Doherty Power Amplifier Envelope Tracking for High-PAPR Signals
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Solution Overview
Problem
Existing power amplifiers in wireless communication base stations suffer from limited efficiency improvements when handling signals with high peak-to-average power ratios due to the use of power back-off methods, leading to increased energy consumption and reduced symmetry in Doherty amplifiers.
Innovation Solution
Implementing an envelope tracking technology in combination with a Doherty amplifier, where the operating voltages of both the main and auxiliary power amplifiers are adjusted simultaneously, allowing for improved symmetry and efficiency, and removing the high-pass blocking capacitor to enhance power amplification efficiency, particularly for signals with high peak-to-average power ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power back-off method is used to amplify signals with high peak-to-average power ratio, then linearity of power amplifier is improved, but power amplification efficiency is greatly decreased
Solution Approach 1:
The power amplifier is segmented into a main power amplifier and an auxiliary power amplifier. The main power amplifier handles the carrier signal while the auxiliary power amplifier handles the peak signal components. This segmentation allows each amplifier to operate in its optimal efficiency region while maintaining overall linearity through proper signal combining.
Solution Approach 2:
The patent implements dynamic voltage control where the auxiliary power amplifier's operating voltage is dynamically adjusted based on the envelope of the input signal. This dynamic operation allows the amplifier to adapt its efficiency characteristics to the instantaneous signal conditions, improving overall power amplification efficiency while maintaining linearity.
2Reliability
If fixed voltage is used to supply power to auxiliary power amplifier in Doherty amplifier, then breakdown voltage limitation is avoided, but symmetry of Doherty amplifier is reduced and efficiency improvement is limited
Solution Approach 1:
The patent replaces the fixed voltage supply with a dynamic envelope tracking voltage supply for the auxiliary power amplifier. The supply voltage dynamically follows the envelope of the modulating signal, allowing the auxiliary amplifier to operate symmetrically with the main amplifier across the full signal dynamic range. This dynamic voltage control eliminates the efficiency loss associated with fixed voltage operation while respecting breakdown voltage constraints through proper voltage modulation.
Data Source
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AI summary
A power amplification apparatus, a remote radio unit, and a base station are provided to improve power amplification efficiency. The power amplification apparatus includes an envelope modulator (201), a main power amplifier (202), and a first auxiliary power amplifier (203). The envelope modulator (201) is connected to a drain of the main power amplifier (202), and is configured to: obtain an envelope voltage based on a received envelope signal, and output the envelope voltage to the drain of the main power amplifier (202). The main power amplifier (202) is configured to perform amplification processing on a signal input through a gate of the main power amplifier (202), is connected to the envelope modulator (201), to use the envelope voltage received from the envelope modulator (201) as an operating voltage, and is connected to the first auxiliary power amplifier (203), to output the envelope voltage to a drain of the first auxiliary power amplifier (203). The first auxiliary power amplifier (203) performs amplification processing on a signal input through a gate of the first auxiliary power amplifier (203), and is connected to the main power amplifier (202), to use the envelope voltage received from the main power amplifier (202) as an operating voltage.