Dual-Core Power Amplifier Switching for ET Linearity Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-efficiency power amplifiers for mobile wireless communication devices face challenges in maintaining linearity during envelope tracking operations, often requiring complex digital distortion schemes that are sensitive to antenna mismatch and become complicated in wideband transmission signals, especially in uplink carrier aggregation scenarios.
Innovation Solution
A dual core power amplifier system that selectively activates between envelope tracking and non-envelope tracking modes, utilizing separate PA chains optimized for different operational conditions to achieve high efficiency and linearity without digital pre-distortion, and featuring a DC-to-DC converter that adjusts supply voltage based on instantaneous output power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If envelope tracking mode is used to improve power efficiency, then current consumption is reduced, but linearity deteriorates and AMAM- and AMPM conversion increases
Solution Approach 1:
The power amplifier is divided into two separate PA chains: a first PA chain optimized for envelope tracking mode and a second PA chain optimized for non-envelope tracking mode. Each chain has its own power amplifier configured with specific operating parameters to excel in its designated mode, allowing the system to achieve both high efficiency in ET mode and high linearity in non-ET mode without compromise.
Solution Approach 2:
The system dynamically switches between the first PA chain and second PA chain based on the operating mode requirements. The switching mechanism allows the amplifier to adapt its characteristics in real-time, selecting the appropriate chain for the current operational demands, thereby optimizing both efficiency and linearity according to the specific mode being used.
2Reliability
If digital pre-distortion is applied to maintain linearity, then distortion is reduced, but device complexity increases
Solution Approach 1:
The invention extracts and removes the need for complex digital pre-distortion processing by providing a dedicated second PA chain that inherently maintains high linearity in non-envelope tracking mode. This hardware-based solution replaces the software-based DPD approach, eliminating the associated complexity in the baseband processor and transceiver while maintaining or improving linearity performance.
3Device complexity
If a single power amplifier is used to cover all operating conditions, then device complexity is reduced, but performance optimization for specific modes is compromised
Solution Approach 1:
The power amplifier system is segmented into two specialized PA chains, each optimized for specific operating conditions. The first chain targets envelope tracking mode with high efficiency characteristics, while the second chain targets non-envelope tracking mode with high linearity characteristics. This segmentation allows each chain to be finely tuned for its specific purpose, achieving superior mode-specific optimization that a single general-purpose amplifier cannot provide.
4Productivity
If wideband transmission is implemented to increase bandwidth, then communication capacity is improved, but distortion correction becomes nearly impossible due to memory effects
Solution Approach 1:
The system dynamically selects the second PA chain for wideband transmission scenarios where memory effects from duplexers would complicate distortion correction. The second chain's inherent linearity and lack of dependence on complex DPD algorithms enable effective wideband operation without being constrained by the memory effects that plague single-chain envelope tracking amplifiers in wideband applications.
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 approach enables optimal current consumption and high linearity across the entire output power range, reducing complexity and cost by eliminating the need for digital distortion correction in non-envelope tracking mode, while maintaining peak efficiency in envelope tracking mode.
Implementation Method 1
a first power amplifier configured to generate a first output power at a frequency based on an envelope tracking mode of operation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A dual mode, dual core power amplifier (PA) device includes a plurality of PA chains (404, 406) that generate output power according to an envelope tracking mode and a non-envelope tracking mode. The different modes can be selected to generate output power based on a set of predetermined criteria, which can be related to an input signal received by the system and related to a target power. A first PA chain (404) with one or more PA cores is configured to operate in the envelope tracking mode based on at least a portion of the predetermined criteria being identified in the input signal and to generate output power with an envelope voltage supply that changes with an envelope of the input signal. In addition, a second PA chain (406) with one or more PA cores can operate in a constant voltage supply mode or the non-envelope tracking mode according to the predetermined criteria.