Split Envelope Tracking Across Parallel Power Amplifiers
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Solution Overview
Problem
Power amplifier systems face inefficiencies and decreased linearity when powered with a fixed voltage, leading to increased costs and reduced performance, especially with the rise of higher bandwidth communication standards like LTE-Advanced, which require increased power and bandwidth.
Innovation Solution
Implementing an envelope tracking system with multiple fast error amplifiers and DC-DC converters to generate regulated supply voltages, which are combined with power amplifiers in parallel configurations to enhance efficiency and linearity, allowing for increased power delivery and bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed voltage regulator is used to power the power amplifier, then the linearity and compression characteristics are maintained, but the system cost increases and efficiency decreases
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed voltage regulator to an envelope tracking system where the supply voltage dynamically follows the signal envelope. The voltage is no longer static but varies in real-time to match the instantaneous power requirements, improving efficiency while maintaining linearity through adaptive voltage control.
Solution Approach 2:
The invention changes the voltage parameter from a fixed regulated value to a dynamically varying envelope-tracking voltage. By modifying the voltage parameter to follow the signal envelope contours, the system achieves better efficiency without compromising linearity, as the voltage adapts to the instantaneous power demands.
2Reliability
If a fixed voltage regulator is used to power the power amplifier, then the compression characteristics are stable, but the system cost increases
Solution Approach 1:
The patent replaces the static voltage regulator with a dynamic envelope tracking system that adjusts voltage in real-time. This dynamic approach maintains stable compression characteristics while avoiding the need for expensive fixed regulators, as the system adapts to signal conditions rather than requiring complex regulation circuitry.
Solution Approach 2:
The envelope tracking system employs self-service by using the signal envelope itself to control the voltage supply. The system automatically adjusts its own power delivery based on the instantaneous power requirements extracted from the signal, eliminating the need for external fixed regulators and reducing system cost.
3Device complexity
If a single power amplifier is used, then the system is simpler, but the power delivery capability and bandwidth are limited
Solution Approach 1:
The patent applies segmentation by dividing the power delivery function across multiple parallel power amplifiers. Each amplifier handles a portion of the total power, enabling the system to deliver higher overall power while maintaining relative simplicity through modular architecture. The envelope tracking signal is distributed to control each amplifier's output.
Solution Approach 2:
The invention merges multiple power amplifier outputs through a combiner to achieve higher power delivery capability. By combining the outputs of several amplifiers working in parallel under envelope tracking control, the system achieves increased power and bandwidth while keeping individual amplifier designs relatively simple.
4Ease of manufacture
If fixed voltage supply is used, then the system is easier to implement, but the efficiency and linearity decrease
Solution Approach 1:
The patent implements dynamics by replacing the static fixed voltage supply with a dynamic envelope tracking voltage that follows the signal envelope. This dynamic voltage control maintains linearity by adapting to instantaneous power requirements, achieving better performance without significantly complicating the implementation through the use of standard envelope extraction and voltage control circuits.
Data Source
AI summary
Disclosed herein are circuits, devices and methods that address challenges associated with power amplifier systems. A power amplifier system includes two or more fast error amplifiers coupled to corresponding power amplifiers. The fast error amplifiers are configured to generate envelope tracking signals based on a signal envelope, the envelope tracking signals modifying a DC-DC regulated voltage from a DC-DC converter to more efficiently operate the power amplifiers. By splitting the envelope tracking between two or more fast error amplifiers and amplification between corresponding two or more power amplifiers, the power, frequency or bandwidth, linearity, signal-to-noise ratio, efficiency, or the like of the power amplifier system can be improved. Wireless communications configurations with such power amplifier systems can provide uplink carrier aggregation and/or cellular signals based on standards and protocols that require increased bandwidth and/or power.