Nfc field detection system, method and nfc device

Abstract

The application provides an NFC electric field detection system, method and NFC device. The NFC electric field detection system comprises a detection control module. The detection control module is used for detecting that a terminal device is in a low-power card detection (LPCD) mode according to a first radio frequency signal transmitted by the terminal device. In the case of abnormal communication with the terminal device, the detection control module sends a second radio frequency signal to the terminal device to stimulate the terminal device to communicate with the terminal device. The detection control module detects that the terminal device is in the LPCD mode according to the first radio frequency signal transmitted by the terminal device, which comprises obtaining characteristic information of an NFC radio frequency field of the terminal device according to a value of an electric signal corresponding to a field strength of the NFC radio frequency field. In the case that the amplitude strength of the characteristic information meets a threshold value of the LPCD mode, it is detected that the terminal device is in the LPCD mode. Thus, normal communication with the terminal device can be realized, and the effectiveness of communication is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of NFC (Near Field Communication) technology, and in particular to a NFC electric field detection system, method and NFC device. BACKGROUND

[0002] NFC is a commonly used near field communication technology, and is widely used in access control cards, transportation cards, attendance record cards, consumption cards, identity cards and other scenarios.

[0003] Currently, terminal devices generally work in an active mode, and normally listen through a power field to determine whether a NFC device working in a passive mode is close. However, some terminal devices work in an LCPD (Low Power Card Detection) mode after a screen is on for a period of time in order to reduce power consumption and increase endurance. Once working in the LCPD mode, if the coupling area of an antenna is not enough or the electric field change is not obvious, the terminal device is difficult to exit from the LCPD mode, and thus normal communication can be difficult to perform. SUMMARY

[0004] The present application provides an improved NFC electric field detection system, method and NFC device.

[0005] The present application provides an NFC electric field detection system, comprising:

[0006] A near field communication NFC antenna, configured to receive a first radio frequency signal transmitted by a terminal device in a case where the terminal device is inducted into a NFC radio frequency field;

[0007] A detection control module, configured to detect that the terminal device is in an LCPD (Low Power Card Detection) mode according to the first radio frequency signal, and send a second radio frequency signal for exciting the terminal device to the terminal device through the NFC antenna to communicate with the terminal device in a case where abnormal communication with the terminal device is performed.

[0008] Further, the NFC antenna is configured to induct a field strength of the NFC radio frequency field when the terminal device transmits a NFC signal, and form an electric signal corresponding to the field strength;

[0009] Correspondingly, the detection control module comprises a signal sampling circuit and a control circuit connected with the signal sampling circuit.

[0010] The signal sampling circuit samples the electric signal.

[0011] The control circuit is used for obtaining characteristic information of the NFC radio frequency field of the terminal device according to the value of the electric signal; detecting that the terminal device is in the LPCD mode when the amplitude strength of the characteristic information meets the threshold value of the LPCD mode; and sending the second radio frequency signal to the terminal device when the terminal device does not read data of the NFC electric field detection system.

[0012] Further, the NFC antenna further comprises an NFC coil and a ground noise filtering terminal;

[0013] The NFC coil is used for inducting a radio frequency signal.

[0014] The noise filtering terminal is used for filtering noise signals of the radio frequency signal inducted on the NFC coil, so that the NFC antenna receives normal signals except noise.

[0015] Further, the NFC coil comprises at least a three-terminal coil; and the noise filtering terminal is arranged at the physical center of the antenna.

[0016] Further, the at least a three-terminal coil comprises a single-terminal coil; the noise filtering terminal is one noise filtering terminal; the one noise filtering terminal is arranged at the physical center of the NFC antenna; and the number of terminals of the single-terminal coil is greater than or equal to the number of terminals of the three-terminal coil.

[0017] Alternatively,

[0018] The at least a three-terminal coil comprises a double-terminal coil; correspondingly, the noise filtering terminal is two noise filtering terminals; the two noise filtering terminals are arranged at the physical center of the NFC antenna; and the number of terminals of the double-terminal coil is greater than the number of terminals of the three-terminal coil.

[0019] Further, the detection control module is used for detecting that the terminal device is in a low-power consumption card detection (LPCD) mode according to the first radio frequency signal; and generating a signal for exciting the terminal device when abnormal communication with the terminal device occurs.

[0020] The NFC electric field detection system further comprises an NFC module, which is used for receiving the signal for exciting the terminal device, tuning with the NFC antenna, and sending the modulated second radio frequency signal to the terminal device through the NFC antenna.

[0021] Further, the NFC module comprises a matching circuit and a modulation and demodulation unit connected with the matching circuit.

[0022] The matching circuit is used for tuning with the NFC antenna and sending the matched signal to the modulation and demodulation unit.

[0023] The modulation and demodulation unit is used to receive the matched signal, modulate the matched signal onto a carrier signal to obtain the second radio frequency signal, and send the second radio frequency signal to the NFC antenna.

[0024] The NFC antenna is also used to transmit the second radio frequency signal.

[0025] Furthermore, the matching circuit is located after the routing of the signal sampling circuit;

[0026] The matching circuit includes an impedance element for adjusting impedance parameters and resonant frequency parameters, and also for adjusting the parasitic effects of the matching circuit on the traces of the signal sampling circuit.

[0027] Furthermore, the signal sampling circuit includes an amplitude signal sampling circuit, a voltage acquisition circuit, or a current acquisition circuit for the analog-to-digital converter (ADC).

[0028] Furthermore, the detection and control module is also used to detect that the terminal device is in the LPCD mode based on the first radio frequency signal, and in the case of abnormal communication with the terminal device, determine the terminal type of the terminal device according to the transmission period of the electric field of the terminal device; and send the second radio frequency signal to the terminal device according to the terminal type.

[0029] This application provides an NFC electric field detection method, including:

[0030] Upon sensing the NFC radio frequency field of the terminal device, receive the first radio frequency signal emitted by the terminal device;

[0031] Based on the first radio frequency signal, it is detected that the terminal device is in low-power card detection LPCD mode; in the event of abnormal communication with the terminal device, a second radio frequency signal for stimulating the terminal device is sent to the terminal device through the NFC antenna to communicate with the terminal device.

[0032] This application provides an NFC device, which operates in passive mode, and a terminal device communicating with the NFC device operates in active mode. The NFC device includes the NFC electric field detection system as described in any of the preceding claims.

[0033] This application provides a machine-readable storage medium having a program stored thereon that, when executed by a processor, implements the method described in any of the preceding claims.

[0034] This application provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the method described in any of the preceding claims.

[0035] In some embodiments, the NFC electric field detection system of this application includes an NFC antenna and a detection control circuit. The NFC antenna is used to receive a first radio frequency signal emitted by the terminal device when the NFC radio frequency field of the terminal device is sensed. The detection control module is used to detect that the terminal device is in a low-power card detection (LPCD) mode based on the first radio frequency signal; and in the event of abnormal communication with the terminal device, to send a second radio frequency signal to the terminal device via the NFC antenna to excite the terminal device and communicate with it.

[0036] In this embodiment, the NFC antenna receives a first radio frequency signal transmitted by the terminal device, and the detection control circuit sends a second radio frequency signal to activate the terminal device. Thus, when it is difficult for the terminal device to exit LPCD mode, the second radio frequency signal used to activate the terminal device wakes it up and puts it into normal card detection mode for communication. This enables normal communication with the terminal device and improves communication effectiveness. Attached Figure Description

[0037] Figure 1 The diagram shown is a structural schematic of the NFC electric field detection system according to an embodiment of this application;

[0038] Figure 2 As shown Figure 1 The diagram shows the specific structure of the NFC electric field detection system.

[0039] Figure 3 The diagram shown is a flowchart of the NFC electric field detection method provided in an embodiment of this application. Detailed Implementation

[0040] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0041] The user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of the relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0042] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0043] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0044] It should be noted that the steps of the corresponding methods are not necessarily performed in the order shown and described in this specification in other embodiments. In some other embodiments, the methods may include more or fewer steps than described in this specification. Furthermore, a single step described in this specification may be broken down into multiple steps in other embodiments; and multiple steps described in this specification may be combined into a single step in other embodiments.

[0045] To address the technical problem that terminal devices often struggle to exit LPCD mode, potentially hindering normal communication, this application provides an NFC electric field detection system including an NFC antenna and a detection control circuit.

[0046] The aforementioned NFC antenna is used to receive a first radio frequency signal emitted by the terminal device when the NFC radio frequency field of the terminal device is sensed. The aforementioned detection and control module is used to detect that the terminal device is in low-power card detection (LPCD) mode based on the first radio frequency signal; in the event of abnormal communication with the terminal device, it sends a second radio frequency signal to the terminal device through the NFC antenna to excite the terminal device in order to communicate with the terminal device.

[0047] In this embodiment, the NFC antenna receives a first radio frequency signal transmitted by the terminal device, and the detection control circuit sends a second radio frequency signal to activate the terminal device. Thus, when it is difficult for the terminal device to exit LPCD mode, the second radio frequency signal used to activate the terminal device wakes it up and puts it into normal card detection mode for communication. This enables normal communication with the terminal device and improves communication effectiveness.

[0048] The NFC electric field detection system of this application embodiment can be applied to NFC devices. This NFC device operates in passive mode (hereinafter also referred to as an NFC passive device), and the terminal device communicating with the NFC device operates in active mode.

[0049] It should be noted that the aforementioned terminal devices may be, but are not limited to, mobile terminals or fixed card-reading devices. For example, a mobile terminal may be, but is not limited to, a mobile phone. A fixed card-reading device may be a card reader on a bus.

[0050] Figure 1 The diagram shown is a structural schematic of the NFC electric field detection system 10 according to an embodiment of this application.

[0051] like Figure 1 As shown, the NFC electric field detection system 10 includes an NFC antenna 21 (hereinafter referred to as the antenna) and a detection control module 22 connected to the NFC antenna 21.

[0052] NFC antenna 21 is used to receive a first radio frequency signal emitted by the terminal device when the NFC radio frequency field of the terminal device is sensed. The first radio frequency signal may include, but is not limited to, an NFC signal.

[0053] The aforementioned detection and control module 22 is used to detect that the terminal device is in low-power card detection LPCD mode based on the first radio frequency signal; in the case of abnormal communication with the terminal device, it sends a second radio frequency signal to the terminal device through the NFC antenna 21 to excite the terminal device so as to communicate with the terminal device.

[0054] The aforementioned LPCD mode is a low-power mode that the terminal device enters after a certain unlocking interval to save power when detecting NFC slave devices, and the card detection will also enter LPCD mode.

[0055] The aforementioned second radio frequency signal is a specific signal used to activate the terminal device. The frequency range of this specific signal is between 12MHz and 14MHz. In other words, when the terminal device receives this specific activation signal, it wakes up the LPCD mode and enters the normal card detection mode.

[0056] The aforementioned normal card detection mode refers to the mobile terminal maintaining full-power card detection for a certain period after unlocking in order to improve the NFC speed and success rate. Both the LPCD and normal detection modes involve the terminal device emitting a 13.56MHz sine wave, differing only in transmission time and amplitude, and energy is coupled through a coil.

[0057] Since the second radio frequency (RF) signal is used for excitation, it can be a null carrier signal, containing no information. This not only reduces the system load on the transmitted signal but also improves the efficiency of information transmission. For example, the NFC operating frequency band is 13.56 MHz. The second RF signal can, but is not limited to, a 13.56 MHz null carrier signal. When the terminal device receives the 13.56 MHz RF signal, it wakes up the LPCD mode and enters the normal card detection mode.

[0058] Of course, after the detection and control module 22 sends the second radio frequency signal to the terminal device through the NFC antenna 21 to excite the terminal device, if the communication status of the terminal device does not return to normal, it can retransmit the second radio frequency signal to the terminal device through the NFC antenna 21 multiple times until the terminal device is awakened and put into normal card detection mode, and normal communication with the terminal device is carried out.

[0059] After the aforementioned detection control module 22 sends a second radio frequency signal to the terminal device via the NFC antenna 21 to excite the terminal device, if the terminal device's communication status returns to normal, the terminal device can read predetermined information from the NFC electric field detection system 10. This predetermined information is information pre-set in the NFC device. Thus, the terminal device can read information containing the predetermined information to achieve communication between the terminal device and the NFC device.

[0060] In some examples, the control circuit 222 is further configured to detect that the terminal device is in the LPCD mode based on the first radio frequency signal, and in the event of abnormal communication with the terminal device, determine the terminal type of the terminal device according to the transmission period of the electric field of the terminal device; and send a second radio frequency signal to the terminal device to excite the terminal device according to the terminal type. Thus, by determining the terminal type, the second radio frequency signal can be sent according to the terminal type, improving the accuracy and timeliness of radio frequency signal transmission.

[0061] Different terminal devices have different electric field transmission periods, which can be used to distinguish terminal types. The terminal types discussed in this article include, but are not limited to, different models of terminal devices manufactured by different companies. For example, the electric field transmission period of an iPhone is generally around 300ms.

[0062] Furthermore, based on the terminal type, a second radio frequency signal for exciting the terminal type is determined from the correspondence between different terminal types and the radio frequency signals used for excitation; the second radio frequency signal is then sent to the terminal device.

[0063] In this embodiment, the introduction of the detection and control module 22 enables the NFC device, operating in passive mode, to possess the ability to sense external signals. After sensing by the NFC antenna 21, it has a response strategy, such as transmitting an excitation field or other empty carrier signal. The NFC device can guide or complete the desired communication even under conditions of poor communication quality.

[0064] Figure 2 As shown Figure 1 The diagram shows the specific structure of the NFC electric field detection system 10.

[0065] like Figure 2 As shown, the NFC antenna 21 includes an NFC antenna 21, which, when the terminal device 20 transmits an NFC signal, senses the field strength of the NFC radio frequency field and generates an electrical signal corresponding to the field strength. Furthermore, the NFC antenna 21 includes multiple signal output terminals. For example... Figure 2 The multiple signal output terminals shown include signal output terminal A1 and signal output terminal B1, through which electrical signals are output. The aforementioned NFC antenna 21 can sense the presence and strength of the NFC radio frequency field in real time, thereby avoiding omissions and ensuring the accuracy of the NFC antenna 21 in sensing the NFC radio frequency field strength.

[0066] Accordingly, the aforementioned detection and control module 22 includes a signal sampling circuit 221 and a control circuit 222 connected to the signal sampling circuit 221. Wherein,

[0067] The aforementioned signal sampling circuit 221 is used to sample electrical signals. Continuing... Figure 2 As shown, the signal sampling circuit 221 includes acquisition input terminals connected to the signal output terminals. The signal sampling circuit 221 acquires the electrical signal through the acquisition input terminals. For example, the acquisition input terminals include sampling input terminal A2 and sampling input terminal B2. Figure 2 In the example shown, sampling input terminal B2 is connected to the aforementioned signal output terminal B1, thereby completing the signal acquisition from the antenna's signal output terminal B1. In other examples, sampling input terminal A2 is connected to the aforementioned signal output terminal A1, thereby completing the signal acquisition from the antenna's signal output terminal A1. The acquisition input terminal can be connected to either the aforementioned signal output terminal A1 or the signal output terminal B1.

[0068] Furthermore, the aforementioned signal sampling circuit 221 includes an amplitude signal sampling circuit 221 for an ADC (Analog-to-Digital Converter), a voltage acquisition circuit, or a current acquisition circuit. Thus, the amplitude signal sampling circuit 221 can sample amplitude signals, such as voltage levels. The voltage acquisition circuit or current acquisition circuit can acquire other forms, such as induced current. For example, the current value can be obtained by comparing the voltage level with a resistance. The signal sampling circuit 221 transmits the sampled signal to the control circuit 222.

[0069] The control circuit 222 is used to obtain the characteristic information of the NFC radio frequency field of the terminal device 20 based on the value of the electrical signal. This characteristic information includes, for example, the period and amplitude of the radio frequency field emitted by the terminal device 20. If the amplitude of the characteristic information meets the threshold of the LPCD mode, the terminal device 20 is detected to be in LPCD mode. Furthermore, if the terminal device 20 does not read the data from the NFC electric field detection system 10, a second radio frequency signal is sent to the terminal device 20 to excite it. The failure to read the data from the NFC electric field detection system 10 is used to reflect abnormal communication with the terminal device 20.

[0070] The aforementioned thresholds can be set according to LPCD mode and normal card detection mode, and are not limited here. For example, if the amplitude of the feature information meets the threshold of the aforementioned LPCD mode, such as, but not limited to, a level below 1 volt, the terminal device 20 can be detected to be in LPCD mode. If the amplitude of the aforementioned feature information meets the threshold of the aforementioned LPCD mode, such as, but not limited to, a level above 5 volts, the terminal device 20 can be detected to be in normal card detection mode.

[0071] The control circuit 222 described above may include, but is not limited to, a control chip and its peripheral circuits. For example, the control chip may include, but is not limited to, an MCU (Micro Controller Unit). The peripheral circuits may include, but are not limited to, electronic components such as capacitors and resistors to process signals.

[0072] In this embodiment, the required signal can be collected from the antenna through the signal sampling circuit 221. By combining the detection control module 22 with the NFC antenna 21, and adding the signal sampling circuit 221 to the detection control module 22, it is possible to sense sources that can emit radio frequency fields from external terminal devices 20, which is not yet available. Furthermore, the detection control module 22 can complete subsequent related strategies.

[0073] Combination Figure 2 As shown, the NFC antenna 21 described above may include the following types of NFC antennas 21.

[0074] In such Figure 2 In the embodiment of the NFC antenna 21 shown above, the NFC antenna 21 further includes an NFC coil and a grounded noise-filtering terminal. The NFC antenna 21, which includes a noise-filtering terminal C1, a signal output terminal A1, and a signal output terminal B1, can also be referred to as a three-terminal antenna.

[0075] The aforementioned NFC coil is used to sense radio frequency signals; the noise filtering terminal is used to filter out noise signals from the radio frequency signals sensed on the NFC coil, so that the NFC antenna 21 receives normal signals other than noise.

[0076] It should be noted that the aforementioned noise signal can be, but is not limited to, low-frequency noise. In some examples, the noise-filtering terminal C1 of the NFC antenna 21 is connected to the input terminal C2 of the NFC module 23, and then connected to the board ground to filter out low-frequency noise received on the antenna, thus receiving only the normal communication signal. In other examples, the noise-filtering terminal C1 of the NFC antenna 21 is connected to the input terminal C2 of the NFC module 23, and inductors, capacitors, or other components can be connected in series on this link, and then connected to the board ground to filter out low-frequency noise received on the antenna, thus receiving only the normal communication signal. These normal communication signals are cleaner than the signal before noise filtering. This three-terminal antenna design results in very little or no noise signal received, facilitating high-precision detection.

[0077] The aforementioned NFC coil includes at least a three-terminal coil; the noise-filtering terminal is positioned at the physical center of the antenna. This maintains the balance of the other multiple signal output terminals. Furthermore, the noise-filtering terminal C1 is positioned at the physical center of the antenna, thereby maintaining the balance of signal output terminals A1 and B1.

[0078] In some embodiments of at least three-terminal coils, the at least three-terminal coil includes an odd-numbered terminal coil, and the noise-filtering terminal is a noise-filtering terminal located at the physical center of the NFC antenna 21; the number of terminals of the odd-numbered terminal coil is greater than or equal to the number of terminals of the three-terminal coil.

[0079] In some other embodiments of the at least three-terminal coil, the at least three-terminal coil includes an even-numbered terminal coil, and correspondingly, there are two noise-filtering terminals, which are located at the physical center of the NFC antenna 21 described above; the number of terminals of the even-numbered terminal coil is greater than the number of terminals of the three-terminal coil.

[0080] In this embodiment of the application, the three-terminal antenna proposed in the NFC antenna 21 has its noise filtering terminal C1 connected to the input terminal C2 of the NFC module 23 and connected to the board ground, thereby filtering out noise in a certain frequency band and transmitting a cleaner communication signal to the signal sampling circuit 221, so that the control circuit 222 can make accurate decisions.

[0081] In another embodiment of the NFC antenna 21 described above, the NFC antenna 21 includes only two signal output terminals, namely, signal output terminal A1 and signal output terminal B1. Thus, the coil of the NFC antenna 21 is dual-ended. While sensing the NFC signal (13.56MHz), the coil of the NFC antenna 21 also senses other signals, generating noise in the circuit and affecting subsequent sampling. In this solution, the signal output terminals A1 and B1 of the near-field communication NFC antenna 21 are respectively the sampling input terminal B2 of the NFC module 23 and the aforementioned signal output terminal B1. When the input signal is sufficiently large, the noise may be negligible. This improves the applicability of the NFC antenna 21.

[0082] Continue as Figure 2 As shown, the detection control module 22 is used to detect that the terminal device 20 is in low-power card detection LPCD mode based on the first radio frequency signal; and to generate a signal to excite the terminal device 20 in the event of abnormal communication with the terminal device 20. The NFC electric field detection system 10 also includes an NFC module 23, which is used to receive the signal to excite the terminal device 20, tune it with the NFC antenna 21, and send the modulated second radio frequency signal to the terminal device 20 through the NFC antenna 21. In this way, the signal generated by the detection control module 22 can be modulated by the NFC module 23 and then transmitted through the NFC antenna 21, ensuring the effectiveness of signal transmission.

[0083] Continue as Figure 2 As shown, the NFC module 23 and the detection and control module 22 can achieve bidirectional communication via the control bus. Furthermore, the NFC module 23 is also used to demodulate the received radio frequency signal and send the demodulated signal to the control circuit 222.

[0084] Continue to combine Figure 3 As shown, the NFC module 23 includes a matching circuit 231 and a modulation / demodulation unit 232 connected to the matching circuit 231. Wherein,

[0085] The matching circuit 231 is used to tune with the NFC antenna 21 and transmit the matched signal to the modulation / demodulation unit 232. The matched signal can be a tuned signal after electromagnetic interference filtering. The modulation / demodulation unit 232 is used to receive the matched signal, modulate the matched signal onto a carrier signal to obtain a second radio frequency signal, and transmit the second radio frequency signal to the NFC antenna 21. The NFC antenna 21 is also used to transmit the second radio frequency signal.

[0086] In some examples, the matching circuit 231 is located after the routing of the signal sampling circuit 221. The matching circuit 231 includes impedance elements for adjusting impedance parameters and resonant frequency parameters, and also for adjusting the parasitic effects of the matching circuit 231 on the routing of the signal sampling circuit 221. These impedance elements may include, but are not limited to, variable capacitors, variable inductors, and variable resistors. Furthermore, the variable capacitor resonates with the parasitic inductance of the NFC antenna 21 and filters out electromagnetic interference. The matching circuit 231 then transmits a second radio frequency signal, filtered out of interference, to the modulation / demodulation unit 232. Thus, after the routing of the matching circuit 231 and the signal sampling circuit 221 is arranged, adjusting the impedance parameters of the impedance elements changes the parasitic effects of the matching circuit 231 on the routing of the signal sampling circuit 221.

[0087] In this embodiment, the matching circuit 231 is located after the traces of the signal sampling circuit 221. By adjusting the impedance parameters of the impedance components, the parasitic influence of the matching circuit 231 on the traces of the signal sampling circuit 221 is reduced. This reduces the parasitic influence of the matching circuit 231 on the traces of the signal sampling circuit 221. Furthermore, it avoids the parasitic influence of the matching circuit 231 on the traces of the signal sampling circuit 221.

[0088] The NFC electric field detection system 10 of this application can be applied to, but is not limited to, UnionPay, payment aggregation equipment manufacturers, and related enterprises that develop and produce NFC devices such as mobile phones.

[0089] Based on the same concept as the aforementioned NFC electric field system, this application also proposes an NFC electric field detection method, such as... ​ As shown, the above NFC electric field detection method includes the following steps 310 to 320:

[0090] Step 310: When the NFC radio frequency field of the terminal device is sensed, the first radio frequency signal transmitted by the terminal device is received.

[0091] Step 320: Based on the first radio frequency signal, it is detected that the terminal device is in low power card detection LPCD mode; in the case of abnormal communication with the terminal device, a second radio frequency signal for stimulating the terminal device is sent to the terminal device through the NFC antenna to communicate with the terminal device.

[0092] In some embodiments, step 310 above may further include the NFC antenna sensing the field strength of the NFC radio frequency field when the terminal device transmits an NFC signal, and forming an electrical signal corresponding to the field strength.

[0093] Accordingly, the detection and control module includes a signal sampling circuit and a control circuit connected to the signal sampling circuit. The aforementioned 320 may further include the signal sampling circuit sampling an electrical signal; the control circuit obtaining characteristic information of the NFC radio frequency field of the terminal device based on the value of the electrical signal; detecting that the terminal device is in LPCD mode when the amplitude of the characteristic information meets the threshold of the LPCD mode; and sending a second radio frequency signal to the terminal device to excite the terminal device when the terminal device has not read the data from the NFC electric field detection system.

[0094] In some embodiments, 320 may further include detecting that the terminal device is in a low-power card detection (LPCD) mode based on the first radio frequency signal; and generating a signal to excite the terminal device in the event of abnormal communication with the terminal device. The NFC electric field detection method further includes receiving the signal to excite the terminal device, tuning it with an NFC antenna, and transmitting the modulated second radio frequency signal to the terminal device through the NFC antenna.

[0095] This application also provides an NFC device, which operates in passive mode, and a terminal device communicating with the NFC device operates in active mode. The NFC device includes the NFC electric field detection system described above.

[0096] In the embodiments of this application, the NFC device operating in passive mode can not only passively complete communication, but also actively stimulate the terminal device to wake up the terminal device for communication, and the success rate does not need to completely depend on the terminal device.

[0097] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0098] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0099] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0100] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are quite specific and detailed. However, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this application, and these modifications and improvements all fall within the protection scope of this application.

Claims

1. An NFC electric field detection system, characterized in that, include: The detection control module is used to detect that the terminal device is in low-power card detection LPCD mode based on the first radio frequency signal received from the terminal device; In the event of abnormal communication with the terminal device, a second radio frequency signal is sent to the terminal device to excite the terminal device for communication; wherein, the step of detecting that the terminal device is in a low-power card detection LPCD mode based on the received first radio frequency signal transmitted by the terminal device includes: obtaining characteristic information of the NFC radio frequency field of the terminal device based on the value of the sampled electrical signal corresponding to the field strength of the NFC radio frequency field; and detecting that the terminal device is in the LPCD mode when the amplitude of the characteristic information meets the threshold of the LPCD mode.

2. The NFC electric field detection system as described in claim 1, characterized in that, The detection control module includes a signal sampling circuit and a control circuit connected to the signal sampling circuit; The signal sampling circuit is used to sample the electrical signal corresponding to the field strength of the NFC radio frequency field; The control circuit is used to obtain the characteristic information of the NFC radio frequency field of the terminal device based on the value of the electrical signal; and to detect that the terminal device is in the LPCD mode when the amplitude of the characteristic information meets the threshold of the LPCD mode. If the terminal device does not read the data from the NFC electric field detection system, the second radio frequency signal is sent to the terminal device.

3. The NFC electric field detection system as described in claim 2, characterized in that, The signal sampling circuit includes an amplitude signal sampling circuit, a voltage acquisition circuit, or a current acquisition circuit for an analog-to-digital converter (ADC).

4. The NFC electric field detection system as described in claim 1, characterized in that, The NFC electric field detection system further includes: a near-field communication (NFC) antenna, used to receive a first radio frequency signal transmitted by the terminal device; The detection control module performs the following action in the event of abnormal communication with the terminal device: sending a second radio frequency signal to the terminal device to excite the terminal device, thereby communicating with the terminal device: In the event of abnormal communication with the terminal device, a second radio frequency signal is generated to excite the terminal device; the second radio frequency signal is sent to the terminal device through the near field communication (NFC) antenna to communicate with the terminal device.

5. The NFC electric field detection system as described in claim 4, characterized in that, The detection and control module is used to detect that the terminal device is in low-power card detection LPCD mode based on the first radio frequency signal. In the event of abnormal communication with the terminal device, a signal is generated to stimulate the terminal device. The NFC electric field detection system further includes: an NFC module, used to receive the signal used to excite the terminal device, tune with the near-field communication NFC antenna, and send the modulated second radio frequency signal to the terminal device through the near-field communication NFC antenna.

6. The NFC electric field detection system according to any one of claims 1 to 5, characterized in that, The detection control module performs the following action in the event of abnormal communication with the terminal device: sending a second radio frequency signal to the terminal device to excite the terminal device, thereby communicating with the terminal device: If the terminal device does not read the data from the NFC electric field detection system, the second radio frequency signal is sent to the terminal device to communicate with the terminal device.

7. The NFC electric field detection system as described in any one of claims 1 to 5, characterized in that, The detection control module performs the following action in the event of abnormal communication with the terminal device: sending a second radio frequency signal to the terminal device to excite the terminal device, thereby communicating with the terminal device: In the event of abnormal communication with the terminal device, the terminal type of the terminal device is determined according to the transmission period of the electric field of the terminal device; based on the terminal type, the second radio frequency signal is sent to the terminal device to communicate with the terminal device.

8. The NFC electric field detection system according to any one of claims 1 to 5, characterized in that, The detection control module performs the following action in the event of abnormal communication with the terminal device: sending a second radio frequency signal to the terminal device to excite the terminal device, thereby communicating with the terminal device: In the event of abnormal communication with the terminal device, after sending a second radio frequency signal to the terminal device to excite the terminal device, if the communication status of the terminal device does not return to normal, the second radio frequency signal is retransmitted to the terminal device multiple times until the terminal device is awakened and put into normal card detection mode, and normal communication is established with the terminal device.

9. The NFC electric field detection system as described in claim 5, characterized in that, The near-field communication (NFC) antenna also includes an NFC coil and a grounded noise-filtering terminal; An NFC coil is used to sense radio frequency signals; the radio frequency signals include the first radio frequency signal and / or the second radio frequency signal. The noise filtering terminal is used to filter out the noise signal of the radio frequency signal sensed on the NFC coil, so that the near field communication NFC antenna receives normal signals other than noise.

10. The NFC electric field detection system as described in claim 9, characterized in that, The NFC coil includes at least three terminal coils; the noise-filtering terminal is located at the physical center of the antenna.

11. The NFC electric field detection system as described in claim 10, characterized in that, The at least three-terminal coil includes an odd-numbered terminal coil, and the noise-filtering terminal is a single noise-filtering terminal located at the physical center of the near-field communication (NFC) antenna; the number of terminals of the odd-numbered terminal coil is greater than or equal to the number of terminals of the three-terminal coil. or, The at least three-terminal coil includes an even-numbered terminal coil, and correspondingly, the noise-filtering terminal consists of two noise-filtering terminals, which are located at the physical center of the near-field communication (NFC) antenna; the number of terminals of the even-numbered terminal coil is greater than the number of terminals of the three-terminal coil.

12. The NFC electric field detection system as described in claim 5, characterized in that, The NFC module includes a matching circuit and a modulation / demodulation unit connected to the matching circuit. The matching circuit is used to tune with the near-field communication (NFC) antenna and send the matched signal to the modulation and demodulation unit. The modulation and demodulation unit is used to modulate the matched signal onto a carrier signal to obtain the second radio frequency signal, and then send the second radio frequency signal to the near field communication (NFC) antenna. The near-field communication (NFC) antenna is also used to transmit the second radio frequency signal.

13. The NFC electric field detection system as described in claim 12, characterized in that, The detection control module includes a signal sampling circuit for sampling an electrical signal corresponding to the field strength of the NFC radio frequency field; the matching circuit is located after the traces of the signal sampling circuit. The matching circuit includes an impedance element for adjusting impedance parameters and resonant frequency parameters, and also for adjusting the parasitic effects of the matching circuit on the traces of the signal sampling circuit.

14. An NFC electric field detection method, characterized in that, include: Based on a first radio frequency signal received from a terminal device, the terminal device is detected to be in a low-power card detection LPCD mode; wherein, the step of detecting that the terminal device is in a low-power card detection LPCD mode based on the first radio frequency signal received from the terminal device includes: obtaining characteristic information of the NFC radio frequency field of the terminal device based on the value of the sampled electrical signal corresponding to the field strength of the NFC radio frequency field; and detecting that the terminal device is in the LPCD mode when the amplitude of the characteristic information meets the threshold of the LPCD mode. In the event of abnormal communication with the terminal device, a second radio frequency signal is sent to the terminal device to excite the terminal device in order to communicate with the terminal device.

15. The NFC electric field detection method as described in claim 14, characterized in that, In the event of abnormal communication with the terminal device, sending a second radio frequency signal to the terminal device to excite the terminal device includes: If the terminal device does not read the data from the NFC electric field detection method, the second radio frequency signal is sent to the terminal device.

16. The NFC electric field detection method as described in claim 14, characterized in that, In the event of abnormal communication with the terminal device, sending a second radio frequency signal to the terminal device to excite the terminal device includes: In the event of abnormal communication with the terminal device, a signal is generated to stimulate the terminal device. The system receives the signal used to excite the terminal device, tunes it with the near-field communication (NFC) antenna, and transmits the modulated second radio frequency signal to the terminal device through the NFC antenna.

17. The NFC electric field detection method according to any one of claims 14 to 16, characterized in that, In the event of abnormal communication with the terminal device, sending a second radio frequency signal to the terminal device to excite the terminal device in order to communicate with the terminal device includes: If the terminal device does not read the data from the NFC electric field detection system, the second radio frequency signal is sent to the terminal device to communicate with the terminal device.

18. The NFC electric field detection method according to any one of claims 14 to 16, characterized in that, In the event of abnormal communication with the terminal device, sending a second radio frequency signal to the terminal device to excite the terminal device includes: In the event of abnormal communication with the terminal device, the terminal type of the terminal device is determined according to the transmission period of the electric field of the terminal device; based on the terminal type, the second radio frequency signal is sent to the terminal device.

19. The NFC electric field detection method according to any one of claims 14 to 16, characterized in that, In the event of abnormal communication with the terminal device, sending a second radio frequency signal to the terminal device to excite the terminal device in order to communicate with the terminal device includes: In the event of abnormal communication with the terminal device, after sending a second radio frequency signal to the terminal device to excite the terminal device, if the communication status of the terminal device does not return to normal, the second radio frequency signal is retransmitted to the terminal device multiple times until the terminal device is awakened and put into normal card detection mode, and normal communication is established with the terminal device.

20. The NFC electric field detection method according to any one of claims 14 to 16, characterized in that, In the event of abnormal communication with the terminal device, sending a second radio frequency signal to the terminal device to excite the terminal device in order to communicate with the terminal device includes: It is tuned to the NFC antenna and transmits the matched signal; After the matched signal is modulated onto a carrier signal, the second radio frequency signal is obtained, and the second radio frequency signal is sent to the near field communication (NFC) antenna.

21. An NFC device, characterized in that, The NFC device operates in passive mode, and the terminal device communicating with the NFC device operates in active mode. The NFC device includes the NFC electric field detection system as described in any one of claims 1-13.

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