Hybrid power amplifiers - a review

With the aim of synthesizing high-fidelity voltage waveforms without penalizing the system efficiency, several works have proposed hybrid power amplifiers (HPAs) composed of linear and switching amplifiers, combining the features of each approach. The HPAs can be classified as envelope, parallel and series configurations, depending on how the connection between the linear and switching amplifiers is implemented. This way, through a fair review of literature, this work identifies the features of each configuration and presents the main topologies and control techniques proposed hitherto. Therefore, this paper can be useful for selecting an adequate hybrid arrangement for a given application. Finally, future trends in research in hybrid power amplifiers are also addressed.