Power supply structure for long-distance low-frequency RFID card reading equipment

Abstract

The utility model relates to the technical field of power supply interference prevention, and discloses a power supply structure for long-distance low-frequency RFID card reading equipment, which comprises a power supply shell and a switching power supply circuit board arranged in the power supply shell, the switching power supply circuit board is provided with an alternating current input end with a ground wire pin, a USB direct current output end, a common mode inductance coil, a transformer, a first Y capacitor bank and a second Y capacitor bank, wherein the first Y capacitor bank is used for grounding transformation and connected to the input end of the switching power supply circuit board, and the second Y capacitor bank is connected to the output end of the switching power supply circuit board. The first Y capacitor bank is connected between the alternating current input end and the common mode inductance coil, a rectifier bridge BD1 is connected between the common mode inductance coil and the transformer, and the second Y capacitor bank is connected to the transformer. According to the utility model, high-frequency signal interference is effectively suppressed by accessing the common-mode inductance coil, interference and influence of electromagnetic clutters on surrounding equipment are effectively prevented by grounding transformation of the Y capacitor, and normal work of electric equipment is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of power supply anti-interference technology, specifically a power supply structure for a long-range low-frequency RFID card reader. Background Technology

[0002] Electronic products all rely on power supplies, especially those powered by the mains. Power supply interference prevention is an important technical field, particularly in electronic equipment, scientific research experiments, and industrial applications, where the stability and purity of the power supply are crucial for the normal operation of the equipment.

[0003] A search revealed that patent application number CN201310547513.X discloses a novel RFID reader power supply, comprising a first to an eighth capacitor, a first diode, a second diode, a first inductor, a second inductor, a battery, a resistor, a low-voltage converter, a voltage conversion chip, a charging controller, and a high-voltage converter. The positive terminal of the battery is connected to the positive terminal of the first diode and subjected to a positive voltage, while the negative terminal of the battery is grounded. This novel RFID reader power supply, during use, allows for flexible adjustment and selection of the output voltage based on the RFID charging voltage. Furthermore, this power supply possesses advantages such as good stability, high efficiency, and low spurious emissions, making it a superior choice for applications in RFID handheld readers and other devices, and thus worthy of widespread adoption.

[0004] When current RFID reader power supplies are running, various interference signals generated by the power grid and circuits can easily intrude from the power supply end and affect the normal operation of the equipment. In particular, low-frequency RFID reader devices have higher requirements for power supply. Therefore, we need to propose a power supply structure for long-range low-frequency RFID reader devices to effectively suppress high-frequency signal interference. Utility Model Content

[0005] The purpose of this utility model is to provide a power supply structure for a long-range low-frequency RFID card reader. By connecting a common-mode inductor coil, high-frequency signal interference is effectively suppressed. By modifying the grounding of the Y capacitor, electromagnetic noise is effectively prevented from interfering with and affecting surrounding equipment, thus ensuring the normal operation of the electrical equipment and solving the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a power supply structure for a long-range low-frequency RFID card reader, comprising a power supply housing and a switching power supply circuit board installed inside the power supply housing. The switching power supply circuit board is provided with an AC input terminal with a ground wire, a USB DC output terminal, a common-mode inductor, a transformer, and a Y capacitor group one connected to the input terminal of the switching power supply circuit board and a Y capacitor group two connected to the output terminal of the switching power supply circuit board for grounding modification. The Y capacitor group one is connected between the AC input terminal and the common-mode inductor. A rectifier bridge BD1 is connected between the common-mode inductor and the transformer. The Y capacitor group two is connected to the transformer.

[0007] Preferably, the AC input terminal includes an AC input N line, an AC input L line, and an AC input ground line, and the Y capacitor group one includes a Y capacitor two connected to the AC input N line and a Y capacitor one connected to the AC input L line, with the terminals of the Y capacitor two and the Y capacitor one connected to the AC input ground line.

[0008] Preferably, one end of the common mode inductor is connected in parallel with a capacitor CX1, a series resistor R16 and a resistor R18, a series resistor R15 and a resistor R17, and a varistor. One end of the common mode inductor is connected to the AC input N line and the AC input L line respectively, and a fuse is connected to the AC input L line.

[0009] Preferably, the other end of the common mode inductor is connected between pin 1 and pin 2 of the rectifier bridge BD1, and capacitors EC1 and EC2 are connected in parallel between pins 3 and 4 of the rectifier bridge BD1. A resistor R1 and an inductor L1 are connected in parallel between one end of capacitor EC1 and one end of capacitor EC2, and a resistor R2 is connected in parallel between the other end of capacitor EC1 and the other end of capacitor EC2.

[0010] Preferably, a resistor R3, a resistor R4, and a diode D1 are connected between pins 6 and 7 of the transformer, and a capacitor C1 is connected in parallel with the resistor R3; a capacitor EC4, a capacitor EC5, a resistor R14, and a capacitor C3 are connected in parallel between pins 4 and 5 of the transformer, and the two ends of the capacitor C3 are respectively connected between pins 1 and 4 of the USB DC output terminal; a diode D3 is connected between pin 5 of the transformer and one end of the capacitor EC4, and a capacitor C2 and a resistor R13 are connected in series in parallel with the diode D3; an inductor L2 is connected between the capacitors EC4 and EC5.

[0011] Preferably, the switching power supply circuit board is further provided with a power control chip U1, pins 5 and 6 of the power control chip U1 are connected to pin 6 of the transformer, resistors R5 and R6 are connected between pin 3 of the rectifier bridge BD1 and pin 1 of the power control chip U1, and pins 1 and 2 of the power control chip U1 are connected to pin 3 of the transformer.

[0012] Preferably, the second Y capacitor group includes a third Y capacitor and a fourth Y capacitor connected in series and grounded. One end of the third Y capacitor is connected to pin 7 of the transformer, and one end of the fourth Y capacitor is connected to the AC input ground line. The third Y capacitor has capacitors CY2 and CY3 connected in parallel and in series.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] This invention effectively suppresses high-frequency signal interference by connecting a common-mode inductor coil, and effectively prevents electromagnetic noise from interfering with and affecting surrounding equipment by modifying the grounding of a Y capacitor, thus ensuring the normal operation of electrical equipment. Attached Figure Description

[0015] Figure 1 This is a front view of the power supply casing of this utility model;

[0016] Figure 2 This is a side view of the power supply housing of this utility model;

[0017] Figure 3 This is a top view of the power supply casing of this utility model;

[0018] Figure 4 This is a top view of the switching power supply circuit board of this utility model;

[0019] Figure 5 This is a circuit diagram of the switching power supply circuit board of this utility model;

[0020] Figure 6 This is a front view of the common-mode inductor coil of this utility model;

[0021] Figure 7 This is a side view of the common-mode inductor coil of this utility model;

[0022] Figure 8 This is a top view of the common-mode inductor coil of this utility model.

[0023] In the diagram: 100, power supply casing; 200, switching power supply circuit board; 1, AC input N line; 2, AC input L line; 3, AC input ground line; 4, Y capacitor one; 5, Y capacitor two; 6, fuse; 7, varistor; 8, transformer; 9, common mode inductor; 10, Y capacitor three; 11, Y capacitor four; 12, USB DC output terminal. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] Please see Figure 1-8 This utility model provides a technical solution: a power supply structure for a long-range low-frequency RFID card reader, including a power supply housing 100, a switching power supply circuit board 200 installed inside the power supply housing 100, an AC input terminal with a ground wire, a USB DC output terminal 12, a common mode inductor coil 9, a transformer 8, and a Y capacitor group one connected to the input terminal of the switching power supply circuit board 200 and a Y capacitor group two connected to the output terminal of the switching power supply circuit board 200 for grounding modification. The Y capacitor group one is connected between the AC input terminal and the common mode inductor coil 9, and a rectifier bridge BD1 is connected between the common mode inductor coil 9 and the transformer 8. The Y capacitor group two is connected to the transformer 8.

[0026] The AC input live wire L and AC input neutral wire N on the primary side of the switching power supply circuit board are connected in series with a Y capacitor and then connected to the primary side AC input ground wire; the negative terminal of the switching power supply output is connected to the output side ground; the output side ground is connected in series with a Y capacitor and then connected to the input side AC input ground wire.

[0027] By modifying the grounding of the input and output terminals of the power supply and adding a specific common-mode filter inductor, electromagnetic noise can be effectively prevented from interfering with and affecting surrounding equipment, thus ensuring the normal operation of electrical equipment.

[0028] Common mode inductor coil 9 Figure 3 The LF1 common-mode inductor 9 includes ferrite, terminal electrodes, a coil, and a plating layer. The coil is wound around the ferrite, and terminal electrodes are located at the four corners of the ferrite. See the structural diagram of this common-mode inductor 9. Figure 4 As shown. By utilizing the low pass and high impedance of the common-mode inductor coil 9, which has a specific impedance at a specific frequency, EMC interference within the RFID frequency band is effectively suppressed, ensuring the normal operation of the electrical equipment.

[0029] The power supply structure of this application has a simple overall design, is safe and reliable, small in size and low in cost, and effectively reduces EMC interference of long-distance low-frequency RFID card reading devices.

[0030] The AC input terminal includes AC input N line 1, AC input L line 2 and AC input ground line 3. Y capacitor group one includes Y capacitor two 5 connected to AC input N line 1 and Y capacitor one 4 connected to AC input L line 2. The terminals of Y capacitor two 5 and Y capacitor one 4 are connected to AC input ground line 3.

[0031] One end of the common mode inductor coil 9 is connected in parallel with a capacitor CX1, resistors R16 and R18, resistors R15 and R17, and a varistor 7. One end of the common mode inductor coil 9 is connected to the AC input N line 1 and the AC input L line 2, and a fuse 6 is connected to the AC input L line 2.

[0032] Varistor 7 is Figure 3 MOV1 in the middle, fuse 6 is Figure 3 F1 in the game.

[0033] The other end of the common mode inductor coil 9 is connected between pin 1 and pin 2 of rectifier bridge BD1. Capacitor EC1 and capacitor EC2 are connected in parallel between pin 3 and pin 4 of rectifier bridge BD1. Resistor R1 and inductor L1 are connected in parallel between one end of capacitor EC1 and one end of capacitor EC2. Resistor R2 is connected in parallel between the other end of capacitor EC1 and the other end of capacitor EC2.

[0034] Transformer 8 Figure 3 The transformer 8 is labeled T1. Resistors R3 and R4, and diode D1 are connected between pins 6 and 7. A capacitor C1 is connected in parallel with resistor R3, and one end of resistor R3 is connected to capacitor EC2. Capacitors EC4 and EC5, resistor R14, and capacitor C3 are connected in parallel between pins 4 and 5 of transformer 8. The two ends of capacitor C3 are connected between pins 1 and 4 of the USB DC output terminal 12, respectively. A diode D3 is connected between pin 5 of transformer 8 and one end of capacitor EC4. A capacitor C2 and resistor R13 are connected in series in parallel with diode D3. An inductor L2 is connected between capacitors EC4 and EC5.

[0035] The switching power supply circuit board 200 is also equipped with a power control chip U1. Pins 5 and 6 of the power control chip U1 are connected to pin 6 of the transformer 8. Resistors R5 and R6 are connected between pin 3 of the rectifier bridge BD1 and pin 1 of the power control chip U1. Pins 1 and 2 of the power control chip U1 are connected to pin 3 of the transformer 8.

[0036] A resistor R10 and a diode D2 are connected between pin 1 of the power control chip U1 and pin 3 of the transformer 8. A resistor R7 and a resistor R8 are connected in parallel between pin 2 of the power control chip U1 and pin 3 of the transformer 8. A resistor R9 and a resistor R11 are connected between pin 2 and pin 4 of the power control chip U1. A resistor R12 is connected in parallel with resistor R11. A capacitor EC3 and a capacitor C4 are connected in parallel between pin 1 of the power control chip U1 and the terminals of resistors R9 and R11.

[0037] Y capacitor group two includes Y capacitor three 10 and Y capacitor four 11 connected in series and grounded. One end of Y capacitor three 10 is connected to pin 7 of transformer 8, and one end of Y capacitor four 11 is connected to AC input ground wire 3. Y capacitor three 10 is connected in parallel with capacitors CY2 and CY3 connected in series.

[0038] Y capacitor 310 Figure 3 The capacitors CY1 and Y are 11. Figure 3 The capacitor CY6 and the Y capacitor-4 are... Figure 3 The capacitors CY4 and Y are 5. Figure 3 The capacitor CY5 in the middle.

[0039] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A power supply structure for a long-range low-frequency RFID card reader, characterized in that: The device includes a power supply housing (100) and a switching power supply circuit board (200) installed inside the power supply housing (100). The switching power supply circuit board (200) is provided with an AC input terminal with a ground pin, a USB DC output terminal (12), a common mode inductor (9), a transformer (8), and a Y capacitor group one connected to the input terminal of the switching power supply circuit board (200) and a Y capacitor group two connected to the output terminal of the switching power supply circuit board (200) for grounding modification. The Y capacitor group one is connected between the AC input terminal and the common mode inductor (9). A rectifier bridge BD1 is connected between the common mode inductor (9) and the transformer (8). The Y capacitor group two is connected to the transformer (8).

2. The power supply structure for a long-range low-frequency RFID card reader according to claim 1, characterized in that: The AC input terminal includes an AC input N line (1), an AC input L line (2), and an AC input ground line (3). The Y capacitor group one includes a Y capacitor two (5) connected to the AC input N line (1) and a Y capacitor one (4) connected to the AC input L line (2). The terminals of the Y capacitor two (5) and the Y capacitor one (4) are connected to the AC input ground line (3).

3. The power supply structure for a long-range low-frequency RFID card reader according to claim 1, characterized in that: One end of the common mode inductor (9) is connected in parallel with a capacitor CX1, a series resistor R16 and a resistor R18, a series resistor R15 and a resistor R17, and a varistor (7). One end of the common mode inductor (9) is connected to the AC input N line (1) and the AC input L line (2), and a fuse (6) is connected to the AC input L line (2).

4. The power supply structure for a long-range low-frequency RFID card reader according to claim 1, characterized in that: The other end of the common mode inductor (9) is connected between pin 1 and pin 2 of the rectifier bridge BD1. A capacitor EC1 and a capacitor EC2 are connected in parallel between pin 3 and pin 4 of the rectifier bridge BD1. A resistor R1 and an inductor L1 are connected in parallel between one end of the capacitor EC1 and one end of the capacitor EC2. A resistor R2 is connected in parallel between the other end of the capacitor EC1 and the other end of the capacitor EC2.

5. The power supply structure for a long-range low-frequency RFID card reader according to claim 1, characterized in that: A resistor R3, a resistor R4, and a diode D1 are connected between pins 6 and 7 of the transformer (8). A capacitor C1 is connected in parallel with the resistor R3. A capacitor EC4, a capacitor EC5, a resistor R14, and a capacitor C3 are connected in parallel between pins 4 and 5 of the transformer (8). The two ends of the capacitor C3 are connected between pins 1 and 4 of the USB DC output terminal (12). A diode D3 is connected between pin 5 of the transformer (8) and one end of the capacitor EC4. A capacitor C2 and a resistor R13 are connected in series in parallel with the diode D3. An inductor L2 is connected between the capacitors EC4 and EC5.

6. The power supply structure for a long-range low-frequency RFID card reader according to claim 1, characterized in that: The switching power supply circuit board (200) is also provided with a power control chip U1. Pins 5 and 6 of the power control chip U1 are connected to pin 6 of the transformer (8). Resistors R5 and R6 are connected between pin 3 of the rectifier bridge BD1 and pin 1 of the power control chip U1. Pins 1 and 2 of the power control chip U1 are connected to pin 3 of the transformer (8).

7. The power supply structure for a long-range low-frequency RFID card reader according to claim 1, characterized in that: The second Y capacitor group includes a Y capacitor three (10) and a Y capacitor four (11) connected in series and grounded. One end of the Y capacitor three (10) is connected to pin 7 of the transformer (8), and one end of the Y capacitor four (11) is connected to the AC input ground wire (3). The Y capacitor three (10) is connected in parallel with capacitors CY2 and CY3 connected in series.

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