Wireless Charging Transmitter Merging Wall Adapter
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Solution Overview
Problem
Wireless charging is less efficient than wired charging, and the use of a wall adapter further reduces power transfer efficiency in typical wireless charging transmitters.
Innovation Solution
A wireless charging transmitter design that merges the wall adapter into a single resonant power stage by providing rectified mains voltage directly to a half-bridge converter, eliminating the need for a separate voltage reduction step, and includes a communication demodulation controller to adjust the driving signal frequency and duty cycle based on charging information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wall adapter is used to convert AC mains voltage to lower DC voltage in a typical wireless charging transmitter, then USB standard compatibility is achieved, but power transfer efficiency deteriorates
Solution Approach 1:
The patent merges the wall adapter functionality into the wireless charging transmitter by integrating a rectifier circuit and half-bridge converter. The rectifier circuit receives AC mains input voltage and provides rectified mains voltage directly to the half-bridge converter, eliminating the need for a separate wall adapter and reducing power loss through consolidation of power conversion stages
Solution Approach 2:
The half-bridge converter serves multiple functions: it directly receives rectified AC mains voltage, generates the time-varying driving signal for the transmitter coil, and provides power scaling. This multi-functional design eliminates the need for separate voltage reduction components while maintaining USB standard compatibility through controlled output parameters
2Power
If a separate wall adapter is used for voltage reduction, then voltage conversion is achieved, but device complexity increases
Solution Approach 1:
The patent combines the wall adapter's voltage conversion function with the wireless charging transmitter's power transmission function. The rectifier circuit and half-bridge converter are integrated into the transmitter architecture, creating a single unified device that performs both voltage conversion and wireless power transmission without requiring external wall adapter hardware
Solution Approach 2:
The half-bridge converter is designed to perform multiple functions simultaneously: voltage reduction from rectified mains voltage, generation of high-frequency AC drive signals for the transmitter coil, and provision of power to control circuitry. This multi-functionality consolidates what would traditionally require separate components into a single integrated circuit
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 design enhances system efficiency, reduces costs, and improves power scalability while maintaining compatibility with USB standards, leading to more efficient power transfer to devices.
Implementation Method 1
Inductive coupling using a transmitter coil and a receiver coil is used to transfer power
Implementation Method 2
a rectifier circuit for receiving an alternating current (AC) mains input voltage, and for providing a rectified mains voltage
Implementation Method 3
providing a time-varying driving signal to the transmitter coil, the time-varying driving signal having a frequency and a duty cycle
Implementation Method 4
a communication demodulation controller coupled to the transmitter coil to receive charging information from a receiver battery inductively coupled to the transmitter coil through load modulation
Data Source
AI summary
A wireless charging transmitter has a rectifier circuit, a transmitter coil, a transmitter coil driving circuit, and a control circuit. The rectifier circuit receives an alternating current (AC) mains input voltage and provides a rectified mains voltage. The transmitter coil is provided for inductively coupling with a receiver coil on a device having a battery to be charged. The transmitter coil driving circuit directly receives the rectified mains voltage, and for providing a time-varying driving signal to the transmitter coil. The control circuit is coupled to the transmitter coil to receive charging information from a receiver battery inductively coupled to the transmitter coil through load modulation. In response, the control circuit controls a frequency and duty cycle of the time-varying driving signal based at least in part on the charging information.