Envelope-Tracked Doherty Power Amplifier for Back-Off Efficiency
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Solution Overview
Problem
Power amplifiers in radio base stations face efficiency losses when amplifying signals with high peak-to-average ratios, particularly when using the power back-off method, leading to increased energy consumption and limited improvement in power amplification efficiency.
Innovation Solution
A power amplifier configuration that includes an envelope modulator connected to both the main and auxiliary power amplifiers, providing adjustable envelope voltages for optimal operating conditions, enhancing symmetry and reducing efficiency losses by combining envelope tracking with Doherty amplifier efficiency advantages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power back-off method is used to amplify signals with high peak-to-average ratio, then linearity of the power amplifier is improved, but power amplification efficiency dramatically decreases and energy consumption increases greatly
Solution Approach 1:
The power amplifier is segmented into a main power amplifier and an auxiliary power amplifier operating in parallel. The main amplifier handles the majority of the signal power while the auxiliary amplifier supplements during high-power periods, allowing each segment to operate in its optimal efficiency region while maintaining overall linearity for high peak-to-average ratio signals
Solution Approach 2:
The patent implements dynamic operation by adjusting the operating states of the main and auxiliary power amplifiers based on the instantaneous signal envelope. The auxiliary amplifier is dynamically activated or deactivated depending on the signal power level, enabling the system to adapt between high linearity mode and high efficiency mode in real-time
2Use of energy by moving object
If an envelope tracking amplifier and Doherty amplifier are combined, then power amplification efficiency is improved under back-off, but loss of power amplification efficiency is easily caused and improvement is limited
Solution Approach 1:
The patent changes the operating parameters of the power amplifiers by applying different envelope voltages to the main and auxiliary amplifiers. The envelope modulator dynamically adjusts the drain voltage of each amplifier based on the signal envelope, optimizing the operating point to maintain high efficiency while avoiding the efficiency losses encountered in conventional combined approaches
Data Source
AI summary
A power amplifier, a radio remote unit (RRU), and a base station, where the power amplifier includes an envelope controller, a main power amplifier, and an auxiliary power amplifier. The main power amplifier and the auxiliary power amplifier both set an envelope voltage output by the envelope modulator as operating voltages, and because the operating voltages of the main power amplifier and the auxiliary power amplifier may be adjusted simultaneously, symmetry of the power amplifier is improved, and an efficiency loss occurring probability is low, thereby enhancing efficiency of the power amplifier.