Large Signal Determination of Non-Linear Output Capacitance of Gallium-Nitride Field Effect Transistors from Switch-Off Voltage Transients ? A Numerical Method

David Pentz; Andrea Joannou

Large Signal Determination of Non-Linear Output Capacitance of Gallium-Nitride Field Effect Transistors from Switch-Off Voltage Transients ? A Numerical Method

David Pentz

Andrea Joannou

Vol. 18, No. 6, pp. 1912-1919, Nov. 2018

10.6113/JPE.2018.18.6.1912

GaN FET

Large signal analysis

Numerical method

Output capacitance

Switching transients

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Abstract

The output capacitance of power semiconductor devices is important in determining the switching losses and in the operation of some resonant converter topologies. Thus, it is important to be able to accurately determine the output capacitance of a particular device operating at elevated power levels so that the contribution of the output capacitance discharge to switch-on losses can be determined under these conditions. Power semiconductor switch manufacturers usually measure device output capacitance using small-signal methods that may be insufficient for power switching applications. This paper shows how first principle methods are applied in a novel way to obtain more relevant large signal output capacitances of Gallium-Nitride (GaN) FETs using the drain-source voltage transient during device switch-off numerically. A non-linear capacitance for an increase in voltage is determined with good correlation. Simulations are verified using experimental results from two different devices. It is shown that the large signal output capacitance as a function of the drain-source voltage is higher than the small signal values published in the data sheets for each of the devices. It can also be seen that the loss contribution of the output capacitance discharging in the channel during switch-on correlates well with other methods proposed in the literature, which confirms that the proposed method has merit.

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Cite this article

[IEEE Style]

D. Pentz and A. Joannou, "Large Signal Determination of Non-Linear Output Capacitance of Gallium-Nitride Field Effect Transistors from Switch-Off Voltage Transients ? A Numerical Method," Journal of Power Electronics, vol. 18, no. 6, pp. 1912-1919, 2018. DOI: 10.6113/JPE.2018.18.6.1912.

[ACM Style]

David Pentz and Andrea Joannou. 2018. Large Signal Determination of Non-Linear Output Capacitance of Gallium-Nitride Field Effect Transistors from Switch-Off Voltage Transients ? A Numerical Method. Journal of Power Electronics, 18, 6, (2018), 1912-1919. DOI: 10.6113/JPE.2018.18.6.1912.