Wireless Power Receiver Antenna Switching for NFC Waveform Integrity
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Solution Overview
Problem
Wireless power receivers face challenges in efficiently separating charging and communication phases, leading to power loss and potential waveform distortions that affect communication, especially in NFC applications, due to the shared use of antennas for both functions.
Innovation Solution
The implementation of a wireless power receiver with dedicated charge switches and communicator switches that decouple the antenna from the rectifier during communication phases, using a full-bridge rectifier with Shockley diodes and a power management unit, and employing bypass switches to manage antenna voltage and prevent waveform distortions, allowing efficient charging and communication in the 13.56 MHz NFC band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the antenna is shared for both communication and charging functions, then device complexity is reduced, but power loss and waveform distortions occur during communication phases
Solution Approach 1:
The patent implements dynamic switching of the antenna connection state using charge switches. During charging phases, the antenna is connected to the rectifier to transfer power. During communication phases, the charge switches dynamically disconnect the antenna from the rectifier while maintaining connection to the communicator unit, preventing power loss and waveform distortions. This dynamic reconfiguration allows the single antenna to serve both functions without the drawbacks of permanent dedicated connections.
2Power
If the antenna is connected to the rectifier during communication phase, then power transfer efficiency is improved, but communication quality deteriorates due to waveform distortions
Solution Approach 1:
The patent segments the antenna's functional connections by implementing separate charge switches for different operational modes. The antenna connection is segmented into a charging path (through charge switches to rectifier) and a communication path (through communicator switches to communicator unit). During communication phases, the charge switches open to disconnect the rectifier path, while communicator switches maintain the communication path, ensuring clean waveforms without rectifier-induced distortions while preserving power transfer capability when needed.
3Reliability
If charge switches are used to decouple antenna from rectifier, then communication quality is improved, but device complexity increases
Solution Approach 1:
The charge switches and communicator switches are designed as multi-functional components that serve dual purposes. The charge switches not only control power transfer timing but also protect the rectifier from communication signals. The communicator switches simultaneously route communication signals and maintain antenna tuning. This multi-functionality reduces the need for additional dedicated components, mitigating the complexity increase despite the addition of switching elements.
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 configuration enables efficient power transfer during charging while preventing communication disruptions, ensuring regulatory compliance and maintaining the integrity of NFC waveforms, thus providing sufficient power for wearables and small devices without the need for additional antennas.
Implementation Method 1
a rectifier having a first input coupled to the antenna via the first charge switch and having a first output
Implementation Method 2
a capacitor. The capacitor may comprise a first terminal permanently connected to the first terminal of the antenna and a second terminal permanently connected to the second terminal of the antenna
Implementation Method 3
A charging arrangement can be used to provide electrical power to a wireless power receiver
Data Source
AI summary
A wireless power receiver (11) comprises an antenna (13), a capacitor (14) having a first terminal permanently connected to a first terminal (16) of the antenna (13) and a second terminal permanently connected to a second terminal (17) of the antenna (13), a first charge switch (18), a rectifier (15) having a first input (19) coupled to the antenna (13) via the first charge switch (18) and having a first output (22), and a communicator unit (35) with a first terminal coupled to the antenna (13).