Ground noise reduction device of LIN communication photoelectric converter

Abstract

The utility model discloses a bottom noise reduction device of an LIN communication photoelectric converter, which belongs to the technical field of noise control of vehicle-mounted photoelectric communication and comprises a circuit board body, an RC filter circuit is arranged on the circuit board body and comprises an input end and a resistor, the input end is used for being connected with the vehicle-mounted LIN communication photoelectric converter, and the resistor is connected with the circuit board body. The capacitor is connected with an output end of a to-be-tested product; the circuit board body is provided with a first wiring terminal which is convenient to disassemble and assemble the resistor and a second wiring terminal which is convenient to disassemble and assemble the capacitor. According to the utility model, the RC filtering principle is combined, the device can be matched with a vehicle-mounted LIN communication photoelectric converter in the market, and the space radiation energy in the frequency range of 150kHz-500kHz is reduced under the condition that the normal communication of a vehicle-mounted test product is not influenced, so that the ground noise of the electromagnetic compatibility emission test of the vehicle-mounted product meets the test requirement that the ground noise is lower than the limit value of 6dB.

Description

Technical Field

[0001] This utility model mainly relates to the field of noise control technology in vehicle-mounted optoelectronic communication, specifically a noise reduction device for a LIN communication optoelectronic converter. Background Technology

[0002] For LIN communication-based automotive products, electromagnetic compatibility (EMC) emission testing requires isolating the host computer from the automotive product via LIN communication optoelectronic converters and optical fibers. This eliminates interference from external auxiliary equipment or test computers, ensuring that the noise floor of the anechoic chamber meets standard requirements.

[0003] However, in the automotive electromagnetic compatibility industry, for LIN optoelectronic converters, brands such as MK, EMCTOOLS, and Rongxiang often experience increased radiated energy in the 150kHz-500kHz frequency band during operation, making the testing environment unable to meet the 6dB testing requirements. In other words, some automotive LIN communication optoelectronic converters on the market exceed the CISPR 25 CLASS 5 limit during data transmission and reception in the 150kHz-500kHz range. Therefore, it is necessary to provide a noise reduction device for LIN communication optoelectronic converters. Utility Model Content

[0004] This utility model provides a solution that addresses the problem of overly simplistic existing technical solutions. It offers a significantly different solution, primarily a noise reduction device for LIN communication optoelectronic converters. This device is compatible with automotive LIN communication optoelectronic converters on the market and reduces the spatial radiation energy in the 150kHz-500kHz frequency band of the LIN communication optoelectronic converter without affecting the normal communication of the automotive test products. This allows the noise floor of the anechoic chamber to meet the testing requirements.

[0005] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows:

[0006] A noise reduction device for a LIN communication optoelectronic converter includes a circuit board body. The circuit board body is provided with an RC filter circuit. The RC filter circuit includes an input terminal for connecting the vehicle-mounted LIN communication optoelectronic converter, a resistor, a capacitor, and an output terminal for connecting the product under test. The circuit board body is provided with a first terminal for easy installation and removal of the resistor and a second terminal for easy installation and removal of the capacitor.

[0007] On the one hand, noise reduction is achieved using the RC filtering principle; on the other hand, for different automotive products under test, normal communication of the automotive test products can be ensured by replacing resistors with different resistance values ​​and / or capacitors with different capacitance values. Therefore, this invention can be used in conjunction with automotive LIN communication optoelectronic converters on the market, ensuring normal LIN communication connection of the automotive products first, and then reducing the spatial radiation energy in the 150kHz-500kHz frequency band.

[0008] Specifically, both the first and second terminals include a partition plate and a main block. Two main blocks, a pressure plate 34, and a screw 35 are provided between the three partition plates. The main block has a screw hole and a screw is threadedly connected to it. A conductive pin is passed through the main block and located next to the screw hole. A pressure plate is fitted on the screw. An extension strip is formed on two opposite sides of the pressure plate, which can be inserted into the main block and contact the conductive pin.

[0009] Furthermore, the top of the screw is formed with a horn-shaped portion, which facilitates manual tightening, thereby avoiding the need to use tools to install resistors and capacitors, making the application more convenient.

[0010] As an optimization of the above solution, the pressure plate is provided with guide limiting cylinders on both opposite sides for the leads of resistors or capacitors to pass through. The two guide limiting cylinders located on both sides of the pressure plate can limit the leads of resistors / capacitors, preventing the leads of resistors / capacitors from accidentally coming loose before the screws are tightened, thereby ensuring the stable fixation of the leads of resistors / capacitors.

[0011] Furthermore, one end of the guide limiting cylinder is formed into a small circular opening that matches the pins of the resistor or capacitor, and the other end of the guide limiting cylinder is a large circular opening. The inner diameter of the guide limiting cylinder is gradually reduced from the large circular opening side to the small circular opening side, which facilitates the insertion of the resistor / capacitor pins and can accurately guide the resistor / capacitor pins to the small circular opening.

[0012] Furthermore, the guide limiting cylinder is embedded in the main body block, and the bottom of the small circular opening is flush with the upper surface of the main body block, which makes it easy to limit the resistor / capacitor pins to the upper surface of the main body block, which is beneficial for the subsequent pressing and fixing of the resistor / capacitor pins by the pressing plate.

[0013] Furthermore, the circuit board is equipped with a male connector for connecting to the input terminal of the RC filter circuit, which facilitates connection to the vehicle-mounted LIN communication optoelectronic converter.

[0014] Furthermore, the circuit board is provided with a third terminal block connected to the output of the RC filter circuit, which can easily lead out two power lines to connect the LIN signal line and ground line of the product under test (a vehicle-mounted product based on LIN communication).

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] This invention features an RC filter circuit for noise reduction. Furthermore, the inclusion of first and second terminals allows for easy replacement of resistors and capacitors with varying values. Compared to fixed RC filters (which can disrupt LIN communication between the host computer and the vehicle-mounted product for different applications), this invention allows for convenient and reliable switching to appropriate resistor and capacitor values ​​for different vehicle-mounted products. This ensures normal LIN communication for the vehicle-mounted product while reducing spatial radiation energy in the 150kHz-500kHz frequency band. Therefore, this invention can be used with commercially available vehicle-mounted LIN communication photoelectric converters. Without affecting the normal communication of the vehicle-mounted test product, it reduces spatial radiation energy in the 150kHz-500kHz frequency band of the LIN communication photoelectric converter, thus ensuring the noise floor of the anechoic chamber meets testing requirements.

[0017] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of one embodiment of the present utility model;

[0019] Figure 2 This is a schematic diagram of the terminal block structure in one embodiment of the present invention;

[0020] Figure 3 This is a three-dimensional structural diagram of another embodiment of the present invention;

[0021] Figure 4 This is a cross-sectional view of the guide limiting cylinder in this utility model;

[0022] Figure 5 This is a schematic diagram of the terminal block structure in another embodiment of the present invention.

[0023] Reference numerals: 1. Circuit board body; 2. Male connector; 3. First terminal block; 31. Separator plate; 32. Main body block; 33. Conductive pin; 34. Pressure plate; 35. Screw; 351. Horn part; 36. Guide limiting cylinder; 361. Small circular opening; 362. Large circular opening; 4. Second terminal block; 5. Third terminal block. Detailed Implementation

[0024] To facilitate understanding of this utility model, a more comprehensive description of the utility model will be given below with reference to the accompanying drawings, which show several embodiments of the utility model. However, the utility model can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the disclosure of the utility model more thorough and comprehensive.

[0025] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly associated with those skilled in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0027] Example: Please refer to the appendix for details. Figure 1 A noise reduction device for a LIN communication optoelectronic converter, comprising:

[0028] The circuit board body 1 is used to implement the arrangement of the RC filter circuit. The RC filter circuit includes an input terminal for connecting the vehicle-mounted LIN communication optoelectronic converter, resistors, capacitors, and an output terminal for connecting the product under test.

[0029] Male connector 2 is connected to one end of the circuit board 1 and is used to connect the vehicle-mounted LIN communication optoelectronic converter and connect to the input end of the RC filter circuit.

[0030] The first terminal 3 is used to connect a resistor;

[0031] The second terminal 4 is used to connect a capacitor;

[0032] The third terminal 5 leads out two power lines, which are used to connect the LIN signal line and ground line of the product under test (a vehicle-mounted product based on LIN communication) to the output of the RC filter circuit.

[0033] In application, the aforementioned noise reduction device employs the RC filtering principle, allowing low-frequency signals to pass while attenuating high-frequency signals. At low frequencies, the capacitor's impedance is relatively high, and the signal is mainly transmitted through the resistor, resulting in minimal attenuation. At high frequencies, the capacitor's impedance decreases, and most high-frequency signals are bypassed to ground by the capacitor, thus achieving low-pass filtering and ultimately noise reduction.

[0034] For different automotive products under test, due to differences in internal circuitry, if the RC filter only has a single resistor and capacitor value, it will be incompatible with the automotive product due to the cutoff frequency. During testing, it was found that adding this RC filter would cause LIN communication between the host computer and the automotive product to be interrupted. To avoid affecting the normal communication of the automotive test product, this invention uses terminal blocks to connect the resistors and capacitors, making it easy to replace resistors and capacitors with different values. By adjusting the appropriate resistors and capacitors, the effect of normal communication connection and reducing the noise floor of the LIN communication photoelectric converter can be achieved. For example, in a practical application, an automotive product using LIN communication was tested. Because the LIN noise floor did not meet the 6dB requirement, an RC filter needed to be added. However, initially, after adding it, it was found that the LIN communication of the host computer was interrupted. Subsequently, the capacitor value was continuously adjusted until a suitable capacitor (0.4uF), a uF-level capacitor, was selected, achieving normal communication connection and meeting the 6dB noise floor target.

[0035] In this embodiment, the male connector 2 is a DB9 male connector, which can be directly plugged into the LIN communication optoelectronic converter.

[0036] In this embodiment, the first terminal block 3, the second terminal block 4, and the third terminal block 5 all use "KF7.62-2P" type terminal blocks. Their lower ends have leads for insertion into the circuit board body 1 and soldering, ensuring reliable soldering. The upper ends of the terminal blocks have two nuts. For different samples, after determining the appropriate resistance and capacitance values, the upper nuts are loosened with a Phillips screwdriver, the leads of the metal film resistor and monolithic capacitor are inserted under the nuts, and the nuts are tightened with the Phillips screwdriver. After installing the resistors and capacitors, the multimeter probes are placed above the nuts to read the resistance and capacitance values. The multimeter reading is then observed to determine if the resistor and capacitor connections are accurate.

[0037] In another embodiment, please refer to the appendix for details. Figure 2 The aforementioned terminal block includes a separator plate 31, a main body block 32, conductive leads 33, a pressure plate 34, and a screw 35. Two main body blocks 32 are positioned between the three separator plates 31. Each main body block 32 has a screw hole adapted to the screw 35. The conductive leads 33 are located beside the screw hole and extend through to the bottom of the main body block 32. The pressure plate 34 is fitted onto the screw 35 and is positioned above the main body block 32. Two opposite sides of the pressure plate 34 have extension strips formed for insertion into the main body block 32, which can move down with the pressure plate 34 to contact the conductive leads 33. In application, the leads of the resistor or capacitor are inserted between the pressure plate 34 and the main body block 32. Then, the screw 35 is tightened with a screwdriver. The screw 35 presses against the pressure plate 34, which presses the leads of the resistor or capacitor firmly onto the main body block 32.

[0038] In another embodiment, please refer to the appendix for details. Figure 3 and attached Figure 4 Each pressure plate 34 on the first terminal 3 / second terminal 4 is provided with a guide limiting cylinder 36 embedded on the main body block 32 on both opposite sides. One end of the guide limiting cylinder 36 is formed into a small circular opening 361 that matches the lead of the resistor / capacitor, and the other end of the guide limiting cylinder 36 is a large circular opening 362. The inner diameter of the guide limiting cylinder 36 gradually decreases from the large circular opening 362 side to the small circular opening 361 side, so as to guide the lead of the resistor / capacitor to the small circular opening 361. The bottom of the small circular opening 361 is flush with the upper surface of the main body block 32, so as to limit the lead of the resistor / capacitor to the position attached to the main body block 32, which is beneficial to the subsequent pressing and fixing of the lead of the resistor / capacitor by the pressure plate 34.

[0039] In application, the resistor / capacitor leads are first inserted into the large circular opening 362 side of one guide limiting cylinder 36, passing through the guide limiting cylinder 36 and then passing under the pressure plate 34, and then inserted into the large circular opening 362 side of the other guide limiting cylinder 36 until they pass out of the guide limiting cylinder 36. The two guide limiting cylinders 36 located on both sides of the pressure plate 34 can limit the resistor / capacitor leads, preventing accidental loosening of the resistor / capacitor leads before tightening the screw 35, and ensuring stable fixation of the resistor / capacitor leads.

[0040] In another embodiment, please refer to the appendix for details. Figure 5 The top of the screw 35 is formed with a horn portion 351, which makes it easy to manually tighten the screw 35 without the need for tools such as screwdrivers or screwdrivers, making it more convenient to use.

[0041] In summary, this invention can reduce the noise floor of the LIN communication optoelectronic converter during long-distance communication without affecting the customer's samples, thereby ensuring that the LIN communication optoelectronic converter meets the noise floor requirements of EMC emission tests.

[0042] The present invention has been described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvement made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, shall be within the protection scope of the present invention.

Claims

1. A noise reduction device for a LIN communication optoelectronic converter, characterized in that: The circuit board includes a circuit board body (1), which is provided with an RC filter circuit, and the circuit board body (1) is provided with a first terminal (3) for easy installation and removal of resistors and a second terminal (4) for easy installation and removal of capacitors.

2. The noise reduction device for a LIN communication optoelectronic converter according to claim 1, characterized in that: The first terminal (3) and the second terminal (4) both include a partition plate (31) and a main body block (32). Two main bodies block (32), a pressure plate (34), and a screw (35) are provided between the three partition plates (31). The main body block (32) has a screw hole and a screw (35) is threadedly connected to it. A conductive pin (33) is passed through the main body block (32) and located next to the screw hole. The pressure plate (34) is fitted on the screw (35). The two opposite sides of the pressure plate (34) are formed with extension strips that can be inserted into the main body block (32) and contact the conductive pin (33).

3. The noise reduction device for a LIN communication optoelectronic converter according to claim 2, characterized in that: The top of the screw (35) is formed with a ram's horn (351).

4. The noise reduction device for a LIN communication optoelectronic converter according to claim 2, characterized in that: The pressure plate (34) is provided with guide limiting cylinders (36) on both opposite sides for the pins of resistors or capacitors to pass through.

5. The noise reduction device for a LIN communication optoelectronic converter according to claim 4, characterized in that: One end of the guide limiting cylinder (36) is formed into a small circular opening (361) that is compatible with the pin of the resistor or capacitor, and the other end of the guide limiting cylinder (36) is a large circular opening (362). The inner diameter of the guide limiting cylinder (36) is gradually reduced from the side of the large circular opening (362) to the side of the small circular opening (361).

6. The noise reduction device for a LIN communication optoelectronic converter according to claim 5, characterized in that: The guide limiting cylinder (36) is embedded in the main body block (32), and the bottom of the small circular opening (361) is flush with the upper surface of the main body block (32).

7. The noise reduction device for a LIN communication optoelectronic converter according to claim 1, characterized in that: The circuit board (1) is provided with a male connector (2) that connects to the input terminal of the RC filter circuit.

8. The noise reduction device for a LIN communication optoelectronic converter according to claim 1, characterized in that: The circuit board body (1) is provided with a third terminal (5) connected to the output of the RC filter circuit.

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