NFC Antenna Switch Circuit for Low-Crosstalk Multi-Antenna Routing
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Solution Overview
Problem
Existing NFC applications face challenges with increased design complexity and crosstalk due to the implementation of multiple antennae.
Innovation Solution
An NFC circuit switch design incorporating transistors and capacitors to manage multiple antennae, using a voltage-controlled MOS transistor system that reduces crosstalk and improves switching speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple antennae are implemented in an NFC circuit, then the number of supported NFC applications increases, but design complexity and crosstalk increase
Solution Approach 1:
The patent merges multiple antenna switching functions into a single integrated circuit switch that can handle multiple antennae simultaneously. The circuit switch integrates multiple transistors and capacitors in a compact configuration that provides antenna selection, isolation, and matching functions all in one component, thereby increasing adaptability while controlling design complexity.
Solution Approach 2:
The NFC circuit switch is designed as a universal component that can support multiple NFC applications and antenna configurations through a single device. The circuit switch can dynamically connect different antennae to the NFC controller based on application requirements, providing multi-functionality without requiring separate dedicated circuits for each antenna.
2Adaptability or versatility
If multiple antennae are implemented in an NFC circuit, then the number of supported NFC applications increases, but crosstalk increases
Solution Approach 1:
The patent extracts and eliminates crosstalk through the circuit switch architecture that provides isolation between multiple antenna paths. The switch uses transistor-based isolation mechanisms and dedicated capacitive coupling to separate signal paths, removing the harmful crosstalk effect while maintaining the ability to support multiple antennae for diverse NFC applications.
3Speed
If a voltage-controlled MOS transistor system is used, then switching speed improves, but power consumption increases
Solution Approach 1:
The voltage-controlled MOS transistor system operates using periodic switching controlled by the NFC controller. The transistors are switched on and off in synchronized periods that match the NFC communication protocol requirements, achieving fast switching speeds only when needed during active communication phases while remaining in low-power states during idle periods.
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
The solution allows for flexible and efficient management of up to 64 antennae with reduced crosstalk and improved switching speed, enabling cost-effective and versatile NFC system applications.
Implementation Method 1
a first transistor coupling a first NFC signal input node and the matching circuit; a second transistor coupling a second NFC signal input node and the matching circuit
Implementation Method 2
a third transistor coupling the first node to ground
Implementation Method 3
a first capacitor coupling a first conduction node of the first transistor to the first output node; a second capacitor coupling the first output node to ground
Implementation Method 4
the first node being coupled to a first voltage rail via a first resistor
Data Source
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AI summary
The present disclosure relates to an NFC circuit switch comprising: - an antenna matching circuit having a first and a second output nodes configured to be coupled to an antenna; - a first transistor (Q1) coupling a first NFC signal input node (RFO+) and the matching circuit; - a second transistor (Q5) coupling a second NFC signal input node (RFO-) and the matching circuit; a controlling node of the first and second transistors being coupled together to a first node, the first node being coupled to a first voltage (K+) rail via a first resistor (R1); and - a third transistor (Q4) coupling the first node to ground; the first voltage (K+) absolute value being superior to a maximum voltage present between first and second NFC signal input nodes added to the threshold voltage of the first or second transistors.