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An envelope tracking RF power amplifier with capacitive charge pump modulator

Published online by Cambridge University Press:  06 April 2016

Gavin Tomas Watkins  and
Konstantinos Mimis
Gavin Tomas Watkins*
Affiliation:
Toshiba Research Europe Limited, 32 Queen Square, Bristol BS1 4ND, UK. Phone: +44 (0)117 906 0740
Konstantinos Mimis
Affiliation:
Toshiba Research Europe Limited, 32 Queen Square, Bristol BS1 4ND, UK. Phone: +44 (0)117 906 0740
*
Corresponding author:G. T. Watkins Email: [email protected]
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Abstract

An envelope tracking (ET) radio frequency (RF) power amplifier (PA) is described intended for handsets and applications where a large number of PAs are needed. Instead of the usual split frequency architecture, a linear tracking charge pump structure is proposed. This allows the supply voltage of an RF PA to increase during the peaks of a high peak-to-average power ratio signal. When combined with an LDMOS RF PA, 42.9% efficiency was achieved at 31.3 dBm output power (POUT) when amplifying a 5 MHz bandwidth 8 dB PAPR 3rd Generation Partnership Project (3GPP) long term evolution signal. The first channel adjacent power ratio (ACPR) without digital pre-distortion was −30.4 dBc, meeting the 3GPP handset emission mask. The ACPR could be improved to −32.5 dBc by adopting a curved envelope shaping function at a reduced efficiency of 38.9%.

Keywords

Circuit design and applicationsPower amplifiers and linearizers
Type
Research Papers
Information
International Journal of Microwave and Wireless Technologies , Volume 8 , Special Issue 4-5: EuMW 2015 Special Issue , June 2016 , pp. 683 - 690
Copyright
Copyright © Cambridge University Press and the European Microwave Association 2016 

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