Reduction of oscillations in a GaN bridge leg using active gate driving with sub-ns resolution, arbitrary gate-impedance patterns

Harry Dymond, David Liu, Joyce Wang, Jeremy Dalton, Neville McNeill, Dinesh Pamunuwa, Simon Hollis, Bernard Stark

Research output: Chapter in Book/Report/Conference proceedingConference contribution book

10 Citations (Scopus)


Active gate driving provides an opportunity to reduce EMI in power electronic circuits. Whilst it has been demonstrated for MOS-gated silicon power semiconductor devices, reported advanced gate driving in wide-bandgap devices has been limited to a single impedance change during the device switching transitions. For the first time, this paper shows multi-point gate signal profiling at the sub-ns resolution required for GaN devices. A high-speed, programmable active gate driver is implemented with an integrated high-speed memory and output stage to realise arbitrary gate pull-up and pulldown resistance profiles. The nominal resistance range is 120 μΩ to 64 Ω, and the timing resolution of impedance changes is 150 ps. This driver is used in a 1 MHz GaN bridge leg that represents a synchronous buck converter. It is demonstrated that the gate voltage profile can be manipulated aggressively in nanosecond scale. It is observed that by profiling the first 5 ns of the control device's gate voltage transient, a reduction in switch-node voltage oscillations is observed, resulting in an 8-16 dB reduction in spectral power between 400 MHz and 1.8 GHz. This occurs without an increase in switching loss. A small increase in spectral power is seen below 320 MHz. As a baseline for comparison, the GaN bridge leg is operated with a fixed gate drive strength. It is concluded that p-type gate GaN HFETs are actively controllable, and that EMI can be reduced without increasing switching loss.
Original languageEnglish
Title of host publication2016 IEEE Energy Conversion Congress and Exposition (ECCE)
Place of PublicationPiscataway, N.J.
ISBN (Print)978-1-5090-0738-7
Publication statusPublished - 18 Sep 2016
Event8th IEEE Energy Conversion Congress and Exposition -
Duration: 18 Sep 201622 Sep 2016


Conference8th IEEE Energy Conversion Congress and Exposition


  • logic gates
  • oscillators
  • gallium nitride
  • electromagnetic interference

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