Passive Wireless Charging Adapter for Mismatched Coil Sizes
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Solution Overview
Problem
Existing wireless charging technologies face inefficiencies when charging small-form-factor devices due to mismatched coil sizes and increased foreign-object heating, particularly in wearable technology, as they are not compatible with standard Qi chargers.
Innovation Solution
A passive adapter for magnetic inductive wireless charging, comprising two coils of differing sizes connected by a capacitor and separated by a core material to prevent mutual coupling, allowing for efficient power transfer between existing chargers and small-form-factor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a standard Qi wireless charger with a fixed-size transmitter coil is used, then charging of medium-sized devices like smartphones is efficient, but charging of small-form-factor devices results in poor coupling and low power-transfer efficiency
Solution Approach 1:
The patent divides the wireless charging system into two separate coils: a first coil that interfaces with the standard Qi transmitter and a second coil that interfaces with the small-form-factor receiver. This segmentation allows each coil to be optimized for its specific device type, resolving the contradiction between maintaining standard compatibility and adapting to smaller devices.
Solution Approach 2:
The patent introduces a passive adapter as an intermediary device between the standard Qi transmitter and the small-form-factor receiver. The adapter contains the dual-coil structure that bridges the size mismatch, enabling efficient power transfer while maintaining compatibility with existing chargers.
2Productivity
If a larger transmitter coil is used for standard Qi charging, then power transfer to medium devices is efficient, but foreign-object heating of metal housings in small devices increases
Solution Approach 1:
The patent applies local quality by creating a localized magnetic field through the second coil that is specifically sized and positioned to match the small receiver coil. This concentrates the magnetic flux where it is needed while minimizing exposure to surrounding metal housing, thereby reducing foreign-object heating while maintaining efficient power transfer.
3Adaptability or versatility
If the coil sizes are mismatched between transmitter and receiver, then existing Qi standards can be maintained, but magnetic coupling and charging efficiency significantly decrease
Solution Approach 1:
The passive adapter serves as an intermediary that resolves the size mismatch contradiction. The first coil maintains compatibility with standard Qi transmitters while the second coil is sized optimally for small receivers, and the capacitor couples these two coils to enable efficient magnetic coupling across the size difference.
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 adapter significantly improves magnetic coupling and power-transfer efficiency, reducing foreign-object heating and enabling high-efficiency wireless charging beyond standard distances, specifically for small-form-factor devices like wearable technology.
Implementation Method 1
the first coil configured to generate an electric current based on exposure of the first coil to a first magnetic field
Implementation Method 2
a capacitor electrically connected to the first coil, the capacitor configured to store energy based on the electric current generated by the first coil
Implementation Method 3
the second coil configured to generate a second magnetic field based on the stored energy from the capacitor
Implementation Method 4
separated by a core material that prevents mutual coupling between the coils
Data Source
AI summary
This document describes a passive adapter for wireless charging of an electronic device and associated methods and systems. The described passive adapter includes two coils connected by a capacitor and separated by a core material that prevents mutual coupling between the coils. These two coils may have differing sizes, such that one coil can size-match to a transmitter coil of an existing wireless charger and the second coil can size-match to a smaller (or larger) receiver coil in a wireless-power receiver to charge a battery of the wireless-power receiver. In aspects, these two coils may be separated by a distance that enables the passive adapter to act as a passive repeater by bridging a space between the transmitter coil and the receiver coil.