Smart Card Internal Voltage Circuit Segmentation
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Solution Overview
Problem
Smart cards face challenges in minimizing leakage current and generating accurate internal voltages in both contact and contactless modes, as existing technologies struggle to efficiently manage voltage transitions between these modes.
Innovation Solution
An internal voltage generating circuit is designed with a controller, first and second regulators, and voltage application units, which differentially amplify and regulate voltages to enable or disable regulators based on control signals, ensuring optimal voltage output in contactless and contact modes, and prioritizing modes based on stored priority information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single voltage generation circuit is used for both contact and contactless modes, then device complexity is reduced, but voltage accuracy and leakage current control deteriorate
Solution Approach 1:
The voltage generation circuit is segmented into two independent circuits: a first voltage generation circuit for contactless mode and a second voltage generation circuit for contact mode. Each circuit is optimized for its specific operating mode, allowing independent control of voltage generation and regulation processes. This segmentation enables precise voltage control for each mode while maintaining overall system manageability through modular architecture.
Solution Approach 2:
The system dynamically switches between the first and second voltage generation circuits based on the detected card type (contactless or contact). The controller activates the appropriate circuit and disables the other, ensuring that each circuit operates only in its optimized mode. This dynamic adaptation allows the system to maintain high voltage accuracy and low leakage current by always using the circuit specifically designed for the current operating mode.
2Reliability
If voltage levels are optimized for one mode, then performance in that mode improves, but performance in the other mode deteriorates
Solution Approach 1:
The voltage generation system is divided into two separate circuits, each optimized for a specific operating mode. The first circuit generates voltages optimized for contactless mode operation, while the second circuit generates voltages optimized for contact mode operation. This segmentation allows each circuit to be fine-tuned for its specific mode without compromising the other mode's performance requirements.
Solution Approach 2:
The controller provides universal control over both voltage generation circuits, enabling the system to adapt to different card types and operating modes. By implementing a unified control mechanism that can selectively activate either the first or second circuit based on detected card type, the system achieves multi-mode versatility while maintaining mode-specific optimization through the use of dedicated circuits.
3Measurement precision
If regulators are always enabled for voltage regulation, then voltage precision improves, but leakage current increases
Solution Approach 1:
The regulators are dynamically enabled or disabled based on the current operating mode and voltage generation requirements. In contactless mode, the first regulator is enabled to provide precise voltage regulation while the second regulator is disabled to minimize leakage current. Conversely, in contact mode, the second regulator is enabled while the first is disabled. This dynamic control strategy ensures that voltage precision is maintained when needed while minimizing energy loss and leakage current when the corresponding circuit is not active.
Solution Approach 2:
The harmful effect of leakage current is eliminated by extracting or removing the inactive regulator from the operational circuit. When a voltage generation circuit is not needed for a particular mode, its corresponding regulator is completely disabled and taken out of the active circuit path, preventing any leakage current from flowing through it. This approach effectively removes the source of energy loss while maintaining the capability to provide precise regulation when the regulator is needed.
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 effectively minimizes leakage current and generates precise internal voltages in both contact and contactless modes, ensuring stable operation of smart cards by adapting voltage levels and enabling seamless transitions between modes.
Implementation Method 1
a differential amplifier for differentially amplifying the first and second voltages and outputting an amplified voltage of the amplification as the second control signal
Data Source
AI summary
An internal voltage generating circuit includes a first voltage application unit, a second voltage application unit, a first regulator, a second regulator, and a controller. The first and second voltage application units respectively provide a first voltage and a second voltage. The controller generates a bulk voltage, a first control signal, and a second control signal from the first and second voltages. The first regulator is enabled or disabled according to the first control signal and generates and outputs the first internal voltage based on the bulk voltage, the first voltage, and a first reference voltage. The second regulator is enabled or disabled according to the second control signal and generates and outputs the second internal voltage based on the bulk voltage, the second voltage, and a second reference voltage.