Envelope Tracking Power Amplifier Supply for Multi-Band Carrier Aggregation
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Solution Overview
Problem
Current envelope tracking systems face inefficiencies in multimode multiband power amplifiers, particularly in adapting to inter-band and intra-band carrier aggregation scenarios, which limits their ability to support high transmission bandwidths and maintains linearity, leading to increased costs and PCB area requirements.
Innovation Solution
The implementation of a system that utilizes dual-mode DC-DC converters, one optimized for envelope tracking (ET) and the other for average power tracking (APT), allowing dynamic selection of power amplifiers based on transmission modes and signal characteristics to optimize current consumption and maintain linearity across various frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single DC-DC converter is used for power amplifier supply, then device complexity is reduced, but the ability to support multiple transmission modes (ET and APT) and frequency bands is limited
Solution Approach 1:
The first DC-DC converter is designed to operate in both envelope tracking (ET) mode and average power tracking (APT) mode, making it a universal power supply solution. This allows a single converter to serve multiple transmission modes and frequency bands, eliminating the need for separate dedicated converters for each mode while maintaining full functionality across all operational scenarios.
2Use of energy by moving object
If envelope tracking is implemented across all frequency bands and transmission modes, then power efficiency is improved, but device complexity and cost increase
Solution Approach 1:
The system dynamically selects between ET mode and APT mode based on the current transmission scenario. The first DC-DC converter can switch between operating modes, and the control component determines the appropriate mode based on signal characteristics and transmission requirements. This dynamic adaptation allows the system to achieve high power efficiency when ET is beneficial while avoiding unnecessary complexity when APT is sufficient.
3Reliability
If multiple DC-DC converters are used for each frequency band, then isolation between supply domains is improved, but PCB area and cost increase
Solution Approach 1:
The power supply system is segmented into two independent domains: the first DC-DC converter serving ET/APT modes and the second DC-DC converter dedicated to TDD modes. This segmentation provides electrical isolation between different transmission modes and frequency bands, preventing interference while maintaining compact PCB layout. The selective operation of these segmented domains achieves isolation without requiring separate converters for every frequency band.
4Productivity
If envelope tracking is used for high bandwidth transmission, then transmission capacity is improved, but maintaining linearity becomes more difficult
Solution Approach 1:
The control component acts as an intermediary that coordinates between the modulated signal processing and the DC-DC converter operation. It analyzes the signal characteristics and determines the appropriate operating mode (ET or APT) to maintain linearity. The control component adjusts the supply voltage timing and magnitude based on the modulated signal envelope, ensuring that the power amplifier operates in the linear region even during high bandwidth transmission scenarios.
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 efficient envelope tracking in multiple frequency bands, reduces costs and PCB area, and improves isolation between power amplifier supply domains, enhancing overall system performance and efficiency.
Implementation Method 1
Due to a voltage conversion from the battery voltage down to the lower PA supply voltage, the battery current is reduced.
Implementation Method 2
Envelope tracking describes an approach to RF amplifier operation, for example, in which the power supply voltage applied to the power amplifier is constantly adjusted to ensure that the amplifier is operating at or close to peak efficiency for the given instantaneous output power requirements.
Data Source
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AI summary
Envelope tracking (ET) is enabled in connection with single-band or multi-band transmission. One example system includes two or more power amplification components associated with distinct frequency bands, with at least one including a first power amplifier (PA) configured to operate in an ET mode, and at least one including a second PA configured to operate in an average power tracking (APT) mode of operation. A first DC-to-DC converter is configured to provide a first supply voltage according to the ET mode to each first PA, and a second DC-to-DC converter is configured to provide a second supply voltage according to the APT mode to each second PA. A control component is configured to determine a present transmission mode and to select on that basis one or more PAs, wherein the control component selects at most one of the first PAs and at most one of the second PAs.