Supply Modulator Switching for Power Amplifier Envelope Tracking
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Solution Overview
Problem
Existing power amplifiers in wireless communication devices face efficiency issues due to high peak-to-average power ratio (PAPR) and high bandwidth, leading to decreased power amplifier efficiency, especially when powered by a battery.
Innovation Solution
A supply modulator is designed to operate in average power tracking (APT) or discrete level-envelope tracking (DL-ET) modes, featuring a multiple output voltage regulator, a switching regulator, and a switch array to dynamically adjust the output voltage and improve power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a power amplifier operates at high PAPR and high bandwidth, then communication performance is improved, but power efficiency deteriorates
Solution Approach 1:
The supply modulator dynamically adjusts the power supply voltage to the power amplifier based on the instantaneous envelope of the RF signal. By tracking the signal envelope in real-time, the power amplifier operates at optimal efficiency points across varying signal conditions, resolving the contradiction between maintaining high communication performance and improving power efficiency.
Solution Approach 2:
The invention changes the operating parameters of the power amplifier by modulating its supply voltage according to the signal characteristics. The supply modulator transforms the fixed power supply into a dynamic one that adapts voltage levels based on PAPR conditions, enabling the power amplifier to maintain high efficiency while supporting high PAPR and bandwidth operations.
2Ease of operation
If a power amplifier is powered by battery, then portability is improved, but power efficiency deteriorates due to high PAPR operation
Solution Approach 1:
The supply modulator incorporates a feedback mechanism that monitors the RF signal envelope and adjusts the power supply voltage accordingly. This closed-loop control ensures that the power amplifier receives precisely the voltage needed for each signal condition, minimizing energy waste and extending battery life while maintaining portability.
Solution Approach 2:
The supply modulator performs preliminary action by pre-adjusting the power supply voltage before the power amplifier processes each signal segment. By anticipating the required voltage based on envelope detection, the system prevents energy inefficiency before it occurs, optimizing battery consumption during portable operation.
3Device complexity
If conventional power supply is used, then device simplicity is maintained, but energy waste increases
Solution Approach 1:
The supply modulator acts as an intermediary component between the battery and the power amplifier. This mediator transforms the fixed battery output into a dynamically adjusted power supply, reducing energy waste without requiring fundamental changes to the existing device architecture. The modulator integrates seamlessly into the power delivery path, maintaining relative device simplicity while dramatically improving energy efficiency.
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
The supply modulator enhances power efficiency by reducing heat loss and minimizing energy waste, thereby improving the overall performance and battery life of wireless communication devices.
Implementation Method 1
a switching regulator configured to output a switching regulator voltage
Implementation Method 2
a coupling capacitor having an end connected to the switch array and another end connected to the power amplifier
Data Source
AI summary
A supply modulator including a multiple output voltage regulator (MOVR) configured to output voltages in a discrete level-envelope tracking mode (DLETM) having different levels from each other respectively corresponding to reference output voltage signals, a switching regulator configured to output a switching regulator voltage, an output voltage being based on the switching regulator voltage and a selected voltage among the voltages in the DLETM and based on the switching regulator voltage in an average power tracking mode, a switching regulator controller configured to sense an output current of the MOVR to obtain a sensing value, and control the switching regulator based on the sensing value in the DLETM, a switch array comprising switches respectively corresponding to the voltages and configured to selectively connect the selected voltage to a power amplifier by performing a switching operation, and a switch controller configured to control the switching operation.