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High-efficiency high-voltage class F amplifier for high-frequency wireless ultrasound systems

This paper presents a novel amplifier that satisfies both low distortion and high efficiency for high-frequency wireless ultrasound systems with limited battery life and size. While increasing the amplifier efficiency helps to address the problems for wireless ultrasound systems, it can cause signal...

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Detalles Bibliográficos
Autores principales: Kim, Kyeongjin, Choi, Hojong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8006987/
https://www.ncbi.nlm.nih.gov/pubmed/33780492
http://dx.doi.org/10.1371/journal.pone.0249034
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author Kim, Kyeongjin
Choi, Hojong
author_facet Kim, Kyeongjin
Choi, Hojong
author_sort Kim, Kyeongjin
collection PubMed
description This paper presents a novel amplifier that satisfies both low distortion and high efficiency for high-frequency wireless ultrasound systems with limited battery life and size. While increasing the amplifier efficiency helps to address the problems for wireless ultrasound systems, it can cause signal distortion owing to harmonic components. Therefore, a new type of class F amplifier is designed to achieve high efficiency and low distortion. In the amplifier, the resonant circuit at each stage controls the harmonic components to reduce distortion and improve efficiency. Transformers with a large shunt resistor are also helpful to reduce the remaining noise in the input signal. The proposed class F amplifier is tested using simulations, and the voltage and current waveforms are analyzed to achieve correct operation with adequate efficiency and distortion. The measured performance of the class F amplifier has a gain of 23.2 dB and a power added efficiency (PAE) of 88.9% at 25 MHz. The measured DC current is 121 mA with a variance of less than 1% when the PA is operating. We measured the received echo signal through the pulse-echo response using a 25-MHz transducer owing to the compatibility of the designed class F amplifier with high- frequency transducers. The measured total harmonic distortion (THD) of the echo signal was obtained as 4.5% with a slightly low ring-down. The results show that the low THD and high PAE of the new high-efficiency and high-voltage amplifier may increase battery life and reduce the cooling fan size, thus providing a suitable environment for high-frequency wireless ultrasound systems.
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spelling pubmed-80069872021-04-07 High-efficiency high-voltage class F amplifier for high-frequency wireless ultrasound systems Kim, Kyeongjin Choi, Hojong PLoS One Research Article This paper presents a novel amplifier that satisfies both low distortion and high efficiency for high-frequency wireless ultrasound systems with limited battery life and size. While increasing the amplifier efficiency helps to address the problems for wireless ultrasound systems, it can cause signal distortion owing to harmonic components. Therefore, a new type of class F amplifier is designed to achieve high efficiency and low distortion. In the amplifier, the resonant circuit at each stage controls the harmonic components to reduce distortion and improve efficiency. Transformers with a large shunt resistor are also helpful to reduce the remaining noise in the input signal. The proposed class F amplifier is tested using simulations, and the voltage and current waveforms are analyzed to achieve correct operation with adequate efficiency and distortion. The measured performance of the class F amplifier has a gain of 23.2 dB and a power added efficiency (PAE) of 88.9% at 25 MHz. The measured DC current is 121 mA with a variance of less than 1% when the PA is operating. We measured the received echo signal through the pulse-echo response using a 25-MHz transducer owing to the compatibility of the designed class F amplifier with high- frequency transducers. The measured total harmonic distortion (THD) of the echo signal was obtained as 4.5% with a slightly low ring-down. The results show that the low THD and high PAE of the new high-efficiency and high-voltage amplifier may increase battery life and reduce the cooling fan size, thus providing a suitable environment for high-frequency wireless ultrasound systems. Public Library of Science 2021-03-29 /pmc/articles/PMC8006987/ /pubmed/33780492 http://dx.doi.org/10.1371/journal.pone.0249034 Text en © 2021 Kim, Choi http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Kim, Kyeongjin
Choi, Hojong
High-efficiency high-voltage class F amplifier for high-frequency wireless ultrasound systems
title High-efficiency high-voltage class F amplifier for high-frequency wireless ultrasound systems
title_full High-efficiency high-voltage class F amplifier for high-frequency wireless ultrasound systems
title_fullStr High-efficiency high-voltage class F amplifier for high-frequency wireless ultrasound systems
title_full_unstemmed High-efficiency high-voltage class F amplifier for high-frequency wireless ultrasound systems
title_short High-efficiency high-voltage class F amplifier for high-frequency wireless ultrasound systems
title_sort high-efficiency high-voltage class f amplifier for high-frequency wireless ultrasound systems
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8006987/
https://www.ncbi.nlm.nih.gov/pubmed/33780492
http://dx.doi.org/10.1371/journal.pone.0249034
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