Multiphase PWM Power Amplifier for Low-Inductance Envelope Feeding
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Solution Overview
Problem
Current radio frequency power amplifiers face challenges with high inductance in the feeding loop, leading to low video bandwidth (VBW) and impaired digital predistortion (DPD) correction performance, especially in multi-carrier and multimode base stations with high peak-to-average ratios.
Innovation Solution
The implementation of a multiphase pulse width modulator connected to N switching amplifiers and N low-pass filters reduces the inductance of the power amplifier feeding loop, increasing VBW and enhancing DPD correction performance by generating multiphase pulse-width modulation signals, amplifying, and filtering them to improve the envelope tracking efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional power amplifier feeding loop structure is used, then the structure is simple, but the inductance is high leading to low VBW and impaired DPD correction performance
Solution Approach 1:
The patent segments the power amplifier structure into multiple parallel switching amplifiers (first, second, third switching amplifiers) with dedicated low-pass filters for each. This segmentation allows each branch to have optimized, lower inductance values while maintaining overall system functionality, thereby improving VBW and DPD correction performance without excessive complexity increase.
Solution Approach 2:
The patent introduces a multi-branch parallel architecture that adds dimensional complexity to the feeding loop structure. By distributing the signal path across multiple parallel channels with different phase relationships, the system achieves lower effective inductance and higher VBW, trading structural complexity for performance improvement.
2Loss of energy
If envelope tracking technology is implemented to achieve high efficiency, then power amplification efficiency improves, but the high peak-to-average ratio signals require complex multi-carrier processing
Solution Approach 1:
The patent divides the high peak-to-average ratio signal processing into multiple parallel switching amplifier branches, each handling simplified two-state signals. This segmentation reduces the processing complexity in each individual channel while maintaining the ability to efficiently handle the overall high PAR signal through parallel envelope tracking.
Solution Approach 2:
The patent employs periodic switching action in each amplifier branch, where switching amplifiers operate in periodic on/off states controlled by pulse-width modulation signals. This periodic operation enables efficient envelope tracking for high PAR signals while simplifying the instantaneous processing requirements in each channel.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces the inductance of the envelope feeding loop, thereby increasing VBW and improving DPD correction performance, enhancing the overall efficiency and accuracy of power amplification in base stations.
Implementation Method 1
a multiphase pulse width modulator, N switching amplifiers, and N low-pass filters. The multiphase pulse width modulator is connected to the N switching amplifiers, and is configured to generate N multiphase pulse-width modulation PWM signals
Implementation Method 2
A switching amplifier Sn is configured to: receive an n th PWM signal; and amplify the n th PWM signal to generate an n th amplified signal
Implementation Method 3
The low-pass filter Fn includes a radio frequency decoupling capacitor and a feeder; and one end of the radio frequency decoupling capacitor is connected to the feeder, and the other end of the radio frequency decoupling capacitor is grounded
Data Source
Figure 1
Figure 1-1
Figure 2
AI summary
Embodiments of the present invention provide a power amplifier, a radio remote unit RRU, and a base station. A multiphase pulse width modulator performs modulation to generate N multiphase pulse-width modulation PWM signals; the multiphase pulse-width modulation PWMn signal is amplified; the multiphase pulse-width modulation PWMn signal is filtered; and combination is performed at a drain or a collector of a power amplifier transistor. According to the new radio frequency amplifier provided in this application, envelope feeding loop inductance can be effectively reduced, so that video bandwidth is increased and DPD correction performance is improved.