Power sampling resistor of large-current circuit and implementation method

Abstract

The application provides a power sampling resistor of a large-current circuit and an implementation method, and belongs to the technical field of laser driver, the power sampling resistor comprises a PCB board, a heat dissipation device and a laser driving circuit module; the front surface of the PCB board is provided with a plurality of alloy sampling resistors; the alloy sampling resistors are uniformly arranged on the PCB board and are connected in series one by one; the start end and the end of the series-connected alloy sampling resistors are fixedly connected with a welding nail respectively, the welding nail is perpendicular to the surface of the PCB board; a heat-conducting insulating potting adhesive layer is arranged on the surface of the PCB board, and the heat-conducting insulating potting adhesive layer covers the series-connected alloy sampling resistors; the back surface of the PCB board is fixed on the heat dissipation device through a silicone grease layer, and the PCB board is fixed in the laser driving circuit module through the welding nail. The application realizes the collection of a large current under relatively small power consumption, guarantees that the sampling resolution is not affected by temperature, and the pin structure is consistent with the actual use and low in cost.

Description

Technical Field

[0001] This invention belongs to the field of laser driving technology, specifically relating to a power sampling resistor for a high-current circuit and its implementation method. Background Technology

[0002] Power sampling resistors are resistors categorized according to the product's intended use.

[0003] In the field of laser drivers, power sampling resistors used for power feedback by acquiring output current are typically TO-247 packaged power resistors. However, with the development of laser drivers, existing TO-247 packaged power resistors can no longer meet the sampling requirements of high-current circuits. Firstly, the maximum operating current of TO-247 packaged power resistors is limited to 25A, restricting the laser's drive current. Secondly, the TO-247 packaged power resistor uses a molded plastic package structure, resulting in relatively poor heat dissipation, especially when the operating current reaches 25A, the temperature can reach as high as 85℃. Furthermore, TO-247 packaged power resistors are planar non-inductive resistors with resistance values ​​mostly between 0.05Ω and 10KΩ, resulting in high power consumption and cost. Additionally, the planar non-inductive resistors used in TO-247 packaged power resistors have straight pins, making installation inconvenient. In practical use, the pins need to be bent, and for large-scale applications, each pin needs to be bent individually, increasing labor costs.

[0004] In summary, existing planar non-inductive resistors in TO-247 packages cannot be used as power sampling resistors in laser drivers due to limitations in operating current, package structure, resistance value, and pin count.

[0005] This is a shortcoming of the existing technology. Therefore, it is very necessary to provide a power sampling resistor for a high current circuit and its implementation method to address the above-mentioned defects in the existing technology. Summary of the Invention

[0006] To address the shortcomings of existing TO-247 packaged power resistors in laser driving applications, which cannot meet the sampling requirements of high-current circuits, this invention provides a power sampling resistor and its implementation method for high-current circuits to solve the aforementioned technical problems.

[0007] In a first aspect, the present invention provides a power sampling resistor for a high-current circuit, including a PCB board, a heat dissipation device, and a laser driving circuit module. Several alloy sampling resistors are located on the front of the PCB board; Alloy sampling resistors are evenly distributed on the PCB board and connected in series in sequence; The series-connected alloy sampling resistors are fixedly connected to a soldering pin at both ends, and the soldering pins are perpendicular to the surface of the PCB board. A thermally conductive and insulating potting compound layer is provided on the surface of the PCB board, and the thermally conductive and insulating potting compound layer covers the series-connected alloy sampling resistors; The back of the PCB board is fixed to the heat dissipation device with a layer of thermal paste, and the PCB board is fixed to the laser drive circuit module with soldering pins.

[0008] Furthermore, the PCB board has fixing holes and two mounting holes; The PCB board is fixed to the heat dissipation device through mounting holes; One mounting hole is connected to the beginning of the series-connected alloy sampling resistor, and the other mounting hole is connected to the end of the series-connected alloy sampling resistor. The solder pins are fixed to the PCB board through the mounting holes.

[0009] Furthermore, each alloy resistor adopts a symmetrical series structure, including connecting resistors and two resistor columns; The two resistor columns have the same number of resistors, and the two resistor columns are symmetrically arranged side by side on the PCB board; The alloy resistors in each resistor column are arranged horizontally and connected in series from beginning to end; The PCB board includes a top side and a bottom side, and the alloy resistors in the two resistor columns are parallel to the top side and the bottom side; Two mounting holes are located on the bottom edge of the PCB board, and each hole is connected to the bottom end of a resistor array. The connecting resistor is located on the upper side of the PCB board and is connected to the upper end of the resistor array at the upper side. The mounting hole is located in the area between the connecting resistor and the two resistor columns; The fixing holes and the two mounting holes are distributed in an isosceles triangle, and the distance from the fixing holes to the bottom edge of the PCB board is greater than half the length of the PCB board.

[0010] Furthermore, the number of connecting resistors is one; The connecting resistor is horizontally positioned on the side of the PCB board, and its two ends are connected to the upper endpoints of the two resistor columns, respectively.

[0011] Furthermore, the number of connecting resistors is two; The two connecting resistors are arranged vertically symmetrically, and each is positioned above a resistor column; The lower ends of the two connecting resistors are connected to the upper ends of the corresponding resistor array, and the upper ends of the two connecting resistors are connected to each other; The mounting holes are located in the area between the two connecting resistors, the connecting lines of the connecting resistors, and the two resistor arrays.

[0012] Furthermore, a mica sheet is placed between the silicone grease layer and the heat dissipation device; The alloy sampling resistor is an electron beam welded alloy sampling resistor; The PCB board uses a double-layer conductive PCB board; The welding studs are made of tin-plated copper.

[0013] Secondly, the present invention provides a method for implementing a power sampling resistor in a high-current circuit, comprising the following steps: S1. Select the alloy sampling resistors and their quantity with corresponding parameters according to the driving current of the laser driving circuit module; S2. Connect the selected alloy sampling resistors in series and arrange them evenly on the PCB board, and set a soldering pin at the beginning and end of the series alloy resistors respectively; S3. Install a heat dissipation device on the PCB board with alloy sampling resistors, fix it to the laser drive circuit module with soldering nails, and then seal it with thermally conductive insulating potting compound.

[0014] Furthermore, the specific steps of step S1 are as follows: S11. Obtain the drive current of the laser drive module; S12. Select the electron beam alloy sampling resistor with the set parameters as the sampling resistor; S13. Calculate the required number of electron beam alloy sampling resistors based on the driving current of the laser driving module and the resistance value of the electron beam alloy sampling resistor.

[0015] Furthermore, the specific steps of step S2 are as follows: S21. Determine the number of electron beam alloy sampling resistors; S22. When the number of electron beam alloy sampling resistors is odd, set a connection resistor and proceed to step S23; When the number of electron beam alloy sampling resistors is even, two connection resistors are set; S23. Divide the alloy resistors other than the connecting resistors into two groups to generate two resistor columns, which are symmetrically arranged side by side on the PCB board. S24. Arrange the electron beam alloy sampling resistors in each resistor column horizontally, and connect them in series from beginning to end; S25. Set a mounting hole on the lower side of each of the two resistor columns on the PCB board, and connect the mounting hole to the endpoint on the lower side of the corresponding resistor column; S26. Connecting resistors are placed on the upper side of the two resistor columns and connected to the endpoints on the upper side of the two resistor columns; S27. Fixing holes are provided on the PCB board between the two resistor rows and the connecting resistor. The fixing holes and the two mounting holes are arranged in an isosceles triangle, and the distance between the fixing holes and the lower edge of the PCB board is greater than half the length of the PCB board. S28. Solder a tin-plated soldering pin at each of the two mounting holes, with the tin-plated soldering pin perpendicular to the PCB board surface.

[0016] Furthermore, the specific steps of step S3 are as follows: S31. Apply silicone grease to the back of the PCB board after the electron beam alloy sampling resistors have been laid out, place mica sheets on it, and then install it onto the heat dissipation device through the fixing holes. S32. Use soldering pins to solder the PCB board to the laser drive circuit module; S33. Use thermally conductive and insulating potting compound to seal the PCB board for waterproofing.

[0017] The beneficial effects of this invention are as follows: The power sampling resistor and implementation method for high-current circuits provided by this invention can collect large currents with relatively low power consumption. The sampling resolution is not affected by temperature. When used in laser driving circuits, the response time and rise time of the current are no different from those of using TO-247 packaged power resistors. The pin structure is in line with practical use, and the cost is greatly reduced compared to TO-247 packaged power resistors.

[0018] Furthermore, the design principle of this invention is reliable, the structure is simple, and it has a very wide range of application prospects.

[0019] Therefore, it is evident that the present invention has outstanding substantive features and significant progress compared with the prior art, and the beneficial effects of its implementation are also obvious. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the main structure of the power sampling resistor in the high-current circuit of the present invention.

[0022] Figure 2 This is a side view schematic diagram of the power sampling resistor structure of the high current circuit of the present invention.

[0023] Figure 3 This is a schematic diagram of an asymmetrical layout of alloy resistors connected in series on a PCB board.

[0024] Figure 4 This is a structural diagram of a PCB board with mounting holes and fixing holes on one side.

[0025] Figure 5 This is a temperature comparison table of the power sampling resistor of the high current circuit of this invention and the original TO-247 packaged sampling resistor after use.

[0026] Figure 6 This is a comparison table of the power sampling resistor parameters of the high-current circuit of this invention and the original TO-247 package sampling resistor parameters.

[0027] Figure 7 This is a schematic flowchart of Embodiment 3 of the method for implementing the power sampling resistor in the high-current circuit of the present invention.

[0028] Figure 8 This is a schematic flowchart of Embodiment 4 of the method for implementing the power sampling resistor in the high-current circuit of the present invention.

[0029] In the diagram, 1-PCB board; 2-soldering pin; A-fixing hole; B-mounting hole; R1-first resistor; R2-second resistor; R3-third resistor; R4-fourth resistor; R5-fifth resistor; R6-sixth resistor; R7-seventh resistor; R8-eighth resistor; R9-ninth resistor; R10-tenth resistor. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0031] Example 1: like Figure 1 and Figure 2 As shown, the present invention provides a power sampling resistor for a high current circuit, including a PCB board 1, a heat dissipation device and a laser driving circuit module; Several alloy sampling resistors are provided on the front side of PCB board 1; Alloy sampling resistors are evenly distributed on PCB board 1 and connected in series in sequence; A welding nail 2 is fixedly connected to the beginning and end of the series alloy sampling resistors, and the welding nail 2 is perpendicular to the surface of the PCB board 1. A thermally conductive and insulating potting compound layer is provided on the surface of PCB board 1, and the thermally conductive and insulating potting compound layer covers the series-connected alloy sampling resistor; The back of PCB 1 is fixed to the heat dissipation device by a layer of thermal paste, and PCB 1 is fixed to the laser drive circuit module by soldering nails 2.

[0032] Example 2: like Figure 1 and Figure 2As shown, the present invention provides a power sampling resistor for a high current circuit, including a PCB board 1, a heat dissipation device and a laser driving circuit module; the PCB board 1 adopts a double-layer conductive PCB board; the double-layer current-conducting PCB board increases the heat dissipation area; The front side of PCB board 1 has several alloy sampling resistors; the alloy sampling resistors are electron beam soldered alloy sampling resistors; Alloy sampling resistors are evenly distributed on PCB board 1 and connected in series in sequence; A soldering nail 2 is fixedly connected to the beginning and end of the series alloy sampling resistors, and the soldering nail 2 is perpendicular to the surface of the PCB board 1; the soldering nail 2 is a tin-plated copper nail. A thermally conductive and insulating potting compound layer is provided on the surface of PCB board 1, and the thermally conductive and insulating potting compound layer covers the series-connected alloy sampling resistor; The back of PCB 1 is fixed to the heat dissipation device with a layer of silicone grease, and PCB 1 is fixed to the laser drive circuit module with solder nails 2; after applying a layer of silicone grease to the back of PCB 1, a highly insulating mica sheet is placed on it and then fixed to the heat dissipation device through fixing holes. PCB board 1 has a fixing hole A and two mounting holes B; PCB board 1 is fixed to the heat dissipation device through mounting hole A; One mounting hole B is connected to the beginning of the series alloy sampling resistor, and the other mounting hole B is connected to the end of the series alloy sampling resistor. The soldering nail 2 is fixed to the PCB board 1 through the mounting hole. Each alloy resistor adopts a symmetrical series structure, including a connecting resistor and two resistor columns; The two resistor columns have the same number of resistors, and the two resistor columns are symmetrically arranged side by side on PCB board 1; The alloy resistors in each resistor column are arranged horizontally and connected in series from beginning to end; PCB board 1 includes an upper side and a lower side, and the alloy resistors in the two resistor columns are parallel to the upper side and the lower side; Two mounting holes B are located on the lower side of PCB board 1, and are connected to the lower end of a resistor array at the lower side of the board. The connecting resistor is located on the upper side of PCB board 1 and is connected to the upper end of the resistor array at the upper side. The fixing hole A is located in the area between the connecting resistor and the two resistor columns; The fixing hole A and the two mounting holes B are distributed in an isosceles triangle, and the distance from the fixing hole A to the lower side of the PCB board 1 is greater than half the length of the PCB board 1. The number of connected resistors is two; The two connecting resistors are arranged vertically symmetrically, and each is positioned above a resistor column; The lower ends of the two connecting resistors are connected to the upper ends of the corresponding resistor array, and the upper ends of the two connecting resistors are connected to each other; The fixing hole A is located in the area between the two connecting resistors, the connecting lines of the connecting resistors, and the two resistor columns.

[0033] In the above embodiment 2, the number of connecting resistors can also be one; The connecting resistor is horizontally positioned on the side of the PCB board, and its two ends are connected to the upper endpoints of the two resistor columns, respectively.

[0034] In the above embodiment 2, the specific parameters of the selected electron beam welding type alloy sampling resistor are as follows: rated power range of 3W-7W, resistance range of 0.2mΩ-5mΩ, accuracy class of 1%, resistance temperature coefficient of ±20ppm, hot spot type <3uV / ℃, and operating temperature range of -55℃ to +170℃. The selected electron beam welding alloy sampling resistor has a small resistance value, low power, high accuracy, high overload, and high reliability. The sampling current can be between 24A and 187A, which fully meets the 50A current acquisition requirement of the laser drive circuit module. This application uses electron beam welding alloy sampling resistors connected in series, which is suitable for high-current circuits where temperature has a significant impact on sampling resolution. Therefore, the selected electron beam welding alloy sampling resistors are used as power sampling resistors, and their resistance values ​​cannot be too small. Given that the resistance values ​​of electron beam welding alloy sampling resistors are relatively small, ranging from 0.2mΩ to 5mΩ, in practical applications, the electron beam welding alloy sampling resistors need to be connected in series to ensure sampling resolution in high-current circuits, reduce errors, and also ensure that the overall resistance value of the power sampling resistors in this application is not too large, so as not to cause an increase in power loss of the laser driver section.

[0035] In the above embodiment 2, the insulating mica sheet isolates the heat dissipation device, and the thermally conductive and insulating potting compound is used to achieve both insulation and waterproofing while ensuring a considerable heat dissipation effect. The tin-plated copper nail 2 is installed perpendicular to the PCB board 1 at a 90-degree angle, which facilitates installation.

[0036] In the above embodiment 2, taking the number of alloy sampling resistors as 10 as an example, it includes the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9 and the tenth resistor R10. The first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 form a resistor column from bottom to top, and the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, and the tenth resistor R10 form another resistor column from top to bottom; the two resistor columns are arranged symmetrically. The fifth resistor R5 and the sixth resistor R6 are connection resistors. The fifth resistor R5 is placed above the fourth resistor R4 and perpendicular to the fourth resistor R4. The sixth resistor R6 is placed above the seventh resistor R7 and perpendicular to the seventh resistor R7. The first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 form a resistor array from bottom to top. The seventh resistor R7, the eighth resistor R8, the ninth resistor R9, and the tenth resistor R10 are connected in series. The fifth resistor R5 and the sixth resistor R6 are connected above each other via PCB traces. The mounting hole A is located between the fifth resistor R5 and the sixth resistor R6 and their PCB traces, and between the fourth resistor R4 and the seventh resistor R7. A mounting hole B is provided below the first resistor R1 and below the tenth resistor R10. The mounting hole B below the first resistor R1 is connected to the beginning of the first resistor R1, and the mounting hole B below the tenth resistor R10 is connected to the end of the tenth resistor R10. The fixing hole A and the two mounting holes B form an isosceles trapezoid, and the distance between the fixing hole A and the lower edge of the PCB board 1 is greater than half the length of the PCB board 1; The symmetrical arrangement of the two resistor columns ensures that the power sampling resistor generates heat evenly and has a stable current response time during use. Mounting hole A is located in the upper half of the PCB board, while mounting hole B is located in the lower half of the PCB board. This ensures that the device heats up evenly and does not warp when actually collecting currents of 25A~50A.

[0037] Compared with the solution in this application, if the following is adopted Figure 3 The resistor array shown adopts an asymmetrical structure. Figure 3 The layout of the present application is more compact, but the heat generation is uneven during use. When used to collect currents above 30A, the temperature difference between dense and non-dense areas becomes more obvious, and the current response time becomes unstable.

[0038] Compared with the solution in this application, the following is adopted: Figure 4 The diagram shows a symmetrical structure. Although the fixing hole A and mounting hole B are also in the shape of an isosceles triangle, the mounting hole B is located at the bottom, while the fixing hole A is located in the middle of the PCB board or towards the mounting hole B. However, in actual use, this layout has strict requirements for installation. If the fixing position is subjected to too much force, the upper part of the resistor array will slightly tilt up, causing serious heat generation.

[0039] When using the same heat dissipation device, the power sampling resistor used in this application has the following parameters compared to the resistor parameters of the original TO-247 package: Figure 6As shown, the temperature comparison between the self-made power sampling resistor of this application and the original TO-247 packaged power sampling resistor under different operating currents is as follows: Figure 5 As shown, the self-made power sampling resistor in this application has a resistance of 20MΩ and a power of 50W. Figure 5 The temperature measured by the sampling resistor is the temperature after the potting compound has been applied. The temperature measured with the potting compound applied is about 8°C higher than the temperature without the potting compound applied.

[0040] Depend on Figure 5 and Figure 6 As can be seen, the power sampling resistor provided in this application can sample a large current with relatively low power consumption. The sampling resolution is not affected by temperature. When used in a laser driver circuit module, the response time and rise time of the current are no different from those of a power resistor using a TO-247 package. The pin configuration is suitable for practical use, and the cost is greatly reduced compared to a TO-247 packaged power resistor.

[0041] Example 3: like Figure 7 As shown, the present invention provides a method for implementing a power sampling resistor in a high-current circuit, comprising the following steps: S1. Select the alloy sampling resistors and their quantity with corresponding parameters according to the driving current of the laser driving circuit module; S2. Connect the selected alloy sampling resistors in series and arrange them evenly on the PCB board, and set a soldering pin at the beginning and end of the series alloy resistors respectively; S3. Install a heat dissipation device on the PCB board with alloy sampling resistors, fix it to the laser drive circuit module with soldering nails, and then seal it with thermally conductive insulating potting compound.

[0042] Example 4: like Figure 8 As shown, the present invention provides a method for implementing a power sampling resistor in a high-current circuit, comprising the following steps: S1. Select the alloy sampling resistors and their quantity according to the driving current of the laser driving circuit module; the specific steps of step S1 are as follows: S11. Obtain the drive current of the laser drive module; S12. Select the electron beam alloy sampling resistor with the set parameters as the sampling resistor; S13. Calculate the required number of electron beam alloy sampling resistors based on the driving current of the laser driving module and the resistance value of the electron beam alloy sampling resistor. S2. Connect the selected alloy sampling resistors in series and arrange them evenly on the PCB board, and set a soldering pin at the beginning and end of the series-connected alloy resistors respectively; the specific steps of step S2 are as follows: S21. Determine the number of electron beam alloy sampling resistors; S22. When the number of electron beam alloy sampling resistors is odd, set a connection resistor and proceed to step S23; When the number of electron beam alloy sampling resistors is even, two connection resistors are set; S23. Divide the alloy resistors other than the connecting resistors into two groups to generate two resistor columns, which are symmetrically arranged side by side on the PCB board. S24. Arrange the electron beam alloy sampling resistors in each resistor column horizontally, and connect them in series from beginning to end; S25. Set a mounting hole on the lower side of each of the two resistor columns on the PCB board, and connect the mounting hole to the endpoint on the lower side of the corresponding resistor column; S26. Connecting resistors are placed on the upper side of the two resistor columns and connected to the endpoints on the upper side of the two resistor columns; S27. Fixing holes are provided on the PCB board between the two resistor rows and the connecting resistor. The fixing holes and the two mounting holes are arranged in an isosceles triangle, and the distance between the fixing holes and the lower edge of the PCB board is greater than half the length of the PCB board. S28. Solder a tin-plated soldering pin at each of the two mounting holes, with the tin-plated soldering pin perpendicular to the PCB board surface; S3. Install a heat dissipation device on the PCB board with the alloy sampling resistors, and fix it to the laser drive circuit module with soldering pins. Then, seal it with thermally conductive and insulating potting compound. The specific steps of step S3 are as follows: S31. Apply silicone grease to the back of the PCB board after the electron beam alloy sampling resistors have been laid out, place mica sheets on it, and then install it onto the heat dissipation device through the fixing holes. S32. Use soldering pins to solder the PCB board to the laser drive circuit module; S33. Use thermally conductive and insulating potting compound to seal the PCB board for waterproofing.

[0043] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the invention should also be covered within the protection scope of the invention. Therefore, the protection scope of the invention should be determined by the scope of the claims.

Claims

1. A power sampling resistor for a high-current circuit, characterized in that, Includes PCB board, heat dissipation device and laser drive circuit module; Several alloy sampling resistors are located on the front of the PCB board; Alloy sampling resistors are evenly distributed on the PCB board and connected in series in sequence; The series-connected alloy sampling resistors are fixedly connected to a soldering pin at both ends, and the soldering pins are perpendicular to the surface of the PCB board. A thermally conductive and insulating potting compound layer is provided on the surface of the PCB board, and the thermally conductive and insulating potting compound layer covers the series-connected alloy sampling resistors; The back of the PCB board is fixed to the heat dissipation device with a layer of thermal paste, and the PCB board is fixed to the laser drive circuit module with soldering nails; The PCB board has mounting holes and two mounting holes; The PCB board is fixed to the heat dissipation device through mounting holes; One mounting hole is connected to the beginning of the series-connected alloy sampling resistor, and the other mounting hole is connected to the end of the series-connected alloy sampling resistor. The solder pins are fixed to the PCB board through the mounting holes. Each alloy resistor adopts a symmetrical series structure, including a connecting resistor and two resistor columns; The two resistor columns have the same number of resistors, and the two resistor columns are symmetrically arranged side by side on the PCB board; The alloy resistors in each resistor column are arranged horizontally and connected in series from beginning to end; The PCB board includes a top side and a bottom side, and the alloy resistors in the two resistor columns are parallel to the top side and the bottom side; Two mounting holes are located on the bottom edge of the PCB board, and each hole is connected to the bottom end of a resistor array. The connecting resistor is located on the upper side of the PCB board and is connected to the upper end of the resistor array at the upper side. The mounting hole is located in the area between the connecting resistor and the two resistor columns; The fixing holes and the two mounting holes are distributed in an isosceles triangle, and the distance from the fixing holes to the bottom edge of the PCB board is greater than half the length of the PCB board.

2. The power sampling resistor for the high-current circuit as described in claim 1, characterized in that, The number of connected resistors is one; The connecting resistor is horizontally positioned on the side of the PCB board, and its two ends are connected to the upper endpoints of the two resistor columns, respectively.

3. The power sampling resistor for the high-current circuit as described in claim 1, characterized in that, The number of connected resistors is two; The two connecting resistors are arranged vertically symmetrically, and each is positioned above a resistor column; The lower ends of the two connecting resistors are connected to the upper ends of the corresponding resistor array, and the upper ends of the two connecting resistors are connected to each other; The mounting holes are located in the area between the two connecting resistors, the connecting lines of the connecting resistors, and the two resistor arrays.

4. The power sampling resistor for the high-current circuit as described in claim 1, characterized in that, A mica sheet is also placed between the silicone grease layer and the heat dissipation device; The alloy sampling resistor is an electron beam welded alloy sampling resistor; The PCB board uses a double-layer conductive PCB board; The welding studs are made of tin-plated copper.

5. A method for implementing a power sampling resistor in a high-current circuit, characterized in that, The power sampling resistor applicable to the high-current circuit according to any one of claims 1-4 includes the following steps: S1. Select the alloy sampling resistors and their quantity with corresponding parameters according to the driving current of the laser driving circuit module; S2. Connect the selected alloy sampling resistors in series and arrange them evenly on the PCB board, and set a soldering pin at the beginning and end of the series alloy resistors respectively; S3. Install a heat dissipation device on the PCB board with alloy sampling resistors, fix it to the laser drive circuit module with soldering nails, and then seal it with thermally conductive insulating potting compound.

6. The method for implementing a power sampling resistor in a high-current circuit as described in claim 5, characterized in that, The specific steps of step S1 are as follows: S11. Obtain the drive current of the laser drive module; S12. Select the electron beam alloy sampling resistor with the set parameters as the sampling resistor; S13. Calculate the required number of electron beam alloy sampling resistors based on the drive current of the laser drive module and the resistance value of the electron beam alloy sampling resistor.

7. The method for implementing a power sampling resistor in a high-current circuit as described in claim 6, characterized in that, The specific steps of step S2 are as follows: S21. Determine the number of electron beam alloy sampling resistors; S22. When the number of electron beam alloy sampling resistors is odd, set a connection resistor and proceed to step S23; When the number of electron beam alloy sampling resistors is even, two connection resistors are set; S23. Divide the alloy resistors other than the connecting resistors into two groups to generate two resistor columns, which are symmetrically arranged side by side on the PCB board. S24. Arrange the electron beam alloy sampling resistors in each resistor column horizontally, and connect them in series from beginning to end; S25. Set a mounting hole on the lower side of each of the two resistor columns on the PCB board, and connect the mounting hole to the endpoint on the lower side of the corresponding resistor column; S26. Connecting resistors are placed on the upper side of the two resistor columns and connected to the endpoints on the upper side of the two resistor columns; S27. Fixing holes are provided on the PCB board between the two resistor rows and the connecting resistor. The fixing holes and the two mounting holes are arranged in an isosceles triangle, and the distance between the fixing holes and the lower edge of the PCB board is greater than half the length of the PCB board. S28. Solder a tin-plated soldering pin at each of the two mounting holes, with the tin-plated soldering pin perpendicular to the PCB board surface.

8. The method for implementing a power sampling resistor in a high-current circuit as described in claim 7, characterized in that, The specific steps of step S3 are as follows: S31. Apply silicone grease to the back of the PCB board after the electron beam alloy sampling resistors have been installed, place mica sheets on it, and then install it onto the heat dissipation device through the fixing holes. S32. Use soldering pins to solder the PCB board to the laser drive circuit module; S33. Use thermally conductive and insulating potting compound to seal the PCB board for waterproofing.

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