NFC electric field detection system and method and NFC equipment

Abstract

The invention provides an NFC electric field detection system, an NFC electric field detection method and NFC equipment. The NFC electric field detection system comprises an NFC antenna and a detection control circuit. Wherein the near field communication (NFC) antenna is used for receiving a first radio frequency signal transmitted by the terminal equipment under the condition that an NFC radio frequency field of the terminal equipment is sensed. The detection control module is used for detecting that the terminal equipment is in a low power consumption card detection (LPCD) mode according to the first radio frequency signal; and under the condition of abnormal communication with the terminal equipment, sending a second radio frequency signal for exciting the terminal equipment to the terminal equipment through the NFC antenna so as to communicate with the terminal equipment. Therefore, normal communication with the terminal equipment can be realized, and the effectiveness of communication is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of NFC (Near Field Communication), and in particular to an NFC electric field detection system, method and NFC device. Background Art

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

[0003] At present, terminal devices generally work in active mode, and normally use the electric field to monitor whether there is an NFC device working in passive mode approaching. However, in order to reduce power consumption and increase battery life, some terminal devices work in LPCD (Low Power Card Detection) mode after the screen is on for a period of time. Once working in LPCD mode, if the coupling area of ​​the antenna is not enough or the electric field change is not obvious, it is difficult for the terminal device to exit the LPCD mode, and it may be difficult to communicate normally. Summary of the invention

[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 the terminal device when sensing an NFC radio frequency field of the terminal device;

[0007] A 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; in the case of abnormal communication with the terminal device, send a second radio frequency signal for stimulating the terminal device to the terminal device through the NFC antenna to communicate with the terminal device.

[0008] Furthermore, the NFC antenna is used to sense the field strength of the NFC radio frequency field when the terminal device transmits an NFC signal, and form an electrical signal corresponding to the field strength;

[0009] Accordingly, the detection control module includes a signal sampling circuit and a control circuit connected to the signal sampling circuit;

[0010] The signal sampling circuit samples the electrical signal;

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

[0012] Furthermore, the NFC antenna also includes an NFC coil and a grounded noise filtering terminal;

[0013] NFC coil, used to sense radio frequency signals;

[0014] The noise filter terminal is used to filter out the noise signal of the radio frequency signal induced by the NFC coil, so that the NFC antenna receives a normal signal except the noise.

[0015] Furthermore, the NFC coil includes at least a three-terminal coil; and the noise filtering terminal is placed at the physical center of the antenna.

[0016] Furthermore, the at least three-terminal coil includes an odd-terminal coil, the noise filtering terminal is one noise filtering terminal, and the one noise filtering terminal is placed at the physical center of the NFC antenna; the number of terminals of the odd-terminal coil is greater than or equal to the number of terminals of the three-terminal coil;

[0017] or,

[0018] The at least three-terminal coil includes an even-numbered terminal coil, and accordingly, the noise filtering terminals are two noise filtering terminals, and the two noise filtering terminals are placed at the physical center of the NFC antenna; the number of terminals of the even-numbered terminal coil is greater than the number of terminals of the three-terminal coil.

[0019] Furthermore, the detection control module is used to detect that the terminal device is in a low power consumption card detection LPCD mode according to the first radio frequency signal; and generate a signal for stimulating the terminal device in the case of abnormal communication with the terminal device;

[0020] The NFC electric field detection system further includes: an NFC module, which is used to receive the signal used to excite the terminal device, tune with the NFC antenna, and send the modulated second radio frequency signal to the terminal device through the NFC antenna.

[0021] Furthermore, the NFC module includes a matching circuit and a modulation and demodulation unit connected to the matching circuit;

[0022] The matching circuit is used to tune with the NFC antenna and send the matched signal to the modem 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 further used to send the second radio frequency signal.

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

[0026] The matching circuit includes an impedance element, which is used to adjust impedance parameters and resonant frequency parameters, and is also used to adjust the parasitic effect of the matching circuit on the routing of the signal sampling circuit.

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

[0028] Furthermore, the detection control module is also used to detect that the terminal device is in the LPCD mode based on the first RF 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 RF signal to the terminal device based on the terminal type.

[0029] The present application provides an NFC electric field detection method, comprising:

[0030] When an NFC radio frequency field of a terminal device is sensed, receiving a first radio frequency signal transmitted by the terminal device;

[0031] Based on the first radio frequency signal, it is detected that the terminal device is in a low power consumption 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.

[0032] The present application provides 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. The NFC device includes the NFC electric field detection system as described in any one of the above items.

[0033] The present application provides a machine-readable storage medium having a program stored thereon. When the program is executed by a processor, the method described in any one of the above items is implemented.

[0034] The present application provides a computer program product, comprising a computer program / instruction, which implements any of the above methods when executed by a processor.

[0035] In some embodiments, the NFC electric field detection system of the present application includes an NFC antenna and a detection control circuit. The NFC antenna is used to receive a first radio frequency signal transmitted by a terminal device when sensing the NFC radio frequency field of the terminal device. 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; 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.

[0036] In the embodiment of the present application, the NFC antenna receives the first radio frequency signal transmitted by the terminal device, and the detection control circuit sends the second radio frequency signal for stimulating the terminal device. In this way, when it is difficult for the terminal device to exit the LPCD mode, the second radio frequency signal for stimulating the terminal device is used to wake up the terminal device and put it in the normal card detection mode to communicate with the terminal device. In this way, normal communication with the terminal device can be achieved, and the effectiveness of communication can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The figure shows a schematic diagram of the structure of an NFC electric field detection system according to an embodiment of the present application;

[0038] Figure 2 Shown Figure 1 The specific structural schematic diagram of the NFC electric field detection system shown;

[0039] Figure 3 The figure shows a flow chart of an NFC electric field detection method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present 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, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of relevant countries and regions, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0042] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

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

[0044] It should be noted that: in other embodiments, the steps of the corresponding method are not necessarily performed in the order shown and described in this specification. In some other embodiments, the steps included in the method may be more or less than those described in this specification. In addition, a single step described in this specification may be decomposed into multiple steps for description in other embodiments; and multiple steps described in this specification may be combined into a single step for description in other embodiments.

[0045] In order to solve the technical problem that it is difficult for a terminal device to exit the LPCD mode and thus it may be difficult to communicate normally, an embodiment of the present application provides an NFC electric field detection system including an NFC antenna and a detection control circuit.

[0046] The NFC antenna is used to receive the first radio frequency signal transmitted by the terminal device when sensing the NFC radio frequency field of the terminal device. The detection control module is used to detect that the terminal device is in the low power consumption card detection LPCD mode according to the first radio frequency signal; in the case of abnormal communication with the terminal device, the 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.

[0047] In the embodiment of the present application, the NFC antenna receives the first radio frequency signal transmitted by the terminal device, and the detection control circuit sends the second radio frequency signal for stimulating the terminal device. In this way, when it is difficult for the terminal device to exit the LPCD mode, the second radio frequency signal for stimulating the terminal device is used to wake up the terminal device and put it in the normal card detection mode to communicate with the terminal device. In this way, normal communication with the terminal device can be achieved, and the effectiveness of communication can be improved.

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

[0049] It should be noted that the terminal device may be, but is not limited to, a mobile terminal or a fixed card swiping device. For example, the mobile terminal may be, but is not limited to, a mobile phone. The fixed card swiping device may be a card swiping machine on a bus.

[0050] Figure 1 FIG. 1 is a schematic diagram of the structure of an NFC electric field detection system 10 according to an embodiment of the present application.

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

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

[0053] The detection control module 22 is used to detect that the terminal device is in the low power consumption card detection LPCD mode based on the first radio frequency signal; 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 21 to communicate with the terminal device.

[0054] The above LPCD mode is for the terminal device to enter the low power consumption mode after a certain period of unlocking interval in order to save power consumption when detecting the NFC slave device, and then the card detection will also enter the LPCD mode.

[0055] The second radio frequency signal is a specific signal for stimulating the terminal device. The frequency band of the specific signal is between 12Mhz and 14Mhz. That is, when the terminal device receives the specific signal for stimulating, it wakes up the LPCD mode and enters the normal card inspection mode.

[0056] The above-mentioned normal card detection mode means that the mobile terminal will maintain full power card detection for a period of time after unlocking in order to improve the speed and success rate of NFC. The above-mentioned LPCD and normal detection modes are both 13.56MHz sine waves emitted by the terminal device, but the transmission time and amplitude are different, and the energy is coupled through the coil.

[0057] Since the second RF signal is a signal for excitation, the second RF signal can be an empty carrier signal and does not contain any information. In this way, not only the system burden of the transmission signal is reduced, but also the efficiency of information transmission is improved. Exemplarily, the operating frequency band of NFC is a frequency of 13.56Mhz. The second RF signal can be, but is not limited to, an empty carrier signal of 13.56Mhz. In this way, when the terminal device receives the 13.56M RF signal, it wakes up the LPCD mode and enters the normal card inspection mode.

[0058] Of course, after the detection control module 22 sends the second radio frequency signal used to stimulate the terminal device to the terminal device through the NFC antenna 21, if the communication of the terminal device has not recovered to normal, the second radio frequency signal can be resent to the terminal device through the NFC antenna 21 multiple times until the terminal device is awakened to the normal card detection mode and communicates normally with the terminal device.

[0059] After the detection control module 22 sends the second radio frequency signal for stimulating the terminal device to the terminal device through the NFC antenna 21, if the communication of the terminal device is restored to normal communication, the terminal device can read the predetermined information in the NFC electric field detection system 10. The predetermined information is information pre-set in the NFC device. In this way, the terminal device can read the predetermined information to realize the communication between the terminal device and the NFC device.

[0060] In some examples, the control circuit 222 is further used to detect that the terminal device is in the LPCD mode based on the first RF 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 a second RF signal for stimulating the terminal device to the terminal device according to the terminal type. In this way, by determining the terminal type, the second RF signal can be sent according to the terminal type, thereby improving the accuracy and timeliness of RF signal transmission.

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

[0062] Furthermore, according to the terminal type, a second radio frequency signal for stimulating the terminal type is determined from the correspondence between different terminal types and radio frequency signals used for stimulation; and the second radio frequency signal is sent to the terminal device.

[0063] In the embodiment of the present application, by introducing the detection control module 22, the NFC device working in the passive mode has the ability to sense the outside world. After the NFC antenna 21 senses, it has a response strategy, such as the emission of the excitation field and other action carrier signals. The NFC device can guide or complete the desired communication under the condition of poor communication quality.

[0064] Figure 2 Shown Figure 1 A schematic diagram of the specific structure of the NFC electric field detection system 10 is shown.

[0065] like Figure 2 As shown, the NFC antenna 21 includes an NFC antenna 21, which is used to sense the field strength of the NFC radio frequency field when the terminal device 20 transmits an NFC signal, and form an electrical signal corresponding to the field strength. Further, the NFC antenna 21 includes a plurality of signal output terminals. Figure 2 The multiple signal output terminals shown include signal output terminal A1 and signal output terminal B1, and electrical signals are output through the multiple signal output terminals. The NFC antenna 21 can sense the field strength of the NFC radio frequency field in real time, thereby avoiding omissions and achieving the accuracy of the NFC antenna 21 sensing the field strength of the NFC radio frequency field.

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

[0067] The signal sampling circuit 221 is used to sample electrical signals. Figure 2 As shown, the signal sampling circuit 221 includes a collection input terminal connected to the signal output terminal. The signal sampling circuit 221 collects the electrical signal through the collection input terminal. Exemplarily, the collection input terminal includes a sampling input terminal A2 and a sampling input terminal B2. Figure 2 In the example shown, the sampling input terminal B2 is connected to the signal output terminal B1, thereby completing the signal acquisition of the signal output terminal B1 of the antenna. In other examples, the sampling input terminal A2 is connected to the signal output terminal A1, thereby completing the signal acquisition of the signal output terminal A1 of the antenna. The acquisition input terminal can be connected to either end of the signal output terminal A1 or the signal output terminal B1.

[0068] Furthermore, the signal sampling circuit 221 includes an amplitude signal sampling circuit 221, a voltage acquisition circuit or a current acquisition circuit of an ADC (Analog-to-Digital Converter). In this way, the amplitude signal sampling circuit 221 can sample an amplitude signal, such as a level amplitude. The voltage acquisition circuit or the current acquisition circuit can acquire other forms such as induced current. For example, the current value can be obtained by the level amplitude and the 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 according to the value of the electrical signal; the characteristic information of the NFC radio frequency field is such as the period of the radio frequency field strength transmitted by the terminal device 20, the amplitude strength and other related information. When the amplitude strength of the characteristic information meets the threshold of the LPCD mode, it is detected that the terminal device 20 is in the LPCD mode; and when the terminal device 20 does not read the data of the NFC electric field detection system 10, a second radio frequency signal for stimulating the terminal device 20 is sent to the terminal device 20. The data of the NFC electric field detection system 10 that is not read is used to reflect abnormal communication with the terminal device 20.

[0070] The above thresholds can be set according to the LPCD mode and the normal card inspection mode, and are not limited here. Exemplarily, the amplitude strength of the characteristic information meets the threshold of the LPCD mode, such as but not limited to a level lower than 1 volt, and the terminal device 20 can be detected to be in the LPCD mode. The amplitude strength of the above characteristic information meets the threshold of the LPCD mode, such as but not limited to a level higher than 5 volts, and the terminal device 20 can be detected to be in the normal card inspection mode.

[0071] The control circuit 222 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, resistors, and capacitors to process the signal.

[0072] In the embodiment of the present application, the required signal can be collected from the antenna through the signal sampling circuit 221. By combining the detection control module 22 with the above-mentioned NFC antenna 21, a signal sampling circuit 221 is added to the detection control module 22, so as to complete the lack of sensing of the source of the external terminal device 20 that can emit the radio frequency field, and further complete the subsequent related strategies through the detection control module 22.

[0073] Combination Figure 2 As shown, the NFC antenna 21 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 also includes an NFC coil and a grounded noise filter terminal. The NFC antenna 21 including the noise filter terminal C1, the signal output terminal A1 and the signal output terminal B1 can also be called a three-terminal antenna.

[0075] The NFC coil is used to sense radio frequency signals; the noise filter terminal is used to filter out noise signals of the radio frequency signals sensed by the NFC coil, so that the NFC antenna 21 receives normal signals except for the noise.

[0076] It should be noted that the above-mentioned noise signal can be but is not limited to low-frequency noise. In some examples, the noise filter terminal C1 of the above-mentioned NFC antenna 21 is connected to the input terminal C2 of the NFC module 23, and then connected to the single board ground to filter out the low-frequency noise received on the antenna, and then only receive normal signals for communication. In other examples, the noise filter terminal C1 of the above-mentioned NFC antenna 21 is connected to the input terminal C2 of the NFC module 23, and the link can be connected in series with devices such as inductors and capacitors, and then connected to the single board ground to filter out the low-frequency noise received on the antenna, and then only receive normal signals for communication. These normal signals for communication are purer than the signals before the noise is filtered out. This three-terminal antenna receives very little noise signal, or even no noise signal, which is convenient for high-precision detection.

[0077] The NFC coil includes at least three terminals; the noise filter terminal is placed at the physical center of the antenna. In this way, the balance of the other multiple signal output terminals can be maintained. Furthermore, the noise filter terminal C1 is placed at the physical center of the antenna, thereby maintaining the balance of the signal output terminal A1 and the signal output terminal B1.

[0078] In some embodiments of the at least three-terminal coil, the at least three-terminal coil includes an odd-terminal coil, the noise filtering terminal is one noise filtering terminal, and the one noise filtering terminal is placed at the physical center of the NFC antenna 21; the number of terminals of the odd-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 accordingly, the noise filtering terminals are two noise filtering terminals, and the two noise filtering terminals are placed at the physical center of the above-mentioned NFC antenna 21; the number of terminals of the even-numbered terminal coil is greater than the number of terminals of the three-terminal coil.

[0080] In the embodiment of the present application, the three-terminal antenna proposed in the NFC antenna 21, the noise filter terminal C1 of the above-mentioned NFC antenna 21 is connected to the input terminal C2 of the NFC module 23, and is connected to the single board ground, so as to filter out the noise in a certain frequency band, and then a purer communication signal can be transmitted to the signal sampling circuit 221, so that the control circuit 222 can make an accurate decision.

[0081] In another embodiment of the above-mentioned NFC antenna 21, the above-mentioned NFC antenna 21 only includes two signal output terminals, namely, the signal output terminal A1 and the signal output terminal B1. In this way, the NFC antenna 21 coil is double-ended. While the coil of the NFC antenna 21 senses the NFC signal (13.56MHz), it also senses other signals and forms noise on the circuit, affecting subsequent sampling. In this solution, the signal output terminal A1 and the signal output terminal B1 of the near field communication NFC antenna 21 are respectively the sampling input terminal B2 of the NFC module 23 and the above-mentioned signal output terminal B1. When the input signal is large enough, the noise may be negligible. In this way, the scope of application of the NFC antenna 21 is improved.

[0082] Continue as Figure 2 As shown, the detection control module 22 is used to detect that the terminal device 20 is in the low power consumption card detection LPCD mode according to the first radio frequency signal; and generate a signal for stimulating the terminal device 20 in the case 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 for stimulating the terminal device 20, tune 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 to ensure the effectiveness of signal transmission.

[0083] Continue as Figure 2 As shown, the NFC module 23 and the detection control module 22 can achieve two-way communication through the control bus. Further, 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 2 As shown, the NFC module 23 includes a matching circuit 231 and a modulation and demodulation unit 232 connected to the matching circuit 231.

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

[0086] In some examples, the matching circuit 231 is after the routing of the signal sampling circuit 221. The matching circuit 231 includes an impedance element for adjusting impedance parameters and resonant frequency parameters, and is also used to adjust the parasitic effect of the matching circuit 231 on the routing of the signal sampling circuit 221. The impedance element may include, but is not limited to, a variable capacitor, a variable inductor, and a variable resistor. Further, the variable capacitor resonates with the parasitic inductance of the NFC antenna 21 and filters out electromagnetic interference. The matching circuit 231 also sends the second RF signal after filtering out interference to the modem unit 232. In this way, after the routing of the matching circuit 231 and the routing of the signal sampling circuit 221 are arranged, the impedance parameters of the impedance element are adjusted to change the parasitic effect of the matching circuit 231 on the routing of the signal sampling circuit 221.

[0087] In the embodiment of the present application, the matching circuit 231 is arranged after the routing of the signal sampling circuit 221, and the parasitic effect of the matching circuit 231 on the routing of the signal sampling circuit 221 is reduced by adjusting the impedance parameters of the impedance element. In this way, the parasitic effect of the matching circuit 231 on the routing of the signal sampling circuit 221 can be reduced. Furthermore, the parasitic effect of the matching circuit 231 on the routing of the signal sampling circuit 221 is avoided.

[0088] The application scenarios of the NFC electric field detection system 10 of the present application may include but are not limited to UnionPay, aggregated payment equipment vendors, and mobile phone and other related enterprises that develop and produce NFC devices.

[0089] Based on the same application concept as the above-mentioned NFC electric field system, the present application embodiment also proposes an NFC electric field detection method, such as Figure 3 As shown, the above NFC electric field detection method includes the following steps 310 to 320:

[0090] Step 310: receiving a first radio frequency signal transmitted by the terminal device when the NFC radio frequency field of the terminal device is sensed.

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

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

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

[0094] In some embodiments, the above 320 may further include 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 stimulating the terminal device in the case of abnormal communication with the terminal device. The NFC electric field detection method also includes receiving a signal for stimulating the terminal device, tuning the NFC antenna, and sending the modulated second radio frequency signal to the terminal device through the NFC antenna.

[0095] An embodiment of the present application further provides an NFC device, the NFC device operates in a passive mode, a terminal device communicating with the NFC device operates in an active mode, and the NFC device includes any one of the above NFC electric field detection systems.

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

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

[0098] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0099] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0100] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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 only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the inventive concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. An NFC electric field detection system, characterized in that: include: A detection control module, configured to detect that the terminal device is in a low power consumption card detection LPCD mode according to a received first radio frequency signal transmitted by the terminal device; In case of abnormal communication with the terminal device, a second radio frequency signal for stimulating the terminal device is sent to the terminal device to communicate with the terminal device.

2. The NFC electric field detection system according to 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 an electrical signal corresponding to the field strength of the NFC radio frequency field; The control circuit is used to obtain characteristic information of the NFC radio frequency field of the terminal device according to the value of the electrical signal; and detect that the terminal device is in the LPCD mode when the amplitude strength of the characteristic information meets the threshold of the LPCD mode; When the terminal device does not read the data of the NFC electric field detection system, the second radio frequency signal is sent to the terminal device.

3. The NFC electric field detection system according to claim 2, characterized in that: The signal sampling circuit includes an amplitude signal sampling circuit, a voltage sampling circuit or a current sampling circuit of an analog-to-digital converter ADC.

4. The NFC electric field detection system according to claim 1, characterized in that: The NFC electric field detection system further includes: a near field communication NFC antenna, configured to receive a first radio frequency signal transmitted by the terminal device; The detection control module executes the sending of the second radio frequency signal for stimulating the terminal device to the terminal device in the case of abnormal communication with the terminal device, so as to communicate with the terminal device in the following manner: In case of abnormal communication with the terminal device, a second radio frequency signal for stimulating the terminal device is generated; and the second radio frequency signal is sent to the terminal device through the NFC antenna to communicate with the terminal device.

5. The NFC electric field detection system according to claim 4, characterized in that: The detection control module is used to detect that the terminal device is in a low power consumption card detection LPCD mode according to the first radio frequency signal; In case of abnormal communication with the terminal device, generating a signal for stimulating the terminal device; The NFC electric field detection system further includes: an NFC module, which is used to receive the signal used to excite the terminal device, tune with the NFC antenna, and send the modulated second radio frequency signal to the terminal device through the 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 executes the sending of the second radio frequency signal for stimulating the terminal device to the terminal device in the case of abnormal communication with the terminal device, so as to communicate with the terminal device in the following manner: In a case where the terminal device does not read the data of 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 according to any one of claims 1 to 5, characterized in that: The detection control module executes the sending of the second radio frequency signal for stimulating the terminal device to the terminal device in the case of abnormal communication with the terminal device, so as to communicate with the terminal device in the following manner: In case 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 executes the sending of the second radio frequency signal for stimulating the terminal device to the terminal device in the case of abnormal communication with the terminal device, so as to communicate with the terminal device in the following manner: In case of abnormal communication with the terminal device, after sending a second radio frequency signal for stimulating the terminal device to the terminal device, if the communication status of the terminal device has not recovered to normal communication, the second radio frequency signal is resent to the terminal device multiple times until the terminal device is awakened to a normal card inspection mode and normal communication is performed with the terminal device.

9. The NFC electric field detection system according to any one of claims 1 to 5, characterized in that: The NFC electric field detection system further includes: a near field communication NFC antenna, configured to receive a first radio frequency signal transmitted by the terminal device; The NFC antenna also includes an NFC coil and a grounded noise filtering terminal; An NFC coil, used for sensing a radio frequency signal; the radio frequency signal includes the first radio frequency signal and / or the second radio frequency signal; The noise filter terminal is used to filter out the noise signal of the radio frequency signal induced by the NFC coil, so that the NFC antenna receives a normal signal except the noise.

10. The NFC electric field detection system according to claim 9, characterized in that: The NFC coil includes at least a three-terminal coil; the noise filtering terminal is placed at the physical center of the antenna.

11. The NFC electric field detection system according to claim 10, characterized in that: The at least three-terminal coil includes an odd-terminal coil, the noise filtering terminal is one noise filtering terminal, and the one noise filtering terminal is placed at the physical center of the NFC antenna; the number of terminals of the odd-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 accordingly, the noise filtering terminals are two noise filtering terminals, and the two noise filtering terminals are placed at the physical center of the 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 according to any one of claims 1 to 5, characterized in that: The NFC electric field detection system further includes: a near field communication NFC antenna, configured to receive a first radio frequency signal transmitted by the terminal device; The NFC module includes a matching circuit and a modulation and demodulation unit connected to the matching circuit; The matching circuit is used to tune with the NFC antenna and send the matched signal to the modem 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 send the second radio frequency signal to the NFC antenna; The NFC antenna is further used to send the second radio frequency signal.

13. The NFC electric field detection system according to 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 arranged after the routing of the signal sampling circuit; The matching circuit includes an impedance element, which is used to adjust impedance parameters and resonant frequency parameters, and is also used to adjust the parasitic effect of the matching circuit on the routing of the signal sampling circuit.

14. A NFC electric field detection method, characterized in that: include: According to the received first radio frequency signal transmitted by the terminal device, it is detected that the terminal device is in a low power consumption card detection LPCD mode; In case of abnormal communication with the terminal device, a second radio frequency signal for stimulating the terminal device is sent to the terminal device to communicate with the terminal device.

15. The NFC electric field detection method according to claim 14, characterized in that: The detecting that the terminal device is in a low power consumption card detection LPCD mode according to the received first radio frequency signal transmitted by the terminal device includes: Sampling an electrical signal corresponding to the field strength of the NFC radio frequency field; According to the value of the electrical signal, characteristic information of the NFC radio frequency field of the terminal device is obtained; when the amplitude strength of the characteristic information meets the threshold of the LPCD mode, it is detected that the terminal device is in the LPCD mode; The sending, when performing abnormal communication with the terminal device, to the terminal device a second radio frequency signal for stimulating the terminal device comprises: In a case where the terminal device does not read data of the NFC electric field detection method, the second radio frequency signal is sent to the terminal device.

16. The NFC electric field detection method according to claim 14, characterized in that: The sending, when performing abnormal communication with the terminal device, to the terminal device a second radio frequency signal for stimulating the terminal device comprises: In case of abnormal communication with the terminal device, generating a signal for stimulating the terminal device; The signal for stimulating the terminal device is received, tuned with an NFC antenna, and the modulated second radio frequency signal is sent 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: The step of sending a second radio frequency signal for stimulating the terminal device to communicate with the terminal device in a case where the communication with the terminal device is abnormal, comprises: In a case where the terminal device does not read the data of 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: The sending, when performing abnormal communication with the terminal device, to the terminal device a second radio frequency signal for stimulating the terminal device comprises: In case 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; and the second radio frequency signal is sent to the terminal device based on the terminal type.

19. The NFC electric field detection method according to any one of claims 14 to 16, characterized in that: The step of sending a second radio frequency signal for stimulating the terminal device to communicate with the terminal device in a case where the communication with the terminal device is abnormal, comprises: In case of abnormal communication with the terminal device, after sending a second radio frequency signal for stimulating the terminal device to the terminal device, if the communication status of the terminal device has not recovered to normal communication, the second radio frequency signal is resent to the terminal device multiple times until the terminal device is awakened to a normal card inspection mode and normal communication is performed with the terminal device.

20. The NFC electric field detection method according to any one of claims 14 to 16, characterized in that: The step of sending a second radio frequency signal for stimulating the terminal device to communicate with the terminal device in a case where the communication with the terminal device is abnormal, comprises: Tune with the NFC antenna and send the matching 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 NFC antenna.

21. An NFC device, characterized in that: 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 NFC electric field detection system according to any one of claims 1 to 13.

Images