Interface circuit of CLF chip in SWP protocol

Abstract

The invention discloses an interface circuit of a CLF chip in an SWP protocol. The interface circuit comprises an input shaping module, an output load modulation module, a current sampling module and an output shaping module, wherein an input end of the input shaping module is connected with a voltage modulation signal output by the CLF chip; an input end of the output load modulation module is connected with an output end of the input shaping module, and an output end of the output load modulation module is connected with a C6 pin of a UICC chip; an input end of the current sampling module is connected with the C6 pin of the UICC chip; an input end of the output shaping module is connected to an output end of the current sampling module; and an output end of the output shaping module is used for outputting a current modulation signal to the CLF chip. According to the interface circuit of the CLF chip in the SWP protocol, the function of the interface circuit of the CLF chip in the SWP protocol can be realized by the aid of a current sampling technique, a voltage signal S1 can be correctly sent to the UICC chip in the SWP protocol, at the same time, a current signal S2 of the UICC chip can also be correctly received, and accordingly, full-duplex communication is realized.

Description

technical field [0001] The invention belongs to the field of CLF chips, and more particularly, relates to an interface circuit for realizing communication between a CLF chip based on a SWP protocol and an NFC SIM card chip in an NFC system. Background technique [0002] NFC (Near Field Communication) is an emerging technology for short-range wireless communication between electronic devices, which needs to connect the CLF chip and the SIM card chip. Among the 8 pins of the SIM card, 5 are conventional pins for daily communication with mobile phones. Among the remaining three pins, C4 and C8 are extended by the International Standards Organization as the high-speed interface of the new generation of SIM cards. Therefore, the C6 pin is used to connect the CLF chip and the SIM card chip, and the connection between them is realized through the SWP (Single Wire Protoco1) protocol. [0003] The SWP protocol is a patent based on the C6 pin of the SIM card proposed by Gemalto. The ...

AI Technical Summary

Problems solved by technology

[0006] The technologies used in the CLF chip interface circuit in the SWP protocol include differential circuit amplification technology and reference comparison technology. However, because the differential circuit amplification technology requires the design of complex amplifiers, the reference comparison technology requires the design of reference circuits and comparison circuits, which increases the complexity of circuit design. and power consumption

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