An nfc tag interface optimized for energy harvesting and small size

Abstract

The invention belongs to the field of wireless communication technology, and specifically relates to an NFC tag interface optimized for energy collection and small size. The NFC tag interface includes an antenna, an adjustable matching circuit, a demodulator, a load modulation circuit, a data interface, and a rectification temperature sensor. voltage circuit and energy collection interface; the antenna, adjustable matching circuit, demodulator, load modulation circuit and data interface constitute an NFC data receiving loop; the antenna, adjustable matching circuit, rectifier and voltage stabilizing circuit and energy collection interface constitute NFC energy receiving circuit. Beneficial effects of the present invention: The present invention allows the NFC communication interface to use a small antenna without affecting the NFC communication performance. Small antennas make device development very flexible and greatly reduce the difficulty of developing NFC systems. The present invention greatly expands the application scope of the NFC communication interface at present and in the next few years.

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] Such as 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 dir...

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, due to the design of the passive NFC tag interface and NFC reader interface 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 the 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

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