Envelope Tracking Supply Circuit for RF Power and Interference Control
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Solution Overview
Problem
Current 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 level based on distance from the base station and environmental factors.
Innovation Solution
The implementation of a mobile device with a power amplifier, buck converter, and error amplifier configuration that adjusts the power amplifier supply voltage based on the RF signal envelope, using a buck converter to control the buck voltage and an error amplifier to generate an output current for efficient power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power amplifier supply voltage is increased to amplify RF signals for transmission, then the transmission power and coverage distance are improved, but the power consumption increases significantly
Solution Approach 1:
The patent applies dynamics by making the power amplifier supply voltage dynamic rather than static. The envelope tracker continuously adjusts the supply voltage to match the instantaneous envelope of the RF signal, allowing the system to use high power only when needed for transmission and reduce power during receive slots or low-signal periods, thereby resolving the contradiction between transmission power and power consumption
Solution Approach 2:
The patent changes the parameter of supply voltage from a constant value to a time-varying parameter that tracks the RF signal envelope. By modifying the supply voltage parameter dynamically based on signal conditions, the system achieves efficient power management that balances transmission requirements with power consumption constraints
2Length of moving object
If the power amplifier continuously operates at high power to ensure signal coverage, then the coverage distance is improved, but signal interference occurs during receive time slots
Solution Approach 1:
The patent implements periodic action by synchronizing the power amplifier operation with the TDMA communication protocol. The envelope tracker enables the power amplifier to operate at high power during transmit time slots and reduce power during receive time slots, creating a periodic on-off pattern that ensures coverage during transmission while preventing interference during reception
Solution Approach 2:
The system uses feedback from the communication protocol timing to control the envelope tracker. The periodic nature of TDMA provides feedback signals that guide when the power amplifier should be active or inactive, allowing the system to maintain coverage distance while avoiding signal interference through timely power adjustment
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 supply voltage in relation to the RF signal envelope, enhancing energy efficiency and preventing signal interference by optimizing power amplifier performance.
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 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 can include a buck converter and an error amplifier configured to operate in parallel to control the voltage level of the power amplifier supply voltage based on an envelope of an RF signal amplified by the power amplifier. The buck converter can convert a battery voltage into a buck voltage that is based on an error current, and the error amplifier can generate the power amplifier supply voltage by adjusting the magnitude of the buck voltage using an output current that is based on the RF input signal's envelope. The error amplifier can control the buck converter by changing a magnitude of the error current in relation to a magnitude of the output current.