Research And Design Of Front-End Analog Circuits In Dual Interface Card

In recent years, Dual Interface Card is becoming the mainstream among many smart cards. With the development of technology and economic, the performance of Dual Interface Card is continuously improved, and become popular in daily life.In this paper, a new system design of dual Interface card front-end analog circuits is proposed based on the original contactless card. The main parts in this paper, which are contactless interface circuits, power management and security circuits, are designed and simulated. The contactless interface circuits is for the energy transmitting and information exchange when it is used as a contactless card. The design of three-level range-limit structure can improve the demodulation performance, the compatibility of different demodulation modes TypeA and TypeB, and it also provides communication mode auto-detection feature. The contactless interface circuit contains a brand new low-power clock recovery circuit. The power management circuitry regulates the input voltage to ensure a stable chip supply. It can automatically identify and switch the mode between contactless and contact-based interface, and it provides power-on-reset signal that can meet the requirement of dual interface card. The security circuits, including the field intensity detection and temperature detection circuit, are used to improving the safety performance. The whole design is implement with SMIC 0.18μm CMOS technology and designing rules. According to the simulation, the results show that all of the designs meet the requirements.