Controlled Rectifier Circuit for Contactless Card Modulation
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Solution Overview
Problem
Existing contactless chip card data transmission systems face challenges such as increased chip area requirements, unpredictable depth of modulation, and potential power supply breaks due to voltage undershoot, which affect communication efficiency and cost-effectiveness.
Innovation Solution
A data transmission unit with a controlled rectifier actuated by a control unit, which functions as both a rectifier and a shunt element, regulating voltage and performing load modulation without additional components, utilizing NMOS transistors to manage voltage and current flow efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shunt rectifier is added in parallel to protect against overvoltage, then voltage stability is improved, but chip area increases
Solution Approach 1:
The patent combines the rectifier and shunt element functions into a single integrated circuit structure. The controlled rectifier uses transistors that can operate in different modes: during normal operation, it rectifies the induced voltage; during overvoltage conditions, it acts as a shunt element to discharge excess current. This merging eliminates the need for separate parallel shunt rectifier circuits, reducing chip area while maintaining voltage stability.
Solution Approach 2:
The controlled rectifier is designed to perform multiple functions: voltage rectification during normal operation and voltage regulation/shunting during overvoltage conditions. By making the rectifier multi-functional, the patent eliminates the need for dedicated shunt protection circuits, thereby reducing overall chip area while ensuring reliable voltage stabilization.
2Reliability
If additional rectifier components are added for voltage regulation, then power supply stability is improved, but device complexity increases
Solution Approach 1:
The patent merges voltage rectification and voltage regulation functions into a single controlled rectifier circuit. The same transistor-based rectifier structure that converts AC to DC also provides overvoltage protection by shunting excess current to ground when needed, controlled by a simple control unit that monitors voltage levels.
Solution Approach 2:
The controlled rectifier is designed as a universal component that adapts its function based on operating conditions. It serves as a rectifier during normal operation and as a voltage regulator/shunt during overvoltage events, eliminating the need for separate regulation circuits and reducing overall device complexity.
3Use of energy by moving object
If the coupling factor between reader and chip card is increased to improve power transfer, then power supply efficiency is improved, but overvoltage risk increases
Solution Approach 1:
The patent implements a feedback control mechanism where a control unit continuously monitors the voltage output of the rectifier. When overvoltage conditions are detected (indicating strong coupling and high induced voltage), the control unit activates the shunt function of the controlled rectifier to discharge excess current, thereby protecting the chip while maintaining efficient power transfer.
Solution Approach 2:
The controlled rectifier is designed to preemptively counteract overvoltage effects by rapidly switching to shunt mode when voltage thresholds are exceeded. This preliminary anti-action prevents overvoltage damage before it can affect the chip, allowing the system to operate at high coupling factors for efficient power transfer without compromising safety.
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 solution reduces chip area requirements, stabilizes power supply, and ensures predictable modulation depth, enhancing communication reliability and cost-effectiveness by integrating multiple functions into a single controlled rectifier.
Implementation Method 1
The induced voltage is rectified by a rectifier 5 and is smoothed by means of a smoothing capacitor 6, and is used to supply the chip 7 mounted on the chip card with the voltage RFVDD.
Implementation Method 2
The induced voltage is rectified by a rectifier 5 and is smoothed by means of a smoothing capacitor 6
Implementation Method 3
If the voltage induced between RF1 and RF2 is too high, the shunt element actuation unit 10 is used to actuate the shunt element 9 such that the output of the shunt rectifier 8 is shorted to ground.
Data Source
AI summary
A data transmission method and a unit for performing data transmission. The method and unit include use of a data transmission interface having a controlled rectifier. The data transmission interface is actuated by a rectifier actuation unit.