Digital Predistortion Circuit for Multi-Voltage Power Amplifiers
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Solution Overview
Problem
Existing power amplifiers face challenges in reducing nonlinear distortion while managing power consumption effectively, particularly when operating in nonlinear regions.
Innovation Solution
A power amplification system that employs a digital predistortion circuit and an output switch circuit to selectively output discrete voltages, using different parameter sets for predistortion based on power modes, thereby reducing nonlinear distortion and regulating power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If digital predistortion is employed to reduce nonlinear distortion in power amplifier, then signal quality is improved, but calculation load and power consumption increase
Solution Approach 1:
The patent segments the discrete voltage levels into multiple subsets, where each subset corresponds to a specific parameter set for digital predistortion. The output switch circuit selectively outputs discrete voltages from different subsets based on the operating mode, allowing the DPD circuit to use different parameter sets (first parameters for first subset, second/third parameters for second subset) to reduce calculation load while maintaining signal quality.
Solution Approach 2:
The patent implements dynamic switching between different discrete voltage subsets and corresponding parameter sets based on operating conditions. The output switch circuit dynamically selects which subset to use, and the DPD circuit dynamically switches between different parameter sets, optimizing the balance between signal quality and power consumption in real-time.
2Use of energy by moving object
If multiple discrete voltages are supplied to power amplifier to improve power-added efficiency, then energy efficiency is improved, but nonlinear distortion increases when operating in nonlinear region
Solution Approach 1:
The patent applies different parameter sets locally to different voltage subsets. The first parameter set is used when higher discrete voltages (first subset) are supplied, while the second or third parameter sets are used when lower discrete voltages (second subset) are supplied. This local adaptation of parameters compensates for the increased nonlinear distortion that occurs at different operating points, maintaining signal quality across the full voltage range.
Solution Approach 2:
The patent changes the parameters of the digital predistortion model based on the supplied voltage level. By switching between different parameter sets corresponding to different voltage subsets, the system adapts the predistortion characteristics to match the operating conditions, effectively compensating for nonlinear distortion while maintaining the power efficiency benefits of multiple discrete voltage levels.
Data Source
AI summary
A power amplification system includes: a power amplifier; an output switch circuit configured to selectively output at least one of three or more discrete voltages as a power supply of the power amplifier; and a digital predistortion circuit configured to generate distortions in an input signal of the power amplifier. In a first mode, the digital predistortion circuit is configured to generate distortions in an input signal of the power amplifier by using a first mathematical-expression model for digital predistortion with a first parameter set. In a second mode with a lower average voltage of the power supply than the first mode, the digital predistortion circuit generates the distortions by using at least a different parameter set from the first parameter set, such as a second mathematical-expression model for digital predistortion with a second parameter set or the first mathematical-expression model with a third parameter set.