Envelope Tracker Boost Control for RF Power Amplifier Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power amplifiers in communication systems face inefficiencies when generating high transmit power with low battery voltage, leading to wasted power due to the fixed battery voltage being higher than the RF signal envelope, resulting in reduced power-added efficiency (PAE).
Innovation Solution
A technique for generating a variable boosted supply voltage using a boost converter and envelope amplifier, which receives an envelope signal and adjusts the power supply voltage based on the envelope of the RF signal, enabling the power amplifier to operate efficiently even with low battery voltage by tracking the RF signal envelope.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a fixed battery voltage is used to power the power amplifier, then the amplifier can operate with simple power supply, but the power-added efficiency is reduced because the fixed voltage is higher than the RF signal envelope causing wasted power
Solution Approach 1:
The patent applies dynamics by transforming the fixed battery voltage into a dynamic envelope-tracking voltage that varies with the RF signal envelope. The envelope tracker circuit dynamically adjusts the supply voltage to match the instantaneous envelope of the RF signal, enabling the power amplifier to operate efficiently across different signal conditions while maintaining simple overall system architecture.
Solution Approach 2:
The patent changes the voltage parameter from a fixed value to a variable value that tracks the RF signal envelope. By using the envelope tracker to generate a supply voltage that dynamically follows the envelope of the modulated RF signal, the system achieves higher power-added efficiency without requiring complex reconfiguration of the power supply architecture.
2Power
If the supply voltage is increased to provide high transmit power, then the power amplifier can deliver higher output power, but the battery life is reduced due to increased power consumption
Solution Approach 1:
The patent applies periodic action by using the envelope tracker to periodically adjust the supply voltage in synchronization with the RF signal envelope. The voltage is increased only during periods when the RF signal requires high power transmission, and reduced during periods of lower signal power, thereby extending battery life while maintaining the ability to deliver high transmit power when needed.
Solution Approach 2:
The system dynamically adjusts the supply voltage to match the instantaneous power requirements of the RF signal, avoiding continuous high voltage operation. This dynamic voltage scaling enables the power amplifier to deliver high transmit power during peak signal conditions while consuming less power during low-signal periods, thus extending battery life.
3Use of energy by moving object
If envelope tracking is implemented to improve efficiency, then power-added efficiency increases, but the device complexity increases due to additional circuits
Solution Approach 1:
The envelope tracker circuit performs multiple functions: it extracts the envelope from the RF signal, generates the tracking voltage, and supplies power to the amplifier. By consolidating these functions into a single integrated circuit, the system achieves high power-added efficiency without proportionally increasing overall device complexity.
Solution Approach 2:
The patent merges the envelope detection and voltage regulation functions into a single envelope tracker circuit that works in conjunction with the power amplifier. This integration reduces the number of separate components needed compared to traditional approaches, achieving high efficiency while limiting the increase in device complexity.
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 improves power-added efficiency (PAE) of the power amplifier by closely matching the supply voltage to the RF signal envelope, reducing wasted power and allowing operation with lower battery voltages, thus enhancing energy efficiency and extending battery life.
Implementation Method 1
The boost converter may receive a power supply voltage (e.g., a battery voltage) and at least one signal determined based on the envelope signal and may generate the variable boosted supply voltage based on the power supply voltage and the at least one signal
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
In an exemplary design, an apparatus (100) includes an amplifier (170), a boost converter (180), and a boost controller (190). The amplifier (170) receives an envelope signal (Venv) and a variable boosted supply voltage (Vboost) and provides an output voltage (Vout) and an output current (lout). The boost converter (180) receives a power supply voltage (Vbat) and at least one signal determined based on the envelope signal (Venv) and generates the variable boosted supply voltage (Vboost) based on the power supply voltage (Vbat) and the at least one signal. The boost controller (190) generates the at least one signal (e.g., an enable signal and/or a threshold voltage) for the boost converter (180) based on the envelope signal (Venv) and/or the output voltage (Vout). The boost converter (180) generates the variable boosted supply voltage (Vboost) based on the power supply voltage (Vbat) and the threshold voltage.