Wireless Power Receiver Impedance Control for In-Band Data
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Solution Overview
Problem
Wireless charging systems face challenges in efficiently transmitting power and data between devices while ensuring minimal power consumption and effective communication, particularly during start-up and varying load conditions.
Innovation Solution
The system incorporates a wireless power transmitting device and a receiving device with capacitor switching circuitry and a ballast load, allowing for impedance adjustment and in-band data transmission using amplitude-shift keying (ASK) and frequency-shift keying (FSK) modulation, enabling coordinated operation and data exchange while maintaining efficient power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the wireless power receiving device uses a fixed load configuration, then the circuit is simple, but power consumption is inefficient and overvoltage protection may trigger during light loading conditions
Solution Approach 1:
The patent implements dynamic load adjustment through capacitor switching circuitry that can change the impedance of the wireless power receiving circuitry based on operating conditions. A ballast load is used to provide minimum current during start-up, and capacitors are switched in or out to adjust the overall impedance, allowing the system to adapt to varying power transfer conditions and prevent overvoltage protection triggering while maintaining efficient power consumption.
2Use of energy by moving object
If the system uses impedance adjustment circuitry for efficient power transfer, then power consumption is optimized, but the device complexity increases
Solution Approach 1:
The patent combines multiple functions into unified circuit elements. The capacitor switching circuitry serves both to adjust impedance for efficient power transfer and to enable in-band data communication through modulation. The ballast load provides both minimum current during start-up and acts as a modulation element for data transmission. This multi-functionality reduces the need for separate dedicated circuits, thereby limiting the increase in overall device complexity.
3Loss of information
If the system implements in-band communication through modulation, then data transmission capability is improved, but power consumption increases
Solution Approach 1:
The patent merges the power transfer and data communication functions into a single in-band communication channel. Data is transmitted by modulating the impedance of the power receiving circuitry using the same coil and rectifier that receive power. The capacitor switching circuitry and ballast load serve dual purposes: maintaining efficient power transfer and enabling data modulation. This merging eliminates the need for separate communication hardware and reduces overall power consumption compared to using dedicated communication transceivers.
4Reliability
If the ballast load is used during start-up to ensure minimum current, then power transfer reliability is improved, but power consumption increases during operation
Solution Approach 1:
The patent employs periodic or conditional activation of the ballast load. During start-up operations, the ballast load is activated to ensure minimum current flow and reliable power transfer initialization. Once the wireless power receiving device is fully operational and the load is drawing sufficient current, the ballast load is turned off or its current is reduced. The capacitor switching circuitry periodically adjusts impedance based on detected loading conditions, ensuring the ballast load operates only when necessary, thereby minimizing overall power consumption while maintaining reliability during critical start-up phases.
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 ensures reliable power transmission and data communication between devices, optimizing power usage by adjusting impedance and load conditions, thereby reducing power consumption and preventing overvoltage protection triggering, even during light loading conditions.
Implementation Method 1
The coil of the portable electronic device receives alternating-current wireless power signals from a coil in the wireless charging mat
Implementation Method 2
The rectifier circuitry converts the received signals into direct-current power
Data Source
AI summary
A wireless power receiving device has a coil that receives wireless power signals from a wireless power transmitting device and has a rectifier that produces direct-current power across rectifier output terminals using the received wireless power signals. A load in the wireless power receiving device receives a direct-current output voltage from the rectifier output terminals. In-band communications are supported in which an amplitude-shift keying communications scheme or other communications scheme is used by a data transmitter in the wireless power receiving device to transmit in-band data through the coil. In-band data is transmitted by modulating one or more transistors that are coupled to the coil and other wireless power receiving circuitry in series with one or more capacitors and is transmitted by modulating current flow through a ballast transistor or other adjustable load that is coupled across the rectifier output terminals.