NFC-Latched Load Disconnect Circuit for Safe Wireless Power
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Solution Overview
Problem
Wireless devices are not designed to be powered by conventional induction cooktops, and attempting to do so is hazardous due to the lack of safety and control over power transfer.
Innovation Solution
A power circuit using near field communication (NFC) for resonant power transmission, which includes a relay to selectively couple or decouple a load, a latching circuit to control the relay, and a storage element powered by the NFC circuit to delay decoupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional induction cooktops are used to power wireless devices, then power transmission can occur, but hazardous conditions arise due to lack of safety and control
Solution Approach 1:
The patent introduces an intermediary system consisting of a controller, NFC circuit, and power circuit that mediates between the induction cooktop and the wireless device. The NFC circuit establishes communication protocols, the controller manages power transmission parameters, and the power circuit executes controlled power delivery, thereby eliminating hazardous uncontrolled power transmission while maintaining reliable power transfer.
2Reliability
If a relay is used to selectively decouple the load, then safety control is improved, but device complexity increases due to additional components
Solution Approach 1:
The patent merges multiple functions into integrated circuits: the NFC circuit combines communication and identification functions, the controller integrates power management and control logic, and the power circuit combines relay control with power transmission. This consolidation achieves safety control through the relay while minimizing device complexity by avoiding separate dedicated components for each function.
3Reliability
If a latching circuit with storage element is used to delay decoupling, then reliable operation is ensured, but device complexity and power consumption increase
Solution Approach 1:
The latching circuit with storage element is designed to be self-regulating: the storage element automatically maintains the latched state without continuous external control signals, and the circuit self-resets when power transmission is complete or interrupted. This self-service mechanism ensures reliable operation during transient conditions while minimizing the need for additional control components and reducing overall device complexity.
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 solution enables safe and controlled power transfer to wireless devices from induction cooktops, preventing hazardous conditions and ensuring reliable operation.
Implementation Method 1
A power circuit with near field communication (NFC) using a resonant power transmission to power an appliance
Implementation Method 2
This technology operates on the principles of electromagnetic induction, a process by which electrical current is generated in a conductor by varying the magnetic field around it
Implementation Method 3
The decoupling is delayed as a function of a capacitor and a plurality of resistors, and the capacitor is energized with power from the NFC circuit
Data Source
AI summary
A power circuit for resonant power transmission to an appliance that receives power through an electromagnetic transmission from a power transmitter. The power circuit uses a near field communication (NFC) to detect wireless communication to the appliance. A relay that selectively decouples a load when the appliance and the power transmitter are not in a connected state. A latching circuit is used to trigger the relay in a connected state. The relay is held close by a storage element that is powered from by an NFC circuit.