Battery FPCB Wiring Layout for Speaker EMI Reduction
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Solution Overview
Problem
Existing electronic devices face challenges in managing electromagnetic interference and noise due to the integration of various components, particularly in miniaturized wearable devices where a battery and speaker are closely stacked, leading to inefficiencies in current flow and increased noise generation.
Innovation Solution
The electronic device incorporates a flexible printed circuit board connected to the battery, with power and ground wirings configured to manage current flow differently based on the length difference between the anode and cathode, minimizing electromagnetic interference and noise by controlling the winding direction of currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the battery and speaker are closely stacked to achieve miniaturization, then the device size is reduced, but electromagnetic interference and noise increase
Solution Approach 1:
The flexible printed circuit board serves as an intermediary component positioned between the battery and speaker. The ground wiring on the FPCB acts as a shielding layer that intercepts and redirects electromagnetic interference, preventing it from reaching the speaker while maintaining close stacking of components for miniaturization.
Solution Approach 2:
The ground wiring is extracted and extended beyond the battery boundaries to surround the speaker area. This separate ground path is specifically designed to manage electromagnetic interference without affecting the compact overall device structure.
2Device complexity
If uniform current flow is used in all wirings, then the circuit design is simplified, but electromagnetic interference and noise increase
Solution Approach 1:
Different wiring regions are assigned different current flow characteristics. The power wiring carries current in one direction while the ground wiring carries current in the opposite direction. This local differentiation of current flow directions creates opposing magnetic fields that cancel each other, reducing electromagnetic interference without significantly complicating the overall circuit design.
3Device complexity
If the anode and cathode have the same length, then the battery structure is symmetric and simple, but current flow generates electromagnetic interference affecting the speaker
Solution Approach 1:
The anode and cathode are designed with different lengths, creating an asymmetric battery structure. This asymmetry causes the current flow paths to be unequal, which when combined with the opposing current directions in the power and ground wirings, generates magnetic fields that cancel each other out, reducing electromagnetic interference.
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 effectively reduces electromagnetic interference and noise, enhancing the performance and reliability of miniaturized wearable devices by optimizing current flow and reducing electromagnetic disturbances.
Implementation Method 1
A first current having a first winding direction generated due to a length difference between the cathode and the anode may flow in the battery. A second current having a second winding direction opposite to the first winding direction may flow in a wiring disposed closer to the speaker between the power wiring and the ground wiring.
Data Source
AI summary
An electronic device according to an embodiment of the disclosure may include: a battery including an anode having a first length and a cathode having a second length different from the first length, a flexible printed circuit board electrically connected to the battery and surrounding at least part of a side surface of the battery, and a speaker stacked with the battery. The flexible printed circuit board may include a power wiring electrically connected to the anode and a ground wiring electrically connected to the cathode. A first current of a first winding direction generated due to a length difference between the cathode and the anode may flow in the battery, and a second current of a second winding direction opposite to the first winding direction may flow in a wiring disposed closer to the speaker between the power wiring and the ground wiring.