Power Amplifier IC Detection of Foreign Objects in Wireless Charging
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Solution Overview
Problem
Conventional wireless power transmission systems face challenges in accurately distinguishing between valid receivers and foreign objects, leading to potential damage to objects with magnetic strips or RFID chips and requiring precise positioning, which is inefficient and can cause damage to both the system and foreign objects.
Innovation Solution
A wireless power transmission system utilizing a power amplifier controller integrated circuit with multiple measurement points to monitor impedance changes, allowing for instant detection of foreign objects and preventing damage by adjusting power transmission accordingly, without the need for bulky isolators or complex handshake protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional wireless power transmission systems use traditional foreign object detection methods, then they can detect the presence of objects, but they cannot accurately distinguish between valid receivers and foreign objects, leading to potential damage
Solution Approach 1:
The patent segments the impedance detection process into multiple measurement points along the power amplifier output path. By measuring impedance at different locations (at the power amplifier output, at the antenna, and between them), the system can detect impedance changes caused by foreign objects with higher precision and distinguish them from valid receivers through pattern recognition
Solution Approach 2:
The system implements continuous feedback by monitoring impedance changes at multiple measurement points during power transmission. When impedance changes indicating a foreign object are detected, the system provides feedback to adjust or terminate power transmission, preventing damage to the foreign object while maintaining accurate detection capability
2Productivity
If wireless power transmission systems require precise positioning for charging, then power transfer efficiency is improved, but user convenience deteriorates due to the need for exact placement
Solution Approach 1:
The patent implements dynamic foreign object detection that continuously monitors impedance changes as devices are placed or moved on the charging surface. The system adapts its detection thresholds and measurement frequency based on the charging state, allowing users to place devices flexibly while maintaining charging efficiency through real-time adjustments
3Measurement precision
If additional components like isolators or complex handshake protocols are added to detect foreign objects, then detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the power amplifier controller IC perform multiple functions: it controls the power amplifier for wireless power transmission, monitors impedance at multiple measurement points for foreign object detection, and provides protection against foreign objects. This multi-functionality eliminates the need for separate detection components, reducing system complexity while maintaining detection capability
Solution Approach 2:
The system uses its existing power transmission infrastructure (power amplifier and impedance measurement capability) to perform foreign object detection without requiring external sensors or additional hardware. The power amplifier controller IC leverages the impedance changes that naturally occur during power transmission to detect and classify foreign objects
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 solution enhances the efficiency of wireless charging by reducing power loss and cost, preventing damage to both the transmitter and foreign objects, and enabling continuous operation during charging without the need for additional complex components.
Implementation Method 1
a power amplifier controller integrated circuit with multiple measurement points to monitor impedance changes
Data Source
AI summary
A wireless power transmitting system includes a power amplifier comprising a plurality of measurement points and a power amplifier controller integrated circuit (IC). In some embodiments, the power amplifier controller IC performs synchronization of the various components of the power amplifier, conducts impedance and temperature measurements at the measurements points, determines if a foreign object is within the transmission range of the wireless power transmitter, and decides if a shutdown of the power amplifier is needed. In some embodiments, the power amplifier controller IC determines through a transmitter controller IC, the presence of a foreign object within the transmission range and adjusts the power transmission to one or more receivers.