Wireless Charging Resonance Circuit Overvoltage Switching
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Solution Overview
Problem
Existing wireless charging technologies face issues with overvoltage protection in electronic devices, particularly when using parallel resonance, which can lead to increased current burden and potential damage to reception coils and internal circuits due to voltage spikes.
Innovation Solution
An electronic device with a first and second overvoltage protection (OVP) circuit is implemented, where the first OVP circuit disconnects parallel connection between a reception coil and capacitor upon overvoltage occurrence, and the second OVP circuit protects the switching device from voltage spikes, using a control circuit to manage the on/off states based on threshold voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If parallel resonance is used to increase voltage induced to the reception coil for remote power transmission, then wireless power transmission efficiency is improved, but overvoltage occurs in the internal circuit
Solution Approach 1:
The control circuit detects the voltage level before it becomes excessively high and proactively switches the switching device to disconnect the parallel resonance circuit. This preliminary action prevents overvoltage from occurring in the first place, rather than reacting after overvoltage damage has been caused.
Solution Approach 2:
The switching device acts as an intermediary between the parallel resonance circuit and the internal circuit. It can be switched to disconnect the capacitor from the reception coil, thereby mediating the voltage transmission and preventing overvoltage from reaching the internal circuit while still allowing power transmission functionality.
2Reliability
If second OVP circuit is added to protect switching device from voltage spike, then switching device reliability is improved, but device complexity increases
Solution Approach 1:
The second OVP circuit is designed to perform multiple functions: it protects the switching device from voltage spike damage, and simultaneously serves as a charging pathway for the battery. By making the protection circuit multi-functional, the patent reduces the need for separate dedicated protection and charging circuits, thereby mitigating the increase in device complexity.
Solution Approach 2:
The patent merges the overvoltage protection function with the battery charging function in the second OVP circuit. Instead of having separate circuits for protection and charging, these functions are combined into a single integrated pathway, reducing the overall complexity of the device while maintaining both protection and charging capabilities.
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 prevents overvoltage and voltage spikes, protecting internal circuits and switching devices, while allowing energy charging through voltage spikes, without requiring separate power for control.
Implementation Method 1
power is transmitted between a first coil of a transmitter and a second coil of a receiver. A magnetic field is generated at the transmitter, and current is induced or resonated according to a change in the magnetic field at the receiver, thereby generating energy
Implementation Method 2
an electronic device may use parallel resonance by connecting a reception coil to a capacitor in parallel, for increasing a voltage induced to the reception coil
Data Source
AI summary
An electronic device may include: a resonance circuit which comprises a battery, a coil and a capacitor, and receives power wirelessly; a rectifier which rectifies AC power, provided from the resonance circuit, to DC power; a DC/DC converter which converts and outputs the DC power provided from the rectifier; a charger which charges the battery by using the converted power provided from the DC/DC converter; a first OVP circuit which selectively connects the coil to the capacitor; a second OVP circuit which is connected in parallel to the first OVP circuit; a detection circuit which detects a rectified voltage; a control circuit; and a communication circuit, wherein the control circuit, on the basis that the detected rectified voltage is equal to or greater than a first threshold voltage, controls the first OVP circuit so as to be in an off state so that the coil is not connected to the capacitor, and on the basis that the detected rectified voltage is less than a second threshold voltage, controls the first OVP circuit so that the first OVP circuit is switched from the off state to an on state so that the coil is connected to the capacitor, wherein the second threshold voltage may be smaller than the first threshold voltage.