IC Card Resonance Tuning for Stable Stacked Contactless Power
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Solution Overview
Problem
Conventional contactless IC card systems face issues with maintaining a stable power supply voltage due to resonance frequency drift and changes in load current, especially when multiple cards are stacked or operate near each other, leading to unreliable data communication.
Innovation Solution
A contactless communication device with a resonance frequency variable circuit, rectifier, detector, and controller that adjusts the resonance frequency based on detected excess current to maintain a minimum voltage and stabilize operation, using a detector to identify changes in load current and adjust the resonance frequency accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple IC cards are placed close to each other or stacked, then the communication capacity and functionality are enhanced, but resonance frequency drift occurs leading to power supply voltage instability
Solution Approach 1:
The patent implements a feedback mechanism where the system detects the actual resonance frequency of the antenna and automatically adjusts it to maintain optimal communication performance. The controller monitors communication status and resonance frequency deviations caused by multiple cards, then dynamically tunes the antenna resonance frequency to compensate for drift, ensuring stable power supply voltage and reliable data transmission even when multiple IC cards are stacked or placed close together.
Solution Approach 2:
The patent changes the resonance frequency parameter of the antenna dynamically based on detection results. When multiple IC cards are detected or resonance frequency drift is identified, the system adjusts the antenna's resonance frequency to a corrected value, thereby maintaining stable electromagnetic coupling and power transfer efficiency despite the presence of multiple cards or environmental variations.
2Reliability
If resonance frequency is corrected by changing antenna parameters, then communication reliability is improved, but power supply voltage decreases due to induced voltage reduction
Solution Approach 1:
The patent employs dynamic adjustment of the antenna's resonance frequency based on real-time detection of communication status and resonance conditions. Rather than using a fixed resonance frequency, the system continuously adapts the resonance parameter to maintain optimal power transfer and communication reliability, balancing the trade-off between frequency correction benefits and power supply voltage maintenance.
3Device complexity
If conventional IC cards are used without resonance frequency control, then device complexity is low, but data communication becomes unreliable when multiple cards are stacked
Solution Approach 1:
The patent introduces a feedback-based resonance frequency detection and control system that automatically monitors communication status and adjusts antenna resonance parameters. This feedback mechanism enables the system to detect when multiple IC cards are stacked or when resonance frequency drift occurs, and automatically corrects the resonance frequency to maintain reliable data communication without requiring complex manual intervention or system redesign.
Solution Approach 2:
The patent implements a self-service mechanism where the contactless communication device autonomously detects resonance frequency drift and performs self-correction by adjusting its own antenna resonance frequency. The system monitors its own communication status and power transfer efficiency, then automatically tunes parameters to maintain optimal performance, reducing the need for external intervention or complex external control systems.
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 device ensures stable operation of contactless IC cards by maintaining a minimum voltage and preventing power supply voltage instability, even when multiple cards are stacked or positioned close together, thereby ensuring reliable data communication.
Implementation Method 1
an antenna that receives power from a transceiver device through contactless communication
Implementation Method 2
resonance frequency f0 of the resonance circuit is equal to carrier frequency fc of received electromagnetic waves
Data Source
AI summary
An IC card includes: a coil antenna that receives power from a transceiver device through contactless communication; a resonance frequency variable circuit that changes the resonance frequency of the coil antenna; a rectifier that rectifies an antenna output current output by the coil antenna; a controller that consumes a load current; a detector that detects an excess current that is a difference between a rectified output current output by the rectifier and the load current; and a resonance frequency controller that changes the resonance frequency of the coil antenna by controlling the resonance frequency variable circuit according to a detection signal output by the detector and indicating a detection result of the excess current.