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Accurate Measurement of Dynamic ON-state Resistance of GaN Devices under Reverse and Forward Conduction in High Frequency Power Converter

Li, Ke; Videt, Arnaud; Idir, Nadir; Evans, Paul; Johnson, Mark


Ke Li

Arnaud Videt

Nadir Idir

Associate Professor

Professor of Advanced Power Conversion


Because of trapped charges in GaN transistor structure, device dynamic ON-state resistance RDSon is increased when it is operated in high frequency switched power converters, in which device is possibly operated by zero voltage switching (ZVS) to reduce its turn-ON switching losses. When GaN transistor finishes ZVS during one switching period, device has been operated under both reverse and forward conduction. Therefore its dynamic RDSon under both conduction modes needs to be carefully measured to understand device power losses. For this reason, a measurement circuit with simple structure and fast dynamic response is proposed to characterise device reverse and forward RDSon. In order to improve measurement sensitivity when device switches at high frequency, a trapezoidal current mode is proposed to measure device RDSon under almost constant current, which resolves measurement sensitivity issues caused by unavoidable measurement circuit parasitic inductance and measurement probes deskew in conventional device characterisation method by triangle current mode. Proposed measurement circuit and measurement method is then validated by first characterising a SiC-MOSFET with constant RDSon. Then, the comparison on GaN-HEMT dynamic RDSon measurement results demonstrates the improved accuracy of proposed trapezoidal current mode over conventional triangle current mode when device switches at 1MHz.


Li, K., Videt, A., Idir, N., Evans, P., & Johnson, M. (2020). Accurate Measurement of Dynamic ON-state Resistance of GaN Devices under Reverse and Forward Conduction in High Frequency Power Converter. IEEE Transactions on Power Electronics, 35(9), 9652-9662.

Journal Article Type Article
Acceptance Date Dec 17, 2019
Online Publication Date Feb 17, 2020
Publication Date Sep 1, 2020
Deposit Date Jan 9, 2020
Publicly Available Date Mar 9, 2020
Journal IEEE Transactions on Power Electronics
Print ISSN 0885-8993
Electronic ISSN 1941-0107
Publisher Institute of Electrical and Electronics Engineers
Peer Reviewed Peer Reviewed
Volume 35
Issue 9
Pages 9652-9662
Keywords GaN transistor, Dynamic ON-state resistance, High switching frequency, Reverse conduction, Forward conduction, Soft switching
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