Wireless Power Voltage Regulation Using LSK Impedance Modulation
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Solution Overview
Problem
Existing wireless power transfer (WPT) systems face inefficiencies at light-load conditions due to unregulated transmitters and complex, costly designs that require additional components and sensing coils, leading to bandwidth limitations and reduced dynamic performance.
Innovation Solution
Implementing a wireless hysteretic control system that achieves both transmitter power regulation and receiver voltage regulation without off-chip components or coils, using a monolithic chip design with integrated current sensors to maintain efficient power transfer and stability across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If linear analog control methodologies are used for TX regulation, then voltage regulation is achieved, but system complexity increases due to extra discrete components
Solution Approach 1:
The patent combines the TX regulation functionality with the existing LSK backscattering communication channel by modulating the TX coil impedance through the same load switch that controls power transfer. This merging eliminates the need for separate regulation circuits and discrete components, reducing system complexity while maintaining regulation capability
Solution Approach 2:
The load switch in the TX circuit serves dual purposes: it controls power transfer to the RX and simultaneously regulates TX output voltage by modulating coil impedance. This multi-functionality eliminates dedicated regulation components, reducing overall system complexity
2Reliability
If linear analog control methodologies are used for TX regulation, then voltage regulation is achieved, but bandwidth limitations occur
Solution Approach 1:
The patent employs pulse-based LSK modulation where the load switch operates in periodic on/off cycles to control power transfer and regulate voltage. This periodic switching action enables high-frequency operation and fast transient response, overcoming the bandwidth limitations of continuous linear analog control
Solution Approach 2:
The patent replaces linear analog control mechanisms with digital-like pulse switching control. By using discrete on/off switching instead of continuous analog adjustment, the system achieves higher bandwidth and faster response while maintaining regulation accuracy
3Speed
If nonlinear constant-idle-time control is used, then bandwidth limitations are eliminated, but light-load efficiency suffers
Solution Approach 1:
The patent implements dynamic load switching control where the TX load switch is activated only when power transfer is needed. At light-load or no-load conditions, the TX coil is disconnected from the power source, eliminating idle power consumption while maintaining the capability for fast transient response when load changes occur
4Reliability
If an extra sensing coil is added to extract LSK signals, then TX regulation is enabled, but TX coil area increases significantly
Solution Approach 1:
The patent makes the main TX coil perform dual functions: power transfer and LSK signal generation. By modulating the impedance of the existing TX coil through load switching, the system eliminates the need for a separate sensing coil, maintaining regulation capability while minimizing coil area
Solution Approach 2:
The patent extracts the LSK signal generation function from a separate sensing coil and integrates it into the main TX coil's operation. By using the same coil for both power transfer and regulation signaling, the system removes the redundant sensing coil component, reducing overall area
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 approach enables instant load-transient response and enhanced end-to-end efficiency, particularly at light-load conditions, by dynamically adjusting power transmission based on impedance changes, reducing system complexity and cost while maintaining stability.
Implementation Method 1
a transmitter coil connected to output nodes of the transmitter, wherein the transmitter coil can be separated from the receiver coil by an insulating dielectric
Implementation Method 2
wherein the transmitter coil can be separated from the receiver coil by an insulating dielectric
Data Source
AI summary
A variety of applications can include wireless power and voltage regulation for wireless power transfer systems. A receiver can receive power wirelessly from a transmitter to provide an output voltage. The receiver can regulate the output voltage with respect to a window defining an upper threshold and a lower threshold and can generate a first signal in response to the output voltage exceeding the upper threshold voltage and a second signal in response to the output voltage reducing below the lower threshold voltage. The receiver can change its input impedance and control reception of the power in response to the first and second signals. A transmitter can sense current in the power transistors or the coil of the transmitter in response to the change of input impedance of the receiver. The sensed current can be used to modify the current to the output of the transmitter to adjust the transmitted power.