PCB Charging Coil With Ferrite Frame for Loose Hearing Aid Placement
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Solution Overview
Problem
Inductive charging systems for ITE hearing aids face challenges due to varying form factors and placement issues, leading to low coupling factors and increased interference, which are addressed by magnetic resonant charging with a specialized charging coil design.
Innovation Solution
A charging coil comprising a printed circuit board (PCB) coil and a frame-shaped ferrite tile, with a central opening, enhances magnetic resonance charging by increasing inductance and quality factor, reducing stray fields, and minimizing interference through a layered design with ground traces and ferrite material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If inductive charging is used with conventional copper coils, then energy transfer is achieved, but coupling factor is low and interference increases due to varying ITE hearing aid form factors and placement positions
Solution Approach 1:
The patent transitions from conventional inductive charging to magnetic resonant charging by changing the operating parameters (frequency, coil design, ferrite material integration) to achieve stronger coupling and reduced sensitivity to placement variations, directly resolving the low coupling factor issue with varying form factors
Solution Approach 2:
The charging coil integrates ferrite tiles with PCB traces to form a composite structure that enhances magnetic field concentration and coupling efficiency, improving both energy transfer and reliability while reducing interference from placement variations
2Adaptability or versatility
If transmitter coil size is increased to accommodate largest ITE hearing aid form factors, then charging capability is improved, but device size and complexity increase
Solution Approach 1:
The patent uses multi-layer PCB construction with ferrite tiles integrated between layers, creating a three-dimensional coil structure that achieves large effective charging area without increasing the planar footprint, thus maintaining compact device size while accommodating diverse hearing aid form factors
Solution Approach 2:
The charging coil design embeds ferrite tiles within the PCB layer structure and integrates multiple functional elements (coil traces, ground layers, ferrite shielding) in a nested configuration, reducing overall device complexity while achieving versatile charging capability
3Loss of energy
If receiver coil is placed close to transmitter coil for maximum energy transfer, then charging efficiency is improved, but placement freedom is reduced making alignment complicated
Solution Approach 1:
The patent employs magnetic resonance at specific frequencies to enhance the coupling between transmitter and receiver coils, allowing efficient energy transfer at larger distances and with greater placement freedom, eliminating the need for precise alignment while maintaining charging efficiency
Solution Approach 2:
Ferrite tiles serve as magnetic field intermediaries that concentrate and guide magnetic flux between the transmitter and receiver coils, enabling efficient coupling over larger air gaps and reducing sensitivity to misalignment, thus improving both charging efficiency and placement freedom
4Loss of energy
If conventional copper wire is used for transmitter coil, then ohmic resistance is low reducing heat loss, but inductance and quality factor are insufficient for magnetic resonant charging
Solution Approach 1:
The patent combines PCB copper traces with ferrite tiles to create a composite charging coil that achieves high inductance and quality factor necessary for magnetic resonant charging, while the PCB structure maintains low ohmic resistance, resolving the trade-off between power characteristics and energy loss
Solution Approach 2:
The patent replaces conventional wire-wound coil construction with PCB-based coil traces, achieving lower ohmic resistance through optimized trace geometry and better thermal management, while integrating ferrite materials to compensate for reduced inductance, thus maintaining low energy loss while improving power characteristics
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 design achieves high charging efficiency, reduced crosstalk, and compatibility with diverse ITE hearing aid sizes, allowing loose placement and efficient energy transfer.
Implementation Method 1
The operation of wireless charging is the induction of an electromagnetic field in the (secondary) receiver coil when current is fluctuating in the (primary) transmitter coil
Implementation Method 2
a frame shaped ferrite tile (8). The PCB coil (6) is arranged on the ferrite tile (8)
Implementation Method 3
magnetic resonant charging with a specialized charging coil design
Data Source
AI summary
A charging coil for a hearing aid charger for magnetic resonance charging of a hearing aid. The charging coil has a printed circuit board coil and a frame shaped ferrite tile with a central opening for receiving and securing the hearing aid. The printed circuit board coil is arranged on the frame shaped ferrite tile.