Smart Card Multi-Function Interface Controller
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Solution Overview
Problem
The existing ISO 7816 protocol for contact type smart cards limits communication bandwidth, making it inadequate for applications requiring transmission of large data such as audio and video files, as it only allows for eight defined contact pads with reserved pads not utilized for additional functions.
Innovation Solution
A smart card with a first ISO 7816 interface and a second multi-function interface using a subset of contact pads C4, C6, and C8, along with a controller to determine priority between the interfaces, allowing for additional functions like MMC, SD, USB, and other interfaces without requiring additional contact pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If additional contact pads are added to the smart card to support high-data-rate transactions, then the communication bandwidth is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies multi-functionality by enabling reserved contact pads (C4, C6, C8) to serve dual purposes: their original ISO 7816 functions and additional high-speed interface functions. The controller dynamically configures these pads to operate as data lines, clock lines, or control lines depending on the active interface mode, allowing a single contact pad to fulfill multiple roles and thereby increase communication bandwidth without adding physical pads.
Solution Approach 2:
The patent implements dynamic configuration of contact pad functions through a controller that can switch between different interface modes (ISO 7816, MMC, SD, USB). The contact pads' electrical characteristics and signal assignments are dynamically adjusted based on the detected interface type and operational requirements, enabling the system to adapt its bandwidth and functionality in real-time without physical reconfiguration.
2Adaptability or versatility
If multiple interface protocols are integrated into the smart card, then the adaptability and versatility are improved, but the device complexity increases
Solution Approach 1:
The patent achieves interface compatibility through a universal controller architecture that can interpret and manage multiple interface protocols (ISO 7816, MMC, SD, USB). The same physical contact pads are configured to different electrical standards and signal assignments depending on which interface protocol is detected and activated, allowing a single smart card design to support multiple interface types without requiring separate hardware for each protocol.
Solution Approach 2:
The patent employs preliminary detection and configuration mechanisms where the controller identifies the connected interface type during initialization and pre-configures the contact pads according to the detected protocol requirements. This preliminary setup ensures that the smart card is ready to operate with the specific interface protocol before actual data transmission begins, simplifying the integration of multiple protocols by handling configuration automatically.
3Productivity
If reserved contact pads are repurposed for additional functions, then the productivity and data transmission capability are improved, but the reliability of original ISO 7816 operations may be compromised
Solution Approach 1:
The patent ensures reliability by implementing dynamic switching between interface modes. The controller monitors the active interface protocol and dynamically reconfigures the contact pads to maintain proper signal levels and electrical characteristics for the current mode. When ISO 7816 protocol is active, the reserved pads are configured to their original specifications, ensuring stable and reliable operation. When high-speed interfaces are activated, the pads are reconfigured accordingly, maintaining reliability within each operational context.
Solution Approach 2:
The patent maintains reliability through parameter changes that adapt the electrical characteristics of contact pads based on the active interface protocol. The controller adjusts voltage levels, signal timing, and impedance matching parameters to match the requirements of either ISO 7816 or high-speed interfaces. This parameter adaptation ensures that each interface protocol operates within its specified electrical parameters, maintaining reliability while enabling enhanced data transmission capability when needed.
Data Source
AI summary
A smart card includes a first interface configured to perform a first type interfacing operation with a host using a plurality of contact pads defined by a contact type smart card protocol, a second interface configured to perform a second type interfacing operation with the host using a subset of the plurality of contact pads, and a controller configured to determine a priority between the first and second interfaces.