Non-contact card chip automatic temperature protection circuit

Abstract

The invention provides a contactless card chip automatic temperature protection circuit, the contactless card chip automatic temperature protection circuit comprises a temperature detection circuit and a resonance circuit, the temperature detection circuit comprises a temperature detection module and a voltage conversion module; the resonant circuit is composed of a variable capacitor parallel resonant capacitor and a parallel antenna. As the variable capacitor is added in the resonant circuit, after the output voltage of the temperature detection circuit rises, the output voltage controls the capacitance value of the variable capacitor to be increased, and the resonant frequency of the resonant circuit is reduced; when the resonant frequency of the resonant circuit deviates from 13.56 MHz, the energy received by the non-contact card is reduced, and the temperature of the chip of the non-contact card is reduced, so that the automatic temperature protection circuit can effectively protect the chip of the non-contact intelligent card exposed in large field intensity from being damaged by high temperature, and compared with a traditional intelligent card, the automatic temperature protection circuit has the advantages that the cost is reduced, and the working efficiency is improved. The application field intensity range of the non-contact card chip is improved, and the performance stability and the use reliability of the non-contact card chip are enhanced.

Description

technical field [0001] The invention relates to the field of non-contact card technology, in particular to an automatic temperature protection circuit for a non-contact card chip. Background technique [0002] In the 13.56MHz high-frequency smart card application, the passive card obtains energy from the card reader through inductive coupling, and the amount of energy obtained directly determines the core performance of the card such as operating frequency and response time. The greater the energy, the better the performance of the card, and the lower the energy, the worse the performance of the card. In the design of smart card chips, more energy is usually obtained by adjusting the resonance frequency and improving the efficiency of the rectifier circuit, but too much energy will also cause certain damage to the chip. [0003] see figure 1 It is a block diagram of the analog front-end circuit of a common contactless smart card chip, which mainly includes three parts: a r...

AI Technical Summary

Problems solved by technology

Usually when the field power is greater than 7A / m, the bypass current Ipass may reach more than 60mA, and the card will heat up due to excessive power

[0005] Excessive temperature will reduce the working performance and reliability of the card chip, and even damage the package of the card

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