Multi-Envelope Tracking for High-Bandwidth Power Amplifiers
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Solution Overview
Problem
Power amplifier systems face inefficiencies and decreased linearity when supplied with a fixed voltage, leading to increased costs and reduced performance, especially with the rise of high-bandwidth communication standards like LTE-Advanced, which require higher 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
1Ease of manufacture
If a fixed voltage is supplied to power amplifier systems, then the system cost is reduced, but the efficiency and linearity of the power amplifier deteriorate
Solution Approach 1:
The patent implements envelope tracking that dynamically adjusts the supply voltage to the power amplifier based on the instantaneous envelope of the modulated signal. This dynamic voltage adjustment allows the power amplifier to operate at optimal efficiency across varying signal conditions, resolving the contradiction between using simple fixed voltage (low cost) and maintaining high efficiency.
2Device complexity
If a fixed voltage is supplied to power amplifier systems, then the system complexity is reduced, but the linearity of the power amplifier deteriorates
Solution Approach 1:
The envelope tracking system employs feedback mechanisms where the instantaneous envelope of the modulated signal is detected and used to control the supply voltage to the power amplifier. This feedback loop ensures that the power amplifier maintains accurate linearity by adjusting the supply voltage in real-time according to the signal characteristics, resolving the contradiction between system complexity and linearity performance.
3Loss of energy
If envelope tracking is implemented to improve efficiency, then the power amplifier efficiency improves, but the system complexity increases due to additional regulators
Solution Approach 1:
The patent employs a single DC-DC converter that serves multiple functions: it provides the regulated supply voltage to the power amplifier and simultaneously generates the envelope tracking signal through coordination with the error amplifiers. This multi-functional approach reduces the need for separate dedicated components, thereby improving efficiency while limiting the increase in system complexity.
4Power
If multiple power amplifiers are used in parallel to increase power output, then the power delivery increases, but the device complexity increases
Solution Approach 1:
The patent combines multiple power amplifiers in parallel configuration to achieve higher power output while using a shared DC-DC converter and envelope tracking system. The error amplifiers and voltage regulation infrastructure are shared across all power amplifier channels, which allows the system to scale power output without proportionally increasing the complexity of the support infrastructure.
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.