Hybrid Power Supply Modulator for RF Envelope Tracking Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing RF power amplifiers in wireless communication devices face challenges in maintaining high efficiency due to high peak-to-average power ratio (PAPR) characteristics, leading to power loss and inefficient battery usage, particularly in back-off power regions, as they struggle to instantaneously follow envelope signals and maintain coupling voltages across terminals.
Innovation Solution
A power supply modulator with a hybrid structure of a linear regulator and a switching regulator, combined with a mode-based connection circuit and coupling voltage management circuit, which selectively applies voltages to maintain target coupling voltages across terminals in various modulation modes, ensuring efficient power use and improved modulation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a hybrid structure of switching regulator and linear regulator is used to achieve high bandwidth and high efficiency, then power efficiency is improved, but coupling voltage cannot be maintained at target level due to floating state and surrounding noise
Solution Approach 1:
A coupling voltage management circuit is introduced as an intermediary component between the hybrid regulator structure and the coupling circuit. This management circuit actively monitors and adjusts the coupling voltage to maintain it at the target level, compensating for the floating state and noise issues that would otherwise prevent reliable operation.
Solution Approach 2:
The coupling voltage management circuit implements a feedback mechanism by continuously monitoring the actual coupling voltage and comparing it with the target coupling voltage. Based on this comparison, the management circuit adjusts the voltage applied to the coupling circuit to maintain the coupling voltage at the desired target level, ensuring stable operation despite the hybrid structure's inherent instability.
2Use of energy by moving object
If APT technology is used to regulate power supply voltage while tracking average power, then back-off power region efficiency is improved, but power supply voltage cannot instantaneously follow envelope signal causing additional power loss
Solution Approach 1:
The system dynamically switches between APT mode and ET mode based on operating conditions. The coupling voltage management circuit enables the system to transition from static average power tracking to dynamic envelope tracking when instantaneous response is required, allowing the power supply voltage to follow the envelope signal closely and reduce power loss during transient conditions.
Solution Approach 2:
The power supply modulator is designed with multi-functionality, capable of operating in both APT mode and ET mode. The coupling voltage management circuit orchestrates the switching between these two modes, allowing the system to leverage the efficiency benefits of APT in steady-state conditions while utilizing the fast response of ET when instantaneous tracking is needed, thereby minimizing overall power loss.
3Device complexity
If fixed power supply is used in RF power amplifier, then circuit structure is simplified, but power efficiency is low in both peak power and back-off power regions due to high PAPR characteristic
Solution Approach 1:
The power supply modulator is segmented into distinct functional modules: a switching regulator for gross power adjustment, a linear regulator for fine power adjustment, and a coupling voltage management circuit for voltage stabilization. This segmentation allows each module to specialize in specific tasks, achieving high power efficiency across different operating regions while maintaining manageable overall system complexity.
Solution Approach 2:
The system merges two different regulator architectures (switching regulator and linear regulator) into a hybrid structure that combines their advantages. The switching regulator provides high efficiency for bulk power conversion, while the linear regulator provides precise voltage control for fine adjustments. This merging creates a unified power supply system that achieves high efficiency across both peak and back-off power regions.
Data Source
AI summary
A power supply modulator includes: a linear regulator; a switching regulator; and a mode-based connection circuit. The mode-based connection circuit includes a coupling circuit configured to drop an output signal of the linear regulator by a target coupling voltage in an envelope tracking (ET) modulation mode; and a coupling voltage management circuit configured to monitor a coupling voltage of the coupling circuit in another modulation mode, and selectively apply a voltage to the coupling voltage based on a monitoring result such that the coupling voltage is maintained at the target coupling voltage.