Envelope Tracking Supply Control for RF Power Amplifiers
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Solution Overview
Problem
Existing power amplifier systems in mobile devices face inefficiencies in managing RF signal amplification, leading to high power consumption and potential signal interference, particularly in managing the power amplifier supply voltage in relation to the RF signal envelope.
Innovation Solution
A mobile device configuration that includes a power amplifier, a buck converter, and an error amplifier, where the error amplifier generates an output current based on the RF signal envelope to adjust the buck voltage and control the power amplifier supply voltage, using a buck converter with a buck controller, inductor, and switches to manage current flow efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power amplifier supply voltage is increased to amplify RF signals, then the signal transmission capability is improved, but the power consumption increases
Solution Approach 1:
The patent implements dynamic supply voltage adjustment by tracking the envelope of the RF signal. The power amplifier supply voltage is dynamically modified to match the instantaneous envelope amplitude, allowing the system to use high voltage only when signal amplification is needed, and reduce voltage during low-signal periods, thus resolving the contradiction between transmission capability and power consumption
Solution Approach 2:
The patent employs feedback mechanisms where the envelope detector continuously monitors the RF signal envelope and feeds this information back to the supply voltage controller. This closed-loop feedback ensures the supply voltage accurately tracks the signal envelope, optimizing the balance between transmission performance and power efficiency
2Use of energy by moving object
If the power amplifier supply voltage is dynamically adjusted based on RF signal envelope, then power consumption is reduced, but the system complexity increases
Solution Approach 1:
The patent segments the power amplifier system into distinct functional modules: envelope detector, supply voltage controller, and power amplifier. This segmentation allows each component to perform its specific function independently, simplifying the overall design and control while achieving dynamic voltage adjustment and reduced power consumption
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 configuration reduces power consumption by dynamically adjusting the power amplifier supply voltage based on the RF signal envelope, improving energy efficiency and preventing signal interference by optimizing voltage levels.
Implementation Method 1
The buck converter is configured to convert a battery voltage into a buck voltage, and to control a magnitude of the buck voltage based on an error current
Implementation Method 2
The error amplifier is configured to generate an output current based on an envelope of the RF input signal and to generate the power amplifier supply voltage by adjusting the magnitude of the buck voltage using the output current
Implementation Method 3
The power amplifier is configured to receive a power amplifier supply voltage and to amplify a radio frequency (RF) input signal to generate an RF output signal
Data Source
AI summary
Apparatus and methods for envelope tracking systems are disclosed herein. In certain implementations, an envelope tracking system for generating a power amplifier supply voltage for a power amplifier is provided. The envelope tracking system includes a DC-to-DC converter that generates a regulated voltage from a battery voltage and controls a voltage of the regulated voltage using a low frequency feedback signal. The envelope tracking system further includes an error amplifier that generates an output current using an envelope signal and a high frequency feedback signal. The low frequency feedback signal is based on a low frequency component of the power amplifier supply voltage and the high frequency feedback signal is based on a high frequency component of the power amplifier supply voltage. The error amplifier generates the power amplifier supply voltage by adjusting the magnitude of the regulated voltage using the output current.