CN117748753A

CN117748753A - NFC performance improving device, NFC device and terminal equipment

Info

Publication number: CN117748753A
Application number: CN202211110500.1A
Authority: CN
Inventors: 卢友顺; 赵晶剑
Original assignee: Shanghai Fudan Microelectronics Group Co Ltd
Current assignee: Shanghai Fudan Microelectronics Group Co Ltd
Priority date: 2022-09-13
Filing date: 2022-09-13
Publication date: 2024-03-22

Abstract

The invention discloses a device for improving NFC performance, an NFC device and terminal equipment, wherein the device comprises: the NFC antenna, the NFC controller and the antenna matching module are coupled with the NFC antenna, the rectifying module is coupled with the antenna matching module, and the resonance control module; the antenna matching module is used for forming a resonant circuit with the NFC antenna; the NFC controller is used for establishing communication with the NFC reader-writer; the resonance control module is used for tuning the resonance circuit to a first working mode before the NFC controller establishes communication with the NFC reader-writer; tuning the resonant circuit to a second operating mode after receiving the first command signal; the Q value of the first working mode is larger than that of the second working mode; the rectification module is used for converting the radio frequency alternating voltage into direct voltage and outputting direct current only in the second working mode. The NFC interface energy collection method and the NFC interface energy collection device can improve NFC communication distance and meet energy collection and communication application requirements of the NFC interface.

Description

NFC performance improving device, NFC device and terminal equipment

Technical Field

The invention relates to the technical field of NFC (Near Field Communication ), in particular to a device for improving NFC performance, and further relates to an NFC device and terminal equipment.

Background

Currently, with more and more NFC mobile phone models being loaded, NFC-based applications are more widely used, such as payment, pairing, peer-to-peer transmission, NFC electronic price tags, NFC intelligent locks and the like. NFC uses a magnetic field as an information carrier, achieves a communication distance (a few centimeters) which is much shorter than that of traditional wireless communication, and has the advantages of passive communication, high safety, wide use and the like.

An important part of the NFC standard is the inheritance of the high frequency RFID (Radio Frequency Identification ) passive interface, allowing communication between the NFC reader interface and the NFC tag. The design of the traditional NFC tag is derived from RFID, and the signal receiving, transmitting and energy coupling are all performed through the same antenna, so that the energy conversion efficiency is very low, and only simple operation of the passive device, such as reading and writing of internal memory, cannot be achieved, and a great number of increasingly-used applications for the NFC passive interface, such as for intelligent wearable devices, NFC intelligent locks, passive electronic ink tags, future internet of things, etc., can be limited.

Disclosure of Invention

The embodiment of the invention provides a device for improving NFC performance, an NFC device and terminal equipment, which are used for solving the problem of energy limitation of the conventional NFC device and meeting the application requirements of an NFC interface.

Therefore, the embodiment of the invention provides the following technical scheme:

in one aspect, the present invention provides an apparatus for improving NFC performance, the apparatus comprising: the NFC antenna, the NFC controller and the antenna matching module are coupled with the NFC antenna, the rectifying module is coupled with the antenna matching module, and the resonance control module;

the NFC antenna is used for inducing and generating radio frequency alternating voltage to realize NFC communication and NFC energy reception;

the antenna matching module is used for forming a resonant circuit with the NFC antenna so as to adjust load impedance and tune the NFC antenna;

the NFC controller is used for establishing communication with the NFC reader-writer;

the resonance control module is used for tuning the resonance circuit to a first working mode before the NFC controller establishes communication with the NFC reader-writer; tuning the resonant circuit to a second mode of operation after receiving the first command signal; the Q value of the first working mode is larger than that of the second working mode;

the rectification module is used for converting the radio frequency alternating voltage into direct voltage and outputting direct current only in the second working mode.

Optionally, the resonance control module includes: the device comprises an AC-DC conversion unit, a control unit and an electronic switch unit, wherein one end of the control unit is connected with the output end of the AC-DC conversion unit, the other end of the control unit is connected with the control end of the electronic switch unit, and one end of the control unit is also connected with the output end of the first instruction signal;

the AC-DC conversion unit is used for converting the radio frequency alternating voltage into direct voltage;

the control unit is used for grounding the output end of the electronic switch unit or grounding one output end of the rectifying module when the amplitude of the direct current voltage exceeds a control threshold value so that the resonant circuit works in the first working mode; and after receiving the first instruction signal, disconnecting the output end of the resonant circuit connected with the ground, or disconnecting the output end of the rectifying module connected with the ground, so that the resonant circuit works in the second working mode.

Optionally, the first instruction signal is from the NFC controller or an external host controller.

Optionally, the AC-DC conversion unit is a half-wave rectification circuit or a full-wave rectification circuit.

Optionally, the rectification module is a half-wave rectification circuit or a full-wave rectification circuit.

Optionally, the resonant circuit is a series resonant circuit, or a series-parallel resonant circuit.

Optionally, the apparatus further comprises: an energy storage module coupled to the rectifying module;

the energy storage module is used for storing energy according to the direct-current voltage output by the rectifying module.

Optionally, a filtering and clipping module is further coupled between the rectifying module and the energy storage module;

the filtering and amplitude limiting module is used for smoothing the radio frequency alternating voltage and limiting the amplitude of the direct voltage output by the rectifying module.

Optionally, the apparatus further comprises: a buck module coupled between the NFC antenna and the NFC controller;

the step-down module is used for reducing the radio frequency alternating voltage to the working voltage interval of the NFC controller.

In another aspect, an embodiment of the present invention further provides an NFC device, including the foregoing device for improving NFC performance.

On the other hand, the embodiment of the invention also provides terminal equipment, which comprises the NFC device.

Optionally, the terminal device is any one of the following: intelligent wearable device, NFC electric toothbrush, NFC intelligent lock, passive electronic ink label and thing networking device.

According to the NFC performance improving device provided by the embodiment of the invention, the antenna matching module and the NFC antenna form the resonant circuit, the resonant circuit is tuned and controlled by the resonant control module, and the resonant circuit is tuned to the first working mode before the NFC controller starts working, so that the Q value of the resonant circuit reaches the maximum value, the radio frequency alternating current voltage fed into the NFC controller is improved in a multiplied way, the NFC controller can obtain enough energy to work, the NFC communication distance is improved, and the user experience is improved.

Further, the rectification module converts the radio frequency alternating voltage into direct current voltage, and outputs direct current when the resonance circuit works in a second working mode, accordingly, the energy storage module is used for collecting the direct current energy storage, and the stored energy can be provided for an external load or an external main controller for use.

Further, the NFC antenna and the antenna matching module can be connected into the rectifying module in various modes, so that the implementation mode of the resonant circuit is enriched, and the energy storage module can collect higher NFC energy.

Further, the radio frequency alternating voltage of the NFC antenna is reduced by the voltage reducing module and then is loaded onto the NFC controller, so that the influence of the internal amplitude limiting bleeder circuit of the NFC controller on the radio frequency alternating voltage generated by the NFC antenna is greatly reduced, and the influence on the energy collection efficiency is avoided.

Drawings

Fig. 1 is a schematic diagram of a conventional NFC reader-writer in communication with an NFC device;

fig. 2 is a schematic structural diagram of an apparatus for improving NFC performance according to an embodiment of the present invention;

fig. 3 is a schematic diagram of another structure of an apparatus for improving NFC performance according to an embodiment of the present invention;

FIG. 4 is a specific circuit diagram of an apparatus for enhancing NFC performance according to an embodiment of the present invention;

fig. 5 is a schematic diagram showing a modified structure of an AC-DC conversion unit in the embodiment of the present invention;

fig. 6 is a schematic diagram of another modified structure of an AC-DC conversion unit in the embodiment of the present invention;

fig. 7 is a schematic diagram of another modified structure of an AC-DC conversion unit in an embodiment of the present invention;

fig. 8 is a schematic diagram of a modified structure of an electronic switch unit in an embodiment of the present invention;

fig. 9 is a schematic diagram of another modification of the electronic switch unit in the embodiment of the present invention.

Detailed Description

The principles and spirit of the present invention will be described below with reference to exemplary embodiments shown in the drawings. It should be understood that these embodiments are described only to enable those skilled in the art to better understand and to practice the invention, and are not intended to limit the scope of the invention in any way.

The communication procedure between the NFC reader-writer and the NFC device will be briefly described first.

As shown in fig. 1, the NFC reader 101 generates a radio frequency field with a center frequency of 13.56MHz, and modulates information to be transmitted to the radio frequency field. When the NFC device 102 is located in the radio frequency field, information sent by the NFC reader 101 is received through the receiving antenna. The conventional NFC device controls the amount of energy received from the rf field by changing the load of the receiving antenna, so as to achieve the purpose of modulating and transmitting information.

NFC readers need to generate energy by themselves, and are generally applied to smart phones, tablet computers, POS terminals, while NFC devices are generally used on low-power consumption and low-energy devices, such as smart cards, smart devices, and the like.

Because the design of the NFC tag interface and the NFC reader interface directly inherits from the RFID, the energy transmission efficiency is low, the NFC tag interface can only acquire little energy from the NFC reader interface, and the performance of the NFC tag is greatly influenced due to the limitation of the antenna size, such as unstable communication performance, very close communication distance or complete incapability of communication, so that the application of the NFC tag is limited.

For this reason, an embodiment of the present invention provides a device for improving NFC performance, as shown in fig. 2, which is a schematic structural diagram of the device.

The device for improving NFC performance in this embodiment includes: an NFC antenna 601, an NFC controller 607 and antenna matching module 602 coupled with the NFC antenna 601, a rectifying module 603 coupled with the antenna matching module 602, and a resonance control module 608. Wherein:

the NFC antenna 601 is configured to generate a radio frequency ac voltage, so as to implement NFC communication and NFC energy reception, where the NFC antenna 601 may be a coil antenna;

the antenna matching module 602 is configured to form a resonant circuit with the NFC antenna 601 to adjust a load impedance, transform the load impedance to an antenna optimal load impedance, and tune the NFC antenna 601 to a frequency around 13.56 MHz;

the NFC controller 607 is configured to establish communication with an NFC reader/writer;

the rectifying module 603 is configured to convert a radio frequency ac voltage generated by the NFC antenna 601 into a dc voltage; the rectifying module 603 may specifically adopt a bridge full rectifier or a synchronous rectifier;

the resonance control module 608 is configured to tune the resonance circuit to a first operation mode before the NFC controller 607 establishes communication with the NFC reader/writer; after receiving the first instruction signal, the resonant circuit is tuned to receive the first instruction signal to a second working mode; the Q value of the first working mode is larger than that of the second working mode.

The Q value is a parameter representing the frequency selectivity of a circuit and the energy loss at the frequency, for a resonant circuit formed by the NFC antenna 601 and the antenna matching module 602, the higher the Q value, the lower the equivalent serial resistance value is compared with the inductance expansion or capacitance resistance of the circuit, the lower the loss in the oscillation process is, and the higher the energy transmission efficiency is; conversely, the smaller the Q value, the greater the loss in the oscillation process, and the lower the energy transmission efficiency.

In the embodiment of the present invention, the resonant circuit formed by the antenna matching module 602 and the NFC antenna 601 is tuned by the resonance control module 608, so that the resonant circuit has a higher Q value before the NFC controller 607 establishes communication with the NFC reader-writer, and thus the rf ac voltage of the NFC antenna 601 is multiplied by Q, and the rf ac voltage output to the NFC controller 607 is also multiplied. Since the resonant control module 608 operates with a lower rf ac voltage than the NFC controller 607 does, it will operate earlier than the NFC controller 607 does. Under the condition that the output radio frequency field of an external NFC reader-writer such as an NFC mobile phone is weak, if the Q value of the resonant circuit is high at this time, the radio frequency voltage amplitude of the NFC antenna 601 can be multiplied by Q times, so that the NFC controller 607 can obtain enough energy to work. The resonance control mode greatly improves the communication distance of NFC in a weak radio frequency field and improves user experience.

It should be noted that, in a specific application, after the NFC controller 607 establishes communication with the NFC reader/writer, the resonance control module 608 may tune the resonance circuit to the second operation mode according to the first command signal sent by the NFC controller 607 or the external host controller. Specifically, the NFC controller 607 may send the first instruction signal after receiving the control instruction of the NFC reader/writer, or notify the external host controller; accordingly, after the external host controller receives the notification of the NFC controller 607, the external host controller sends the first instruction signal to the resonance control module 608.

In addition, it should be noted that the rectifying module outputs the direct current only in the second operation mode. That is, in the first operation mode, the rectifying module does not output a direct current.

In one non-limiting embodiment, the energy storage module coupled to the rectifying module 603 may be used to collect the DC energy and store the energy, where the stored energy may be provided to an external load or an external host controller, specifically, directly provided to the external load or the host controller, or provided after passing through a DC-DC voltage stabilizing module. Whether the energy collected by the energy storage module is output or not can be controlled by an instruction of an external main controller or can be automatically controlled according to the received energy, and the embodiment of the invention is not limited.

As shown in fig. 3, in another non-limiting embodiment, the apparatus for improving NFC performance according to the present invention may further include any one or more of the following modules: the device comprises a filtering and clipping module 604, a power storage module 609 coupled to the filtering and clipping module 604, a step-down module 605 and a resonance module 606 coupled in turn between the NFC antenna 601 and the NFC controller 607. Wherein:

the energy storage module 609 is configured to store energy according to the dc voltage output by the rectifying module 603, and the energy storage module 609 may specifically be a rechargeable battery or a large capacity capacitor (such as hundreds to thousands UF or higher). In this embodiment, a charge-discharge switch 619 may also be provided within the energy storage module 609. The charge-discharge switch 619 is used to control the coupling or decoupling of the energy storage module 609 from the filtering clipping module 604.

The step-down module 605 is configured to reduce the radio frequency ac voltage to an NFC controller working voltage interval;

the filtering and limiting module 604 is configured to smooth the rf ac voltage and limit the amplitude of the dc voltage output by the rectifying module 603; the resonance module 606 is used to make the NFC controller 607 input impedance equivalent to a pure resistance.

The step-down module 605 may be implemented by a capacitor, a diode (such as a light emitting diode or a cascaded schottky diode), or an inductor, which acts to step down the radio frequency voltage of the NFC antenna 601 to be lower than the limiter operating voltage of the NFC controller 607, so as to prevent the 13.56MHz radio frequency signal received by the NFC controller 607 from exceeding the limiter operating voltage thereof. If the clipping operation voltage of the NFC controller 607 is exceeded, the internal bleeder module and clipping module of the NFC controller 607 are triggered to start working, which results in additional white loss of NFC energy.

In a specific application, the filtering and clipping module 604 may adopt a combination structure of a capacitor and a voltage stabilizing circuit, where the capacitor is used to smooth the rf ac voltage, store energy, and output dc voltage; the voltage stabilizing circuit is used for limiting the amplitude of the output direct-current voltage and avoiding damaging the rear-end electronic element.

In a specific application, the NFC controller 607 may be an NFC communication chip (may be an NFC channel chip, or a microprocessor with an NFC communication circuit) manufactured based on a CMOS process. A voltage limiter 617 is typically integrated inside the chip in order to limit the peak-to-peak value of the radio frequency voltage input by the chip to the highest limit level allowed, avoiding over-voltage damage of the chip. The voltage limiter 617 may be designed to limit 5-7 v voltage with a maximum operating current of 30-50 ma and a maximum operating power of 150 mW-350 mW. If the radio frequency power input at the chip port exceeds the above limit, the chip will be damaged. The chip is internally integrated with an NFC receiving and transmitting communication circuit, and is externally provided with a communication bus and a control input/output interface.

The resonance module 606 may be an inductor, and resonate with an input capacitor of the NFC controller 607 near a carrier working frequency, so that the input impedance of the NFC controller 607 is equivalent to a pure resistor, when the device works in a weak radio frequency field environment, the input capacitor of the NFC controller 607 cannot shunt the radio frequency ac voltage input by the chip due to resonance with the inductor, and the NFC controller 607 can obtain the energy received by the antenna 601 at the highest efficiency, increase the working distance when the weak radio frequency field is generated, and improve and enhance the user experience.

In a specific application, whether the energy storage module 609 is connected to the filtering and limiting module 604 may be determined by an internal detection circuit according to an input voltage, for example, monitoring a voltage output by the filtering and limiting module 604, and when the voltage is greater than a set voltage value, the energy storage module 609 is connected to the filtering and limiting module 604 to collect energy, or controlled by an external instruction. Of course, the default state of the energy storage module 609 may also be set to be coupled to the filtering and clipping module 604, which is not limited in this embodiment of the present invention. The output of the energy storage module 609 may be provided directly to an external load or an external host controller, or may be provided to an external load or an external host controller after passing through a voltage stabilizing module such as a DC-DC voltage stabilizing module.

In the embodiment shown in fig. 3, the resonance control module 608 rectifies the rf ac voltage generated by the NFC antenna 601 into a dc voltage, when the amplitude of the dc voltage exceeds the control threshold of the control unit in the resonance control module 608, the electronic switch unit 682 is closed, and the capacitance in the antenna matching module 602 is shorted to ground, so that the capacitance in the antenna matching module 602 and the NFC antenna 601 form the maximum Q value of the resonant circuit, and thus the rf ac voltage generated by the NFC antenna 601 is multiplied by Q, and the rf ac voltage output to the NFC controller 607 is also multiplied. The resonant control module 608 operates with a lower rf ac voltage than the NFC controller 607, which may operate earlier than the NFC controller 607. When the output rf field of the external NFC reader-writer, such as an NFC mobile phone, is weaker, the Q value of the resonant circuit is higher, the rf voltage amplitude of the NFC antenna 601 is multiplied by Q, the rf ac voltage is added to the NFC controller 607 through the step-down module 605, and exceeds the minimum working rf voltage of the NFC controller 607, so that the NFC controller 607 can obtain enough energy to start working. The resonance control mode improves NFC communication distance in a weak radio frequency field and improves user experience. When the device is put into an external NFC high-power reader-writer, after the NFC controller 607 receives a switch instruction to ground by the resonance control module 608 sent by the external NFC reader-writer, the NFC controller 607 can directly control or notify the main controller to control the resonance control module 608 to switch off the electronic switch unit, and at this time, the rectifying module 603 is capacitively connected to the NFC antenna 601 through the antenna matching module 602. The radio frequency ac voltage generated by the NFC antenna 601 is rectified by the rectifying module 603 to obtain a dc voltage, and then the dc voltage is sent to the energy storage module 609 through the filtering and limiting module 604.

Fig. 4 is a specific circuit diagram of an apparatus for improving NFC performance according to an embodiment of the present invention.

In this embodiment, the antenna matching module 602 is implemented using a capacitor, and as shown in fig. 4, the antenna matching module 602 includes: capacitors Cs1 and Cs2 connected to one output terminal of the NFC antenna 601, respectively, and a capacitor Cp connected between two input terminals of the antenna matching block 602. The resonant circuit formed by the antenna matching module 602 and the NFC antenna 601 is a series-parallel resonant circuit.

In a variant structure of the antenna matching module 602, the capacitor Cp may be omitted, and the antenna matching module 602 and the NFC antenna 601 form a series resonant circuit.

In another variant structure of the antenna matching module 602, the capacitor Cp may be further connected between two output ends of the antenna matching module 602, where the antenna matching module 602 and the NFC antenna 601 form a series-parallel resonant circuit.

In another variant structure of the antenna matching module 602, a capacitor may be connected between two input ends and two output ends of the antenna matching module 602, respectively, where the antenna matching module 602 and the NFC antenna 601 form a series-parallel resonant circuit.

Regardless of which circuit is used, the NFC antenna 601 can be tuned to around 13.56MHz to transform the rectified load impedance to the antenna's optimal load impedance by selecting an appropriate capacitance value.

In this embodiment, the rectifying module 603 employs a bridge full rectifier.

In this embodiment, the filter clipping module 604 includes a capacitor C and a zener diode DZ.

In this embodiment, the buck module 605 is implemented using two capacitors C1 and C2. In a variant, it is also possible to implement a diode (light-emitting diode or cascade schottky diode), i.e. a diode is used instead of the two capacitors C1 and C2 in fig. 4. It should be noted that the capacitance is calculated according to the radio frequency ac voltage of the NFC antenna 601 and the equivalent impedance of the NFC controller 607 in the two working environments of the NFC device for weak rf field working distance and maximum energy harvesting. The specific calculation method can refer to the calculation of the existing related circuit, and is not described herein.

In this embodiment, the resonance module 606 is implemented using an inductance L1. In a variant, the resonant module 606 may also be implemented without any circuit elements.

In this embodiment, the resonance control module 608 includes an AC-DC conversion unit 681, a resistor R, and an electronic switching unit 682. One end of the resistor R is connected to the output end of the AC-DC conversion unit 681, the other end is connected to the control end of the electronic switch unit 682, and one end of the resistor R is also connected to the output end of the first command signal. Wherein:

the AC-DC conversion unit 681 is configured to convert the radio frequency AC voltage into a DC voltage;

in this embodiment, the resistor R is used as a control unit, and the electronic switch unit 682 is used to control the output end of the electronic switch unit 682 to be grounded when the amplitude of the dc voltage exceeds the working threshold value, that is, one output end of the resonant circuit is grounded, or one output end of the rectifying module 603 is grounded, so that the resonant circuit works in the first working mode; and after receiving the first instruction signal, disconnecting the output end of the resonant circuit connected with the ground, or disconnecting the output end of the rectifying module connected with the ground, so that the resonant circuit works in the second working mode.

In this embodiment, the AC-DC conversion unit 681 is a half-wave rectification circuit formed by two diodes, wherein the anode of the first diode D1 is connected to the RF2 end of the NFC antenna 601, and the cathode of the first diode D1 is connected to the resistor R as the output end of the AC-DC conversion unit 681; an anode of the second diode D2 is connected to the output terminal of the rectifying module 603, and a cathode of the second diode D2 is connected to the RF2 terminal of the NFC antenna 601.

In this embodiment, the electronic switching unit 682 includes: and the electronic switches S1 and S2, wherein one output end of the electronic switch S1 and one output end of the electronic switch S2 are respectively connected with two input ends RECIN2 and RECIN1 of the rectifying module 603, the other signal ends of the electronic switch S1 and the electronic switch S2 are respectively grounded, the control ends of the electronic switch S1 and the electronic switch S2 are connected, and are connected to one end of the resistor R and the output end of the first instruction signal, so that synchronous control is carried out on the electronic switch S1 and the electronic switch S2.

After AC-DC conversion unit 681 outputs a rectified DC voltage, and when the DC voltage exceeds the electronic switch closing operation threshold, electronic switches S1 and S2 are closed, and the resonant circuit formed by the capacitors in NFC antenna 601 and antenna matching module 602 operates in the first operation mode, and the Q value is the highest, so that NFC controller 607 can obtain enough energy to start to operate. After the electronic switch unit 682 receives the first instruction signal, the electronic switches S1 and S2 are turned off, and at this time, the rectifying module 603 is connected to the NFC antenna 601 through the capacitors Cs1 and Cs2 of the antenna matching module 602, and at this time, the resonant circuit formed by the capacitors in the NFC antenna 601 and the antenna matching module 602 works in the second working mode, and its Q value is lower than that of the first working mode.

It should be noted that, in practical application, the AC-DC conversion unit 681 and the electronic switch unit 682 in the resonance control module 608 are not limited to the above circuit structure, and other modified structures are also possible, which will be exemplified below.

As shown in fig. 5, a schematic diagram of a modified structure of the AC-DC conversion unit in the embodiment of the present invention is shown.

In this embodiment, the AC-DC conversion unit 681 employs a half-wave rectification circuit composed of two groups of diodes, wherein the first group of bistable diodes includes a fifth diode D5 and a sixth diode D6, and the connection terminals of the fifth diode D5 and the sixth diode D6 are used as the first input terminal of the AC-DC conversion unit 681; the second group of bistable diodes includes a third diode D3 and a fourth diode D4, and the connection terminals of the third diode D3 and the fourth diode D4 serve as the second input terminal of the AC-DC converting unit 681.

Referring also to fig. 4, one connection manner of the AC-DC conversion unit 681 of this embodiment is: the first input end is connected with the RF1 end of the NFC antenna, and the second input end is connected with the RF2 end of the NFC antenna; another connection mode is as follows: the first input is connected to the rfin_ic1 terminal of the resonance module 606, and the second input is connected to the rfin_ic2 terminal of the resonance module 606. In both the above connection modes, the anode of the third diode and the anode of the sixth diode may be connected to the output terminal of the rectifying module 603 or to ground.

As shown in fig. 6, another modified structure of the AC-DC conversion unit in the embodiment of the present invention is schematically shown.

In this embodiment, the AC-DC conversion unit 681 is composed of a capacitor C and a voltage doubler module, and is a half-wave rectification circuit.

As shown in fig. 7, another modified structure of the AC-DC conversion unit in the embodiment of the present invention is schematically shown.

In this embodiment, the AC-DC conversion unit 681 is also composed of a capacitor C and a voltage doubler module, and is a full-wave rectification circuit.

The connection between the input and output of the AC-DC conversion unit 681 in the embodiment shown in fig. 6 and fig. 7 is similar to that in fig. 5, and will not be described here again.

Referring to fig. 8, fig. 8 is a schematic diagram showing a modified structure of an electronic switching unit in the embodiment of the present invention.

In this embodiment, the electronic switch unit 682 includes: and an electronic switch S5, where one signal end of the electronic switch S5 is connected to the output of the AC-DC conversion unit 681 in fig. 4, the other signal end is grounded, and the control end is connected to the output end of the rectifying module 603 in fig. 4, that is, the closing and opening of the output of the rectifying module 603 is controlled by the closing and opening of the electronic switch S5, so as to change the Q value of the resonant circuit formed by the capacitors in the NFC antenna 601 and the antenna matching module 602. The electronic switching unit of this embodiment can reduce the volume and cost of the electronic switching unit relative to the electronic switching unit of fig. 4, but the performance is slightly inferior to the electronic switching unit of fig. 4.

Referring to fig. 9, fig. 9 is a schematic diagram showing another modification of the electronic switch unit in the embodiment of the present invention.

In this embodiment, the electronic switch unit 682 includes: an electronic switch S6, an electronic switch S7, and capacitors C1 and C2 connected to the electronic switch S6 and the electronic switch S7, respectively. One signal end of the electronic switch S6 and one signal end of the electronic switch S7 are connected to the output of the AC-DC conversion unit 681 in fig. 4, the other signal end is grounded, and the control ends of the electronic switch S6 and the electronic switch S7 are respectively connected to the two output ends RF2 and RF1 of the NFC antenna 601 in fig. 4 through the capacitors C1 and C2.

The capacitors C1 and C2 may resonate with the antenna instead of the capacitors Cs1 and Cs2 shown in fig. 4.

The operation principle of the electronic switch unit 682 in this embodiment is the same as that of the electronic switch unit 682 in fig. 4, and will not be described here again.

Correspondingly, the embodiment of the invention also provides an NFC device, which comprises the NFC performance improving device.

Correspondingly, the embodiment of the invention also provides terminal equipment, and the NFC device of the terminal equipment. The terminal device may be, but is not limited to, any of the following: smart wearable devices (e.g., NFC bracelets, NFC watches, NFC glasses, etc.), NFC electric toothbrushes, NFC smart locks, passive electronic ink devices, internet of things devices, etc.

In a specific implementation, regarding each apparatus and each module/unit included in each product described in the above embodiments, it may be a software module/unit, or a hardware module/unit, or may be a software module/unit partially, or a hardware module/unit partially.

For example, for each device or product applied to or integrated on a chip, each module/unit included in the device or product may be implemented in hardware such as a circuit, or at least part of the modules/units may be implemented in software program, where the software program runs on a processor integrated inside the chip, and the rest (if any) of the modules/units may be implemented in hardware such as a circuit; for each device and product applied to or integrated in the chip module, each module/unit contained in the device and product can be realized in a hardware manner such as a circuit, different modules/units can be located in the same component (such as a chip, a circuit module and the like) or different components of the chip module, or at least part of the modules/units can be realized in a software program, the software program runs on a processor integrated in the chip module, and the rest (if any) of the modules/units can be realized in a hardware manner such as a circuit; for each device, product, or application to or integrated with the terminal, each module/unit included in the device, product, or application may be implemented by using hardware such as a circuit, different modules/units may be located in the same component (for example, a chip, a circuit module, or the like) or different components in the terminal, or at least part of the modules/units may be implemented by using a software program, where the software program runs on a processor integrated inside the terminal, and the remaining (if any) part of the modules/units may be implemented by using hardware such as a circuit.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be assessed accordingly to that of the appended claims.

Claims

1. An apparatus for improving NFC performance, the apparatus comprising: the NFC antenna, the NFC controller and the antenna matching module are coupled with the NFC antenna, the rectifying module is coupled with the antenna matching module, and the resonance control module;

2. The apparatus of claim 1, wherein the resonance control module comprises: the device comprises an AC-DC conversion unit, a control unit and an electronic switch unit, wherein one end of the control unit is connected with the output end of the AC-DC conversion unit, the other end of the control unit is connected with the control end of the electronic switch unit, and one end of the control unit is also connected with the output end of the first instruction signal;

the control unit is used for controlling the output end of the electronic switch unit to be grounded or grounding one output end of the rectifying module when the amplitude of the direct current voltage exceeds a control threshold value so that the resonant circuit works in the first working mode; and after receiving the first instruction signal, disconnecting the output end of the resonant circuit connected with the ground, or disconnecting the output end of the rectifying module connected with the ground, so that the resonant circuit works in the second working mode.

3. The apparatus of claim 2, wherein the first command signal is from the NFC controller or an external host controller.

4. The apparatus of claim 1, wherein the resonant circuit is a series resonant circuit or a series-parallel resonant circuit.

5. The apparatus according to any one of claims 1 to 4, further comprising: an energy storage module coupled to the rectifying module;

6. The apparatus of claim 5, further coupled between the rectifying module and the energy storage module is a filtered clipping module;

7. The apparatus of claim 6, wherein the apparatus further comprises: a buck module coupled between the NFC antenna and the NFC controller;

8. An NFC device comprising an NFC performance enhancing device according to any of claims 1 to 7.

9. A terminal device, characterized in that it comprises an NFC device according to claim 8.

10. The terminal device according to claim 9, characterized in that the terminal device is any one of the following: intelligent wearable device, NFC electric toothbrush, NFC intelligent lock, passive electronic ink label and thing networking device.