Cross Conduction of GaN HFETs in Half-Bridge Converters

J. Böcker1, C. Kuring1, O. Hilt2, J. Würfl2, S. Dieckerhoff1

Published in:

Proc. Int. Exhibition and Conf. for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management (PCIM Europe 2017), Nuremberg, Germany, May 16-18, ISBN 978-3-8007-4424-4, pp. 1378-1385 (2017).

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Abstract:

Cross conduction in GaN HFETs is particularly critical due to the high dVDS/dt and small gatesource capacitances in conjunction with moderate drain-gate feed-back capacitances. Therefore, the switching speed is limited in current devices, which leads to increased losses. In this work, the turn-on peak current and increased turn-on losses due to cross conduction are investigated for two normallyoff GaN HEFTs in a half-bridge topology. It is shown that a lower turn-off gate driver voltage level reduces cross conduction and can minimize the total device losses, despite of higher dead time conduction losses.

1 Technische Universität Berlin, Germany
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, 12489 Berlin, Germany