Printed Circuit Board Slits for Speaker H-Field Attenuation
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Solution Overview
Problem
The design of portable electronic devices with minimized gaps between the printed circuit board and speaker leads to the formation of H-fields due to return currents, causing unintended speaker operation, which is challenging to attenuate due to the minimized distance.
Innovation Solution
A printed circuit board design with slits and cut regions, including central and symmetric slit portions, is employed to attenuate H-fields by blocking current flows around the speaker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the gap between the printed circuit board and the speaker is minimized to make the device thin and light, then the device thickness and weight are reduced, but the H-field intensity increases causing unintended speaker operation
Solution Approach 1:
The printed circuit board is segmented by introducing multiple slits that divide the ground portion into separate regions. These slits interrupt the return current path, preventing the formation of continuous current loops around the speaker, thereby reducing the H-field intensity while maintaining minimal device thickness.
Solution Approach 2:
The slits act as intermediary structures that block and redirect the return current. By positioning slits between the power consuming component and the speaker, they serve as mediators that prevent harmful current flows from reaching the speaker region, reducing H-field interference without increasing device thickness.
2Object-affected harmful factors
If the return current path is extended to attenuate the H-field by increasing distance, then the H-field intensity is reduced, but the device complexity increases
Solution Approach 1:
Rather than extending the return current path to increase distance, the patent segments the ground portion using slits. This segmentation approach achieves H-field attenuation by interrupting current loops locally, avoiding the need for complex extended path routing while maintaining structural simplicity.
Solution Approach 2:
The slits are strategically positioned in specific regions of the ground portion where return currents flow. This local modification approach targets the problematic areas directly, achieving effective H-field reduction without requiring global structural changes or complex routing extensions throughout the entire circuit board.
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 slits on the printed circuit board effectively attenuate H-fields, reducing their intensity and preventing unwanted speaker operation.
Implementation Method 1
A return current may flow through the portion of the printed circuit board being cut off (e.g., a portion of the printed circuit board surrounding the speaker), and thus an H-field may be formed due to the return current
Data Source
AI summary
An electronic device is provided. The electronic device includes an electronic component including a coil therein, and a printed circuit board that is disposed to surround at least a part of the electronic component and includes plural slits disposed at preset intervals in at least one of regions facing the electronic component, wherein each of the plural slits may include a central slit portion extended along a center of the slit, and a symmetric slit portion extended to be symmetric with respect to the central slit portion.