Wireless Power Noise Compensation via Shielding Layer and Grounding Resistor
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Solution Overview
Problem
Conventional wireless power systems introduce common mode noise to electronic devices via capacitive coupling, affecting voltage-sensitive systems such as capacitive user input and sensors, leading to unpredictable device behavior and user experience issues.
Innovation Solution
The implementation of an electric shielding layer between the receive coil and the housing of the electronic device, coupled with a noise-reduction capacitor and a grounding resistor, to mitigate capacitive coupling and provide a discharge path for stray capacitances, thereby reducing common mode noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If wireless power transfer is implemented using electromagnetic induction, then power transfer capability is improved, but common mode noise is introduced to voltage-sensitive systems
Solution Approach 1:
An electric shielding layer is introduced as an intermediary component between the receive coil and the housing to block capacitive coupling paths. The shielding layer acts as a mediator that prevents direct electrical interaction between the high-voltage receive coil and sensitive circuits, thereby reducing common mode noise while preserving wireless power transfer functionality
Solution Approach 2:
The harmful capacitive coupling effect is extracted and isolated by introducing the electric shielding layer. The shielding layer separates the power transfer path from the sensitive circuit paths, effectively removing the noise transmission mechanism while maintaining the essential power transfer function
2Object-affected harmful factors
If electric shielding layer is added to reduce common mode noise, then noise reduction is improved, but device complexity increases
Solution Approach 1:
The electric shielding layer is implemented as a thin conductive film or coating that can be integrated into the existing housing structure. This approach provides effective electromagnetic shielding while minimizing the increase in device complexity and maintaining a sleek form factor
Solution Approach 2:
The electric shielding layer is combined with the existing housing structure or integrated into the receive coil assembly. By merging the shielding function with existing structural elements, the patent reduces the need for separate components and simplifies the overall device architecture
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 effectively reduces common mode noise, improving the reliability and accuracy of voltage-sensitive systems in electronic devices by providing a controlled discharge path and balancing stray capacitances, thus enhancing user experience.
Implementation Method 1
Common mode noise can affect voltage-sensitive systems within the mobile device via capacitive coupling
Implementation Method 2
A grounding resistor connects the electric shielding layer to a common ground of the electronic device, thereby defining a discharge path from the electric shielding layer to common ground
Implementation Method 3
the noise-reduction capacitor balances stray capacitances (e.g., between inner and outer sections of the receive coil) that may develop between the receive coil and the electric shielding layer
Implementation Method 4
A conventional wireless power system includes a transmit coil that magnetically couples to a receive coil within the electronic device to deliver power by electromagnetic induction
Data Source
AI summary
Disclosed are devices, systems, and methods for reducing common mode noise induced in wireless charging circuits of electronic devices. For an electronic device having an inductive receiving coil near an electric shielding layer, differences in parasitic capacitances of the loops of the inductive receiving coil with an electric shielding layer can induce common mode noise. Common mode noise is reduced by a noise-reduction capacitor from the inductive receiving coil to the electric shielding layer together with a grounding resistor from the electric shielding layer to a common ground of the wireless charging circuit.