Efficient Transponder Power Supply with Reduced Capacitor Size
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Summary
Problems
Conventional transponder power supplies face inefficiencies due to the need for large capacitors to store energy during type A gaps in RFID communication, which increases the size of contactless chip cards and reduces energy efficiency during field pauses.
Innovation solutions
A transponder power supply system that includes an emergency circuit with a charging circuit and an output stage, where the charging circuit charges an emergency capacitor to a voltage higher than the antenna input signal, and the output stage uses a step-down converter to provide a supply current, allowing for more efficient energy storage and transfer.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If a large capacitor is used to store energy during type A gaps, then the transponder can survive longer field pauses, but the area of the analog frontend increases significantly
Why choose this principle:
The patent changes the voltage parameter by which the capacitor is charged. Instead of charging the capacitor to the antenna signal voltage level, the system rectifies and charges the capacitor to a higher voltage level (e.g., 5V or higher) during active communication. This voltage parameter change allows the capacitor to store the same amount of energy with a smaller capacitance value, thereby reducing the physical area while maintaining the ability to survive longer field pauses.
Principle concept:
If a large capacitor is used to ensure energy supply during field pauses, then reliability is improved, but device complexity increases
Why choose this principle:
The patent makes the power supply circuit multi-functional by using the same rectification and charging circuitry for both normal operation and emergency power storage. The charging circuit serves dual purposes: powering the transponder during active communication and charging the capacitor for use during field pauses. This eliminates the need for separate dedicated emergency power circuitry, reducing overall device complexity while maintaining reliability.
Application Domain
Data Source
AI summary:
A transponder power supply system that includes an emergency circuit with a charging circuit and an output stage, where the charging circuit charges an emergency capacitor to a voltage higher than the antenna input signal, and the output stage uses a step-down converter to provide a supply current, allowing for more efficient energy storage and transfer.
Abstract
A transponder power supply for providing a supply current based on an antenna input signal. The transponder power supply comprises an emergency circuit comprising a charging circuit, an emergency capacitor, and an output stage. The charging circuit is configured to charge the emergency capacitor based on the antenna input signal to a maximum voltage which is higher than a voltage of the antenna input signal. The output stage is configured to provide a contribution to the supply current using a charge of the emergency capacitor.