Wireless power receiver circuit and method
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Solution Overview
Problem
Wireless charging systems face interruptions in power transmission, leading to disruptions in power delivery to loads, particularly during temporary interruptions or measurements, which can affect the reliability and efficiency of the charging process.
Innovation Solution
A wireless power receiver circuit that includes an LC tank, a rectifier, a filtering capacitor, and a switching converter, controlled by a controller to maintain power delivery by switching transistors during interruptions, and increasing effective capacitance during ping processes to enhance startup and filtering performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a switched-mode power supply is used to provide power during wireless charging, then power delivery can be maintained during interruptions, but the complexity of the circuit increases
Solution Approach 1:
The switched-mode power supply dynamically switches between bypass mode and active switching mode based on wireless power reception status. During normal operation, the system operates in bypass mode with transistors off for simplicity. When interruption is detected, the controller activates the switching transistors to maintain power delivery, thus adapting the circuit complexity to operational needs
Solution Approach 2:
The switched-mode power supply is designed to perform multiple functions: it acts as a simple bypass path during normal wireless power reception and transitions to an active power conversion mode when wireless power is interrupted. This multi-functionality allows a single circuit to handle both normal and interruption scenarios without requiring separate dedicated circuits
2Stability of the object's composition
If the filtering capacitor has large capacitance for better filtering, then power stability improves, but the startup time increases due to slower charging
Solution Approach 1:
The system applies partial capacitance during startup by keeping the switched-mode power supply in bypass mode initially, allowing the filtering capacitor to charge partially through the rectifier. When interruption occurs, the switching converter activates to provide excessive power delivery capability, thus achieving both fast startup and stable power delivery without requiring the capacitor to be fully charged beforehand
3Loss of energy
If the switched-mode power supply operates in bypass mode during normal operation, then efficiency is improved, but power delivery cannot be maintained during interruptions
Solution Approach 1:
The controller continuously monitors the wireless power reception status and provides feedback control. When wireless power reception is interrupted, the controller detects the change and activates the switching transistors of the switched-mode power supply to maintain power delivery to the load, ensuring continuity despite the bypass mode operation during normal conditions
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
Ensures uninterrupted power to loads during temporary power interruptions and accelerates the startup process by reducing effective capacitance during ping events, improving overall charging efficiency and reliability.
Implementation Method 1
The Qi standard uses inductive charging operating between 80 kHz and 300 kHz to wirelessly transmit power from a transmitter to a receiver
Implementation Method 2
rectifying a voltage of the LC tank using a rectifier
Data Source
AI summary
In an embodiment, a method for providing power to a load using a wireless power receiver includes: wirelessly receiving power using an LC tank; rectifying a voltage of the LC tank using a rectifier; setting a switched-mode power supply coupled between the rectifier and the load in bypass mode; after setting the switched-mode power supply in bypass mode, providing power to the load without switching transistors of the switched-mode power supply; and when wireless power reception is interrupted, providing power to the load by switching one or more transistors of the switched-mode power supply.