Push–Pull Class [Formula Omitted] RF Power Amplifier

• Published in: IEEE transactions on power electronics Vol. 35; no. 10; p. 10515
• Main Authors: Gu, Lei, Zulauf, Grayson, Zhang, Zhemin, Chakraborty, Sombuddha, Rivas-Davila, Juan
• Format: Journal Article
• Language: English
• Published: New York The Institute of Electrical and Electronics Engineers, Inc. (IEEE) 01.01.2020
• Subjects: Circuit design; Converters; Efficiency; Electric vehicles; Energy conversion efficiency; Magnetic materials; Magnetic semiconductors; NMR; Nuclear magnetic resonance; Numerical methods; Power amplifiers; Radio frequency; Topology; Wide bandgap semiconductors; Wireless power transmission
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2020.2981312

The Class [Formula Omitted]/EF[Formula Omitted] amplifier is an attractive topology for high-voltage and high-frequency power conversion because of the high efficiency, reduced device voltage stress, simplicity of gate driving, and load-independent ZVS operation. Due to many degrees of freedom for tuning, previous studies can only solve the single-ended [Formula Omitted] circuit using numerical methods. This work focuses on improving the design and operating characteristics of a push–pull [Formula Omitted] amplifier with a [Formula Omitted] network connected between the switch nodes, or a PPT [Formula Omitted] amplifier. The PPT [Formula Omitted] amplifier has less circulating energy and achieves higher cutoff frequency [Formula Omitted] than other [Formula Omitted]/EF[Formula Omitted] circuits. We, then, present a series-stacked input configuration to reduce the switch voltage stress and improve the efficiency and power density. A compact 6.78-MHz, 100-V, 300-W prototype converter is demonstrated that uses low-cost Si devices and achieves 96% peak total efficiency and maintains above 94.5% drain efficiency across a wide range of voltage and power. Together with the advances in wide-bandgap semiconductors and magnetic materials, the PPT [Formula Omitted] circuit opens more possibilities for the state-of-the-art performance of solid-state RF amplifiers in high-frequency, high-power applications, including wireless charging for electric vehicles, plasma RF drives, and nuclear magnetic resonance spectroscopy.