Wireless Battery Charging Circuit Switching for Lower Heat
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Solution Overview
Problem
Existing wireless battery charging systems, such as those using buck chargers, suffer from inefficiencies that lead to wasted energy and increased heating in devices like smartphones, prolonging charging times.
Innovation Solution
A wireless battery charging system that incorporates a closed-loop DC-DC converter and an open-loop switched capacitor charger, with a controller managing the switching between them based on specific voltage and current thresholds to optimize charging phases, thereby enhancing efficiency and reducing waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a buck charger is used to step down the output voltage to battery charging voltage, then the charging function is achieved, but energy efficiency deteriorates and device heating increases
Solution Approach 1:
The charging process is divided into multiple phases (pre-charge phase, constant current charging phase, constant voltage charging phase), and different charging circuits are selectively used for different phases. The first charging circuit (buck charger) is used for pre-charge and constant voltage phases, while the second charging circuit (switched capacitor charger) is used for constant current phases, optimizing efficiency for each stage.
Solution Approach 2:
The system dynamically switches between different charging circuits based on real-time charging conditions and phases. The controller selectively enables or disables the first and second charging circuits during different charging phases to maintain optimal energy efficiency and reduce heating throughout the charging process.
2Productivity
If a buck charger is used for voltage conversion, then the charging function is achieved, but charging time increases due to energy waste
Solution Approach 1:
The charging process is segmented into distinct phases with dedicated charging circuits. The switched capacitor charger (second charging circuit) is specifically used during constant current charging phases where high efficiency is critical for charging speed, while the buck charger (first charging circuit) handles pre-charge and constant voltage phases.
Solution Approach 2:
The system changes operating parameters by switching between different charging circuits with different efficiency characteristics. The controller monitors charging phase and selectively activates the second charging circuit (switched capacitor) during constant current phases to maximize charging speed while maintaining energy efficiency.
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 increases overall charging efficiency, reduces device heating, and shortens charging times by selectively using the most appropriate charger for different phases of the charging process.
Implementation Method 1
The wireless power TX transmits power wirelessly via an inductive coupling to a wireless power receiver (RX)
Data Source
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AI summary
Described herein are wireless battery charging systems and methods for use therewith. Such a system can include a wireless power receiver (RX) that receives power wirelessly from a wireless power transmitter (TX) and in dependence thereon produces a DC output voltage (Vout). The system can also include a closed-loop charger and an open-loop charger each including a voltage input terminal and a voltage output terminal. The voltage input terminal of each of the chargers accepts the output voltage (Vout) from the wireless power RX. The voltage output terminal of each of the chargers is couplable to a terminal of the battery to be charged. A controller selectively enables one of the closed-loop or open-loop chargers at a time so that during a first set of charging phases the closed-loop charger is used to charge the battery, and during a second set of the charging phases the open-loop charger is used.