Dual-PA DPD Circuit With Switched-Capacitor Supply Partitioning
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Solution Overview
Problem
Existing power amplification systems face challenges in efficiently reducing nonlinear distortion in power amplifiers when operating in nonlinear regions, particularly due to the inefficiencies in managing memory requirements for digital predistortion parameters.
Innovation Solution
A power amplification system employing multiple power amplifiers with distinct mathematical-expression models for digital predistortion, combined with a switched-capacitor circuit and pre-regulator circuit to generate and regulate power supply voltages, effectively predistorting input signals to reduce nonlinear distortion while optimizing memory usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple discrete voltages are supplied to a power amplifier with DPD to reduce nonlinear distortion, then signal quality is improved, but the amount of memory required for DPD parameters increases
Solution Approach 1:
The system divides the power amplification function into multiple power amplifiers (first PA and second PA), each handling different signal components or operating conditions. This segmentation allows each amplifier to use optimized DPD models with reduced memory requirements while collectively maintaining high signal quality.
Solution Approach 2:
Different mathematical-expression models for DPD are applied to different power amplifiers based on their specific operating characteristics. The first PA uses a first DPD model optimized for its discrete voltage supply regime, while the second PA uses a second DPD model suited for its regulated voltage supply, allowing each to achieve optimal performance with minimal memory usage.
2Measurement precision
If a single power amplifier uses DPD parameters stored in memory to reduce nonlinear distortion, then distortion reduction is achieved, but device complexity increases
Solution Approach 1:
The system segments the DPD processing across multiple power amplifiers, each with its own simplified DPD model and parameter set. This distributes the computational complexity and memory requirements across multiple devices rather than concentrating them in a single complex system.
Solution Approach 2:
The system changes the operational parameters of different power amplifiers - specifically the power supply voltage characteristics (discrete vs. regulated) - to enable the use of different, optimized DPD mathematical models that are simpler and require less memory while still achieving effective distortion reduction.
3Use of energy by moving object
If multiple discrete voltages are generated using a switched-capacitor circuit to improve power amplifier efficiency, then power-added efficiency is improved, but circuit complexity increases
Solution Approach 1:
The voltage generation function is segmented between two separate circuits: a switched-capacitor circuit that generates multiple discrete voltages for the first PA, and a pre-regulator circuit that generates a regulated voltage for the second PA. This segmentation allows each circuit to be optimized for its specific function with minimal complexity.
Solution Approach 2:
The pre-regulator circuit serves a dual function: it regulates voltage for the second power amplifier directly, and also provides the regulated voltage as input to the switched-capacitor circuit for generating discrete voltages. This multi-functionality reduces overall system complexity by eliminating redundant voltage regulation stages.
Data Source
AI summary
A power amplification system includes: a first power amplifier configured to amplify a first radio-frequency signal; a second power amplifier configured to amplify a second radio-frequency signal; a switched-capacitor circuit configured to generate multiple discrete voltages based on a regulated voltage supplied from a pre-regulator; an output switch circuit configured to selectively output at least one of the multiple discrete voltages as a first power supply of the first power amplifier; and a digital predistortion circuit configured to predistort the first and second radio-frequency signals. The pre-regulator circuit is configured to convert an input voltage to the regulated voltage. The regulated voltage is provided as a second power supply of the second power amplifier without using the switched-capacitor circuit. The digital predistortion circuit predistorts the first radio-frequency signal by using a first mathematical-expression model for digital predistortion. The first mathematical-expression model is not applied on the second radio-frequency signal.