Wireless Charging PCB Layout for Accurate Foreign Object Detection
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Solution Overview
Problem
Existing wireless power transmission systems face issues with energy loss and potential device damage due to foreign objects, such as metal, which can cause unintended heating and user injury, and require separate detection coils that may interfere with antennas.
Innovation Solution
A wireless power transmission apparatus with integrated Foreign Object Detection (FOD) coils and antennas on a printed circuit board, where a processor controls connections based on output voltage and stored transfer cycle information to manage power transmission and detection, reducing interference and enhancing foreign object detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate detection coils are used for foreign object detection, then detection capability is improved, but interference with antennas and manufacturing complexity increase
Solution Approach 1:
The patent combines the antenna and FOD coils into a single integrated structure where the FOD coils are formed on the same printed circuit board as the antenna. This merging eliminates the need for separate assembly of detection coils and antennas, reducing manufacturing complexity while maintaining detection capability through the integrated design.
2Ease of manufacture
If FOD coils are positioned close to the antenna on the same circuit board, then manufacturing complexity is reduced, but electromagnetic interference increases
Solution Approach 1:
The patent applies local quality by creating spatial separation between the antenna and FOD coils on the printed circuit board. The FOD coils are positioned in a first area while the antenna is positioned outside this first area, ensuring that each component has its own dedicated space to minimize electromagnetic interference while maintaining the benefits of integration.
3Productivity
If foreign objects are not detected, then power transmission continues, but energy loss and device damage occur
Solution Approach 1:
The patent implements a feedback mechanism where the processor continuously monitors the output voltage or current from the FOD coils to detect foreign objects. When a foreign object is detected through changes in electrical parameters, the system provides feedback to interrupt the power transmission, preventing energy loss and potential device damage while maintaining continuity when no foreign objects are present.
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 integrated solution effectively detects foreign objects, prevents power transmission interruptions, and reduces manufacturing costs by eliminating assembly deviations, thereby ensuring safe and efficient wireless power transfer.
Implementation Method 1
Wireless power transmission technologies include a magnetic induction method using a magnetic induction phenomenon between primary coils and secondary coils
Implementation Method 2
In order to detect such a foreign object, a wireless power transmission apparatus includes Foreign Object Detection (FOD) coils
Data Source
AI summary
A wireless power transmission apparatus includes: a housing; a plate coupled with an upper portion of the housing; a power transmitting coil positioned inside the housing and configured to transmit wireless power to an electronic device put on the plate; a printed circuit board positioned between the plate and the power transmitting coil, and comprising at least one layer in which an antenna and a plurality of Foreign Object Detection (FOD) coils are formed; a processor electrically connected to the power transmitting coil and the printed circuit board; and a switch device configured to perform switching to a connection between the antenna and the processor or a connection between the plurality of FOD coils and the processor.