching conditions is required to identify system-level advantages.