Envelope Tracker Capacitive Loading Reduction via Star Network Topology
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Solution Overview
Problem
Existing power amplifiers in RF electronic systems face challenges in reducing power consumption and improving efficiency, particularly due to high capacitive loading in envelope tracking modules, which increases cost and power consumption, and requires large bypass capacitors that can lead to instability and increased size.
Innovation Solution
The implementation of a power amplifier system with power amplifiers connected in a star configuration, utilizing a distributed capacitance for RF grounding and eliminating the need for local bypass capacitors, and an envelope tracker with reduced capacitive loading, achieving efficient power supply management and reduced size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If envelope tracking is used to reduce power amplifier power consumption, then power efficiency is improved, but capacitive loading increases causing the envelope tracker to become larger and consume more power
Solution Approach 1:
The power amplifier system is divided into multiple independent power amplifier modules, each with its own star network. The envelope tracker controls multiple power amplifiers independently, distributing the capacitive loading across separate control channels rather than having one large envelope tracker control all amplifiers simultaneously.
Solution Approach 2:
The patent transitions from a traditional parallel connection topology to a star network topology. This dimensional change in the electrical connection architecture allows the envelope tracker to control multiple power amplifiers through a centralized star node, reducing the overall capacitive loading on the envelope tracker while maintaining effective power supply control.
2Reliability
If large bypass capacitors are used to handle capacitive loading, then power supply stability is improved, but device size and cost increase
Solution Approach 1:
The patent extracts the bypass capacitor function from the traditional power supply network and relocates it to the star node of each power amplifier module. This allows the use of smaller, distributed capacitance at the star node rather than requiring large bypass capacitors in the traditional configuration, thereby reducing overall device size while maintaining power supply stability.
Solution Approach 2:
The star node acts as an intermediary between the envelope tracker and the power amplifier modules. It provides a localized capacitance that mediates the capacitive loading effects, allowing the envelope tracker to operate with reduced loading while maintaining stable power supply to the amplifiers without requiring large bypass capacitors.
3Ease of manufacture
If traditional power amplifier connection topology is used, then ease of manufacture is maintained, but capacitive loading requires expensive and large envelope trackers
Solution Approach 1:
Multiple power amplifier modules are merged into a single system through the star network architecture. The envelope tracker controls multiple amplifiers through the shared star node, combining the functionality of multiple independent control channels into a unified system that reduces overall capacitive loading and eliminates the need for large, expensive envelope trackers.
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 the size and cost of the envelope tracker, provides a low impedance path for RF signals, and improves power amplifier stability and efficiency, enabling efficient operation across varying voltage standing wave ratios without the need for large bypass capacitors.
Implementation Method 1
a distributed capacitance of the first star network is configured to operate as a low impedance path to radio frequency signals
Data Source
AI summary
Apparatus and methods for reducing capacitive loading of an envelope tracker are disclosed. In one embodiment, a wireless device comprises an envelope tracker including an output configured to generate a power amplifier supply voltage, a plurality of power amplifiers, and a power supply network configured to provide the power amplifier supply voltage to the plurality of power amplifiers. The power amplifier supply network includes a first inductor electrically connected between a supply input of a first power amplifier and the output of the envelope tracker, and a second inductor electrically connected between a supply input of a second power amplifier and the output of the envelope tracker. The first inductor resonates with a distributed capacitance of the power supply network at a frequency greater than the envelope tracker's modulation bandwidth of, and the second inductor resonates with the distributed capacitance at a frequency greater than the envelope tracker's modulation bandwidth.