The thesis focuses on the characterization of Class-D power audio amplifiers whose output stages employ gallium nitride (GaN) transistors. The theoretical part presents the basic characteristics of audio amplifiers, the operating principle of Class-D amplifiers, and their advantages compared to conventional linear amplifiers. The basic output-stage topologies and the properties of GaN transistors that make them suitable for use in high-frequency switching converters and audio amplifiers are also presented.
Two Class-D audio amplifier evaluation boards, the EPC9192 and the GS-EVB-AUD-BUNDLE2-GS, are investigated. The measurement equipment and the measurement setup, including an audio analyzer and a reference load, are described. Measurements of frequency response, harmonic and intermodulation distortion, signal-to-noise ratio, output noise, and efficiency at different output power levels were performed for both amplifiers.
The thesis thus contributes to a better understanding of the operation of Class-D power audio amplifiers based on GaN technology and provides a direct comparison of two different implementations. The characterization results provide insight into their advantages and limitations and can serve as a useful reference when selecting a suitable amplifier for the requirements of a particular audio application.
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