IEEE Open Journal of Power Electronics (Jan 2020)

The Impact of Multi-MHz Switching Frequencies on Dynamic On-Resistance in GaN-on-Si HEMTs

  • Grayson Zulauf,
  • Mattia Guacci,
  • Juan M. Rivas-Davila,
  • Johann W. Kolar

DOI
https://doi.org/10.1109/OJPEL.2020.3005879
Journal volume & issue
Vol. 1
pp. 210 – 215

Abstract

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Dynamic on-resistance (dRon), where the on-resistance immediately after turn-on is higher than the DC resistance, increases the conduction losses in power converters with gallium nitride high-electron-mobility transistors (GaN HEMTs). There exist no direct dRon measurements in the literature above 1 MHz, leaving designers unable to predict conduction losses in emerging multi-MHz applications. We address this literature gap by collecting the first on-state voltage dRon measurements at multi-MHz frequencies, with a focus on the zero-voltage-switching conditions that are predominantly employed at high frequency. On the selected commercially-available HEMT with a breakdown voltage below 200 V, the dynamic contribution asymptotes above ≈ 2 MHz, a finding predicted by the slow time constants of the traps that cause dRon. For the tested HEMT, we find a maximum dRon increase over the DC resistance of 2× in a multi-MHz, zero-voltage-switched application.

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