Near field communication NFC device and communication method thereof

Abstract

The present application discloses an NFC device and a communication method thereof, belonging to the field of communication technology. The device includes: a differential full-bridge drive module, a first DC drive module and a coil antenna, the differential full-bridge drive module is used to output an AC drive voltage; the first DC drive module is used to output a first DC drive voltage; the coil antenna includes a first sub-antenna and a second sub-antenna, the first sub-antenna and the second sub-antenna are insulated and nested, the first sub-antenna is connected to the differential full-bridge drive module to generate a high-frequency alternating magnetic field based on the AC drive voltage, and the second sub-antenna is connected to the first DC drive module to generate a first constant magnetic field based on the first DC drive voltage.

Description

Technical Field

[0001] The present invention relates to the field of near field communication, and in particular to a near field communication (NFC) device and a communication method thereof. Background Art

[0002] Near Field Communication (NFC) is a near field communication technology based on 13.56MHz. It is a point-to-point near field communication function, mainly including access cards, transportation cards, attendance cards, ID cards and other scenarios.

[0003] Currently, the working modes of NFC devices include reader mode and card emulation mode. Generally, NFC devices, including electronic devices with NFC card reading and / or card emulation functions, card readers, card emulation devices, etc., implement the NFC antenna function by installing a flexible circuit board coil antenna or an antenna on the top of the shell. However, the positions of different models vary greatly, and users are usually not clear about the NFC antenna position of the model they are using. In addition, in different scenarios, the shape of the card reader carrier is different and the position of the card reader is not conspicuous, making it difficult for users to accurately find the card swiping position and align it with the NFC coil of the NFC device.

[0004] At the same time, as a near-field communication technology, the transmission power and characteristics will weaken as the distance between the two communicating NFC devices increases or they are misaligned. Alignment is required for successful card swiping. If the user does not align the position, near-field communication will fail. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide an NFC device and a communication method thereof, which can solve the problem of near field communication failure caused by misalignment of the NFC antenna position.

[0006] In a first aspect, an embodiment of the present application provides a near field communication (NFC) device, including: a differential full-bridge drive module, a first DC drive module, and a coil antenna.

[0007] The differential full-bridge driving module is used to output an AC driving voltage;

[0008] The first DC driving module is used to output a first DC driving voltage;

[0009] The coil antenna includes a first sub-antenna and a second sub-antenna, the first sub-antenna and the second sub-antenna are insulated and nested, the first sub-antenna is connected to the differential full-bridge drive module to generate a high-frequency alternating magnetic field based on the AC drive voltage, and the second sub-antenna is connected to the first DC drive module to generate a first constant magnetic field based on the first DC drive voltage.

[0010] In a second aspect, an embodiment of the present application provides a communication method of an NFC device, which is applied to the device as described in the first aspect above, and the method includes:

[0011] When an external magnetic field is detected, controlling the first DC drive module to start up to output the first DC drive voltage;

[0012] The second sub-antenna generates a first constant magnetic field based on the first DC driving voltage;

[0013] Data is transmitted and received between the NFC device and a first NFC device corresponding to the external magnetic field through the high-frequency alternating magnetic field generated by the first sub-antenna based on the AC driving voltage output by the differential full-bridge driving module.

[0014] In a third aspect, an embodiment of the present application provides a near field communication (NFC) device, including: a differential full-bridge drive module, a first DC drive module, and a coil antenna.

[0015] The differential full-bridge driving module is used to output an AC driving voltage;

[0016] The first DC driving module is used to output a first DC driving voltage;

[0017] The coil antenna includes a first sub-antenna and a second sub-antenna, the first sub-antenna and the second sub-antenna are connected in series and nested, the second sub-antenna is connected to the differential full-bridge drive module to generate a high-frequency alternating magnetic field based on the AC drive voltage, and the first sub-antenna and the second sub-antenna connected in series are connected to the first DC drive module to generate a constant magnetic field in a first direction based on the first DC drive voltage.

[0018] In a fourth aspect, an embodiment of the present application provides a communication method of an NFC device, which is applied to the device as described in the third aspect above, and the method includes:

[0019] When an external magnetic field is detected, controlling the first DC drive module to start up to output the first DC drive voltage;

[0020] The first sub-antenna and the second sub-antenna connected in series generate a first constant magnetic field based on the first DC driving voltage;

[0021] Data is transmitted and received between the NFC device and a first NFC device corresponding to the external magnetic field through the high-frequency alternating magnetic field generated by the second sub-antenna based on the alternating voltage output by the differential full-bridge driving module.

[0022] In an embodiment of the present application, a high-frequency AC magnetic field for near-field communication is generated based on an AC drive signal by a sub-antenna connected to the differential full-bridge driver module, and a constant magnetic field is generated based on a DC drive signal by a sub-antenna connected to the first DC driver module. Thus, when two NFC devices perform near-field communication, a magnetic attraction force is generated based on the constant magnetic field between the two to attract one of the NFC devices to be placed in the optimal sensing area of ​​the other NFC device, and the two NFC devices are accurately and quickly aligned, thereby successfully performing near-field communication and improving the working efficiency of the card reading or card emulation mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural block diagram of the NFC device of the first embodiment of the present application.

[0024] Figure 2 It is a circuit structure diagram of the NFC device of the first embodiment of the present application.

[0025] Figure 3 It is a schematic diagram of an application scenario of an NFC device according to the first embodiment of the present application.

[0026] Figure 4 This is one of the flow charts of the communication method of the NFC device of the first embodiment of the present application.

[0027] Figure 5 This is the second flow chart of the communication method of the NFC device of the first embodiment of the present application.

[0028] Figure 6 This is the third flow chart of the communication method of the NFC device of the first embodiment of the present application.

[0029] Figure 7 It is a structural block diagram of an NFC device according to the second embodiment of the present application.

[0030] Figure 8 This is one of the circuit structure diagrams of the NFC device of the second embodiment of the present application.

[0031] Fig. 9 This is the second circuit structure diagram of the NFC device of the second embodiment of the present application.

[0032] Fig.10 This is one of the flow charts of the communication method of the NFC device of the second embodiment of the present application.

[0033] Fig.11 This is the second flow chart of the communication method of the NFC device of the second embodiment of the present application. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0035] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0036] The NFC device and the communication method thereof provided in the embodiments of the present application are described in detail below through specific embodiments and their application scenarios in conjunction with the accompanying drawings.

[0037] Figure 1 is a structural block diagram of an NFC device according to an embodiment of the present application, Figure 1 and Figure 3 The NFC device 100 of the embodiment of the present application includes: a differential full-bridge driving module 10, a first DC driving module 20 and a coil antenna 50, wherein the differential full-bridge driving module 10 is used to output an AC driving voltage; the first DC driving module 20 is used to output a first DC driving voltage; the coil antenna 50 includes a first sub-antenna 52 and a second sub-antenna 54, wherein the first sub-antenna 52 and the second sub-antenna 54 are insulated and nested, the first sub-antenna 52 is connected to the differential full-bridge driving module 10 to generate a high-frequency alternating magnetic field based on the AC driving voltage, and the second sub-antenna 54 is connected to the first DC driving module 20 to generate a first constant magnetic field based on the first DC driving voltage.

[0038] In this embodiment, the differential full-bridge driver module 10 is controlled by an NFC driver controller 30 built into an NFC chip (IC) of the NFC device, and the NFC IC is a component dedicated to near field communication. The first DC driver module 20 can be controlled by an application processor 70 different from the NFC driver controller 30, and the application processor 70 is the main processor of the NFC device 100 and is independent of the NFC IC.

[0039] An NFC device may be an electronic device with NFC point-to-point communication function, including a card reader, a mobile terminal with a card reading function or a card emulation function, and the like.

[0040] In this embodiment, the differential full-bridge driver module 10 is used to generate an AC drive voltage. After the NFC driver controller 30 controls the differential full-bridge driver module 10 to be enabled, the AC drive voltage is generated and provided to the first sub-antenna 52 of the coil antenna 50 to generate a high-frequency alternating magnetic field of 13.56 MHz, thereby enabling data transmission and reception between two NFC devices, namely, the card reader device and the card emulation device.

[0041] The first DC driving module 20 is used to generate a DC driving voltage. After the application processor 70 controls to enable the first DC driving module 20, the DC driving voltage is generated and provided to the second sub-antenna 54 of the coil antenna 50 to generate a constant magnetic field. The constant magnetic field generated by the NFC device communicating with the other end is based on the principle of attraction between opposite magnetic fields. A magnetic attraction is generated between the NFC antennas of two NFC devices, i.e., the card reader device and the card emulation device, through the interaction of the constant magnetic fields of the two NFC devices. The magnetic attraction attracts one NFC device to be placed in the best sensing area of ​​the other NFC device. The two NFC devices are aligned, which can improve the success rate of near field communication.

[0042] The coil antenna 50 includes a first sub-antenna 52 and a second sub-antenna 54, which are insulated and nested. Specifically, the first sub-antenna 52 is connected to the differential full-bridge drive module 10, and receives an AC drive voltage to generate a high-frequency alternating magnetic field. The second sub-antenna 54 is connected to the first DC drive module 20, and receives a first DC drive voltage to generate a constant magnetic field.

[0043] refer to Figure 2 and Figure 3 The first end of the first sub-antenna 52 is connected to the first end of the differential full-bridge driving module 10, and the second end of the first sub-antenna 52 is connected to the second end of the differential full-bridge driving module 10; the first end of the second sub-antenna 54 is connected to an end of the first DC driving module 20 that outputs the first DC driving voltage, and the second end of the second sub-antenna 54 is grounded through the second inductor L2.

[0044] The two ends of the first sub-antenna 52 are connected to the two ends of the differential full-bridge driving module 10 to receive the AC driving voltage generated by the differential full-bridge driving module 10 , thereby generating a high-frequency alternating magnetic field.

[0045] The differential full-bridge driving module 10 may be a multiplexed transceiver (TX) differential full-bridge driving circuit of a conventional NFC IC. The differential full-bridge driving module 10 includes a first driving module corresponding to the upper half bridge and a second driving module corresponding to the lower half bridge.

[0046] like Figure 2 As shown, the first driving module includes: a first switch unit TX1 and a first matching unit, the first end of the first switch unit TX1 is connected to the constant voltage VDDPA, the second end of the first switch unit TX1 is connected to the NFC driving controller 30, and the third end of the first switch unit TX1 is connected to the first matching unit, which is used to alternately turn on and off the first constant voltage VDDPA and the first matching unit to generate a first AC driving voltage; the first matching unit is also connected to one end of the first sub-antenna 52 of the coil antenna 50 to provide the first AC driving voltage to the first sub-antenna 52.

[0047] The second driving module includes: a second switch unit TX2 and a second matching unit, the first end of the second switch unit TX2 is connected to the constant voltage VDDPA, the second end of the second switch unit TX2 is connected to the NFC driving controller 30, and the third end of the second switch unit TX2 is connected to the second matching unit, which is used to alternately turn on and off the second constant voltage VDDPA and the second matching unit to generate a second AC driving voltage; the second matching unit is also connected to the other end of the first sub-antenna 52 of the coil antenna 50 to provide the second AC driving voltage to the first sub-antenna 52.

[0048] Specifically, Figure 2 As shown, the first switch unit TX1 includes a first switch tube 101 and a second switch tube 103, and the first matching unit includes a third inductor L21, a fifth capacitor C11, a sixth capacitor C12 and a seventh capacitor C13. The first end of the first switch tube 101 is connected to the constant voltage VDDPA, the second end of the first switch tube 101 is connected to the NFC drive controller 30, and the third end of the first switch tube 101 is connected to the second switch tube 103 and the third inductor L21 respectively.

[0049] The first end of the second switch tube 103 is connected to the third end of the first switch tube 101 and the third inductor L21, the second end of the second switch tube 103 is connected to the NFC drive controller 30, and the third end of the second switch tube 103 is grounded. The first end of the third inductor L21 is respectively connected to the third end of the first switch tube 101 and the first end of the second switch tube 103, the second end of the third inductor L21 is respectively connected to the fifth capacitor C11 and the sixth capacitor C12, and the second end of the fifth capacitor C11 is grounded.

[0050] The first end of the sixth capacitor C12 is connected to the second end of the third inductor L21 and the first end of the fifth capacitor C11, and the second end of the sixth capacitor C12 is respectively connected to the seventh capacitor C13 and one end of the first sub-antenna 52; the first end of the seventh capacitor C13 is respectively connected to the second end of the sixth capacitor C12 and one end of the first sub-antenna 52, and the second end of the seventh capacitor C13 is grounded; wherein, the NFC drive controller 30 is used to control the conduction and disconnection of the first switch tube 101 and the second switch tube 103.

[0051] Specifically, refer to Figure 2 The second switch unit TX2 includes a third switch tube 203 and a fourth switch tube 205, and the second matching unit includes a fourth inductor L22, an eighth capacitor C21, a ninth capacitor C22 and a tenth capacitor C23; a first end of the third switch tube 203 is connected to a constant voltage VDDPA, a second end of the third switch tube 203 is connected to the NFC drive controller 30, and a third end of the third switch tube 203 is respectively connected to the fourth switch tube 205 and the fourth inductor L22.

[0052] A first end of the fourth switch tube 205 is connected to the third end of the third switch tube 203 and the fourth inductor L22 , a second end of the fourth switch tube 205 is connected to the NFC driving controller 30 , and a third end of the fourth switch tube 205 is grounded.

[0053] The first end of the fourth inductor L22 is respectively connected to the third end of the third switch tube 203 and the first end of the fourth switch tube 205, the second end of the fourth inductor L22 is respectively connected to the eighth capacitor C21 and the ninth capacitor C22, and the second end of the eighth capacitor C21 is grounded. The first end of the ninth capacitor C22 is respectively connected to the second end of the fourth inductor L22 and the first end of the eighth capacitor C21, and the second end of the ninth capacitor C22 is connected to the tenth capacitor C23. The first end of the tenth capacitor C23 is respectively connected to the second end of the ninth capacitor C22 and the other end of the first sub-antenna 52, and the second end of the tenth capacitor C23 is grounded; wherein, the NFC drive controller 30 is also used to control the conduction and disconnection of the third switch tube 203 and the fourth switch tube 205.

[0054] The principle of the differential full-bridge driving module 10 generating the AC driving voltage is as follows:

[0055] In a time period, the NFC driving controller 30 controls the first switch tube 101 of the first switch unit TX1 to be turned on, and turns off the second switch tube 103 of the first switch unit TX1, thereby turning on the constant voltage VDDPA and the first matching unit, and the current corresponding to the constant voltage VDDPA flows in one direction to the first sub-antenna 52 through the first inductor L21 and the sixth capacitor C12.

[0056] After the capacitors of the first matching unit are fully charged, the NFC drive controller 30 turns off the first switch tube 101 of the first switch unit TX1 and turns on the second switch tube 103 of the first switch unit TX1. At the same time, the third switch tube 203 of the second switch unit TX2 is controlled to be turned on, and the fourth switch tube 205 of the second switch unit TX2 is turned off, so as to turn on the constant voltage VDDPA and the second matching unit, and the current corresponding to the constant voltage VDDPA flows to the first sub-antenna 52 in another direction through the fourth inductor L22 and the ninth capacitor C22. The opposite current direction forms an AC drive signal provided to the first sub-antenna 52 by the differential full-bridge drive module 10.

[0057] One end of the second sub-antenna 54 receives the DC power corresponding to the DC driving voltage output by the first DC driving module 20, thereby generating a constant magnetic field. The DC power corresponding to the DC driving voltage flows out through the other end of the second sub-antenna 54 and is grounded through the second inductor L2, forming a DC power transmission path.

[0058] Since the second sub-antenna 54 receives the AC driving voltage and the DC driving voltage at the same time, if the other end of the first sub-antenna 52 is directly grounded, signal and power attenuation will occur.

[0059] Therefore, in one embodiment, the NFC device 100 further includes a second inductor L2, which is disposed between the second sub-antenna 54 and the ground, and is used to ground the direct current corresponding to the constant magnetic field received by the second sub-antenna 54, and to isolate the alternating current corresponding to the high-frequency alternating magnetic field generated by the second sub-antenna 54.

[0060] The second inductor L2 is used to isolate high-frequency signals and pass direct current, thereby preventing the other end of the first sub-antenna 52 from being directly grounded to cause high-frequency signal and power attenuation.

[0061] In this embodiment, the first sub-antenna 52 and the second sub-antenna 54 are independent coil windings insulated from each other and are nested. Figure 2 and Figure 3 As shown, the second sub-antenna 54 is nested inside the first sub-antenna 52, and of course, the first sub-antenna 52 can also be nested inside the second sub-antenna 54. The first sub-antenna 52 and the second sub-antenna 54 are each connected to a corresponding driving module, and generate a high-frequency AC magnetic field and a constant magnetic field in their respective coil windings, which are respectively used for data transmission and reception between the NFC device 100 and the first NFC device 200 of the opposite end communication, and for generating a magnetic attraction force F between the NFC device 100 and the first NFC device 200, so as to achieve rapid alignment of the NFC sensing area of ​​the NFC device 100 and the first NFC device 20, thereby successfully performing near field communication and improving the working efficiency of the card reading or card emulation mode.

[0062] The differential full-bridge driving module 10 is used when the NFC device 100 is in a card reading mode, and drives the first sub-antenna 52 to oscillate, thereby sending data to the first NFC device 200 .

[0063] Figure 3 : is a schematic diagram of an application scenario of an NFC device of an embodiment of the present application, wherein the NFC device 100 and the first NFC device 200 may have the same circuit structure, that is, in addition to being able to realize NFC communication between the two devices, they both have the function of generating a constant magnetic field. The NFC device 100 generates a magnetic field from the S polarity to the N polarity direction as shown in the figure through the first DC driving module 20 and the first sub-antenna 52. The first NFC device 200 generates a magnetic field from the S polarity to the N polarity direction as shown in the figure through the first DC driving module 20 and the first sub-antenna 52. The two constant magnetic fields have the same direction, thereby generating a magnetic attraction F, and realizing the alignment of the NFC sensing areas between the two devices.

[0064] Optionally, the NFC device 100 further includes: a receiving module, which is connected to at least one of the first end and the second end of the first sub-antenna 52 and is used to receive data by detecting a voltage at a corresponding connection end of the first sub-antenna 52 .

[0065] The receiving module is used when the NFC device 100 is in the card emulation mode, and realizes the reception and transmission of data sent by the first NFC device 200 by detecting the carrier voltage sent by the first NFC device 200 received by one end or both ends of the first sub-antenna 52 .

[0066] refer to Figure 2 The receiving module includes a first receiving unit RXP and a second receiving unit RXN. The first receiving unit RXP and the second receiving unit RXN are respectively connected to the two ends of the first sub-antenna 52, and are respectively used to detect the voltages at the two ends of the first sub-antenna 52, so as to receive the transmission data of the first NFC device 200 through the voltages at the positive and negative ends of the first sub-antenna 52.

[0067] In this embodiment, the first receiving unit RXP is connected to the positive terminal of the first sub-antenna 52, which may include directly connecting the first receiving unit RXP to the positive terminal of the first sub-antenna 52, or Figure 2 As shown, after passing through the sixth capacitor C12, it is indirectly connected to the positive terminal of the first sub-antenna 52, and the detected voltage at the first end of the first sub-antenna 52 is the voltage after the positive terminal of the first sub-antenna 52 is attenuated.

[0068] Combination Figure 2The voltage detected by the first receiving unit RXP is input into the NFC processor 31 inside the NFC device after a series of processing by the bias module B, the automatic gain control module AGC, the analog-to-digital conversion module ADC, etc., and the data sent by the first NFC device 200 during the communication between the NFC device 100 and the first NFC device 200 is received according to the detection capacitance.

[0069] In this embodiment, the coil antenna 50 includes, in addition to the first sub-antenna 52 for generating a high-frequency alternating magnetic field for NFC communication, an independent second sub-antenna 54 for generating magnetic attraction, which is directly used to generate a constant magnetic field, and can improve the magnetic attraction performance of the generated magnetic attraction. In addition, the original NFC coil body (such as the first sub-antenna 52) of the electronic device can be reused, and only the routing of the second sub-antenna 54 is increased, and the cost and space increase are very small, which is possible for mass production.

[0070] Based on the above Figures 1 to 3 The present application also provides a communication method of an NFC device, which is applied to the above Figures 1 to 3 The NFC device of any embodiment, such as Figure 4 As shown, the method includes:

[0071] S202, when an external magnetic field is detected, controlling the first DC driving module to start up to output the first DC driving voltage;

[0072] S204, the second sub-antenna generates a first constant magnetic field based on the first DC driving voltage;

[0073] S206: Perform data transmission and reception between the NFC device and a first NFC device corresponding to the external magnetic field through the high-frequency alternating magnetic field generated by the first sub-antenna based on the AC driving voltage output by the differential full-bridge driving module.

[0074] In one embodiment of the present application, the differential full-bridge driver module 10 and the first DC driver module 20 can be in a normally open / normally started state, so that when performing NFC communication, the magnetic attraction force generated by the first DC driver module 20 based on the constant magnetic field can guide the user to quickly align the NFC device with the NFC communication sensing area of ​​the peer device. However, the normally open first DC driver module 20 will cause power consumption problems, heat problems, and magnetic interference problems to the NFC device.

[0075] Therefore, in the above embodiment, the above problem can be solved by starting the first DC driving module 20 after detecting the external magnetic field and before the NFC officially works in S202. The external magnetic field here is the magnetic field generated by the opposite device that can perform NFC communication, including a constant magnetic field or a high-frequency alternating magnetic field.

[0076] Below, the communication method of the NFC device of the embodiment of the present application is described by taking the differential full-bridge driver module 10 controlled by the NFC driver controller and the first DC driver module 20 controlled by the application processor (AP) as an example. Of course, in other embodiments, the differential full-bridge driver module and the first DC driver module can also be controlled by the same controller.

[0077] In one embodiment, the presence of an external magnetic field can be detected by the original Hall sensor of the NFC device. Figure 5 As shown, the following steps are included:

[0078] S302, detect the magnetic field through Hall IC (Hall sensor), if yes, proceed to step S304, otherwise proceed to step S306;

[0079] S304, notifying the AP to start the first DC driving module;

[0080] S306, keeping the first DC drive module turned off;

[0081] S308, after starting the first DC driving module, the NFC device 100 generates a directional constant magnetic field;

[0082] S310, aligning the magnetic attraction force generated by the constant magnetic field to the NFC sensing area;

[0083] S312, communication is completed and the magnetic field is removed;

[0084] S314: After detecting that the magnetic field is weakened, the AP is notified to turn off the first DC driving module.

[0085] In the case where the NFC device itself has a Hall sensor, this embodiment can reuse the Hall sensor. After the Hall sensor senses the existence of an external magnetic field, it notifies the AP to turn on the DC drive source of the first DC drive module and provide a first DC drive voltage to generate a constant magnetic field. It generates magnetic attraction with the external constant magnetic field to perform alignment. After the NFC communication is completed, the two NFC devices will separate, the Hall sensor detects that the external magnetic field has weakened, and then notifies the AP to turn off the first DC drive module to complete the entire process.

[0086] Compared with the first DC drive module normally open solution, this is conducive to reducing the high power consumption of the whole machine, increasing the user's usage time, and reducing the heat and magnetic interference of the whole machine.

[0087] The Hall sensor can be used to detect the presence of a magnetic field. In some cases, the external magnetic field detected by the Hall sensor may not be the high-frequency alternating magnetic field in which the NFC device operates. If the presence of an external magnetic field is detected, the first DC drive module 20 is controlled to start, which will cause NFC to be triggered incorrectly.

[0088] In one embodiment, when an external magnetic field is detected, controlling the first DC drive module to start to output the first DC drive voltage includes: when it is detected that the frequency of the external magnetic field is the same as the frequency of the high-frequency alternating magnetic field, controlling the first DC drive module to start to output the first DC drive voltage.

[0089] That is to say, only when the detected external magnetic field is a high-frequency alternating magnetic field for the operation of the NFC device, the AP controls the first DC driving module 20 to start.

[0090] The method further includes: in the process of the first DC driving module outputting the first DC driving voltage, if the frequency of the detected external magnetic field is lower than a preset threshold, controlling the first DC driving module to be turned off.

[0091] That is to say, when the Hall sensor detects that the external magnetic field becomes weak, the AP controls the first DC driving module 20 to be turned off.

[0092] Since some models do not have electronic devices equipped with Hall sensors, or although they are equipped with Hall sensors, they can only detect the presence or absence of a magnetic field, if a Hall sensor is added only to control the on-off timing of the first DC drive module of the NFC device, the cost is high and may also cause false touches.

[0093] To improve the efficiency of NFC communication, in another embodiment, the receiving module of the NFC device can be used to detect the frequency of the external magnetic field. As described above, the first receiving unit RXP and the second receiving unit RXN can detect the voltage across the first sub-antenna 52, and the NFC processor 31 can obtain the frequency of the external magnetic field by detecting the voltage.

[0094] The specific flow chart is as follows Figure 6 As shown, the following steps are included:

[0095] S402, the NFC processor detects whether the external magnetic field is a 13.56 MHz magnetic field used for NFC communication through the first receiving unit RXP and the second receiving unit RXN, and if so, proceeds to step S404, otherwise, proceeds to step S406;

[0096] S404, triggering an NFC high-frequency alternating magnetic field opening event (field on);

[0097] S406, keeping the first DC drive module turned off;

[0098] S408, the NFC processor 31 notifies the AP to turn on the first DC drive unit;

[0099] S410, after starting the first DC driving module, the NFC device 100 generates a directional constant magnetic field;

[0100] S412, aligning the magnetic attraction force generated by the constant magnetic field to the NFC sensing area;

[0101] S414, the NFC device 100 starts working communication;

[0102] S416, communication is completed and the magnetic field is removed;

[0103] S418, the NFC processor 31 notifies the AP to turn off the first DC driving module after detecting that the magnetic field is weakened;

[0104] S420, triggering an NFC high frequency alternating magnetic field off event (field off).

[0105] The field strength detection function of NFC devices is a technology that detects the strength of NFC signals. It can determine the distance and interaction status between NFC devices by measuring the strength of the electromagnetic field transmitted between them.

[0106] By utilizing the magnetic field detection function of the NFC device 100, after detecting the existence of an external 13.56MHz magnetic field, the system is notified to start the first DC driving module to generate a DC driving voltage, so that the NFC device 100 generates a constant magnetic field and generates a magnetic attraction with the constant magnetic field of the external device, helping the user to align with the NFC sensing area.

[0107] In addition, the magnetic field detection function of the NFC device 100 itself is activated only when the NFC-specific 13.56 MHz magnetic field is detected, which can be used to avoid the problem of false triggering of NFC communication.

[0108] In an embodiment of the present application, the coil antenna includes a first sub-antenna and a second sub-antenna that are insulated from each other. The first sub-antenna connected to the differential full-bridge driver module generates a high-frequency AC magnetic field for near-field communication based on an AC drive signal, and the second sub-antenna connected to the first DC driver module generates a constant magnetic field based on a DC drive signal. Therefore, when two NFC devices perform near-field communication, a magnetic attraction force is generated based on the constant magnetic field between the two to attract one of the NFC devices to be placed in the optimal sensing area of ​​the other NFC device, and the two NFC devices are accurately and quickly aligned, thereby successfully performing near-field communication and improving the working efficiency of the card reading or card simulation mode.

[0109] In another embodiment, the present application also provides a near field communication NFC device, referring to Figure 7The near field communication NFC device includes: a differential full-bridge driving module 10, a first DC driving module 20 and a coil antenna 50, wherein the differential full-bridge driving module 20 is used to output an AC driving voltage; the first DC driving module 20 is used to output a first DC driving voltage; the coil antenna 50 includes a first sub-antenna 52 and a second sub-antenna 54, wherein the first sub-antenna 52 and the second sub-antenna 54 are connected in series and nested, and the second sub-antenna 54 is connected to the differential full-bridge driving module 10 to generate a high-frequency alternating magnetic field based on the AC driving voltage, and the first sub-antenna 52 and the second sub-antenna 54 connected in series are connected to the first DC driving module 20 to generate a constant magnetic field in a first direction based on the first DC driving voltage.

[0110] In this embodiment, the coil antenna 50 includes a first sub-antenna 52 and a second sub-antenna 54, which are connected in series and nested. Specifically, the second sub-antenna 54 is connected to the differential full-bridge drive module 10, receives an AC drive voltage to generate a high-frequency alternating magnetic field, and the first sub-antenna 52 and the second sub-antenna 54 connected in series are connected to the first DC drive module 20, and receive a first DC drive voltage to generate a constant magnetic field.

[0111] refer to Figure 8 and Fig. 9 , one end of the second sub-antenna 54 receives the DC driving voltage output by the first DC driving module 20, and the other end of the second sub-antenna 54 is connected to one end of the first sub-antenna 52 at point a, that is, the end of the second sub-antenna 54 corresponds to the starting end of the first sub-antenna 52, and the second sub-antenna 54 is connected in series with the first sub-antenna 52. For example, if the second sub-antenna group 54 has n coils and the first sub-antenna 52 has m coils, then the second sub-antenna 54 corresponds to (n+m) coils. Then, one end of the second sub-antenna 54 receives the DC driving voltage, which flows through the second sub-antenna 54 and the first sub-antenna 52 connected in series to generate a constant magnetic field, and the DC corresponding to the constant magnetic field flows out through the other end of the first sub-antenna 52 and is grounded through the second inductor L2, forming a DC transmission path.

[0112] The constant magnetic field used for magnetic attraction requires more coils to generate a larger field strength. Therefore, by connecting the first sub-antenna 52 and the second sub-antenna 54 in series to generate a constant magnetic field, the magnetic attraction performance can be improved, which facilitates the rapid alignment of the two communicating NFC devices.

[0113] The second sub-antenna 54 is also connected to the differential full-bridge driving module 10 , so the high-frequency alternating magnetic field generated by the second sub-antenna 54 based on the AC driving voltage provided by the differential full-bridge driving module 10 is used for the NFC device 100 to send data to the first NFC device 200 at the opposite end.

[0114] Combination Figure 8, one end of the second sub-antenna 54 connected to the first DC driving module 20 is also connected to one end of the differential full-bridge driving module 10, and the other end of the second sub-antenna 54 connected to the first sub-antenna 52 at point a is also connected to the other end of the differential full-bridge driving module 10. The second sub-antenna 54 receives the AC driving voltage generated by the differential full-bridge driving module 10, thereby generating a high-frequency alternating magnetic field.

[0115] The differential full-bridge driver module 10 here may have the same Figures 1 to 3 The circuit structure of the differential full-bridge driving module in the NFC device of the embodiment is the same as that of the differential full-bridge driving module in the embodiment. Regarding the principle of the second sub-antenna 54 in this embodiment generating a high-frequency alternating magnetic field according to the AC driving voltage of the differential full-bridge driving module 10, reference can be made to the above Figures 1 to 3 The first sub-antenna 52 connected to the differential full-bridge driving module 10 in the embodiment will not be described in detail here.

[0116] If the second sub-antenna 54 has n coils and the first sub-antenna 52 has m coils, the n coils corresponding to the second sub-antenna 54 generate a high-frequency alternating magnetic field for the NFC device 100 to send data to the first NFC device 200 .

[0117] In the card reading mode, the NFC device 100 sends data to the first NFC device 200. In the card reading mode, the coil windings need to be as few as possible, so the n coils connected to the second sub-antenna 54 generate a high-frequency alternating magnetic field, which can reduce impedance and inductance, and improve the working efficiency of NFC card reading.

[0118] In one embodiment, the first sub-antenna 52 and the second sub-antenna 54 generate a high-frequency alternating magnetic field based on the AC driving voltage provided by the differential full-bridge driving module 10 , so as to enable the NFC device 100 to receive the data sent by the first NFC device 200 .

[0119] The NFC device 100 further includes a receiving module connected to at least one of the first end of the second sub-antenna 54 and the second end of the first sub-antenna 52 , and configured to receive data by detecting a voltage at a corresponding sub-antenna connection end.

[0120] In this embodiment, the NFC device 100 includes a receiving module connected to one end of the sub-antenna to implement single-end detection of a voltage signal at the corresponding connected sub-antenna end.

[0121] In one embodiment, Figure 8As shown, the receiving module includes a first receiving unit RXP and a second receiving unit RXN, the first receiving unit RXP is connected to the first end of the second sub-antenna 54, and is used to detect the first voltage at the first end of the second sub-antenna 54; the second receiving unit RXN is connected to the second end of the first sub-antenna 52, and is used to detect the second voltage at the second end of the first sub-antenna 52; wherein the receiving module receives data based on the detected first voltage and second voltage.

[0122] The receiving module is used when the NFC device 100 is in the card emulation mode, and receives data sent by the first NFC device 200 by detecting the carrier voltage sent by the first NFC device 200 received at both ends of the second sub-antenna 54 and the first sub-antenna 52 connected in series.

[0123] like Figure 8 As shown, in this embodiment, the first receiving unit RXP is indirectly connected to the first end of the second sub-antenna 54 through the sixth capacitor C12, and the voltage detected at the first end of the second sub-antenna 54 is the attenuated voltage of the first end of the second sub-antenna 54. The second receiving unit RXN is directly connected to the second end of the first sub-antenna 52, and the voltage of the first end of the first sub-antenna 52 is detected.

[0124] Combination Figure 8 The voltages detected by the first receiving unit RXP and the second receiving unit RXN are respectively processed by a bias module B, an automatic gain control module AGC, an analog-to-digital conversion module ADC, etc., and then input into the NFC processor 31 inside the NFC device. The data sent by the first NFC device 200 is received during the communication between the NFC device 100 and the first NFC device 200 according to the detected voltages.

[0125] Two ends of the second sub-antenna 54 are connected to two ends of the differential full-bridge driving module 10 respectively, and the other end of the second sub-antenna 54 is also connected in series with the first sub-antenna 52 at point a. In addition to being grounded through the second inductor L2, the other end of the first sub-antenna 52 is also connected to the second receiving unit RXN of the receiving module. The second sub-antenna 54 generates a high-frequency alternating magnetic field according to the AC driving voltage of the differential full-bridge driving module 10.

[0126] If the second sub-antenna 54 has n coils and the first sub-antenna 52 has m coils, the (n+m) coils corresponding to the second sub-antenna 54 and the first sub-antenna 52 connected in series generate a high-frequency alternating magnetic field for the NFC device 100 to receive the data sent by the first NFC device 200.

[0127] In the card emulation mode, the NFC device 100 receives the data sent by the first NFC device 200. In the card emulation mode, as many coil windings as possible are required. Therefore, the (n+m) coils corresponding to the second sub-antenna 54 and the first sub-antenna 52 connected in series generate a high-frequency alternating magnetic field, which can enhance the mutual inductance and improve the success rate of NFC card swiping.

[0128] In this embodiment, the first sub-antenna 52 and the second sub-antenna 54 are coil windings connected in series and are designed to be in a three-tap form. For example, the coil antenna 50 is made into a three-tap form by using the first contact spring 81, the second contact spring 82 and the third contact spring 83. One end of the second sub-antenna 54 is connected to one end of the differential full-bridge driver module 10 through the first contact spring 81, the other end of the second sub-antenna 54 is connected to the other end of the differential full-bridge driver module 10 through the second contact spring 82, and one end of the first sub-antenna 52 is connected to the receiving module through the third contact spring 83.

[0129] The first sub-antenna 52 and the second sub-antenna 54 connected in series are respectively connected to the corresponding driving modules, and an alternating magnetic field and a constant magnetic field are generated in the corresponding coils, which are respectively used for data transmission and reception between the NFC device 100 and the first NFC device 200, and for generating a magnetic attraction force F between the NFC device 100 and the first NFC device 200, so as to achieve rapid alignment of the NFC sensing areas of the NFC device 100 and the first NFC device 20, thereby successfully performing near field communication and improving the working efficiency of the card reading or card emulation mode.

[0130] In this embodiment, by designing the coil antenna 50 into a three-tap form, a large number of coil windings are used in the NFC device card reading mode and when generating magnetic attraction, the card swiping success rate and the magnetic attraction can be improved. In the NFC device card simulation mode, a small number of coil windings are used to improve the card reading success rate. In addition, the original NFC coil body of the electronic device can be reused, and only the corresponding number of coils need to be added. The cost and space increase are very small, and it is possible to mass produce.

[0131] Different external first NFC devices 200 may generate constant magnetic fields in different directions. In order to achieve magnetic attraction between the NFC device 100 and the first NFC device 200, the directions of the constant magnetic fields generated by each device must be the same. Therefore, the NFC device 100 needs to have the function of adjusting the direction of its own magnetic field.

[0132] In this regard, refer to Fig. 9In one embodiment, the NFC device 100 further includes a second DC driving module 80 and a single-pole double-throw switch 63, wherein the moving end of the single-pole double-throw switch 63 is grounded through a second inductor L2, the first fixed end of the single-pole double-throw switch 63 is connected to the first end of the second sub-antenna 54, and the second fixed end of the single-pole double-throw switch 63 is connected to the second end of the first sub-antenna 52; the second DC driving module 80 is used to output a second DC driving voltage and is connected to the second end of the first sub-antenna 52; the first sub-antenna 52 and the second sub-antenna 54 connected in series generate a constant magnetic field in a second direction based on the second DC driving voltage, and the first direction is opposite to the second direction.

[0133] Combination Fig. 9 When the first DC driving module 20 is started, the first DC driving module 20 outputs a DC driving voltage based on the constant voltage VDD, and the corresponding DC current flows into the upper end of the second sub-antenna 54, and is grounded through the lower end of the first sub-antenna 52, the single-pole double-throw switch 63, and the second inductor L2. As a result, the second sub-antenna 54 and the first sub-antenna 52 connected in series can generate a constant magnetic field from the S polarity to the N polarity direction, that is, the S polarity direction as shown in the figure.

[0134] When the second DC driving module 80 is started, the second DC driving module 80 outputs a DC driving voltage based on the constant voltage VDD', and the corresponding DC current flows in through the lower end of the first sub-antenna 52, and is grounded through the upper end of the second sub-antenna 54, the single-pole double-throw switch 63, and the second inductor L2. Thus, the second sub-antenna 54 and the first sub-antenna 52 connected in series can generate a constant magnetic field from the N polarity to the S polarity direction, that is, the N polarity as shown in the figure.

[0135] The second DC driving module 80 provides a DC driving voltage to the second sub-antenna 54 and the first sub-antenna 52 connected in series to generate a constant magnetic field. The constant magnetic field generated by the NFC device communicating with the other end is based on the principle of attraction between opposite magnetic fields, and generates a magnetic attraction between the NFC antennas of the two NFC devices, i.e., the card reader device and the card emulation device. The magnetic attraction attracts one NFC device to be placed in the optimal sensing area of ​​the other NFC device, so that the two NFC devices are aligned.

[0136] The constant magnetic fields corresponding to the second DC driving module 80 and the first DC driving module 20 can be used to generate a constant magnetic field based on the attraction of opposite magnetic fields with the NFC device communicating with the opposite end, but the directions of the constant magnetic fields generated by the second DC driving module 80 and the first DC driving module 20 are opposite. Therefore, only one of the second DC driving module 80 and the first DC driving module 20 is started at the same time to generate a constant magnetic field with the same direction as the constant magnetic field generated by the NFC device communicating with the opposite end.

[0137] In this way, according to the direction of the constant magnetic field generated by the external first NFC device 200, the DC driving source that can generate magnetic attraction between the NFC device 100 and the first NFC device 200, that is, the second DC driving module 80 or the first DC driving module 20, can be started. As a result, the NFC device 100 has the function of adjusting the direction of its own magnetic field.

[0138] The second DC driving module 80 and the first DC driving module 20 can respectively ground the DC power of the constant magnetic field generated by the second sub-antenna 54 and the first sub-antenna 52 in series based on the corresponding constant voltage through the single-pole double-throw switch 63 and the second inductor L2, and isolate the AC power corresponding to the high-frequency alternating magnetic field of the second sub-antenna 54, thereby avoiding attenuation of the high-frequency signal and power received by the second sub-antenna 54 for NFC communication.

[0139] In the embodiment of the present application, the differential full-bridge driver module 10, the first DC driver module 20 and the second DC driver module 80 are independent driver modules. The differential full-bridge driver module 10 can be a differential full-bridge driver circuit that reuses the transceiver (TX) of the conventional NFC IC. The first DC driver module 20 and the second DC driver module 80 are driver modules that are newly added independently of the differential full-bridge driver module 10. The constant voltage VDDPA connected to the differential full-bridge driver module 10 and the constant voltage VDD connected to the first DC driver module 20 can be the same or different. The constant voltage VDD connected to the first DC driver module 20 and the constant voltage VDD' connected to the second DC driver module 80 can be the same or different. The differential full-bridge driver module 10, the first DC driver module 20 and the second DC driver module 80 can also be controlled to start and shut down by different components respectively. For example, the differential full-bridge driver module 10 is controlled by the NFC driver controller 30, and the first DC driver module 20 and the second DC driver module 80 are controlled by the application processor 70.

[0140] The constant voltage VDDPA can be obtained by processing the battery voltage VBAT through a DC-DC converter DC-DC and a low voltage drop linear regulator TXLDO, and provided to the differential full-bridge driver module 10. Similarly, in a similar manner, the constant voltage VDD and the constant voltage VDD' can be obtained based on the battery voltage VBAT, and provided to the first DC driver module 20 and the second DC driver module 80 respectively.

[0141] By setting a DC driving module on an NFC device to provide DC driving to the NFC antenna, the DC driving source is started when near field communication is required, that is, the first DC driving module 20 or the second DC driving module 80 performs DC bias to generate a constant magnetic field, so as to realize magnetic attraction to align the two NFC devices, so as to successfully perform near field communication and improve the success rate of card swiping.

[0142] Optionally, the first DC driving module 20 and the second DC driving module 80 include MOS transistors or triodes. The MOS transistors may include PMOS transistors, NMOS transistors, or a combination of the two.

[0143] The first DC driving module 20 includes a switch unit, a first end of the switch unit is connected to a constant voltage VDD, a second end of the switch unit is connected to one end of the second sub-antenna 54 , and a third end of the switch unit is connected to the application processor 70 .

[0144] The second DC driving module 80 includes a switch unit, a first end of which is connected to a constant voltage VDD′, a second end of which is connected to an end of the first antenna 52 that is not connected to the second sub-antenna 54 , and a third end of which is connected to the application processor 70 .

[0145] The switch unit included in the first DC driving module 20 and / or the second DC driving module 80 may be, for example, Figure 2 , Figure 4 The PN junction half-bridge structure including the first switch unit TX1 or the second switch unit TX2 shown in the figure may also adopt a PN junction full-bridge structure including the first switch unit TX1 and the second switch unit TX2.

[0146] In an embodiment of the present application, a high-frequency AC magnetic field for near-field communication is generated based on an AC drive signal by a second sub-antenna connected to a differential full-bridge driver module, and a constant magnetic field is generated based on a DC drive signal by a first sub-antenna and a second sub-antenna connected in series to a first DC driver module. Thus, when two NFC devices perform near-field communication, a magnetic attraction force is generated based on the constant magnetic field between the two to attract one of the NFC devices to be placed in the optimal sensing area of ​​the other NFC device, and the two NFC devices are accurately and quickly aligned, thereby successfully performing near-field communication and improving the working efficiency of the card reading or card emulation mode.

[0147] Based on the NFC device of the above structure, the present application embodiment also provides a communication method of the NFC device, which is applied to the above Figures 7 to 9 The NFC device of any embodiment, such as Fig.10 As shown, the method includes:

[0148] S212, when an external magnetic field is detected, controlling the first DC driving module to start up to output the first DC driving voltage;

[0149] S214: the first sub-antenna and the second sub-antenna connected in series generate a first constant magnetic field based on the first DC driving voltage;

[0150] S216: Perform data transmission and reception between the NFC device and a first NFC device corresponding to the external magnetic field through the high-frequency alternating magnetic field generated by the second sub-antenna based on the alternating voltage output by the differential full-bridge driving module.

[0151] In one embodiment of the present application, the differential full-bridge driver module 10 and the first DC driver module 20 can be in a normally open / normally started state, so that when performing NFC communication, the user can be guided to quickly align the NFC device with the NFC communication sensing area of ​​the peer device through the magnetic attraction generated by the first DC driver module 20. However, the normally open first DC driver module 20 will cause power consumption problems, heat problems, and magnetic interference problems to the NFC device.

[0152] Therefore, in the above embodiment, the above problem can be solved by starting the first DC driving module 20 after the external magnetic field is detected and before the NFC officially works in S212.

[0153] In one embodiment, the presence of an external magnetic field can be detected by the original Hall sensor of the NFC device. Figure 5 , I will not go into details here.

[0154] Compared with the first DC drive module normally open solution, this is conducive to reducing the high power consumption of the whole machine, increasing the user's usage time, and reducing the heat and magnetic interference of the whole machine.

[0155] The Hall sensor can be used to detect the presence of a magnetic field. In some cases, the external magnetic field detected by the Hall sensor may not be the high-frequency alternating magnetic field in which the NFC device operates. If the presence of an external magnetic field is detected and the second driving module 20 is controlled to start, the NFC may be falsely triggered.

[0156] In one embodiment, when an external magnetic field is detected, controlling the first DC drive module 20 to start to output the first DC drive voltage includes: when it is detected that the frequency of the external magnetic field is the same as the frequency of the high-frequency alternating magnetic field, controlling the first DC drive module to start to output the first DC drive voltage.

[0157] That is to say, only when the detected external magnetic field is a high-frequency alternating magnetic field for the operation of the NFC device, the AP controls the first DC driving module 20 to start.

[0158] Optionally, the method further includes: in the process of the first DC driving module outputting the first DC driving voltage, if the frequency of the detected external magnetic field is lower than a preset threshold, controlling the first DC driving module to be turned off.

[0159] That is to say, when the Hall sensor detects that the external magnetic field becomes weak, it controls the first DC driving module 20 to be turned off.

[0160] In order to improve the efficiency of NFC communication, in another embodiment, the receiving module of the NFC device can be used to detect the frequency of the external magnetic field. The specific flow chart can refer to the above Figure 6 , I will not go into details here.

[0161] By utilizing the magnetic field detection function of the NFC device 100, after detecting the existence of an external 13.56MHz magnetic field, the system is notified to start the first DC driving module to generate a DC driving voltage, so that the NFC device 100 generates a constant magnetic field and generates a magnetic attraction with the constant magnetic field of the external device, helping the user to align with the NFC sensing area.

[0162] In addition, the magnetic field detection function of the NFC device 100 itself is activated only when the NFC-specific 13.56 MHz magnetic field is detected, which can be used to avoid the problem of false triggering of NFC communication.

[0163] As described above, the first DC driving module is used as a DC driving source to drive the second sub-antenna and the first sub-antenna connected in series to generate a magnetic field in a constant direction, and perform NFC communication with a device at the opposite end that also has a constant magnetic field.

[0164] Since different external NFC devices may generate constant magnetic fields in different directions, in order to achieve magnetic attraction between two NFC devices, the directions of the constant magnetic fields generated by each device must be the same. Therefore, NFC devices need to have the function of adjusting the direction of their own magnetic fields.

[0165] Optionally, when an external magnetic field is detected, controlling the first DC drive module to start to output the first DC drive voltage includes: when it is detected that the external magnetic field is a constant magnetic field, determining the magnetic field direction of the constant magnetic field; determining a target drive module among the first DC drive module and the second DC drive module, the second DC drive module being used to output a second DC drive voltage, the DC drive voltage output by the target drive module making the direction of the constant magnetic field generated by the first sub-antenna and the second sub-antenna connected in series be the same as the direction of the external magnetic field; and controlling the target drive module to start to output the DC drive voltage.

[0166] That is, by controlling only the first DC driving module and the second DC driving module, the DC driving module can be started so that the direction of the constant magnetic field generated by the first and second sub-antennas connected in series is the same as the direction of the external constant magnetic field.

[0167] In an embodiment of the present application, the direction of the external constant magnetic field can be detected by an electronic compass, and the corresponding DC drive source can be started according to the direction of the external constant magnetic field to drive the first sub-antenna and the second sub-antenna connected in series to generate a constant magnetic field with the same direction as the external constant magnetic field.

[0168] The specific flow chart is as follows Fig.11 As shown, the following steps are included:

[0169] S602, determine whether a magnetic field is detected; this can be done through the magnetic field detection function of NFC itself or through a Hall sensor; if so, proceed to step S604, otherwise proceed to step S606;

[0170] S604, determining by an electronic compass whether the direction of the magnetic field approaching the NFC is the N pole, that is, determining the direction of the external constant magnetic field, if yes, proceeding to step 608, otherwise proceeding to step 610;

[0171] S606, keeping the first DC driving module and the second DC driving module turned off;

[0172] S608, informing the AP to start the first DC driving module 20 as a DC driving source to output a constant voltage VDD;

[0173] S610, informing the AP to start the second DC driving module 80 as a DC driving source to output a constant voltage VDD';

[0174] S612, after starting the first DC driving module 20, the NFC device generates a constant magnetic field with S polarity, for example;

[0175] S614, after starting the second DC driving module 80, the NFC device generates a constant magnetic field of N polarity;

[0176] S616, aligning the magnetic attraction force generated by the constant magnetic field to the NFC sensing area;

[0177] S618, the NFC device 100 starts working communication;

[0178] S620, communication is completed and the magnetic field is removed;

[0179] S622: After detecting that the magnetic field is weakened, notify the AP to turn off the first DC driving module or the second DC driving module to stop generating the constant magnetic field.

[0180] When external devices generate external constant magnetic fields in different directions, the direction of the constant magnetic field generated by the NFC device itself can be adjusted by detecting the direction of the external constant magnetic field. This realizes the magnetic attraction function of the NFC function, helps users quickly and accurately find the NFC sensing area for swiping / reading cards, and improves the success rate of NFC communication and the user experience.

[0181] In addition, for NFC charging scenarios, magnetic charging can be implemented to avoid the inconvenience caused by users holding the device close to charging for a long time.

[0182] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0183] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, a disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0184] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A near field communication (NFC) device, characterized in that: include: A differential full-bridge driver module, a first DC driver module and a coil antenna, The differential full-bridge driving module is used to output an AC driving voltage; The first DC driving module is used to output a first DC driving voltage; The coil antenna includes a first sub-antenna and a second sub-antenna, the first sub-antenna and the second sub-antenna are insulated and nested, the first sub-antenna is connected to the differential full-bridge drive module to generate a high-frequency alternating magnetic field based on the AC drive voltage, and the second sub-antenna is connected to the first DC drive module to generate a first constant magnetic field based on the first DC drive voltage.

2. The device according to claim 1, characterized in that The first end of the first sub-antenna is connected to the first end of the differential full-bridge driving module, and the second end of the first sub-antenna is connected to the second end of the differential full-bridge driving module; The first end of the second sub-antenna is connected to an end of the first DC driving module that outputs the first DC driving voltage, and the second end of the second sub-antenna is grounded through a second inductor.

3. The device according to claim 2, characterized in that Also includes: Receiver module, The receiving module is connected to at least one of the first end and the second end of the first sub-antenna, and is used to receive data by detecting a voltage of a corresponding connection end of the first sub-antenna.

4. A communication method of an NFC device, characterized in that: Applicable to the device according to any one of claims 1 to 3, the method comprising: When an external magnetic field is detected, controlling the first DC drive module to start up to output the first DC drive voltage; The second sub-antenna generates a first constant magnetic field based on the first DC driving voltage; Data is transmitted and received between the NFC device and a first NFC device corresponding to the external magnetic field through the high-frequency alternating magnetic field generated by the first sub-antenna based on the AC driving voltage output by the differential full-bridge driving module.

5. The method according to claim 4, characterized in that In the case where an external magnetic field is detected, controlling the first DC driving module to start up to output the first DC driving voltage includes: When it is detected that the frequency of the external magnetic field is the same as the frequency of the high-frequency alternating magnetic field, the first DC driving module is controlled to start up to output the first DC driving voltage.

6. The method according to claim 5, characterized in that Also includes: During the process of the first DC driving module outputting the first DC driving voltage, if the detected frequency of the external magnetic field is lower than a preset threshold, the first DC driving module is controlled to be turned off.

7. A near field communication (NFC) device, characterized in that: include: A differential full-bridge driver module, a first DC driver module and a coil antenna, The differential full-bridge driving module is used to output an AC driving voltage; The first DC driving module is used to output a first DC driving voltage; The coil antenna includes a first sub-antenna and a second sub-antenna, the first sub-antenna and the second sub-antenna are connected in series and nested, the second sub-antenna is connected to the differential full-bridge drive module to generate a high-frequency alternating magnetic field based on the AC drive voltage, and the first sub-antenna and the second sub-antenna connected in series are connected to the first DC drive module to generate a constant magnetic field in a first direction based on the first DC drive voltage.

8. The device according to claim 7, characterized in that The first end of the second sub-antenna is respectively connected to the first end of the differential full-bridge driving module and the end of the first DC driving module outputting the first DC driving voltage, and the second end of the second sub-antenna is connected to the first end of the first sub-antenna and the second end of the differential full-bridge driving module; The second end of the first sub-antenna is grounded through a second inductor.

9. The device according to claim 8, characterized in that Also includes: Receiver module, The receiving module is connected to at least one of the first end of the second sub-antenna and the second end of the first sub-antenna, and is used to receive data by detecting the voltage of the corresponding sub-antenna connection end.

10. The device according to claim 9, characterized in that The receiving module includes a first receiving unit and a second receiving unit. The first receiving unit is connected to the first end of the second sub-antenna, and is used to detect a first voltage at the first end of the second sub-antenna; The second receiving unit is connected to the second end of the first sub-antenna, and is used to detect a second voltage at the second end of the first sub-antenna; The receiving module receives data based on the detected first voltage and the second voltage.

11. The device according to any one of claims 7 to 10, characterized in that It also includes a second DC drive module and a single-pole double-throw switch, The moving end of the single-pole double-throw switch is grounded through a second inductor, the first fixed end of the single-pole double-throw switch is connected to the first end of the second sub-antenna, and the second fixed end of the single-pole double-throw switch is connected to the second end of the first sub-antenna; The second DC driving module is used to output a second DC driving voltage and is connected to the second end of the first sub-antenna; The first sub-antenna and the second sub-antenna connected in series generate a constant magnetic field in a second direction based on the second DC driving voltage, and the first direction is opposite to the second direction.

12. The device according to claim 11, characterized in that The first DC driving module and the second DC driving module include MOS tubes or triodes.

13. A communication method of an NFC device, characterized in that: Applicable to the device according to any one of claims 7 to 12, the method comprising: When an external magnetic field is detected, controlling the first DC drive module to start up to output the first DC drive voltage; The first sub-antenna and the second sub-antenna connected in series generate a first constant magnetic field based on the first DC driving voltage; Data is transmitted and received between the NFC device and the first NFC device corresponding to the external magnetic field through the high-frequency alternating magnetic field generated by the second sub-antenna based on the AC driving voltage output by the differential full-bridge driving module.

14. The method according to claim 13, characterized in that In the case where an external magnetic field is detected, controlling the first DC driving module to start up to output the first DC driving voltage includes: When it is detected that the frequency of the external magnetic field is the same as the frequency of the high-frequency alternating magnetic field, the first DC driving module is controlled to start up to output the first DC driving voltage.

15. The method according to claim 14, characterized in that Also includes: During the process of the first DC driving module outputting the first DC driving voltage, if the detected frequency of the external magnetic field is lower than a preset threshold, the first DC driving module is controlled to be turned off.

16. The method according to claim 13, characterized in that The near field communication NFC device further includes a second DC drive module and a single-pole double-throw switch, and when an external magnetic field is detected, the first DC drive module is controlled to start to output the first DC drive voltage, including: When the external magnetic field is detected to be a constant magnetic field, determining the magnetic field direction of the constant magnetic field; Determine a target driving module in the first DC driving module and the second DC driving module, wherein the second DC driving module is used to output a second DC driving voltage, and the DC driving voltage output by the target driving module is to make the direction of the constant magnetic field generated by the first sub-antenna and the second sub-antenna connected in series be the same as the direction of the external magnetic field; The target driving module is controlled to start up to output the DC driving voltage.

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