H-Bridge Envelope Tracking With Sinking Current Recycling
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Solution Overview
Problem
Current power amplifier systems face inefficiencies and linearity issues, particularly with high peak-to-average-power ratio (PAPR) signals in advanced wireless communication systems, which are exacerbated by the need for stringent linearity and broadband performance in 5G and beyond applications.
Innovation Solution
The H-bridge power amplifier arrangement integrates envelope tracking and sinking current recycling, utilizing a novel 'H' bridge structure with dual and triple supply rails to generate sourcing and sinking envelope currents, and a rectifier circuit for power recycling, enhancing efficiency and linearity by directly reusing sinking current for signal correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional power amplifier architectures are used, then the system is simple to implement, but the power efficiency is low
Solution Approach 1:
The power amplifier is segmented into multiple functional blocks including envelope detector, envelope tracker, main RF amplifier, and auxiliary RF amplifier. Each block operates independently to handle specific aspects of the signal amplification, allowing for optimized efficiency in each segment while maintaining overall system performance.
Solution Approach 2:
The power supply voltage to the main RF amplifier is dynamically adjusted through envelope tracking to match the instantaneous envelope of the RF signal. This dynamic voltage control allows the amplifier to operate at peak efficiency across varying output power levels, resolving the contradiction between efficiency and adaptability.
2Use of energy by moving object
If envelope tracking is implemented to enhance power efficiency, then power consumption is reduced, but linearity issues and efficiency degradation occur when average power is greatly backed off
Solution Approach 1:
An auxiliary RF amplifier is introduced as an intermediary component to handle the backed-off average power signals. When the main RF amplifier operates at peak efficiency with dynamic voltage control, the auxiliary amplifier compensates for linearity degradation by providing additional amplification capacity at lower power levels, thereby maintaining overall signal linearity.
Solution Approach 2:
The system dynamically changes operating parameters including supply voltage, current allocation between main and auxiliary amplifiers, and bias conditions to optimize both linearity and efficiency across different operating points. This parameter adaptation allows the system to maintain reliability while achieving high efficiency.
3Productivity
If high PAPR signals are transmitted to achieve high data throughput, then data rate is increased, but average efficiency deteriorates due to significant backoff from peak power level
Solution Approach 1:
The envelope tracking system dynamically adjusts the power supply voltage to the main RF amplifier in real-time according to the instantaneous envelope of the high PAPR signal. This dynamic voltage control enables the amplifier to maintain high efficiency even when transmitting high data throughput signals with large power variations, eliminating the need for conservative backoff.
Solution Approach 2:
The combined main and auxiliary RF amplifier system provides multi-functional capability to handle both peak power signals and backed-off average power signals efficiently. This universal amplifier architecture maintains high average efficiency while supporting high data throughput transmission with high PAPR modulation schemes.
4Reliability
If linear power amplifiers are used to meet noise requirements, then linearity is improved, but power efficiency decreases
Solution Approach 1:
The linear amplification function is segmented between the main RF amplifier operating with envelope tracking and the auxiliary RF amplifier. The main amplifier handles the dynamic envelope tracking for efficiency, while the auxiliary amplifier provides the additional linearization needed for high PAPR signals, dividing the linearity burden to maintain overall efficiency.
Solution Approach 2:
The system dynamically changes the operating class and bias conditions of the amplifiers based on the signal characteristics. By adapting parameters such as supply voltage, bias current, and amplifier class (between Class A, AB, and B), the system achieves both linearity and efficiency requirements without operating the linear amplifier at low efficiency continuously.
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 improves the performance of power amplifiers by simplifying the envelope tracking system, enabling efficient analog or digital transmitter operations, enhancing linearity, and allowing seamless transitions between envelope tracking and average power tracking modes, thereby boosting overall efficiency.
Implementation Method 1
a rectifier circuit for power recycling, enhancing efficiency and linearity by directly reusing sinking current for signal correction
Data Source
AI summary
An H-bridge power amplifier arrangement with envelope tracking is disclosed. The power amplifier arrangement comprises four elements form the four corner bars of a first H-bridge structure with a load formed as the cross bar of the first H-bridge structure. The power amplifier arrangement further comprises a rectifier circuit coupled between the first positive power supply and the third positive power supply configured to recycle the sinking envelope current.