RF Signal Processing Circuit for Doherty Back-Off Efficiency
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Solution Overview
Problem
Conventional power amplifiers in radio frequency signal transmitters suffer from efficiency degradation in high power back-off conditions, particularly in Doherty amplifiers, due to limited load-pull effects and phase/amplitude adjustments, leading to low overall efficiency.
Innovation Solution
A signal processing circuit with a splitter module, radio frequency signal conversion module, first and second branch power amplifiers, and a combiner module, which dynamically adjusts the amplitude and phase of signals based on input power to optimize efficiency by independently controlling the signals entering each branch power amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional two-way Doherty amplifier is used, then efficiency is maintained in power back-off below 6 dB, but efficiency sharply decreases in power back-off beyond 6 dB due to limited load-pull effects
Solution Approach 1:
The patent divides the single power amplifier system into multiple independent power amplifiers (first power amplifier, second power amplifier, third power amplifier, etc.), each capable of independent phase and amplitude adjustment. This segmentation allows each amplifier to operate in optimized regions across different power back-off conditions, resolving the efficiency degradation issue in conventional two-way Doherty amplifiers.
Solution Approach 2:
The patent implements dynamic phase and amplitude adjustment for each power amplifier branch based on real-time signal conditions. The phase difference and amplitude ratios are continuously optimized to maintain maximum efficiency across varying power back-off ranges, transforming the static operation of conventional amplifiers into adaptive dynamic operation.
2Loss of energy
If the auxiliary power amplifier works only with high-level output signals, then high efficiency can be obtained theoretically, but the main power amplifier operates with large load-pull ratio causing sharp efficiency decrease
Solution Approach 1:
The patent enables dynamic control of each power amplifier's operation mode through independent phase and amplitude adjustment. Each amplifier can transition between active and inactive states, and adjust their contribution levels, providing operational flexibility while maintaining high efficiency across different power back-off conditions.
Solution Approach 2:
The patent changes the operational parameters (phase and amplitude) of each power amplifier dynamically based on input signal conditions. By adjusting phase differences and amplitude ratios, the system optimizes the operating point of each amplifier to maintain high efficiency while adapting to varying power back-off requirements.
3Loss of energy
If phase and amplitude adjustment is limited in conventional solutions, then device complexity is reduced, but power amplification efficiency decreases in high power back-off conditions
Solution Approach 1:
The patent segments the signal adjustment function into independent control channels for each power amplifier. Each amplifier receives independently adjusted phase and amplitude control signals, allowing precise optimization without requiring complex inter-dependent adjustment mechanisms, thus managing complexity while improving efficiency.
Solution Approach 2:
The patent implements a universal control mechanism that applies phase and amplitude adjustment across multiple power amplifier branches using similar control architectures. This multi-functional approach allows the same control principles to be applied throughout the system, managing complexity through pattern repetition rather than unique solutions for each branch.
Data Source
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AI summary
Embodiments of this application disclose a signal processing circuit, a radio frequency signal transmitter, and a communications device, and relate to the field of electronic device technologies, to improve power amplification efficiency of the signal processing circuit. The signal processing circuit includes: a splitter module, a radio frequency signal conversion module, a first branch power amplifier, a second branch power amplifier, and a combiner module, where the splitter module is connected to the radio frequency signal conversion module, the radio frequency signal conversion module is connected to the first branch power amplifier and the second branch power amplifier, and the first branch power amplifier and the second branch power amplifier are connected to the combiner module.