Mixed-Signal Power Amplifier for Linear Power-Backoff Efficiency
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Solution Overview
Problem
Conventional power amplifiers face challenges in achieving high linearity and efficiency, particularly in next-generation wireless communication systems operating at mmWave and GHz bands, due to limitations in fully analog and digital PA architectures, which struggle with peak-to-average power ratios, amplitude quantization errors, and control bit accuracy.
Innovation Solution
A mixed-signal power amplification system that combines a main analog power amplification path with an auxiliary digitally controlled path, allowing for precise control and efficient amplification of complex modulated signals, reducing amplitude quantization errors and bandwidth expansion, while maintaining high linearity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If fully analog PAs are designed to achieve peak efficiency at maximum power output, then efficiency is improved, but linearity performance deteriorates during power-back off operations
Solution Approach 1:
The PA is divided into multiple parallel paths: an analog PA path for efficient amplification and a digital PA path for precise amplitude control. This segmentation allows each path to specialize in one function, resolving the contradiction between efficiency and linearity.
Solution Approach 2:
The patent merges analog and digital PA architectures into a hybrid system. The analog path provides high efficiency while the digital path provides precise amplitude control, combining the advantages of both approaches to achieve high efficiency and linearity simultaneously.
2Use of energy by moving object
If fully analog PAs reduce power-back off levels to increase efficiency, then efficiency is improved, but linearity is sacrificed
Solution Approach 1:
The PA system is segmented into analog and digital domains, allowing independent optimization of efficiency (analog path) and linearity (digital path). The digital path maintains precise amplitude control even at reduced power-back off levels.
Solution Approach 2:
A digital signal processing intermediary is introduced to control the amplitude of signals in the analog PA path. This intermediary enables precise amplitude control without requiring large power-back off levels, maintaining both efficiency and linearity.
3Measurement precision
If fully digital PAs employ a large number of weighted PA cells to achieve large output dynamic range and low amplitude quantization error, then amplitude quantization error is reduced, but device complexity increases
Solution Approach 1:
The digital PA is segmented into a smaller array of weighted PA cells compared to conventional fully digital PAs. The analog PA path compensates for the reduced digital resolution, allowing fewer digital cells while maintaining low quantization error.
Solution Approach 2:
The patent changes the operating parameters of the digital PA cells, using fewer cells with optimized weighting. The analog path provides continuous amplitude control that compensates for the coarser digital quantization, reducing overall complexity.
4Manufacturing precision
If fully digital PAs use a large number of amplitude control bits to ensure accurate signal generation, then linearity is improved, but timing synchronization difficulty increases
Solution Approach 1:
The control system is segmented into digital and analog domains. Fewer digital control bits are required since the analog PA path provides continuous amplitude control, reducing timing synchronization requirements while maintaining linearity.
Solution Approach 2:
An analog control intermediary is introduced between the digital control bits and the PA output. This intermediary converts discrete digital control into continuous analog control, reducing the number of digital control bits needed and simplifying timing synchronization while maintaining linearity.
Data Source
AI summary
The disclosed technology includes device, systems, techniques, and methods for amplifying a complex modulated signal with a mixed-signal power amplifier. A mixed-signal power amplifier may include an input network for splitting an input signal to multiple signals with corresponding phase and amplitude offsets, a main power amplification path including at least an analog power amplifier for amplifying a first signal, one or more auxiliary power amplification paths including at least one digitally controlled analog power amplifier in each path for amplifying a second signal, and an output network for combining the two amplified signals. The main power amplification path and the auxiliary power amplification paths can operate together to achieve load modulation to enhance the overall power amplifier efficiency at power back-off mode and the overall power amplifier linearity. The disclosed technology further includes transmission systems incorporating the mixed-signal power amplifier.