Multifunction Card Terminal Segmentation and Shielding
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Solution Overview
Problem
Multifunction card devices face challenges in maintaining reliability and physical integrity when interfacing with various memory card standards, requiring effective management of interfaces, power supply, and electromagnetic interference, especially when operating with multiple interface modes and non-contact interfaces.
Innovation Solution
A multifunction card device with a wiring substrate featuring individualized and communalized external connection terminals, a security controller for independent security processes, and a nonvolatile memory element for power-efficient switch state maintenance, along with an internal or external antenna for non-contact operation, and electromagnetic shielding to prevent interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple interface control modes are supported for different memory card standards, then adaptability is improved, but device complexity increases
Solution Approach 1:
The external connection terminals are segmented into individual terminals (DAT0-DAT7, CMD, CS) and common terminals (Vcc, Vss, CLK) that can be selectively connected based on the interface mode. This segmentation allows the device to support multiple memory card standards (MMC, SD, Memory Stick) by activating only the necessary terminals for each standard, thereby improving adaptability while managing complexity through organized terminal groups.
Solution Approach 2:
The terminal connection mechanism provides universal support for multiple interface standards through a single unified terminal structure. The same physical terminals can be configured to work with different memory card standards by changing the connection configuration, eliminating the need for separate terminal sets for each standard and reducing overall device complexity.
2Adaptability or versatility
If non-contact interface is added for IC card functionality, then adaptability is improved, but electromagnetic interference susceptibility increases
Solution Approach 1:
A shield structure is introduced as an intermediary element between the antenna and the semiconductor chips. This shield acts as a mediator that blocks electromagnetic interference from reaching the sensitive electronic components while allowing the non-contact interface to function. The shield is positioned to create a protective barrier without interfering with the antenna's ability to communicate with external IC cards.
3Adaptability or versatility
If antenna is integrated for non-contact operation, then functionality is improved, but antenna characteristic degradation occurs due to ground pattern
Solution Approach 1:
The ground pattern on the wiring substrate is segmented into multiple separate ground regions rather than forming a continuous closed loop. This segmentation prevents the formation of large current loops that would interfere with the antenna's electromagnetic field. The divided ground pattern maintains the necessary ground connections while eliminating the harmful eddy currents that would degrade antenna performance.
Solution Approach 2:
The potential harmful effect of the ground pattern on antenna performance is converted into a benefit by deliberately designing the ground pattern to be non-closed and segmented. This design choice, which might seem to reduce ground effectiveness, actually improves antenna performance by eliminating electromagnetic interference while still providing adequate grounding for circuit operation.
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
Ensures reliable operation across multiple interface modes, efficient power management, and effective electromagnetic interference protection, enhancing the device's versatility and performance.
Implementation Method 1
the operation power has been obtained with the electromotive force (induced e.m.f.) generated by the electromagnetic induction by transformer coupling
Implementation Method 2
Since a ferrite plate which is a ferromagnetic substance has large magnetic permeability, magnetic flux tries to take the path along it without penetrating the ferrite plate
Implementation Method 3
it has a shield structure for blocking EMI and for protecting the device
Data Source
AI summary
A multifunction card device has an external connection terminal, an interface controller, a memory, and the security controller connected to the interface controller and the external connection terminal. The interface controller has a plurality of interface control modes, and controls an external-interface action and a memory interface action by the control mode according to the instruction from the outside. The external connection terminals have an individual terminal individualized for every interface control mode, and a communalized common terminal. A clock input terminal, a power supply terminal, and an earthing terminal are included in the common terminals. A data terminal, and a dedicated terminal of the security controller are included in the individual terminals. Partial communalization and individualization of an external connection terminal attain a guarantee of the reliability of an interface, and increase control of physical magnitude to some kinds of interface control modes. The security process by a security controller independent interface can also be guaranteed.