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In this work it is presented a design tool to estimate the figures of merit of a radiofrequency power amplifier (RFPA) based on the envelope amplifier (EA) design for an EER (Envelope Elimination and Restoration) application. Using as the input data the transfer function of a buck derived converter for an envelope amplifier application, the main figures of merit of the complete amplifier can be obtained...
High frequency dc-dc switching converters are used as envelope amplifiers in RF transmitters. The dc-dc converter should operate at very high frequency to track an envelope in the MHz range to supply the power amplifier. One of the circuits suitable for this application is a hybrid topology composed of a switched converter and a linear regulator in series that work together to adjust the output voltage...
Modern transmitters usually have to amplify and transmit complex communication signals with simultaneous envelope and phase modulation. Due to this property of the transmitted signal, linear power amplifiers (class A, B or AB) are usually employed as a solution for the power amplifier stage. These amplifiers have high linearity, but suffer from low efficiency when the transmitted signal has high peak-to-average...
Modern transmitters usually have to amplify and transmit signals with simultaneous envelope and phase modulation. Due to this property of the transmitted signal, 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 high peak-to-average power ratio...
Modern transmitters usually have to amplify and transmit signals with simultaneous envelope and phase modulation. Due to this property of the transmitted signal, 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...
A solution combining a multilevel converter in series with a linear regulator to obtain an envelope amplifier was presented recently in for EER. Two possible implementations of the multilevel cell are compared. In, a two-state topology for the multilevel cell is proposed for the envelope amplifier. The three-state cell topology, proposed in this paper, has two main advantages: less number of cells...
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...
The combination of non-linear control and linear control proposed in [1] has a very fast transient response (voltage step from 1 V to 1.5 V in 2 mus). In order to achieve this fast transient response the non-linear scheme is based on measuring the current of the output capacitor of a Buck converter. The design of this current sensor is complex due to parasitic effects such as component tolerances...
The boost topology with ripple cancellation network allows input and output current ripples attenuation, which means the suppression of the input filter and a high reduction of the output filter. However, to achieve the ripple cancellation, the complexity and the number of components of the converter need to be increased as compared with the conventional boost. A detailed analysis is developed to...
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