Fast Error Amplifier Envelope Tracking for MIMO 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 advent of higher bandwidth communication standards like LTE-Advanced, which require increased power and bandwidth.
Innovation Solution
The implementation of an envelope tracking system using a plurality of fast error amplifiers and DC-DC converters to generate regulated supply voltages, which are combined with power amplifiers to split the power load and improve efficiency and linearity, allowing for increased power delivery to antennas.
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 envelope tracking to dynamically adjust the supply voltage to the power amplifier according to the instantaneous signal envelope. This dynamic voltage adjustment maintains optimal compression characteristics and linearity across varying signal conditions while significantly improving power efficiency compared to fixed voltage regulation
Solution Approach 2:
The system changes the supply voltage parameter dynamically based on the signal envelope rather than maintaining a fixed voltage. This parameter change enables the power amplifier to operate at optimal efficiency points while preserving linearity through adaptive voltage control
2Reliability
If a fixed voltage regulator is used to power the power amplifier, then the compression characteristics are maintained, but the system cost increases
Solution Approach 1:
The envelope tracking system dynamically adjusts the supply voltage to maintain optimal compression characteristics across varying signal conditions. This dynamic approach replaces complex fixed voltage regulation circuits with a more efficient adaptive voltage control mechanism that preserves compression characteristics while reducing system cost
3Device complexity
If a single power amplifier is used to handle high power loads, then the system is simpler, but the efficiency and linearity decrease
Solution Approach 1:
The patent divides the power amplifier system into multiple parallel power amplifiers, each handling a portion of the total power load. This segmentation allows each amplifier to operate at optimal efficiency and linearity points while collectively delivering high power output, improving overall system performance
4Device complexity
If a single power amplifier is used to handle high power loads, then the system is simpler, but the linearity decreases
Solution Approach 1:
The system segments the power amplification function across multiple parallel amplifiers, each operating in a linear region. This segmentation maintains superior linearity performance compared to a single high-power amplifier while keeping the overall system relatively simple through parallel architecture
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 enhances the power amplifier's ability to handle higher bandwidths and increased power requirements, improving efficiency, linearity, and signal-to-noise ratio, while reducing noise and increasing the load line capacity, thereby meeting the demands of advanced communication standards.
Implementation Method 1
a regulated supply voltage from a DC-DC converter
Implementation Method 2
a plurality of power amplifiers configured to amplify a portion of an input signal
Implementation Method 3
a combiner configured to generate an output signal by combining amplified signals from the plurality of power amplifiers
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.