Portable NFC field intensity testing device

Abstract

The utility model relates to a portable NFC (Near Field Communication) field intensity testing device, which is used for testing the field intensity of NFC equipment and comprises a PCB (Printed Circuit Board), and an NFC receiving antenna, a resonant capacitor, a Schottky chip and a voltage indicating circuit which are positioned on the PCB, the NFC receiving antenna is electrically connected with a resonant capacitor, the resonant capacitor is electrically connected with a Schottky chip, the Schottky chip is connected in series in a voltage indicating circuit used for displaying NFC field intensity, and the voltage indicating circuit comprises a plurality of light-emitting branches. Compared with the prior art, the device has the advantages of simple structure, accurate detection result, convenience in use and the like.

Description

Technical Field

[0001] The utility model relates to the field of field strength testing devices, in particular to a portable NFC field strength testing device. Background Art

[0002] NFC (near field communication), as an emerging technology developed in recent years, is widely used in electronic devices such as smart phones, bus terminals and POS machines, including mobile payment, access control and anti-counterfeiting functions. With the gradual improvement and promotion of NFC technology, it will gradually be applied to more and more usage scenarios.

[0003] Since NFC is a short-distance high-frequency wireless communication technology, it is often necessary to frequently determine whether NFC is started normally and whether the contactless field strength has reached the requirements after normal startup during product design and debugging. Currently, professional and high-precision testing equipment is usually used on the market to test NFC products, including contactless electrical testers, network analyzers, and oscilloscopes. However, the above-mentioned instruments and equipment are expensive, highly professional in operation, and cumbersome in use. They often require a lot of time and material costs in the testing process, and waste a lot of human resources.

[0004] For example, Chinese patent CN212540548U discloses a portable NFC field strength tester. The portable NFC field strength tester includes: an induction antenna, an impedance matching circuit electrically connected to the induction antenna, a rectifier filter circuit electrically connected to the impedance matching circuit, a voltage sampling circuit electrically connected to the rectifier filter circuit, a main control chip electrically connected to the voltage sampling circuit, and a field strength prompt module electrically connected to the main control chip. The NFC field strength induced voltage can be obtained through the induction antenna, and after rectification and filtering by the rectifier filter circuit, the induced voltage sample is provided to the main control chip through the voltage sampling circuit. The main control chip will derive the field strength according to the sampled induced voltage and provide a field strength prompt module. The user obtains the NFC field strength through the field strength prompt module.

[0005] However, the above-mentioned prior art converts the induced electromotive force into the field strength through the main control chip, and displays it through the structure of the display screen, and is provided with an independent power supply. The structure of the entire field strength tester is relatively complex, and the power supply needs to be charged, the use is relatively cumbersome, the cost is relatively high, and in a small space, the power supply may affect the induced voltage of the coil, thereby affecting the accuracy of the test result. Utility Model Content

[0006] The purpose of the utility model is to provide a portable NFC field strength test device in order to overcome the defects of the above-mentioned prior art that the main control chip, display screen and independent power supply are used to feedback the field strength, the structure is relatively complex and the use is relatively cumbersome.

[0007] The purpose of the utility model can be achieved through the following technical solutions:

[0008] A portable NFC field strength test device is used for testing the field strength of an NFC device. The test device comprises a PCB board, and an NFC receiving antenna, a resonant capacitor, a Schottky chip and a voltage indication circuit located on the PCB board;

[0009] The NFC receiving antenna is electrically connected to a resonant capacitor, the resonant capacitor is electrically connected to a Schottky chip, the Schottky chip is connected in series in a voltage indicating circuit for displaying the NFC field strength, and the voltage indicating circuit includes a plurality of light-emitting branches.

[0010] Preferably, the voltage indicating circuit comprises a first light-emitting branch, a second light-emitting branch and a third light-emitting branch connected in parallel.

[0011] Preferably, the first light-emitting branch includes a first buck diode, a first light-emitting diode and a first current-limiting resistor connected in series in sequence, the input end of the first buck diode is connected to the output end of the Schottky chip, and the other end of the first current-limiting resistor is connected to one end of the Schottky chip.

[0012] Preferably, the second light-emitting branch includes a second buck diode, a second light-emitting diode and a second current-limiting resistor connected in series in sequence, the input end of the second buck diode is connected to the output end of the Schottky chip, and the other end of the second current-limiting resistor is connected to one end of the Schottky chip.

[0013] Preferably, the third light-emitting branch includes a third buck diode, a third light-emitting diode and a third current-limiting resistor connected in series in sequence, the input end of the third buck diode is connected to the output end of the Schottky chip, and the other end of the third current-limiting resistor is connected to one end of the Schottky chip.

[0014] Preferably, the forward rated voltages of the first light emitting diode, the second light emitting diode and the third light emitting diode are sequentially increased in steps, and the first light emitting diode, the second light emitting diode and the third light emitting diode are sequentially distributed on the same side of the PCB board.

[0015] Preferably, the resonant capacitor is connected in parallel to two ends of the NFC receiving antenna, and the two ends of the resonant capacitor are respectively connected to a Schottky chip.

[0016] Preferably, the PCB board is a double-layer structure, and the PCB board is a rectangular structure.

[0017] Preferably, the NFC receiving antenna is located on one side of the PCB board, and the resonant capacitor, the Schottky chip and the voltage indication circuit are located on the other side of the PCB board.

[0018] Preferably, the NFC receiving antenna comprises a multi-turn coil, and the number of the coils is greater than or equal to 2.

[0019] Compared with the prior art, the utility model has the following advantages:

[0020] (1) This solution places the PCB board of the NFC field strength test device in contact with the NFC device. The NFC receiving antenna generates an induced electromotive force through inductive coupling. After being modulated by the resonant capacitor, the induced electromotive force is input into the Schottky chip for rectification and then input into each light-emitting branch of the voltage indication circuit. The field strength of the NFC device corresponds to the magnitude of the induced electromotive force. The field strength is judged by the amount of light emitted by the light-emitting branch.

[0021] Inductive coupling is used to generate an induced electromotive force in the NFC receiving antenna, which is then modulated and rectified to make the light-emitting branch emit light, and the field strength of the NFC device is reflected by the light-emitting branch. The entire test structure is simple, small in size and easy to carry, and no additional power supply is required, and the operation is simple and fast; the generated induced electromotive force is modulated and rectified before testing, which improves the accuracy of the test results; and the Schottky chip has a fast switching speed and can withstand a high reverse voltage, which improves the safety of the circuit in the test device.

[0022] (2) Compared with the method of converting the induced electromotive force into NFC field strength through the main control chip and displaying it on the display screen. This solution uses the corresponding relationship between the field strength and the magnitude of the induced electromotive force, and sets a plurality of light-emitting diodes with stepped distribution of rated voltages. The number of light-emitting diodes emits light to feedback the magnitude of the induced electromotive force, thereby corresponding to the strength of the field strength. The strength of the field strength can be obtained clearly and intuitively without setting up an additional power supply. The structure is simpler, the detection results are more intuitive, and the cost is lower. In addition, in conjunction with the step-down diode set at the front end of the light-emitting diode, the driving voltage of the light-emitting diode can be adaptively adjusted to ensure the safety of the indication circuit and further improve the stability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the principle of the NFC field strength test device provided by the utility model;

[0024] Figure 2 A schematic diagram of the use of the NFC field strength test device provided by the utility model;

[0025] In the figure: 1. PCB board, 2. NFC receiving antenna, 3. resonant capacitor, 4. Schottky chip, 5. voltage indication circuit, 6. NFC device, 51. first light-emitting branch, 511. first buck diode, 512. first light-emitting diode, 513. first current-limiting resistor, 52. second light-emitting branch, 521. second buck diode, 522. second light-emitting diode, 523. second current-limiting resistor, 53. third light-emitting branch, 531. third buck diode, 532. third light-emitting diode, 533. third current-limiting resistor. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0029] In the description of the present utility model, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present utility model.

[0030] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0031] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0032] Example 1

[0033] like Figure 1 and Figure 2 As shown, this embodiment provides a portable NFC field strength test device, which is used to test the field strength of an NFC device 6. The test device includes a PCB board 1, and an NFC receiving antenna 2, a resonant capacitor 3, a Schottky chip 4 and a voltage indication circuit 5 located on the PCB board 1;

[0034] The NFC receiving antenna 2 is electrically connected to the resonant capacitor 3, the resonant capacitor 3 is electrically connected to the Schottky chip 4, the Schottky chip 4 is serially connected in a voltage indicating circuit 5 for displaying the NFC field strength, and the voltage indicating circuit 5 includes a plurality of light-emitting branches.

[0035] Working principle: The PCB board 1 of the NFC field strength test device is contacted with the NFC device 6, and the NFC receiving antenna 2 generates an induced electromotive force through inductive coupling. After frequency modulation by the resonant capacitor 3, it is input to the Schottky chip 4 for rectification, and then input to each light-emitting branch of the voltage indication circuit 5. The field strength of the NFC device 6 corresponds to the size of the induced electromotive force generated, and the field strength is judged by the number of lights emitted by the light-emitting branches.

[0036] In this solution, the PCB board 1 of the NFC field strength test device is brought into contact with the NFC device 6, and the NFC receiving antenna 2 generates an induced electromotive force through inductive coupling. After frequency modulation by the resonant capacitor 3, the induced electromotive force is input into the Schottky chip 4 for rectification, and then input into each light-emitting branch of the voltage indication circuit 5. The field strength of the NFC device 6 corresponds to the size of the induced electromotive force, and the field strength is judged by the amount of light emitted by the light-emitting branch.

[0037] The NFC receiving antenna 2 generates an induced electromotive force by inductive coupling, and the light-emitting branch emits light after frequency modulation and rectification, and the field strength of the NFC device 6 is reflected by the light-emitting branch. The entire test structure is simple, small in size and easy to carry, and no additional power supply is required, and the operation is simple and fast; the generated induced electromotive force is frequency modulated and rectified before testing, which improves the accuracy of the test results; and the Schottky chip 4 has a fast switching speed, can withstand a higher reverse voltage, and improves the safety of the circuit in the test device.

[0038] As a preferred embodiment, the voltage indicating circuit 5 includes a first light-emitting branch 51, a second light-emitting branch 52 and a third light-emitting branch 53 connected in parallel.

[0039] Specifically, the first light-emitting branch 51 includes a first buck diode 511, a first light-emitting diode 512 and a first current-limiting resistor 513 connected in series in sequence, the input end of the first buck diode 511 is connected to the output end of the Schottky chip 4, and the other end of the first current-limiting resistor 513 is connected to one end of the Schottky chip 4.

[0040] The second light-emitting branch 52 includes a second buck diode 521, a second light-emitting diode 522 and a second current-limiting resistor 523 connected in series in sequence. The input end of the second buck diode 521 is connected to the output end of the Schottky chip 4, and the other end of the second current-limiting resistor 523 is connected to one end of the Schottky chip 4.

[0041] The third light-emitting branch 53 includes a third buck diode 531, a third light-emitting diode 532 and a third current-limiting resistor 533 connected in series in sequence. The input end of the third buck diode 531 is connected to the output end of the Schottky chip 4, and the other end of the third current-limiting resistor 533 is connected to one end of the Schottky chip 4.

[0042] The forward rated voltages of the first light emitting diode 512 , the second light emitting diode 522 and the third light emitting diode 532 are sequentially increased in steps, and the first light emitting diode 512 , the second light emitting diode 522 and the third light emitting diode 532 are sequentially distributed on the same side of the PCB board 1 .

[0043] Compared with the main control chip that converts the induced electromotive force into NFC field strength and displays it on the display screen, this solution uses the corresponding relationship between field strength and induced electromotive force, sets multiple light-emitting diodes with stepped distribution of rated voltage, and uses the number of light-emitting diodes to feedback the size of the induced electromotive force, thereby corresponding to the strength of the field strength. The strength of the field strength can be obtained clearly and intuitively, without setting up an additional power supply, with a simpler structure, more intuitive detection results, and lower costs.

[0044] In an optional implementation, in order to more accurately reflect the field strength of the NFC device 6, the number of light-emitting branches can be increased, thereby reducing the voltage gradient between each light-emitting diode, so as to more accurately reflect the field strength according to the number of light-emitting diodes.

[0045] Specifically, the resonant capacitor 3 is connected in parallel to both ends of the NFC receiving antenna 2, and both ends of the resonant capacitor 3 are respectively connected to the Schottky chip 4. The PCB board 1 is a double-layer structure, and the PCB board 1 is a rectangular structure. The structure is simple, easy to carry, and convenient to operate by hand.

[0046] The Schottky chip 4 has a low forward voltage drop, and in the on state, consumes less power and has a higher efficiency. In addition, the Schottky chip 4 also has a fast switching speed, can withstand a higher reverse voltage, and has a smaller package size and lower cost. The Schottky chip 4 can rectify, freewheel, and protect the circuit well. While rectifying the circuit, it can also avoid the harm of the reverse voltage generated by the NFC device 6 to the circuit, ensuring the safety of the circuit.

[0047] Furthermore, the NFC receiving antenna 2 is located on one side of the PCB board 1, and the resonant capacitor 3, the Schottky chip 4 and the voltage indication circuit 5 are located on the other side of the PCB board 1. The NFC receiving antenna 2 includes a multi-turn coil, and the number of coils is greater than or equal to 2. Moreover, the NFC receiving antenna 2 can be etched on the back of the PCB board 1, further optimizing the structure of the test device and improving the portability of the test device.

[0048] The preferred specific embodiments of the utility model are described in detail above. It should be understood that ordinary technicians in this field can make many modifications and changes based on the concept of the utility model without creative work. Therefore, all technical solutions that can be obtained by technicians in this technical field based on the concept of the utility model through logical analysis, reasoning or limited experiments on the basis of the existing technology should be within the scope of protection determined by the claims.

Claims

1. A portable NFC field strength test device, used for testing the field strength of an NFC device (6), characterized in that: The testing device comprises a PCB board (1), and an NFC receiving antenna (2), a resonant capacitor (3), a Schottky chip (4) and a voltage indication circuit (5) located on the PCB board (1); The NFC receiving antenna (2) is electrically connected to a resonant capacitor (3), the resonant capacitor (3) is electrically connected to a Schottky chip (4), the Schottky chip (4) is serially connected in a voltage indicating circuit (5) for displaying the NFC field strength, and the voltage indicating circuit (5) comprises a plurality of light-emitting branches.

2. A portable NFC field strength test device according to claim 1, characterized in that: The voltage indicating circuit (5) comprises a first light-emitting branch (51), a second light-emitting branch (52) and a third light-emitting branch (53) connected in parallel.

3. A portable NFC field strength test device according to claim 2, characterized in that: The first light-emitting branch (51) comprises a first buck diode (511), a first light-emitting diode (512) and a first current-limiting resistor (513) which are connected in series in sequence, the input end of the first buck diode (511) being connected to the output end of the Schottky chip (4), and the other end of the first current-limiting resistor (513) being connected to one end of the Schottky chip (4).

4. A portable NFC field strength test device according to claim 3, characterized in that: The second light-emitting branch (52) comprises a second step-down diode (521), a second light-emitting diode (522) and a second current-limiting resistor (523) which are connected in series in sequence, the input end of the second step-down diode (521) being connected to the output end of the Schottky chip (4), and the other end of the second current-limiting resistor (523) being connected to one end of the Schottky chip (4).

5. A portable NFC field strength test device according to claim 4, characterized in that: The third light-emitting branch (53) comprises a third step-down diode (531), a third light-emitting diode (532) and a third current-limiting resistor (533) which are sequentially connected in series, the input end of the third step-down diode (531) being connected to the output end of the Schottky chip (4), and the other end of the third current-limiting resistor (533) being connected to one end of the Schottky chip (4).

6. A portable NFC field strength test device according to claim 5, characterized in that: The forward rated voltages of the first light-emitting diode (512), the second light-emitting diode (522) and the third light-emitting diode (532) are increased in sequence in steps, and the first light-emitting diode (512), the second light-emitting diode (522) and the third light-emitting diode (532) are sequentially distributed on the same side of the PCB board (1).

7. A portable NFC field strength test device according to claim 1, characterized in that: The resonant capacitor (3) is connected in parallel to two ends of the NFC receiving antenna (2), and the two ends of the resonant capacitor (3) are respectively connected to a Schottky chip (4).

8. The portable NFC field strength test device according to claim 1, characterized in that: The PCB board (1) is a double-layer structure, and the PCB board (1) is a rectangular structure.

9. A portable NFC field strength test device according to claim 8, characterized in that: The NFC receiving antenna (2) is located on one side of the PCB board (1), and the resonant capacitor (3), the Schottky chip (4) and the voltage indication circuit (5) are located on the other side of the PCB board (1).

10. The portable NFC field strength test device according to claim 1, characterized in that: The NFC receiving antenna (2) comprises a multi-turn coil, and the number of the coils is greater than or equal to 2.

Images