Multilevel Power Supply for High Efficiency RF Amplifiers

By M. Vasić, Ó. García, J. Oliver, P. Alou, D. Diaz, J. Cobos. 2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition, 2010

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In radio systems linear power amplifiers (class A, B or AB) are usually used as a solution for the power amplifier stage. These amplifiers have high linearity, but suffer from low efficiency when the transmitted signal has low peak-to-average power ratio. The Kahn envelope elimination and restoration (EER) technique is used to enhance efficiency of RF transmitters, by combining highly efficient, nonlinear RF amplifier (class D or E) with a highly efficient envelope amplifier in order to obtain linear and highly efficient RF amplifier. This paper presents a solution for the envelope amplifier based on a combination of multilevel converter and linear regulator. The proposed solution can reproduce any signal with maximal spectral component of 2 MHz and give instantaneous maximal power of 50 W. The efficiency measurements show that when the signals with low average value are transmitted, it has up to 15% higher efficiency than linear regulator that is used as a conventional solution. Additionally, the algorithm for selection of voltage levels for the multilevel converter is explained, as well.

Subfields: Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/dc7fd2002f859d86f5515611a59b373944a98ed0