NFC tag interface for energy acquisition and small size optimization

Abstract

The invention belongs to the technical field of wireless communication, and specifically relates to an NFC tag interface for energy acquisition and small size optimization. The NFC tag interface comprises an antenna, an adjustable matching circuit, a demodulator, a load modulation circuit, a data interface, a rectifier and voltage regulator circuit, and an energy acquisition interface. The antenna, the adjustable matching circuit, the demodulator, the load modulation circuit and the data interface constitute an NFC data receiving circuit. The antenna, the adjustable matching circuit, the rectifier and voltage regulator circuit and the energy acquisition interface constitute an NFC energy receiving circuit. The beneficial affect are as follows: an NFC communication interface is allowed to use a small antenna without affecting the NFC communication performance; by using a small antenna, equipment development is very flexible, and the difficulty in NFC system development is reduced greatly; and the application scope of NFC communication interfaces at present and in the next few years is expanded greatly.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and in particular relates to an NFC tag interface optimized for energy collection and small size. Background technique [0002] NFC (Near Field Communication) technology is an emerging short-distance secure communication technology in recent years. It uses a magnetic field with a fast attenuation rate in space as the medium for transmitting information, realizing a communication distance of only a few centimeters, and has the advantages of high safety and convenient use. [0003] like figure 1 As shown, there are two common NFC communication interfaces, namely NFC reader interface (Reader) 101 and NFC tag interface (Tag) 102 . Typical NFC communication takes place between these two interfaces. NFC is a half-duplex two-way communication, including two links, namely the reader-to-tag link 103 and the tag-to-reader link 105, each of which is responsible for one communication direct...

AI Technical Summary

Problems solved by technology

When the antenna is small, due to the low coupling coefficient with the NFC reader antenna, coupled with its own low Q value, the efficiency is not high, resulting in a weak load-modulated signal that cannot be reliably received by the NFC reader

Second, because the passive NFC tag interface and NFC reader interface design in the traditional NFC system is directly inherited from RFID, its energy transmission efficiency is very low

However, the disadvantages of active modulation technology are also prominent

First of all, due to the need to actively transmit energy, the signal transmitted by the NFC tag interface must be locked with the frequency and phase of the alternating magnetic field transmitted by the NFC reader interface to avoid signal instability. This solution requires a complex phase-locked loop and phase holding circuit.

This makes the design of the NFC tag interface complicated and the cost rises

Second, the active modulation technique needs to provide energy for the NFC tag interface to transmit, and this technique cannot be used on passive devices such as passive smart cards and tags

Third, due to the complexity that active modulation technology adds to the NFC tag interface, it is difficult to implement NFC energy harvesting for the NFC tag interface using this technology

However, these approaches either increase the cost of the device or limit the performance of the device

Images