Multiphase PWM Power Amplifier Layout for Low-Inductance Envelope Feeding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current radio frequency power amplifiers in base stations face challenges with high inductance in the feeding loop, leading to low video bandwidth (VBW) and impaired digital predistortion (DPD) correction performance due to high peak-to-average ratios in multi-carrier and multimode base stations.
Innovation Solution
A radio frequency power amplifier structure incorporating a multiphase pulse width modulator, N switching amplifiers, and N low-pass filters is introduced, which reduces inductance in the power amplifier feeding loop by using radio frequency decoupling capacitors and low-pass elements to increase VBW and enhance DPD correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional power amplifier structure with feeding loop is used, then the amplifier can operate, but the inductance in the feeding loop is relatively high, resulting in low video bandwidth (VBW) and impaired digital predistortion (DPD) correction performance
Solution Approach 1:
The patent extracts and removes the conventional feeding loop structure from the power amplifier circuit. By eliminating the feeding loop that caused high inductance, the invention directly connects the switching amplifiers to the output, thereby reducing inductance and improving VBW and DPD correction performance
Solution Approach 2:
The patent introduces radio frequency decoupling capacitors as intermediary elements to replace the feeding loop's inductive function. These capacitors provide the necessary RF coupling while having negligible inductance, thus resolving the harmful inductance issue while maintaining circuit functionality
2Loss of energy
If envelope tracking technology is used to achieve high efficiency, then power amplification efficiency is improved, but the high peak-to-average ratio of baseband signals requires the power amplifier to operate in a deep compressed state, which may affect linearity
Solution Approach 1:
The patent employs dynamic voltage regulation through envelope tracking, where the supply voltage to the switching amplifiers is dynamically adjusted according to the signal envelope. This allows the amplifier to operate efficiently across varying signal conditions while maintaining linearity through the switching architecture and digital predistortion correction
Solution Approach 2:
The patent implements digital predistortion (DPD) correction as a feedback mechanism to compensate for nonlinearities introduced by operating in a deep compressed state. The DPD algorithm pre-distorts the input signal to counteract the amplifier's nonlinear behavior, thereby maintaining output linearity while achieving high efficiency
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
The proposed solution effectively reduces inductance in the power amplifier feeding loop, thereby increasing VBW and improving DPD correction performance, ensuring efficient signal amplification without distortion.
Implementation Method 1
A low-pass filter Fn is connected to the switching amplifier Sn, and is configured to filter a signal that is output by the switching amplifier Sn
Implementation Method 2
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
Implementation Method 3
the low-pass filter Fn includes a radio frequency decoupling capacitor and an inductor; and a low-pass element is connected to the inductor
Data Source
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 may be amplified. The multiphase pulse-width modulation PWMn signal may be filtered and a combination may be performed at a drain or a collector of a power amplifier transistor. According to the new radio frequency amplifier in accordance with the disclosure, envelope feeding loop inductance can be effectively reduced, so that video bandwidth is increased and DPD correction performance is improved.