NFC (Near Field Communication) passive tag identification system, NFC passive tag identification method and NFC equipment

Abstract

One or more embodiments of the present specification relate to an NFC passive tag identification system, method, and NFC device. The system comprises an energy collection circuit which is used for collecting and storing electric energy converted from mechanical energy generated by touch between the terminal equipment and the system. The system also comprises a radio frequency transmitting circuit which is connected with the energy collection circuit, is powered by the energy collection circuit, and is used for transmitting an excitation signal for enabling the terminal equipment to quit the low power consumption card detection LPCD mode. In addition, the system also comprises an NFC label circuit which is used for sensing an NFC detection signal sent by the terminal equipment so as to communicate with the terminal equipment.

Description

Technical Field

[0001] The embodiments of the present specification generally relate to the field of near field communication (NFC) technology, and more specifically to an NFC passive tag recognition system, method and NFC device. Background Art

[0002] NFC, or Near Field Communication, is a short-range, high-frequency radio technology that evolved from contactless Radio Frequency Identification (RFID) technology. It supports short-range wireless communication between mobile devices, consumer electronics, PCs, and smart control tools. Its operating frequency is 13.56MHz, and the transmission distance is within 10cm or 20cm. NFC is a wireless connection technology that provides easy, secure, and fast communication, with the characteristics of short distance, high bandwidth, and low energy consumption.

[0003] NFC devices can be divided into passive NFC devices and active NFC devices. Passive NFC devices include NFC tags and other small transmitters, which can send information to other NFC devices without the need for power, so they have the advantages of low cost, long service life and strong environmental adaptability; active NFC devices can send and receive data, and can communicate with each other and with passive devices. Active NFC devices can only work when powered. Summary of the invention

[0004] In view of this, one or more embodiments of the present specification provide an NFC passive tag recognition system, method and NFC device, which can convert the generated mechanical energy into electrical energy for sending a carrier signal of the NFC radio frequency field when a terminal device collides with the system, so that a nearby terminal device such as an NFC card reader exits the LPCD mode and communicates in a normal card inspection mode, thereby improving the NFC tag recognition efficiency in a passive NFC scenario in a low-power and low-cost manner.

[0005] In the first aspect of the present specification, a NFC passive tag identification system is provided. The system includes an energy collection circuit for collecting and storing electrical energy converted from mechanical energy generated by contact between a terminal device and the system. The system also includes a radio frequency transmission circuit connected to the energy collection circuit and powered by the energy collection circuit, and used to send an excitation signal for causing the terminal device to exit a low-power card detection LPCD mode. In addition, the system also includes an NFC tag circuit for sensing an NFC detection signal sent by the terminal device to communicate with the terminal device.

[0006] In a second aspect of the present specification, a method for identifying an NFC passive tag is provided. The method includes collecting and storing electrical energy converted from mechanical energy generated by a collision. The method also includes sending an excitation signal for causing a terminal device to exit a low power consumption card detection LPCD mode based on the electrical energy converted from the mechanical energy generated by the collision. In addition, the method also includes sensing an NFC detection signal sent by the terminal device to communicate with the terminal device.

[0007] In a third aspect of the present specification, an NFC device is provided. The NFC device operates in a passive mode, and a terminal device communicating with the NFC device operates in an active mode. The NFC device includes the system according to the first aspect of the present specification.

[0008] It should be understood that the contents described in the Summary of the Invention are not intended to limit the key or important features of the embodiments of this specification, nor are they intended to limit the scope of this disclosure. Other features of this specification will become easy to understand through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The above and other purposes, features and advantages of the various embodiments of the present specification will become more easily understood through the following detailed description with reference to the accompanying drawings. In the accompanying drawings, various embodiments of the present specification will be described in an exemplary and non-limiting manner, wherein:

[0010] Figure 1 A schematic diagram of the structure of an NFC passive tag recognition system according to some embodiments of this specification is shown;

[0011] Figure 2 A schematic diagram of a stacking structure of an NFC passive tag identification system according to some embodiments of this specification is shown;

[0012] Figure 3 A schematic diagram of a circuit layout of an NFC passive tag identification system according to some embodiments of this specification is shown;

[0013] Figure 4A A schematic diagram of the structure of a radio frequency transmitting circuit according to some embodiments of this specification is shown;

[0014] Figure 4B An equivalent circuit diagram of a radio frequency transmitting circuit according to some embodiments of the present specification is shown;

[0015] Figure 5A A schematic diagram of the structure of an NFC tag circuit according to some embodiments of this specification is shown;

[0016] Figure 5B An equivalent circuit diagram of an NFC tag circuit according to some embodiments of the present specification is shown; and

[0017] Figure 6 A flowchart of an NFC passive tag identification method according to some embodiments of the present specification is shown.

[0018] Throughout the drawings, the same or similar reference numbers denote the same or similar elements. DETAILED DESCRIPTION

[0019] The embodiments of the present specification will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present specification are shown in the accompanying drawings, it should be understood that the present specification can be implemented in various forms and should not be construed as being limited to the embodiments described herein, which are instead provided for a more thorough and complete understanding of the present specification. It should be understood that the drawings and embodiments of the present specification are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0020] In the description of the embodiments of this specification, the term "including" and similar terms should be understood as open inclusion, that is, "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0021] As mentioned above, NFC has been sought after by more and more industries in recent years due to its characteristics of short distance, fast connection, low power consumption, and high compatibility. It has been widely used in scenarios such as mobile payment, data exchange, and access control. Among them, the passive NFC tag is a near-field communication device that does not rely on its own power supply. This tag exchanges data with the NFC reader through a short-range wireless signal. When the NFC reader is close to the passive tag, the electromagnetic field emitted by the reader powers the tag, and the tag's built-in circuit starts working. The tag then transmits the stored data back to the reader through modulation to complete the data interaction.

[0022] Low Power Card Detection (LPCD) mode is a low-power card detection method that allows the NFC reader to detect the proximity of a card without the need for continuous polling. This mode is implemented by periodically sending radio frequency (RF) pulses and monitoring the reflected signal. When a signal change (such as detuning) is detected, it triggers the NFC reader to further communicate.

[0023] When performing NFC tag recognition, terminal devices with NFC card reading functions are usually in active mode, and monitor whether there is an NFC device approaching by emitting an electric field. However, since terminal devices, especially mobile devices, are usually battery-powered, in order to extend battery life and improve battery life, some terminal devices will automatically switch to LPCD mode within a period of time after the screen is turned on. Once in LPCD mode, if the coupling area of ​​the antenna is insufficient or the electric field change is not significant enough, the terminal device may find it difficult to exit this mode, resulting in the normal communication between the terminal device and the NFC tag being blocked, which in turn affects the NFC recognition success rate and the user experience.

[0024] To this end, an NFC passive tag recognition system is provided in the embodiments of this specification. The system can convert the mechanical energy generated when a terminal device collides with the system into electrical energy for sending a carrier signal of the NFC radio frequency field, so that the nearby terminal device such as an NFC card reader exits the LPCD mode and communicates with the NFC tag in the normal card detection mode, thereby improving the NFC recognition efficiency in a low-cost and low-power manner in a passive NFC scenario.

[0025] Figure 1 FIG. 1 shows a schematic diagram of the structure of an NFC passive tag recognition system 100 according to some embodiments of this specification. Figure 1 As shown, the NFC passive tag identification system 100 may include an energy harvesting circuit 102, a radio frequency transmission circuit 104, and an NFC tag circuit 106. The energy harvesting circuit 102 may convert mechanical energy generated by the collision between the terminal device and the system into electrical energy. Methods for converting mechanical energy into electrical energy include but are not limited to utilizing piezoelectric effect, magnetic induction principle, electrostatic induction, mechanical kinetic energy switch, etc.

[0026] The piezoelectric effect is a physical phenomenon that refers to the fact that certain materials (which may be referred to as piezoelectric materials) generate an electric charge or voltage when subjected to mechanical stress (such as stretching, compression, or bending), and vice versa, when an electric field is applied to these materials, they deform. In some embodiments, the energy harvesting circuit 102 can utilize the piezoelectric effect to convert the mechanical energy generated when the terminal device collides with the system 100 into electrical energy to provide energy to the RF transmission circuit 104.

[0027] Optionally, the piezoelectric material can be a piezoelectric sheet, which has a simple structure, low cost, and is easy to integrate. Optionally, the piezoelectric material can also be made of piezoelectric ceramics, piezoelectric crystals, piezoelectric films, and other materials to meet specific scene requirements. For example, the piezoelectric film can be used in scenes with complex surface shapes by taking advantage of its strong flexibility.

[0028] When a part of the conductor of a closed circuit moves in a magnetic field while cutting magnetic flux lines, an induced current will be generated in the conductor. This phenomenon is called electromagnetic induction. The mechanical energy generated by touch (such as pressing, touching, etc.) can be converted into the kinetic energy or deformation energy of the conductor, which in turn drives the conductor to move in the magnetic field, generating an induced current.

[0029] For example, a combination of a spring and an induction coil can be used to achieve the conversion of mechanical energy into electrical energy. Specifically, as a component for receiving and converting mechanical energy, the spring will deform when touched, thereby converting mechanical energy into deformation energy. When the spring (or the conductor connected to it) moves in a magnetic field, it cuts the magnetic flux lines, thereby generating an induced current in the induction coil.

[0030] In addition, the conversion of mechanical energy into electrical energy can also be achieved by utilizing principles such as electrostatic induction and mechanical kinetic energy switches, and this specification does not impose any restrictions on this.

[0031] Since the harvested piezoelectric energy is usually weak and unstable, energy storage elements are needed to store and manage this energy. For example, capacitors or lithium-ion batteries can be used to store electrical energy.

[0032] In actual scenarios, the surface of the system 100 may include words and phrases for guiding the user to use the terminal device to approach and touch the system 100, such as "tap to order", "tap to pay", etc. The terminal device may include but is not limited to a mobile terminal device of the smartphone type with an NFC card reader function, a smart wearable device such as a smart watch and smart glasses, and this specification does not limit this.

[0033] In some embodiments, the energy collection circuit 102 may also be connected to a rectifier circuit and a boost voltage stabilizing circuit. The rectifier circuit can convert alternating current into direct current, and the rectifier circuit may include a Schottky diode rectifier bridge. The boost voltage stabilizing circuit can be used to increase the output voltage to meet the voltage requirement of the radio frequency transmission circuit 104, so that the radio frequency transmission circuit 104 can send an excitation signal. Specifically, the current generated by the energy collection circuit 102 can first be converted into direct current via a Schottky diode rectifier bridge, and the electric energy is charged to a capacitor, and the voltage is boosted (e.g., 3.5V) by a DCDC circuit, and then sent to the radio frequency transmission circuit 104. The radio frequency transmission circuit 104 can send an excitation signal for causing the terminal device to exit the low power consumption card detection LPCD mode based on the energy provided by the energy collection circuit 102.

[0034] The above-mentioned terminal devices with NFC card reading function are usually powered by batteries and are very sensitive to power consumption. In order to control power consumption, they usually make many low-power designs for the transmission power of their own card readers, including setting LPCD mode. For example, most smartphones will automatically switch to LPCD mode after a period of time after the screen is turned on.

[0035] In actual applications, only when the terminal device detects that the RF signal it transmits is sensed by the nearby NFC target device, and the signal strength change caused by this induction reaches or exceeds the preset threshold, the mobile device will wake up from the LPCD mode and enter the normal card reading mode. However, in the LPCD mode, the signal strength emitted by the terminal device is weakened, and the amplitude of the RF signal will be lower than that in the normal card reading mode. This causes the NFC target device to respond to the signal with a corresponding decrease, making it difficult for the terminal device to accurately determine whether there is an NFC target device around based on the change in signal amplitude. Therefore, the terminal device can be stimulated to exit the LPCD mode by actively transmitting a high-intensity excitation signal.

[0036] In some embodiments, the RF transmission circuit 104 may include a first NFC chip connected to the energy collection circuit 102 and an excitation coil connected to the first NFC chip. The first NFC chip may send a carrier signal (i.e., an excitation signal) of an RF field containing a specified data packet (including but not limited to commands such as card search and P2P transmission) to the excitation coil based on the boosted voltage as described above. The excitation signal may then be sent by the excitation coil to form an RF field around the system. Optionally, the excitation signal may also be an empty carrier signal that does not contain any information to reduce the system burden of the transmission signal. The first NFC chip may be any NFC chip that supports the 13.56MHz carrier standard. The above-mentioned first NFC chip and excitation coil may be provided by commercial chips that can be purchased, and this specification does not limit this.

[0037] The NFC tag circuit 106 can sense the NFC detection signal sent by the terminal device to communicate with the terminal device. The NFC tag circuit 106 may include a second NFC chip and an NFC coil. Specifically, the NFC detection signal from the terminal device can be received by the NFC coil, and an electromagnetic induction current can be generated at the same time for the second NFC chip to receive and send data. Similarly, since the communication carrier frequency 13.56MHz of NFC technology has been standardized worldwide, the second NFC chip can be any NFC chip that supports the 13.56MHz carrier standard. The above-mentioned second NFC chip and NFC coil can be provided by commercial chips that can be purchased, and this specification does not limit this.

[0038] In different scenarios, the second NFC chip can contain different information. For example, in a payment scenario, the second NFC chip can contain payment order information. For example, in a food ordering scenario, the second NFC chip can contain menu and seat information. For another example, in a door access control scenario, the second NFC chip can contain identity verification information.

[0039] It should be understood that the architecture and functions in the system 100 are described for exemplary purposes only, and do not imply any limitation on the scope of the present description. The embodiments of the present description may also be applied to other environments with different structures and / or functions.

[0040] The following will combine Figures 2 to 6 The process according to the embodiment of this specification is described in detail. For ease of understanding, the specific data mentioned in the following description are exemplary and are not intended to limit the scope of protection of the present disclosure. It should be understood that the embodiments described below may also include additional actions not shown and / or may omit the actions shown, and the scope of the present disclosure is not limited in this respect.

[0041] Figure 2 FIG. 2 shows a schematic diagram of a stacked structure of an NFC passive tag identification system 200 according to some embodiments of the present specification. It is understood that in this embodiment, the piezoelectric effect is used to achieve the conversion of mechanical energy into electrical energy, which is only an example and does not constitute a limitation to the present application. Figure 2 As shown, the system 200 may include a surface protection layer 202, a functional layer 204, a filling layer 206, an energy supply layer 208 and a substrate layer 210 from top to bottom. The substrate layer and the surface protection layer are the basic carrier and basic protection material of the system 200, and non-metallic materials including but not limited to plastic, rubber, acrylic, paper, etc. may be used. In addition, the top of the surface protection layer 202 may display words and phrases for guiding the user to use the terminal device to approach and touch the system 200.

[0042] like Figure 2 As shown, the functional layer 204 may include an NFC tag circuit 204-1, a radio frequency transmission circuit 204-2, and a filling material. The filling material may be selected from the following: Figure 2 The PVC filling material 204 - 3 shown in FIG. PVC filling material 204 - 3 can wrap and separate the NFC tag circuit 204 - 1 and the radio frequency transmission circuit 204 - 2 .

[0043] like Figure 2 As shown, the energy supply layer 208 may include a piezoelectric material and a filling material. The piezoelectric material may be selected from Figure 2 The piezoelectric sheet 208-1 shown in the figure may be filled with a material such as Figure 2 PU filling material shown. The PU filling material can wrap the piezoelectric sheet 208-1 to ensure that a sufficient amount of compression deformation can be captured.

[0044] Optionally, the piezoelectric sheet 208-1 can be made of PZT, PVDF or other piezoelectric materials. Lead zirconate titanate (PZT) is an important piezoelectric material, which is sintered at high temperature by oxides of lead (Pb), zirconium (Zr) and titanium (Ti). PZT has multiple different composition ratios, the most common of which are PZT-4, PZT-5A, PZT-5H and PZT-8. These PZT materials with different ratios have different performances to meet different application requirements. Polyvinylidene fluoride (PVDF) is a thermoplastic engineering plastic with excellent comprehensive performance, which is formed by free radical polymerization of 1,1-difluoroethylene (VDF) monomer. PVDF has the characteristics of fluororesin and general resin, and has special properties such as piezoelectricity, dielectricity, and thermoelectricity. Specifically, if the piezoelectric sheet 208-1 uses PZT, the filling layer must be made of anti-metal material to avoid the metal on the PZT absorbing electromagnetic waves and thus affecting the recognition efficiency of the NFC tag circuit 204-1.

[0045] Since this system involves two NFC coil circuits, the RF transmission circuit 104 transmits the carrier signal of the RF field through external power supply to make the terminal device exit the LPCD mode, and the NFC tag circuit 106 generates electricity by itself, stores information and responds to the NFC detection signal of the terminal device. When laying out the circuit, it is necessary to avoid interference when the terminal device receives the excitation signal and reads the data stored in the NFC tag circuit. Figure 3 The circuit layout structures of some embodiments of this specification are introduced.

[0046] Figure 3 FIG. 2 shows a schematic diagram of a circuit layout of an NFC passive tag recognition system according to some embodiments of the present specification. Figure 3 As shown, the RF transmission circuit 104 may include a first NFC chip 204 and an excitation coil 206, and the excitation coil 206 may be arranged at the outermost side. The first NFC chip 204 may be powered by the energy collection circuit 202 through the positive voltage supply terminal VDD and the ground terminal VSS. The NFC tag circuit 106 may include a second NFC chip 208 and an NFC coil 210. The NFC tag circuit 106 is located inside the excitation coil 206. In this way, signal interference can be avoided as much as possible.

[0047] In some embodiments, the RF transmission circuit 104 and the NFC tag circuit 106 may be arranged vertically or horizontally, etc. This specification does not limit the specific circuit layout.

[0048] Figure 4A FIG. 4 is a schematic diagram showing a structure of a radio frequency transmission circuit 400 according to some embodiments of the present specification. Figure 4AAs shown, the RF transmission circuit 400 may include a first NFC chip 402, a first low-pass filter 404, a first matching circuit 406, a first current limiting element 408 and an excitation coil 410. The energy collection circuit 202 may supply power to the first NFC chip 402 through the positive voltage supply terminal VDD and the ground terminal VSS, for example, providing a boosted voltage. The first low-pass filter 404 may include an inductor and a capacitor, and utilizes its characteristics of only allowing signals below the cutoff frequency to pass, while signals above the cutoff frequency cannot pass, to filter out the higher harmonics of the crystal oscillator, thereby improving the stability of signal transmission.

[0049] The first matching circuit 406 can be tuned with the excitation coil 410 to adjust the impedance parameters and the resonant frequency parameters. The first current limiting element 408 may include a series resistor, which can adjust the balance between the quality factor (which may be called the Q value) of the excitation coil 410 and the bandwidth of the circuit. The Q value reflects the loss of the coil at the resonant frequency and is inversely proportional to the circuit bandwidth. The excitation coil 410 can send an excitation signal for exciting the terminal device to exit the LPCD mode.

[0050] Figure 4B FIG. 2 shows an equivalent circuit diagram of a radio frequency transmission circuit according to some embodiments of the present specification. Figure 4B As shown, the first NFC chip 402 can be expressed as a chip IC1 for signal modulation and demodulation and data reception and transmission. The current generated by the energy collection circuit 202 flows in from the positive power supply VDD, flows out from the ground VSS after passing through the components, and forms a loop. The chip IC1 may include multiple pins, such as a pin Rx for receiving external data, a transient voltage suppressor Tvss to ground for preventing the circuit from being damaged by transient overvoltage (such as lightning strike, electrostatic discharge, etc.), and differential signal transmission pins Tx+ and Tx- for high-speed, interference-resistant data transmission.

[0051] like Figure 4B As shown, the first low-pass filter 404 can be composed of an inductor L0 and a capacitor C0 to filter out the high-order harmonics of the crystal oscillator. The capacitor C1 and the capacitor C2 can form a first matching circuit 406 to adjust the impedance parameters and the resonant frequency parameters. The resistor R1 can be used as a first current limiting element 408 to adjust the Q value of the coil ANT1, that is, the excitation coil 410 and the bandwidth of the circuit.

[0052] Figure 5A FIG. 5 shows a schematic diagram of the structure of an NFC tag circuit 500 according to some embodiments of this specification. Figure 5AAs shown, the NFC tag circuit 500 may include a second NFC chip 502, a second low-pass filter 504, a second matching circuit 506, a second current limiting element 508, and an NFC coil 510. Similar to the RF transmission circuit 400, the second low-pass filter 504 may include an inductor and a capacitor, and utilizes its characteristics of only allowing signals below the cutoff frequency to pass, while signals above the cutoff frequency cannot pass, to filter out the high harmonics of the crystal oscillator, thereby improving the stability of signal transmission. The second current limiting element 508 may include a series resistor, which can adjust the balance between the quality factor (which may be called the Q value) of the NFC coil 510 and the bandwidth of the circuit.

[0053] The second matching circuit 506 can be tuned with the NFC coil 510 and send the matched signal to the second NFC chip 502. Then, the second NFC chip 502 can modulate the matched signal into a carrier signal and send it to the NFC coil 510. The NFC coil can sense the NFC detection signal sent by the terminal device and send the above carrier signal.

[0054] Figure 5B FIG. 2 shows an equivalent circuit diagram of an NFC tag circuit according to some embodiments of the present specification. Figure 5B As shown, the second NFC chip 502 may be a chip IC2 for signal modulation and demodulation and data reception and transmission, and specific information is stored therein, including but not limited to ordering information, payment information, etc. Similarly, the chip IC2 may include a plurality of pins, such as a pin Rx for receiving external data, a transient voltage suppressor Tvss to ground for preventing the circuit from being damaged by transient overvoltage (such as lightning strike, electrostatic discharge, etc.), and differential signal transmission pins Tx+ and Tx- for high-speed, interference-resistant data transmission.

[0055] like Figure 5B As shown, the second low-pass filter 504 can be composed of an inductor L0 and a capacitor C0 to filter out the high harmonics of the crystal oscillator. Capacitors C1 and C2 can form a second matching circuit 506 to adjust impedance parameters and resonant frequency parameters. Resistor R1 can be used as a second current limiting element 508 to adjust the Q value of coil ANT2, that is, NFC coil 510 and the bandwidth of the circuit. This circuit relies on the electromagnetic induction current of coil ANT2 when the terminal device is close, without the need for an external power supply.

[0056] Figure 6 The flowchart of the NFC passive tag identification method according to some embodiments of the present specification is shown. It should be understood that the method 600 may also include additional actions not shown and / or may omit the actions shown, and the scope of the present disclosure is not limited in this respect.

[0057] like Figure 6As shown, at block 610, method 600 may include: collecting and storing electrical energy converted from mechanical energy generated by the collision. The conversion of mechanical energy to electrical energy may be achieved using piezoelectric effect, electromagnetic induction, and the like. Then, capacitors or lithium-ion batteries may be used to store and manage the electrical energy converted from the mechanical energy.

[0058] In box 620, method 600 may include: based on the electrical energy converted from the mechanical energy generated by the collision, sending an excitation signal for causing the terminal device to exit the low-power card detection LPCD mode. In some embodiments, the electrical energy converted from the mechanical energy can cause the NFC chip to transmit a carrier signal of the radio frequency field. When the terminal device in the low-power card detection LPCD mode approaches the radio frequency field, it will switch from the LPCD mode to the normal card reading mode based on the radio frequency signal. In this way, it is possible to improve the NFC card reading efficiency in a low-cost and low-consumption manner in the NFC passive tag scenario.

[0059] In block 630, method 600 may include: sensing an NFC detection signal sent by the terminal device to communicate with the terminal device. Through the effect of the radio frequency field, the NFC tag circuit carrying specific information can interact with the terminal device in normal card reading mode, thereby achieving efficient communication.

[0060] In addition, the embodiments of this specification also provide an NFC device corresponding to the NFC passive tag recognition system, and the NFC device may include any one of the NFC passive tag recognition systems provided in the above embodiments.

[0061] Specifically, the NFC device may include an NFC passive tag identification system, and the system may include an energy collection circuit 102, a radio frequency transmission circuit 104, and an NFC tag circuit 106. The energy collection circuit 102 may be used to collect and store electrical energy converted from mechanical energy generated by the contact between the terminal device and the system; the radio frequency transmission circuit 104 is connected to the energy collection circuit 102, powered by the energy collection circuit, and may be used to send an excitation signal for causing the terminal device to exit the low power consumption card detection LPCD mode; the NFC tag circuit 106 may be used to sense the NFC detection signal sent by the terminal device to communicate with the terminal device.

[0062] In some embodiments, the energy harvesting circuit may include piezoelectric materials, and the mechanical energy generated by the collision may be converted into electrical energy based on the piezoelectric effect.

[0063] In some embodiments, the piezoelectric material may include a piezoelectric sheet.

[0064] In some embodiments, the energy harvesting circuit may include a spring and an induction coil, and the mechanical energy generated by the collision may be converted into electrical energy based on electromagnetic induction.

[0065] In some embodiments, the system may include a functional layer and a power supply layer, the radio frequency transmitter and the NFC tag module are located in the functional layer, and the energy collection circuit is located in the power supply layer.

[0066] In some embodiments, the system may further include: a surface protection layer, which is located at the top of the system; a filling layer, which is located between the functional layer and the energy supply layer; and a substrate layer, which is located at the bottom of the system.

[0067] In some embodiments, the system may include an excitation layer, a communication layer, and an energy supply layer, wherein the radio frequency transmission circuit is located in the excitation layer, the NFC tag circuit is located in the communication layer, and the energy collection circuit is located in the energy supply layer.

[0068] In some embodiments, the system may further include: a rectifier circuit connected to the energy collection circuit for converting alternating current into direct current; and a boost regulator circuit connected to the rectifier circuit and the RF transmission circuit for increasing the voltage input to the RF transmission circuit.

[0069] In some embodiments, the rectification circuit may include a Schottky diode rectifier bridge.

[0070] In some embodiments, the radio frequency transmission circuit may include: a first NFC chip, connected to the energy collection circuit, powered by the energy collection circuit, and used to send an excitation signal; an excitation coil, connected to the first NFC chip, used to receive the excitation signal from the first NFC chip and send it; and a first matching circuit, connected to the first NFC chip and the excitation coil, used to adjust the impedance parameters and the resonant frequency parameters of the excitation coil.

[0071] In some embodiments, the energy harvesting circuit, the first NFC chip, and the NFC tag circuit are all located inside the excitation coil.

[0072] In some embodiments, the RF transmitting circuit may further include: a first filtering circuit connected to the first NFC chip and used to filter out interference signals in the RF transmitting circuit; and a first current limiting element connected to the excitation coil and used to adjust the quality factor of the excitation coil and the bandwidth of the RF transmitting circuit.

[0073] In some embodiments, the first filtering circuit may include a first low-pass filter, and the interference signal may include a high-order harmonic of a crystal oscillator.

[0074] In some embodiments, the NFC tag circuit may include: an NFC coil, used to sense an NFC detection signal sent by a terminal device and generate an induced current; a second NFC chip, connected to the NFC coil and powered by the induced current, used to send a carrier signal carrying target data to the NFC coil to communicate with the terminal device; and a first matching circuit, connected to the second NFC chip and the NFC coil, used to adjust impedance parameters and resonant frequency parameters of the NFC coil.

[0075] In some embodiments, the NFC tag circuit may further include: a second filtering circuit connected to the second NFC chip, used to filter out interference signals in the NFC tag circuit; and a second current limiting element connected to the NFC coil, used to adjust the quality factor of the NFC coil and the bandwidth of the NFC tag circuit.

[0076] In some embodiments, the second filtering circuit may include a second low-pass filter, and the interference signal may include a high-order harmonic of the crystal oscillator.

[0077] In the embodiments of this specification, the NFC device operates in a passive mode, and the terminal device communicating with the NFC device operates in an active mode.

[0078] In the embodiments of this specification, the NFC device operating in the passive mode can not only complete communication passively, but also actively stimulate the terminal device to communicate in the normal working mode when colliding with the terminal device.

[0079] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0080] The embodiments of the present specification have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

[0081] The above are only optional embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An NFC passive tag recognition system, comprising: An energy harvesting circuit, used to collect and store electrical energy converted from mechanical energy generated by contact between the terminal device and the system; A radio frequency transmission circuit, connected to the energy collection circuit, powered by the energy collection circuit, and used to send an excitation signal for causing the terminal device to exit the low power consumption card detection LPCD mode; as well as The NFC tag circuit is used to sense the NFC detection signal sent by the terminal device to communicate with the terminal device.

2. The system according to claim 1, wherein the energy collection circuit comprises a piezoelectric material, the piezoelectric material comprises a piezoelectric sheet, and the mechanical energy generated by the collision is converted into the electrical energy based on the piezoelectric effect; or The energy collection circuit includes a spring and an induction coil, and the mechanical energy generated by the collision is converted into the electrical energy based on electromagnetic induction. 3 . The system according to claim 1 , wherein the system comprises a functional layer and a power supply layer, the radio frequency transmitter and the NFC tag module are located in the functional layer, and the energy collection circuit is located in the power supply layer.

4. The system according to claim 3, wherein the system further comprises: a surface protection layer, the surface protection layer being located on the top of the system; A filling layer, wherein the filling layer is located between the functional layer and the energy supply layer; as well as A substrate layer is located at the bottom of the system.

5. The system according to claim 1, wherein the system comprises an excitation layer, a communication layer and an energy supply layer, the radio frequency transmission circuit is located in the excitation layer, the NFC tag circuit is located in the communication layer, and the energy collection circuit is located in the energy supply layer.

6. The system of claim 1, wherein the system further comprises: A rectifier circuit, connected to the energy collection circuit, for converting alternating current into direct current, wherein the rectifier circuit comprises a Schottky diode rectifier bridge; as well as The boost and voltage stabilization circuit is connected to the rectifier circuit and the radio frequency transmission circuit, and is used to increase the voltage input to the radio frequency transmission circuit.

7. The system according to claim 1, wherein the radio frequency transmission circuit comprises: A first NFC chip is connected to the energy collection circuit, powered by the energy collection circuit, and used to send the excitation signal; an excitation coil, connected to the first NFC chip, and configured to receive and send the excitation signal from the first NFC chip; a first matching circuit, connected to the first NFC chip and the excitation coil, and configured to adjust an impedance parameter and a resonant frequency parameter of the excitation coil; A first filtering circuit, connected to the first NFC chip, and configured to filter out interference signals in the radio frequency transmission circuit, wherein the first filtering circuit comprises a first low-pass filter, and the interference signals comprise higher harmonics of a crystal oscillator; as well as The first current limiting element is connected to the excitation coil and is used to adjust the quality factor of the excitation coil and the bandwidth of the radio frequency transmission circuit. 8 . The system of claim 7 , wherein the energy harvesting circuit, the first NFC chip, and the NFC tag circuit are all located inside the excitation coil.

9. The system of claim 1, wherein the NFC tag circuit comprises: An NFC coil, used to sense an NFC detection signal sent by the terminal device and generate an induced current; a second NFC chip, connected to the NFC coil, powered by the induced current, and used to send a carrier signal carrying target data to the NFC coil to communicate with the terminal device; a first matching circuit, connected to the second NFC chip and the NFC coil, and configured to adjust an impedance parameter and a resonant frequency parameter of the NFC coil; A second filtering circuit, connected to the second NFC chip, for filtering out interference signals in the NFC tag circuit, wherein the second filtering circuit comprises a second low-pass filter, and the interference signals comprise higher harmonics of a crystal oscillator; as well as The second current limiting element is connected to the NFC coil and is used to adjust the quality factor of the NFC coil and the bandwidth of the NFC tag circuit.

10. An NFC device, wherein the NFC device operates in a passive mode, and a terminal device communicating with the NFC device operates in an active mode, wherein the NFC device comprises the NFC passive tag recognition system according to any one of claims 1 to 9.

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