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, a coil antenna, an NFC drive controller and an application processor, wherein the NFC drive controller is connected to the differential full-bridge drive module and is used to control the differential full-bridge drive module to output an AC drive voltage; the first DC drive module is used to output a first DC drive voltage; the application processor is connected to the first DC drive module and is used to control the activation or shutdown of the first DC drive module; the coil antenna is respectively connected to the differential full-bridge drive module and the first DC drive module, and is used to generate a high-frequency alternating magnetic field based on the AC drive voltage, and to generate a constant magnetic field in a first direction 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, a coil antenna, an NFC drive controller, and an application processor.

[0007] The NFC drive controller is connected to the differential full-bridge drive module and is used to control the differential full-bridge drive module to output an AC drive voltage;

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

[0009] an application processor, connected to the first DC driving module, and used to control the activation or deactivation of the first DC driving module;

[0010] The coil antenna is connected to the differential full-bridge drive module and the first DC drive module respectively, and is used to generate a high-frequency alternating magnetic field based on the AC drive voltage, and to generate a constant magnetic field in a first direction based on the first DC drive voltage.

[0011] 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:

[0012] In the case of detecting an external magnetic field, controlling the first DC drive module to start up through the application processor to output the first DC drive voltage;

[0013] The coil antenna generates a first constant magnetic field based on the first DC driving voltage;

[0014] 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 coil antenna based on the alternating driving voltage output by the differential full-bridge driving module.

[0015] In an embodiment of the present application, a differential full-bridge drive module is used to drive a coil antenna to generate a high-frequency AC magnetic field for near-field communication based on an AC drive signal, and a first DC drive module is used to drive a coil antenna to generate a constant magnetic field for magnetic attraction based on a DC drive signal. 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 simulation mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural block diagram of an NFC device according to an embodiment of the present application.

[0017] Figure 2 It is a circuit structure diagram of the NFC device of the first embodiment of the present application.

[0018] Figure 3 It is a schematic diagram of an application scenario of an NFC device according to the first embodiment of the present application.

[0019] Figure 4 It is a circuit structure diagram of an NFC device according to the second embodiment of the present application.

[0020] Figure 5 is a flow chart of a communication method of an NFC device according to an embodiment.

[0021] Figure 6 It is a flow chart of a communication method of an NFC device according to a specific embodiment of the present application.

[0022] Figure 7 It is a flow chart of a communication method of an NFC device according to another specific embodiment of the present application.

[0023] Figure 8 This is a flow chart of a communication method of an NFC device according to another embodiment of the present application. DETAILED DESCRIPTION

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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 driver module 10, a first DC driver module 20, a coil antenna 50, an NFC driver controller 30 and an application processor 70, wherein the NFC driver controller 30 is connected to the differential full-bridge driver module 10 and is used to control the differential full-bridge driver module 10 to output an AC drive voltage; the first DC driver module 20 is used to output a first DC drive voltage; the application processor 70 is connected to the first DC driver module 20 and is used to control the activation or deactivation of the first DC driver module 20; the coil antenna 50 is respectively connected to the differential full-bridge driver module 10 and the first DC driver module 20, and is used to generate a high-frequency alternating magnetic field based on the AC drive voltage, and to generate a constant magnetic field in a first direction based on the first DC drive voltage.

[0028] In this embodiment, the differential full-bridge driver module 10 is controlled by a driver controller 30 built into the NFC chip (IC) of the NFC device, and the NFC chip (IC) is a component dedicated to near field communication. After the driver controller 30 controls the activation of the differential full-bridge driver module 10, an AC driving voltage is generated, which is provided to the coil antenna 50 to generate a 13.56MHz high-frequency AC magnetic field, thereby enabling data transmission and reception between two NFC devices, namely, the card reader device and the card emulation device.

[0029] 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.

[0030] The first DC driving module 20 may be controlled by an application processor 70 different from the NFC driving controller 30. The application processor 70 may be a main processor of the NFC device 100, independent of the NFC IC. After the application processor 70 enables the first DC driving module 20, a DC driving voltage is generated, and the corresponding current path is provided to the coil antenna 50 along the direction of the dashed arrow in the figure 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 the 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, so that the two NFC devices are aligned.

[0031] In the embodiment of the present application, a DC driving module is provided on an NFC device to provide a DC driving source to the NFC antenna, thereby starting the DC driving source when near field communication is required, that is, the first DC driving module performs DC bias to generate a constant magnetic field, thereby realizing magnetic attraction to align the two NFC devices, so that near field communication can be successfully performed and the success rate of card swiping can be improved.

[0032] Combination Figure 2 Optionally, the first DC driving module 20 includes a third switch unit, a first end of the third switch unit is connected to a constant voltage VDD, a second end of the third switch unit is connected to any one of the first end and the second end of the coil antenna 50, and a third end of the third switch unit is connected to the application processor 70; wherein the application processor 70 is used to control the conduction and disconnection of the third switch unit, one end of the coil antenna 50 is connected to the second end of the third switch unit, and the other end of the coil antenna 50 is grounded through a second inductor L2.

[0033] The first DC driving module 20 is used as a DC driving source to generate a constant current on the coil antenna 50, so as to obtain a constant magnetic field, thereby generating a magnetic attraction with the constant magnetic field generated by another NFC device communicating with the outside, and helping to align the NFC sensing areas corresponding to the coil antennas of the two NFC devices.

[0034] In one embodiment, the third switch unit includes a MOS tube or a triode. The MOS tube may include a PMOS tube, an NMOS tube, or a combination of the two.

[0035] The current path corresponding to the current generated by the DC driving voltage output by the first DC driving module 20 is as follows: Figure 2 As shown by the dotted arrow, the current enters from one end of the coil antenna 50, is transmitted in the circuit formed by the windings of the coil antenna 50, generates a constant magnetic field, and finally is grounded from the other end of the coil antenna 50 through the second inductor L2 to form the required current path.

[0036] Because the coil antenna 50 itself also receives the 13.56 MHz high-frequency signal used for NFC communication, directly grounding the other end of the coil antenna 50 will cause signal and power attenuation. Therefore, in one embodiment, the NFC device also includes a second inductor L2, which is arranged between the grounded end of the coil antenna 50 and the ground, and is used to ground the direct current corresponding to the constant magnetic field of the coil antenna 50, and to isolate the alternating current corresponding to the high-frequency alternating magnetic field of the coil antenna 50.

[0037] The second inductor L2 is used to isolate high-frequency signals and pass direct current, thereby preventing the other end of the coil antenna 50 from being directly grounded, thereby preventing the attenuation of high-frequency signals and power.

[0038] Combination Figure 2 The differential full-bridge driving module 10 includes: a first driving module and a second driving module.

[0039] 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 a first constant voltage, 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, for alternately turning 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 coil antenna 50 to provide the first AC driving voltage to the coil antenna 50.

[0040] The second driving module includes: a second switch unit TX2 and a second matching unit, wherein a first end of the second switch unit TX2 is connected to a second constant voltage, a second end of the second switch unit TX2 is connected to the NFC driving controller 30, and a third end of the second switch unit TX2 is connected to the second matching unit, for alternately turning on and off the second constant voltage 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 coil antenna 50 to provide the second AC driving voltage to the coil antenna 50.

[0041] In the embodiment of the present application, the differential full-bridge driver module 10 can be a differential full-bridge driver circuit that reuses the transceiver (TX) of a conventional NFC IC. The first DC driver module 20 is a driver module that is newly added independent of the differential full-bridge driver module 10. The first constant voltage connected to the first switch unit TX1 of the differential full-bridge driver module 10 and the second constant voltage connected to the second switch unit TX2 of the differential full-bridge driver module 10 can be the same or different. Figure 2 As shown, the first constant voltage and the second constant voltage are the same, both are voltage VDDPA. The constant voltage VDD connected to the first DC drive module 20 can be the same as or different from the constant voltage connected to the differential full-bridge drive module 10. In addition, the differential full-bridge drive module 10 and the first DC drive module 20 can be controlled to start and stop by different components respectively.

[0042] 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 LDO, and provided to the switch unit corresponding to the differential full-bridge driver module 10. Similarly, in a similar manner, the constant voltage VDD can be obtained based on the battery voltage VBAT and provided to the first DC driver module 20.

[0043] Next, combine Figure 2 The circuit structure of an NFC device according to an embodiment of the present application is described.

[0044] like Figure 2 As shown, the first switch unit 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.

[0045] The first end of the first switch tube 101 is connected to the first constant voltage, 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.

[0046] 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.

[0047] The first end of the third inductor L21 is connected to the third end of the first switch tube 101 and the first end of the second switch tube 103 respectively, the second end of the third inductor is connected to the fifth capacitor C11 and the sixth capacitor C12 respectively, and the second end of the fifth capacitor C11 is grounded.

[0048] 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 the first end of the coil antenna 50. The first end of the seventh capacitor C13 is respectively connected to the second end of the sixth capacitor C12 and the first end of the coil antenna 50, and the second end of the seventh capacitor C13 is grounded. 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.

[0049] 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.

[0050] The first end of the third switch tube 203 is connected to the second constant voltage, the second end of the third switch tube 203 is connected to the NFC drive controller 30, and the third end of the third switch tube 203 is connected to the fourth switch tube 205 and the fourth inductor L22 respectively. The 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 respectively, the second end of the fourth switch tube 205 is connected to the NFC drive controller 30, and the third end of the fourth switch tube 205 is grounded.

[0051] The first end of the fourth inductor L22 is connected to the third end of the third switch tube 203 and the first end of the fourth switch tube 205 respectively, the second end of the fourth inductor L22 is connected to the eighth capacitor C21 and the ninth capacitor C22 respectively, and the second end of the eighth capacitor C21 is grounded.

[0052] The first end of the ninth capacitor C22 is connected to the second end of the fourth inductor L22 and the first end of the eighth capacitor C21, respectively, 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 connected to the second end of the ninth capacitor C22 and the second end of the coil antenna 50, respectively, and the second end of the tenth capacitor C23 is grounded. 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.

[0053] In one embodiment, one of the first switch tube 101 and the second switch tube 103 of the first switch unit TX1 is a PMOS tube and the other is an NMOS tube. The first switch unit TX1 corresponds to the first driving module of the upper half bridge of the differential full-bridge driving module 10 .

[0054] Correspondingly, one of the third switch tube 203 and the fourth switch tube 205 of the second switch unit TX2 is a PMOS tube, and the other is an NMOS tube. The second switch unit TX2 corresponds to the second driving module of the lower half bridge of the differential full-bridge driving module 10. The first switch tube 101, the second switch tube 103, the third switch tube 203 and the fourth switch tube 205 form a differential full-bridge driving circuit structure of a PN junction.

[0055] The NFC driving controller 30 controls the differential full-bridge driving module 10 to output an AC driving voltage by controlling the on and off of the first switch tube 101 and the second switch tube 103 , and the on and off of the third switch tube 203 and the fourth switch tube 205 .

[0056] The principle of the differential full-bridge driving module 10 generating the AC driving voltage is as follows:

[0057] 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 to the coil antenna 50 in one direction through the first inductor L21 and the sixth capacitor C12.

[0058] 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 coil antenna 50 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 coil antenna 50 by the differential full-bridge drive module 10.

[0059] In the embodiment of the present application, the first driving module and the second driving module of the differential full-bridge driving module 10 are used as double-ended AC driving, and a high-frequency AC driving signal of 13.56 MHz is alternately emitted to drive the coil antenna 50 to oscillate and communicate, thereby realizing data transmission and reception between the NFC device 100 and the first NFC device 200.

[0060] In addition, a first DC driving module 20 is additionally provided to serve as a DC driving source, and to send out a DC driving voltage signal, so as to generate a constant current on the coil antenna 50, thereby obtaining a constant magnetic field, and generating a magnetic attraction with the constant magnetic field of the external first NFC device 200, so as to achieve alignment of the antenna NFC sensing areas between the NFC device 100 and the first NFC device 200.

[0061] The third switch unit may adopt a PN junction half-bridge structure including the first switch unit TX1 or the second switch unit TX2, or may adopt a PN junction full-bridge structure including the first switch unit TX1 and the second switch unit TX2.

[0062] 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 in the direction from S polarity to N polarity as shown in the figure, and the first NFC device 200 generates a magnetic field in the direction from S polarity to N polarity as shown in the figure. The two constant magnetic fields have the same direction, thereby generating a magnetic attraction force F, and realizing the alignment of the NFC sensing areas between the two devices.

[0063] When the NFC device 100 and the first NFC device 200 have the same circuit structure, after the NFC drive controller 30 controls the differential full-bridge drive module 10 to start, an AC drive voltage signal is provided to the coil antenna 50. After the NFC drive controller 30 controls the first DC drive module 20 to start, the constant voltage VDD is directly input to one end of the coil antenna 50, and flows out from the other end and is grounded after being isolated by the second inductor L2.

[0064] The NFC device 100 and the first NFC device 200 can generate a magnetic attraction F between each other through the above circuit structure, accurately align with the NFC sensing area through the magnetic attraction F, and successfully perform NFC communication.

[0065] Combination Figure 2 In one embodiment, the NFC device 100 further includes a receiving module, the receiving module including a first receiving unit RXP and a second receiving unit RXN, the first receiving unit RXP is connected to the first end of the coil antenna 50, and is used to detect a first voltage at the first end of the coil antenna 50, the second receiving unit RXN is connected to the second end of the coil antenna 50, and is used to detect a second voltage at the second end of the coil antenna 50, wherein the receiving module receives data based on the detected first voltage and the second voltage.

[0066] 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 coil antenna 50 .

[0067] like Figure 2 and Figure 3 As shown, in this embodiment, the first receiving unit RXP is indirectly connected to the first end of the coil antenna 50 through the sixth capacitor C12, and the voltage detected at the first end of the coil antenna 50 is the attenuated voltage of the first end of the coil antenna 50. The second receiving unit RXN is indirectly connected to the second end of the coil antenna 50 through the ninth capacitor C22, and the voltage of the second end of the coil antenna 50 is detected.

[0068] Combination Figure 2 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.

[0069] 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 opposite. Therefore, the NFC device 100 needs to have the function of adjusting the direction of its own magnetic field.

[0070] In this regard, refer to Figure 4In 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 one end of the coil antenna 50, and the second fixed end of the single-pole double-throw switch 63 is connected to the other end of the coil antenna 50; the second DC driving module 80 is used to output a second DC driving voltage and is respectively connected to the application processor 70 and the coil antenna 50; the application processor 70 is also used to control the activation or deactivation of the second DC driving module 80; the coil antenna 50 generates 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.

[0071] The second DC driving module 80 is connected to a constant voltage VDD', and is used to output a DC driving voltage based on the connected constant voltage VDD', so that the direction of the constant magnetic field generated in the coil antenna 50 is opposite to the direction of the magnetic field generated in the coil antenna 50 by the first DC driving module 20 based on the connected constant voltage VDD.

[0072] The second DC driving module 80 and the first DC driving module 20 can be both controlled by the application processor 70 , and the application processor 70 only starts one of the second DC driving module 80 and the first DC driving module 20 at the same time.

[0073] Combination Figure 4 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 coil antenna 50 and is grounded through the lower end of the coil antenna 50, the single-pole double-throw switch 63 and the second inductor L2. As a result, the coil antenna 50 can generate a constant magnetic field from the S polarity to the N polarity direction as shown in the figure.

[0074] 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 into the lower end of the coil antenna 50 and is grounded through the upper end of the coil antenna 50, the single-pole double-throw switch 63 and the second inductor L2. As a result, the coil antenna 50 can generate a constant magnetic field from the S polarity to the N polarity direction as shown in the figure.

[0075] After the application processor 70 enables the second DC driving module 80, the second DC driving module 80 provides a DC driving voltage to the coil antenna 50 to generate a constant magnetic field. The constant magnetic field generated by the NFC device communicating with the other end generates a magnetic attraction between the NFC antennas of the two NFC devices, i.e., the card reader device and the card emulation device, based on the principle that opposite magnetic fields attract each other. 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.

[0076] The constant magnetic field generated by the second DC driving module 80 and the first DC driving module 20 can both be used to generate a constant magnetic field based on the attraction of opposite magnetic fields with the constant magnetic field generated by 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, the application processor 70 only starts the direction of the constant magnetic field generated by the second DC driving module 80 and the first DC driving module 20 at the same time, which is opposite to the constant magnetic field generated by the NFC device communicating with the opposite end.

[0077] In this way, the DC driving source, the second DC driving module 80 or the first DC driving module 20 that can generate magnetic attraction between the NFC device 100 and the first NFC device 200 can be activated according to the direction of the constant magnetic field generated by the external first NFC device 200. That is, the NFC device 100 has the function of adjusting the direction of its own magnetic field.

[0078] Optionally, the second DC driving module 80 includes a fourth switch unit, a first end of the fourth switch unit is connected to a constant voltage VDD', a second end of the fourth switch unit is connected to an end of the coil antenna 50 that is not connected to the second end of the third switch unit, and a third end of the fourth switch unit is connected to the application processor 70. The application processor 70 is used to control the conduction and disconnection of the fourth switch unit, one end of the coil antenna 50 is connected to an end of the fourth switch unit that outputs a DC driving voltage signal, and the other end of the coil antenna 50 is grounded through the single-pole double-throw switch 63 and the second inductor L2.

[0079] The second DC driving module 80 is used as a DC driving source to generate a constant current on the coil antenna 50 based on the DC driving voltage generated by the constant voltage VDD', so as to obtain a constant magnetic field, thereby generating a magnetic attraction with the constant magnetic field generated by another NFC device communicating with the outside, and helping to align the NFC sensing areas corresponding to the coil antennas of the two NFC devices.

[0080] In one embodiment, the fourth switch unit includes a MOS transistor or a triode. The MOS transistor may include a PMOS transistor, an NMOS transistor, or a combination of the two.

[0081] The fourth switch unit may have the same structure as the third switch unit, for example, Figure 2 , Figure 4 The PN junction half-bridge structure of the first switch unit TX1 or the second switch unit TX2 may also be used, or a PN junction full-bridge structure including the first switch unit TX1 and the second switch unit TX2 may be used.

[0082] Similarly, through the single-pole double-throw switch 63 and the second inductor L2, the DC power corresponding to the constant magnetic field generated by the coil antenna 50 based on the DC driving voltage provided by the second DC driving module 80 can be grounded, and the AC power corresponding to the high-frequency alternating magnetic field of the coil antenna 50 can be isolated, thereby avoiding attenuation of the high-frequency signal and power received by the coil antenna 50 for NFC communication.

[0083] In an embodiment of the present application, the AC drive signal provided by the differential full-bridge drive module drives the coil antenna to generate a high-frequency AC magnetic field for near-field communication, and the DC drive signal provided by the first DC drive module drives the coil antenna to generate a constant magnetic field for magnetic attraction. 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.

[0084] 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 1 to 4 An NFC device of an embodiment, such as Figure 5 As shown, the method includes:

[0085] S202, when an external magnetic field is detected, controlling the first DC drive module to start up through the application processor to output the first DC drive voltage;

[0086] S204, the coil antenna generates a first constant magnetic field based on the first DC driving voltage;

[0087] S206: Perform data transmission and reception between the NFC device and the first NFC device through the high-frequency alternating magnetic field generated by the coil antenna based on the AC driving voltage output by the differential full-bridge driving module.

[0088] 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.

[0089] 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.

[0090] In one embodiment, the presence of an external magnetic field can be detected by the original Hall sensor of the NFC device. Figure 6 As shown, the following steps are included:

[0091] S302, detect the magnetic field through Hall IC (Hall sensor), if yes, proceed to step S304, otherwise proceed to step S306;

[0092] S304, notifying an application processor (AP) to start a first DC driving module;

[0093] S306, keeping the first DC drive module turned off;

[0094] S308, after starting the first DC driving module, the NFC device 100 generates a directional constant magnetic field;

[0095] S310, aligning the magnetic attraction force generated by the constant magnetic field to the NFC sensing area;

[0096] S312, communication is completed and the magnetic field is removed;

[0097] S314: After detecting that the magnetic field is weakened, the AP is notified to turn off the first DC driving module.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] In one embodiment, when an external magnetic field is detected, the first DC drive module is controlled by the application processor to start to output the first DC drive voltage, including: 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 drive module is controlled by the application processor to start to output the constant voltage.

[0102] That is to say, the application processor controls the first DC driving module 20 to start only when the detected external magnetic field is a high-frequency alternating magnetic field for the operation of the NFC device.

[0103] 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 by the application processor.

[0104] That is to say, when the Hall sensor detects that the external magnetic field becomes weak, the application processor controls the first DC driving module 20 to be turned off.

[0105] 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.

[0106] To improve the efficiency of NFC communication, in another embodiment, the receiving module of the NFC device 100 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 coil antenna 50, and the NFC processor 31 can obtain the frequency of the external magnetic field by detecting the voltage.

[0107] The specific flow chart is as follows Figure 7 As shown, the following steps are included:

[0108] S402, the NFC processor 31 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;

[0109] S404, triggering an NFC high-frequency alternating magnetic field opening event (field on);

[0110] S406, keeping the first DC drive module turned off;

[0111] S408, the NFC processor 31 notifies the AP to turn on the first DC drive unit;

[0112] S410, after starting the first DC driving module 20, the NFC device 100 generates a directional constant magnetic field;

[0113] S412, aligning the magnetic attraction force generated by the constant magnetic field to the NFC sensing area;

[0114] S414, the NFC device 100 starts working communication;

[0115] S416, communication is completed and the magnetic field is removed;

[0116] S418, the NFC processor 31 notifies the AP to turn off the first DC driving module after detecting that the magnetic field is weakened;

[0117] S420, triggering an NFC high frequency alternating magnetic field off event (field off).

[0118] 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.

[0119] 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.

[0120] 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.

[0121] As described above, the first DC driving module is used as a DC driving source to drive the coil antenna 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.

[0122] 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.

[0123] 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 coil antenna the same as the direction of the external magnetic field; and controlling the target drive module to start to output the DC drive voltage through the application processor.

[0124] That is, the application processor only controls the DC driving module among the first DC driving module and the second DC driving module, so that the direction of the constant magnetic field generated by the coil antenna is the same as the magnetic field direction of the external constant magnetic field.

[0125] In an embodiment of the present application, the direction of the external constant magnetic field can be detected by an electronic compass, and different driving modules can be started according to the direction of the external constant magnetic field to drive the coil antenna to generate a constant magnetic field with the same direction as the external constant magnetic field.

[0126] The specific flow chart is as follows Figure 8 As shown, the following steps are included:

[0127] 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;

[0128] 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;

[0129] S606, keeping the first DC driving module 20 and the second DC driving module 80 turned off;

[0130] S608, informing the AP to start the first DC driving module 20 as a DC driving source to output a first DC driving voltage;

[0131] S610, informing the AP to start the second DC driving module 80 as a DC driving source to output a second DC driving voltage;

[0132] S612, after starting the first DC driving module 20, the NFC device generates, for example, a constant magnetic field from the S polarity to the N polarity direction, that is, the S polarity;

[0133] S614, after starting the second DC driving module 80, the NFC device generates a constant magnetic field from N polarity to S polarity, that is, N polarity;

[0134] S616, aligning the magnetic attraction force generated by the constant magnetic field to the NFC sensing area;

[0135] S618, the NFC device 100 starts working communication;

[0136] S620, communication is completed and the magnetic field is removed;

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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: Differential full-bridge driver module, first DC driver module, coil antenna, NFC driver controller, application processor, second DC driver module and single-pole double-throw switch, The NFC drive controller is connected to the differential full-bridge drive module and is used to control the differential full-bridge drive module to output an AC drive voltage; The first DC driving module is used to output a first DC driving voltage; an application processor, connected to the first DC driving module, and used to control the activation or deactivation of the first DC driving module; The coil antenna is connected to the differential full-bridge drive module and the first DC drive module respectively, and is used to generate a high-frequency alternating magnetic field based on the AC drive voltage, and to generate a constant magnetic field in a first direction based on the first DC drive voltage; 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 one end of the coil antenna, and the second fixed end of the single-pole double-throw switch is connected to the other end of the coil antenna; The second DC driving module is used to output a second DC driving voltage and is connected to the application processor and the coil antenna respectively; The application processor is also used to control the activation or deactivation of the second DC drive module; The coil antenna generates 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.

2. The device according to claim 1, characterized in that The first DC driving module includes a third switch unit, A first end of the third switch unit is connected to a constant voltage, a second end of the third switch unit is connected to any one of the first end and the second end of the coil antenna, and a third end of the third switch unit is connected to the application processor; The application processor is used to control the on and off of the third switch unit, one end of the coil antenna is connected to the second end of the third switch unit, and the other end of the coil antenna is grounded through a second inductor.

3. The device according to claim 2, characterized in that The third switch unit includes a MOS tube or a triode.

4. The device according to any one of claims 2 to 3, characterized in that The differential full-bridge driving module includes a first driving module and a second driving module; The first driving module includes: a first switch unit and a first matching unit, wherein a first end of the first switch unit is connected to a first constant voltage, a second end of the first switch unit is connected to the NFC driving controller, and a third end of the first switch unit is connected to the first matching unit, and is used to alternately turn on and off the first constant voltage and the first matching unit to generate a first AC driving voltage; the first matching unit is also connected to one end of the coil antenna to provide the first AC driving voltage to the coil antenna; The second driving module includes: a second switch unit and a second matching unit, the first end of the second switch unit is connected to a second constant voltage, the second end of the second switch unit is connected to the NFC driving controller, and the third end of the second switch unit is connected to the second matching unit, and is used to alternately turn on and off the second constant voltage 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 coil antenna to provide the second AC driving voltage to the coil antenna.

5. The device according to claim 4, characterized in that The first switch unit includes a first switch tube and a second switch tube, and the first matching unit includes a third inductor, a fifth capacitor, a sixth capacitor and a seventh capacitor; The first end of the first switch tube is connected to the first constant voltage, the second end of the first switch tube is connected to the NFC drive controller, and the third end of the first switch tube is connected to the second switch tube and the third inductor respectively; The first end of the second switch tube is connected to the third end of the first switch tube and the third inductor, the second end of the second switch tube is connected to the NFC drive controller, and the third end of the second switch tube is grounded; The first end of the third inductor is connected to the third end of the first switch tube and the first end of the second switch tube respectively, the second end of the third inductor is connected to the fifth capacitor and the sixth capacitor respectively, and the second end of the fifth capacitor is grounded; The first end of the sixth capacitor is connected to the second end of the third inductor and the first end of the fifth capacitor, and the second end of the sixth capacitor is connected to the seventh capacitor and the first end of the coil antenna respectively; The first end of the seventh capacitor is connected to the second end of the sixth capacitor and the first end of the coil antenna respectively, and the second end of the seventh capacitor is grounded; The NFC drive controller is used to control the on and off of the first switch tube and the second switch tube.

6. The device according to claim 5, characterized in that The second switch unit includes a third switch tube and a fourth switch tube, and the second matching unit includes a fourth inductor, an eighth capacitor, a ninth capacitor and a tenth capacitor; The first end of the third switch tube is connected to the second constant voltage, the second end of the third switch tube is connected to the NFC drive controller, and the third end of the third switch tube is respectively connected to the fourth switch tube and the fourth inductor; The first end of the fourth switch tube is connected to the third end of the third switch tube and the fourth inductor respectively, the second end of the fourth switch tube is connected to the NFC drive controller, and the third end of the fourth switch tube is grounded; The first end of the fourth inductor is connected to the third end of the third switch tube and the first end of the fourth switch tube respectively, the second end of the fourth inductor is connected to the eighth capacitor and the ninth capacitor respectively, and the second end of the eighth capacitor is grounded; The first end of the ninth capacitor is connected to the second end of the fourth inductor and the first end of the eighth capacitor respectively, and the second end of the ninth capacitor is connected to the tenth capacitor; The first end of the tenth capacitor is connected to the second end of the ninth capacitor and the second end of the coil antenna respectively, and the second end of the tenth capacitor is grounded; The NFC drive controller is also used to control the on and off of the third switch tube and the fourth switch tube.

7. A communication method of an NFC device, characterized in that: Applicable to the device according to any one of claims 1 to 6, the method comprising: When an external magnetic field is detected, the application processor controls the first DC drive module to start up to output the first DC drive voltage; The coil 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 coil antenna based on the alternating driving voltage output by the differential full-bridge driving module.

8. The method according to claim 7, characterized in that In the case where an external magnetic field is detected, controlling the first DC drive module to start up to output the first DC drive voltage through the application processor 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 application processor controls the first DC drive module to start up to output the first DC drive voltage.

9. The method according to claim 8, characterized in that Also includes: During 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, the first DC driving module is controlled to be turned off through the application processor.

10. The method according to claim 8, characterized in that In the case where an external magnetic field is detected, controlling the first DC drive module to start up to output the first DC drive voltage through the application processor includes: 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 drive module among the first DC drive module and the second DC drive module, wherein the second DC drive module is used to output a second DC drive voltage, and the DC drive voltage output by the target drive module is to make the direction of the constant magnetic field generated by the coil antenna the same as the direction of the external magnetic field; The target drive module is started by controlling the application processor to output the DC drive voltage.

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