PCB of sampling circuit

Abstract

The utility model discloses a PCB of a sampling circuit, which comprises an input bonding pad, a ground bonding pad, a noise reduction module and a sampling module, and is characterized in that the noise reduction module comprises a first resistor, a second resistor and a third resistor; a first bonding pad of the first resistor is connected with the input bonding pad through a first copper laying area, and a second bonding pad of the first resistor is connected with the ground bonding pad through a second copper laying area; the second resistor and the third resistor are connected to the two ends of the first resistor through a first differential wire; the first differential wire avoids the first copper laying area and the second copper laying area; the sampling module is connected to the second resistor and the third resistor through a second differential wire. According to the technical scheme provided by the embodiment of the invention, through the arrangement of the first differential wire and the second differential wire, interference can be offset through wire-to-wire mutual offset, the error of the sampling module is reduced, the accuracy of the sampling signal is improved, and due to the fact that the differential wires can effectively inhibit electromagnetic interference, the passing rate of a near-field radiation anti-interference test can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, in particular to a PCB board of a sampling circuit. Background Art

[0002] The current sampling circuit is a common circuit usually used to measure the current in the circuit and is used to monitor the power consumption, current waveform, current change, etc. of the circuit.

[0003] During the PCB layout and wiring process, a modular layout is usually adopted to help improve the maintainability, scalability and testability of the circuit board. However, in the prior art, the unreasonable layout, routing and copper plating in the PCB layout and wiring will lead to large current sampling errors, which in turn makes the current sampling inaccurate; secondly, the unreasonable layout will introduce large power noise, resulting in a low pass rate for EMC (Electromagnetic Compatibility) tests, especially near-field radiation anti-interference tests. Utility Model Content

[0004] The utility model provides a PCB board of a sampling circuit to improve the sampling accuracy and near-field radiation anti-interference test pass rate of the PCB board of the sampling circuit.

[0005] According to one aspect of the utility model, a PCB board of a sampling circuit is provided, comprising:

[0006] Input pad and ground pad;

[0007] A noise reduction module, the noise reduction module comprising a first resistor, a second resistor and a third resistor; a first pad of the first resistor is connected to the input pad through a first copper-plated area, and a second pad of the first resistor is connected to the ground pad through a second copper-plated area; the second resistor and the third resistor are connected to two ends of the first resistor through a first differential routing; the first differential routing avoids the first copper-plated area and the second copper-plated area;

[0008] A sampling module is connected to the second resistor and the third resistor through a second differential trace.

[0009] Optionally, the first pad and the second pad of the first resistor are respectively the ends of the first copper-plated area and the ends of the second copper-plated area; the noise reduction module also includes a first capacitor; the second pad of the second resistor is connected to the first pad of the first capacitor, and the second pad of the third resistor is connected to the second pad of the first capacitor.

[0010] Optionally, the first capacitor is located on a side of the third resistor away from the first resistor, or the first capacitor is located on a side of the second resistor away from the first resistor, the first resistor is arranged along a first direction, and the second resistor and the third resistor are arranged along a second direction; the first direction is perpendicular to the second direction.

[0011] Optionally, the sampling module includes a first operational amplifier, a first filtering circuit, a second filtering circuit and a second capacitor;

[0012] The first input pad and the second input pad of the first operational amplifier are connected to the second pad of the second resistor and the second pad of the third resistor through the second differential trace, the first input pad of the first operational amplifier is connected to the first end of the first filter circuit, the second end of the first filter circuit is connected to the ground pad, the second input pad of the first operational amplifier is connected to the first end of the second filter circuit, the second end of the second filter circuit is connected to the output pad of the first operational amplifier, the first power pad of the first operational amplifier is connected to the power pad and to the first pad of the second capacitor, the second pad of the second capacitor is connected to the ground pad through the second copper-plated area, the second power pad of the first operational amplifier is connected to the ground pad, and the output pad of the first operational amplifier is connected to the receiving pad;

[0013] The first filter circuit is located on a side of the first operational amplifier away from the second filter circuit, the second capacitor is located on a side of the first operational amplifier away from the receiving pad, and the second capacitor is arranged along the first direction.

[0014] Optionally, the first filtering circuit includes a fourth resistor and a third capacitor;

[0015] The first pad of the fourth resistor is connected to the first pad of the third capacitor and to the first input pad of the first operational amplifier, the second pad of the fourth resistor is connected to the second pad of the third capacitor and to the second power pad of the first operational amplifier, the second pad of the fourth resistor, the second pad of the third capacitor and the ground pad are connected through the second copper-plated area, and a plurality of vias are provided to connect to the ground plane of the PCB board.

[0016] Optionally, the third capacitor is located on a side of the fourth resistor away from the first operational amplifier, and the third capacitor and the fourth resistor are arranged along the second direction.

[0017] Optionally, the second filtering circuit includes a fifth resistor and a fourth capacitor;

[0018] The first pad of the fifth resistor is connected to the first pad of the fourth capacitor and to the second input pad of the first operational amplifier, and the second pad of the fifth resistor is connected to the second pad of the fourth capacitor and to the output pad of the first operational amplifier.

[0019] Optionally, the fourth capacitor is located on a side of the fifth resistor away from the first operational amplifier, and the fourth capacitor and the fifth resistor are arranged along the second direction.

[0020] Optionally, the PCB board of the sampling circuit also includes a third filtering circuit, a first end of the third filtering circuit is connected to the output end of the sampling module, a second end of the third filtering circuit is connected to the receiving pad, and a third end of the third filtering circuit is connected to the ground pad.

[0021] Optionally, the third filtering circuit includes a sixth resistor and a fifth capacitor; a first pad of the sixth resistor is connected to the output end of the sampling module, a second pad of the sixth resistor is connected to the first pad of the fifth capacitor, and a second pad of the fifth capacitor is connected to the ground pad through a third copper-plated area, and is connected to the ground plane of the PCB board through a via;

[0022] The sixth resistor is located at a side of the fifth capacitor away from the receiving pad, and the sixth resistor and the fifth capacitor are arranged along the second direction.

[0023] The technical solution provided by the embodiment of the utility model is to set the second resistor and the third resistor to be connected to the two ends of the first resistor through the first differential routing, and the first differential routing avoids the first copper-plated area and the second copper-plated area, so as to avoid the electromagnetic radiation generated by the current and other signals passing through the copper-plated area and thus introducing interference. At the same time, the differential routing connection is set, which has a strong anti-interference ability, so the transmission quality of signal sampling can be improved. At the same time, the sampling module is connected to the second resistor and the third resistor through the second differential routing, and the differential lines further cancel each other interference through line-to-line, and other noise interference will not be introduced into the sampling module, which can reduce the error of the sampling module and improve the accuracy of the sampling signal. And because the differential line can effectively suppress electromagnetic interference, it can improve the pass rate of the near-field radiation anti-interference test.

[0024] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present utility model, nor are they intended to limit the scope of the present utility model. Other features of the present utility model will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A schematic diagram of the structure of a PCB board of a sampling circuit provided in an embodiment of the utility model;

[0027] Figure 2 A schematic diagram of the structure of a PCB board of another sampling circuit provided in an embodiment of the utility model;

[0028] Figure 3 A schematic diagram of the structure of a PCB board of another sampling circuit provided in an embodiment of the utility model;

[0029] Figure 4 A schematic diagram of the structure of a PCB board of another sampling circuit provided in an embodiment of the utility model;

[0030] Figure 5 A schematic diagram of the structure of a PCB board of another sampling circuit provided in an embodiment of the utility model;

[0031] Figure 6 A schematic diagram of the structure of a PCB board of another sampling circuit provided in an embodiment of the utility model;

[0032] Figure 7 A schematic structural diagram of a PCB board of another sampling circuit provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the utility model described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0035] Figure 1 A schematic diagram of the structure of a PCB board of a sampling circuit provided by an embodiment of the utility model, referring to Figure 1 The PCB board of the sampling circuit includes an input pad 1, a ground pad 2, a noise reduction module 3 and a sampling module 4, which are all arranged on a substrate 10. The noise reduction module 3 includes a first resistor R1, a second resistor R2 and a third resistor R3; the first pad of the first resistor R1 is connected to the input pad 1 through a first copper-plated area 100, and the second pad of the first resistor R1 is connected to the ground pad 2 through a second copper-plated area 200; the second resistor R2 and the third resistor R3 are connected to both ends of the first resistor R1 through a first differential trace; the first differential trace avoids the first copper-plated area 100 and the second copper-plated area 200; the sampling module 4 is connected to the second resistor R2 and the third resistor R3 through a second differential trace.

[0036] The input pad 1 is used to input a sampling current signal, the first resistor R1 is used to convert the input sampling current signal into a sampling voltage signal, and the second resistor R2 and the third resistor R3 are used to eliminate interference signals generated by the sampling current signal through the first resistor R1.

[0037] Optionally, the first copper-plating area 100 and the second copper-plating area 200 may be continuously laid as required.

[0038] Specifically, the first resistor R1 can be a high-power sampling resistor. The first resistor R1 converts the sampling current signal input by the input pad 1 into a sampling voltage signal. In this process, the first resistor R1 is subjected to a higher current, resulting in a strong magnetic field interference around the first resistor R1, and thus more interference signals. Since the second resistor R2 and the third resistor R3 exist and are arranged close to the first resistor R1, and the second resistor R2 and the third resistor R3 are directly connected to the centers of the two pads of the first resistor R1 through the first differential routing, the radiation interference signal in the copper-plated area can be avoided, and the interference signal generated by the sampling current signal through the first resistor R1 can be eliminated through the differential routing, thereby ensuring the transmission quality of the sampling signal. Further, the sampling module 4 is connected to the second resistor R2 and the third resistor R3 through the second differential routing, so that the sampling voltage signal is transmitted to the sampling module 4, and the second differential line can cancel each other's interference through the line-to-line, and reduce noise, thereby ensuring the sampling accuracy of the sampling module and the pass rate of the field radiation anti-interference test.

[0039] It should be noted that in order to clearly show the connection relationship and positional relationship of the circuit components, some connecting pads or terminals of the circuit components are used to represent the circuit components in the drawings of the embodiments of the utility model. Those skilled in the art can understand that on the final PCB board, the circuit components can be connected to the corresponding pads in the drawings.

[0040] The technical solution provided by the embodiment of the utility model is to set the second resistor R2 and the third resistor R3 to be connected to the two ends of the first resistor R1 through the first differential routing. The first differential routing avoids the first copper-plated area 100 and the second copper-plated area 200, which can avoid the electromagnetic radiation generated by the current and other signals passing through the copper-plated area and then introducing interference. At the same time, the differential routing connection is set, which has a strong anti-interference ability and can improve the transmission quality of signal sampling. At the same time, the sampling module 4 is connected to the second resistor R2 and the third resistor R3 through the second differential routing, and the differential lines further cancel each other through line-to-line interference, and other noise interference will not be introduced to the sampling module 4, which can reduce the error of the sampling module 4 and improve the accuracy of the sampling signal. And because the differential line can effectively suppress electromagnetic interference, it can improve the pass rate of the near-field radiation anti-interference test.

[0041] Figure 2 A schematic diagram of the structure of a PCB board of another sampling circuit provided by an embodiment of the utility model, referring to Figure 2 On the basis of the above embodiment, the first pad and the second pad of the first resistor R1 are respectively the ends of the first copper-plated area 100 and the ends of the second copper-plated area 200; the noise reduction module 3 also includes a first capacitor C1; the second pad of the second resistor R2 is connected to the first pad of the first capacitor C1, and the second pad of the third resistor R3 is connected to the second pad of the first capacitor C1.

[0042] The first capacitor C1 is used to further eliminate the interference signal generated by the sampling current signal passing through the first resistor R1.

[0043] Continue to refer Figure 2 Optionally, the first capacitor C1 is located on a side of the third resistor R3 away from the first resistor R1, or the first capacitor C1 is located on a side of the second resistor R2 away from the first resistor R1, the first resistor R1 is arranged along a first direction, and the second resistor R2 and the third resistor R3 are arranged along a second direction; the first direction is perpendicular to the second direction.

[0044] Among them, the first resistor R1, the second resistor R2, the third resistor R3 and the first capacitor C1 are arranged close to each other, so as to eliminate the interference signal generated by the sampling current signal through the first resistor R1; the first direction Y is a vertical direction, and the second direction X is a horizontal direction. The first resistor R1 is arranged along the first direction Y, which means that the first pad and the second pad of the first resistor R1 are in a vertical direction, and the second resistor R2 is arranged along the second direction X, which means that the first pad and the second pad of the second resistor R2 are in a horizontal direction.

[0045] Optionally, the first capacitor C1 is arranged along the first direction Y.

[0046] Optionally, the second pad of the second resistor R2 and the second pad of the third resistor R3 are connected to two ends of the first capacitor C1 through a third differential trace, and the first pad and the second pad of the first capacitor C1 are connected to the sampling module 4 through a fourth differential trace.

[0047] Specifically, the first pad of the first capacitor C1 is connected to the second input terminal of the sampling module 4, and the second pad of the first capacitor C1 is connected to the first input terminal of the sampling module 4. By setting the first resistor R1 and the first capacitor C1 to be arranged along the first direction Y, and the second resistor R2 and the third resistor R3 to be arranged along the second direction X, the layout between them can be more compact, thereby shortening the current sampling signal path length and reducing interference and loss during signal transmission. The first pad of the first resistor R1 is the end of the first copper-plated area 100, and the second pad of the first resistor R1 is the end of the second copper-plated area 200, so that the second resistor R2 and the third resistor R3 can be connected to the first resistor R1 through the first differential routing without passing through the two copper-plated areas, avoiding the radiation interference signal of the copper-plated. Further, due to the presence of the first capacitor C1, the interference signal generated by the sampling current signal through the first resistor R1 can be further filtered out to ensure the transmission quality of the sampling signal.

[0048] The technical solution provided in this embodiment can make the layout between components more compact by setting the placement of components, reduce interference during signal transmission, and further save space on the PCB board, which is conducive to reducing costs. At the same time, the first capacitor C1 further filters out interference signals, which can improve the accuracy of the sampled signal.

[0049] Figure 3 A schematic diagram of the structure of a PCB board of another sampling circuit provided by an embodiment of the utility model, referring to Figure 3 On the basis of the above embodiments, the sampling module 4 includes a first operational amplifier U1, a first filter circuit 41, a second filter circuit 42 and a second capacitor C2; the first input pad 11 and the second input pad 12 of the first operational amplifier U1 are connected to the second pad of the second resistor R2 and the second pad of the third resistor R3 through a second differential trace, the first input pad 11 of the first operational amplifier U1 is connected to the first end of the first filter circuit 41, the second end of the first filter circuit 41 is connected to the ground pad 2, the second input pad 12 of the first operational amplifier U1 is connected to the first end of the second filter circuit 42, the second end of the second filter circuit 42 is connected to the output pad 13 of the first operational amplifier U1, the first power pad 14 of the first operational amplifier U1 is connected to the power pad 5 and to the first pad of the second capacitor C2, the second pad of the second capacitor C2 is connected to the ground pad 2 through a second copper-plated area, the second power pad 15 of the first operational amplifier U1 is connected to the ground pad 2, and the output pad 13 of the first operational amplifier U1 is connected to the receiving pad 6. The first filter circuit 41 is located at a side of the first operational amplifier U1 away from the second filter circuit 42 , the second capacitor C2 is located at a side of the first operational amplifier U1 away from the receiving pad 6 , and the second capacitor C2 is arranged along the first direction Y.

[0050] Among them, the first input pad 11 of the first operational amplifier U1 serves as the first input end of the sampling module 4, the second input pad 12 of the first operational amplifier U1 serves as the second input end of the sampling module 4, and the output pad 13 of the first operational amplifier U1 serves as the output end of the sampling module 4; the first operational amplifier U1 is used to amplify the sampling voltage signal input at its input end to obtain a sampling voltage, the first filter circuit 41 is used to filter out the interference signal on the first input pad 11 of the first operational amplifier U1, the second filter circuit 42 is used to filter out the interference signal on the output pad 13 of the first operational amplifier U1, and provide a feedback signal for the first operational amplifier U1; the second capacitor C2 is used to further filter out the interference signal.

[0051] Optionally, the second end of the first filter circuit 41 is connected to the ground pad 2 through the second copper-plated area 200 .

[0052] Continue to refer Figure 3Optionally, the noise reduction module 3 also includes a first capacitor C1, a first pad of the first capacitor C1 is connected to the second pad of the second resistor R2, and is connected to the second input pad 12 of the first operational amplifier U1, a second pad of the first capacitor C1 is connected to the second pad of the third resistor R3, and is connected to the first input pad 11 of the first operational amplifier U1, and the first input pad 11 and the second input pad 12 of the first operational amplifier U1 are connected to the first pad and the second pad of the first capacitor C1 through a second differential trace.

[0053] Specifically, the sampling module 4 is arranged close to the receiving pad 6, so that the output pad 13 of the first operational amplifier U1 is close to the receiving pad 6, so as to avoid the problem that the single-ended signal output by the first operational amplifier U1 generates high-frequency resonance due to the parasitic parameters (capacitance and inductance) due to the long wiring, thereby causing large sampling fluctuations and low sampling accuracy. The first filter circuit 41 is arranged close to the input end of the first operational amplifier U1, so as to filter out the interference signal of the first input end of the first operational amplifier U1, and the input sampling current signal of the input pad 1 needs to be connected to the first input pad 11 of the first operational amplifier U1 through the first filter circuit 41, and the second end of the first filter circuit 41 is directly connected to the second power supply pad 15 of the first operational amplifier U1, and does not undergo perforation and layer change, so that the first filter circuit 41 can eliminate the interference signal on the first input pad 11 of the first operational amplifier U1. Furthermore, a via hole is punched on the outside of the first filter circuit 41 to connect to the ground plane of the PCB board (for example, the first filter circuit 41 is connected to the second copper-clad area 200 through a via hole, and the second copper-clad areas 200 arranged in different areas are all connected through via holes) to improve the filtering effect. The second filter circuit 42 is placed close to the output pad 13 of the first operational amplifier U1, and does not change layers through holes, so that the interference signal on the output pad 13 of the first operational amplifier U1 can be filtered out, and because of the close arrangement, the first operational amplifier U1 can quickly respond to the feedback signal of the second filter circuit 42, thereby improving the response speed.

[0054] The technical solution provided in this embodiment is to arrange the first operational amplifier U1 close to the receiving pad 6 so that the single-ended signal output by the first operational amplifier U1 can be input to the receiving pad 6 through a shorter wiring, thereby avoiding the problems of large sampling fluctuations and inability to eliminate high-frequency noise, thereby improving the sampling accuracy and the pass rate of the near-field radiation anti-interference test. By arranging the first filter circuit 41 and the second filter circuit 42 close to the first operational amplifier U1, the sampling voltage signals on the input pad and the output pad 13 of the first operational amplifier U1 can be filtered, further improving the accuracy of the sampling signal.

[0055] Figure 4 A schematic diagram of the structure of a PCB board of another sampling circuit provided by an embodiment of the utility model, referring to Figure 4 On the basis of the above embodiments, the first filtering circuit includes a fourth resistor R4 and a third capacitor C3; a first pad of the fourth resistor R4 is connected to a first pad of the third capacitor C3, and is connected to a first input pad 11 of the first operational amplifier U1; a second pad of the fourth resistor R4 is connected to a second pad of the third capacitor C3, and is connected to a second power pad 15 of the first operational amplifier U1; a second pad of the fourth resistor R4, a second pad of the third capacitor C3 and a ground pad 2 are connected through a second copper-plated area 200, and a plurality of vias are provided to connect to a ground plane of the PCB board.

[0056] The fourth resistor R4 is used for voltage reduction, and the third capacitor C3 is used for energy storage.

[0057] Continue to refer Figure 4 Optionally, the third capacitor C3 is located at a side of the fourth resistor R4 away from the first operational amplifier U1, and the third capacitor C3 and the fourth resistor R4 are arranged along the second direction X.

[0058] Specifically, the third capacitor C3 and the fourth resistor R4 are arranged close to the input end of the first operational amplifier U1, so that the loop formed therebetween is smaller, thereby making the interference generated on the first input pad 11 of the first operational amplifier U1 smaller. The input sampling current signal of the input pad 6 is input to the first input pad 11 of the first operational amplifier U1 through the first pad of the third capacitor C3 and the fourth resistor R4, and the second pad of the third capacitor C3 and the fourth resistor R4 is directly connected to the second power pad 15 of the first operational amplifier U1 without hole exchange layer, and the outer side of the third capacitor C3 and the fourth resistor R4 is connected to the ground plane of the PCB board through a hole, which can improve the filtering effect. And due to the presence of the third capacitor C3, the ground terminal of the first operational amplifier U1 can be grounded through the third capacitor C3, and because the voltage of the third capacitor C3 cannot suddenly change, the interference signal (such as the voltage spike on the ground plane) can be suppressed by the capacitor, and then the interference signal will not enter the first operational amplifier U1, so that the sampling of the first operational amplifier U1 is more accurate. At the same time, it can also prevent the switching noise of the first operational amplifier U1 from being transmitted to the ground plane, thereby improving the stability and reliability of the circuit and reducing the noise level of the system.

[0059] The technical solution provided in this embodiment is to arrange the third capacitor C3 and the fourth resistor R4 close to the input end of the first operational amplifier U1, thereby forming a smaller loop, and can further eliminate the interference signal in the sampled voltage signal, so that the sampling of the first operational amplifier U1 is more accurate, and the sampling accuracy is improved. At the same time, since the second pads of the third capacitor C3 and the fourth resistor R4 are grounded, their reference points can be connected to the ground, effectively consuming the noise or interference signal on the filter capacitor, and the grounding can be used as a low impedance path to guide the interference signal to the ground, thereby reducing their impact on the circuit, improving the filtering efficiency, and improving the filtering effect.

[0060] Figure 5 A schematic diagram of the structure of a PCB board of another sampling circuit provided by an embodiment of the utility model, referring to Figure 5 On the basis of the above embodiments, the second filtering circuit 42 includes a fifth resistor R5 and a fourth capacitor C4; the first pad of the fifth resistor R5 is connected to the first pad of the fourth capacitor C4, and is connected to the second input pad 12 of the first operational amplifier U1, the second pad of the fifth resistor R5 is connected to the second pad of the fourth capacitor C4, and is connected to the output pad 13 of the first operational amplifier U1.

[0061] The fifth resistor R5 is used to achieve stable control of the sampling voltage; the fourth capacitor C4 is used to filter out high-frequency noise components in the sampling voltage to ensure the stability and accuracy of the output sampling signal.

[0062] The first filter circuit 41 includes a fourth resistor R4 and a third capacitor C3.

[0063] Continue to refer Figure 5 Optionally, the fourth capacitor C4 is located at a side of the fifth resistor R5 away from the first operational amplifier U1, and the fourth capacitor C4 and the fifth resistor R5 are arranged along the second direction X.

[0064] Specifically, the fourth resistor R4 and the third capacitor C3 are arranged close to the input end of the first operational amplifier U1, which can eliminate the interference signal on the first input pad 11 of the first operational amplifier U1. Furthermore, the fourth capacitor C4 and the fifth resistor R5 are arranged close to the output end of the first operational amplifier U1, and the output signal of the first operational amplifier U1 is filtered by the fourth capacitor C4 and the fifth resistor R5 and output to the receiving pad 6 without passing through the hole exchange layer to improve the stability of the signal. At the same time, the fourth capacitor C4 and the fifth resistor R5 provide a feedback signal for the first operational amplifier U1, and not passing through the hole exchange layer further makes the feedback signal have no delay and can respond faster.

[0065] The technical solution provided in this embodiment makes the output signal of the first operational amplifier U1 more stable by setting the fourth capacitor C4 and the fifth resistor R5, and because the fourth capacitor C4, the fifth resistor R5 and the first operational amplifier U1 are arranged close to each other and do not pass through the hole, the filter line is shorter and the feedback signal response speed is faster.

[0066] Figure 6 A schematic diagram of the structure of a PCB board of another sampling circuit provided by an embodiment of the utility model, referring to Figure 6 On the basis of the above embodiments, the PCB board of the sampling circuit also includes a third filtering circuit 7, a first end of the third filtering circuit 7 is connected to the output end of the sampling module 4, a second end of the third filtering circuit 7 is connected to the receiving pad 6, and a third end of the third filtering circuit 7 is connected to the ground pad 1.

[0067] The third filtering circuit 7 is used to filter the sampled voltage signal on the receiving pad 6 to improve the stability of the sampled voltage signal.

[0068] Continue to refer Figure 6 Optionally, the third filtering circuit 7 includes a sixth resistor R6 and a fifth capacitor C5; the first pad of the sixth resistor R6 is connected to the output end of the sampling module 4, the second pad of the sixth resistor R6 is connected to the first pad of the fifth capacitor C5, the second pad of the fifth capacitor C5 is connected to the ground pad 1 through the third copper-plated area 201, and is connected to the ground plane of the PCB board through a via; wherein the sixth resistor R6 is located on a side of the fifth capacitor C5 away from the receiving pad 6, and the sixth resistor R6 and the fifth capacitor C5 are arranged along the second direction X and are both arranged on the substrate 10.

[0069] The sixth resistor R6 is used for voltage reduction, and the fifth capacitor C5 is used for energy storage.

[0070] Optionally, the third copper plating area 201 can continue to be laid as required.

[0071] Optionally, the substrate 10 includes at least three layers, namely a TOP layer, a GND layer and a BOTTOM layer from top to bottom, the components are all located in the TOP layer, and the third copper-plated area 201 is located in the GND layer.

[0072] Specifically, the sixth resistor R6 and the fifth capacitor C5 are arranged close to the receiving pad 6. The output signal of the sampling module 4 is filtered by the sixth resistor R6 and the fifth capacitor C5 and then input to the receiving pad 6. A hole is drilled on the outside of the fifth capacitor C5, that is, it is connected to the ground plane of the PCB board through the third copper-plated area 201 to improve the filtering effect.

[0073] The technical solution provided in this embodiment can improve the stability and accuracy of the sampling voltage signal on the receiving pad 6 by setting a sixth resistor R6 and a fifth capacitor C5 at the end of the receiving pad 6.

[0074] Figure 7 A schematic diagram of the structure of a PCB board of another sampling circuit provided by an embodiment of the utility model, referring to Figure 7 On the basis of the above embodiments, the PCB board of the sampling circuit includes an input pad 1, a ground pad 2, a noise reduction module 3, a sampling module 4, a power pad 5, a receiving pad 6 and a third filtering circuit 7, all of which are arranged on a substrate 10.

[0075] Specifically, the PCB boards of the sampling circuit are all laid out on the TOP layer, and the second copper-clad areas 200 laid at different positions are all connected by punching holes, and the second copper-clad area 200 located on the TOP layer and the third copper-clad area 201 located on the GND layer are connected by punching holes. When the input pad 1 inputs the sampling current signal, the sampling current signal is converted into a sampling voltage signal for transmission through the first resistor R1. At this time, since the first resistor R1 is subjected to a higher current and generates more interference signals, the second resistor R2, the third resistor R3 and the first capacitor C1 are arranged close to the first resistor R1, and the interference signal generated by the sampling current signal through the first resistor R1 can be filtered out. The two ends of the first resistor R1 are connected to the two ends of the first capacitor C1 through the first differential routing through the second resistor R2 and the third resistor R3, and the advantages of the differential line can be used to further eliminate the interference signal, so that the quality of the sampling signal transmission is higher. By arranging the noise reduction module 1 away from the sampling module 4, the sampling module 4 can be kept away from the interference source, reducing electromagnetic interference, and making the sampling signal more accurate. The two ends of the first capacitor C1 are connected to the first input pad 11 and the second input pad 12 of the first operational amplifier U1 through the fourth differential routing, which ensures the transmission quality of the sampling signal, and the differential routing cancels out interference between the lines, does not introduce other noise, and can reduce the system noise 470-1000MHz, which is conducive to improving the pass rate of the near-field radiation anti-interference test. By arranging the output pad 13 of the first operational amplifier U1 close to the receiving pad 6, the output sampling voltage signal of the first operational amplifier U1 is transmitted to the receiving pad 6 along a safer and more reliable path. The third capacitor C3 and the fourth resistor R4 are arranged close to the input end of the first operational amplifier U1, so that the loop formed therebetween is smaller and the interference generated on the first input pad 11 of the first operational amplifier U1 is smaller, and the third capacitor C3 and the fourth resistor R4 can further filter out the interference signal in the sampling signal, the fifth resistor R5 and the fourth capacitor C4 are arranged close to the output pad 13 of the first operational amplifier U1, and can eliminate the interference signal in the output sampling voltage signal of the first operational amplifier U1, the sixth resistor R6 and the fifth capacitor C5 are arranged close to the receiving pad 6, and the input sampling voltage signal of the receiving pad 6 is further filtered, thereby improving the sampling accuracy.

[0076] The technical solution provided in this embodiment can better reduce electromagnetic interference by separately arranging the noise reduction module 3 and the sampling module 4, and because of the connection through differential lines, the advantages of differential lines can be effectively utilized, so that the sampling voltage signal output by the first operational amplifier U1 to the receiving pad 6 has a safer and more reliable transmission path. At the same time, since the two ends of the first resistor R1 are connected to the two ends of the first capacitor C1 through the second resistor R2 and the third resistor R3 through differential routing, the two ends of the first capacitor C1 are also connected to the first operational amplifier U1 through differential routing, so that the signal quality of the sampling signal is not affected by the PCB board, which is conducive to improving the sampling accuracy of the sampling signal.

[0077] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0078] The above specific implementations do not constitute a limitation on the protection scope of the present utility model. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A PCB board for a sampling circuit, characterized in that: include: Input pad and ground pad; A noise reduction module, the noise reduction module comprising a first resistor, a second resistor and a third resistor; a first pad of the first resistor is connected to the input pad through a first copper-plated area, and a second pad of the first resistor is connected to the ground pad through a second copper-plated area; the second resistor and the third resistor are connected to two ends of the first resistor through a first differential routing; the first differential routing avoids the first copper-plated area and the second copper-plated area; A sampling module is connected to the second resistor and the third resistor through a second differential trace.

2. The PCB board of the sampling circuit according to claim 1, characterized in that: The first pad and the second pad of the first resistor are respectively the ends of the first copper-plated area and the ends of the second copper-plated area; the noise reduction module also includes a first capacitor; the second pad of the second resistor is connected to the first pad of the first capacitor, and the second pad of the third resistor is connected to the second pad of the first capacitor.

3. The PCB board of the sampling circuit according to claim 2, characterized in that: The first capacitor is located on a side of the third resistor away from the first resistor, or the first capacitor is located on a side of the second resistor away from the first resistor, the first resistor is arranged along a first direction, and the second resistor and the third resistor are arranged along a second direction; the first direction is perpendicular to the second direction.

4. The PCB board of the sampling circuit according to claim 1, characterized in that: The sampling module includes a first operational amplifier, a first filtering circuit, a second filtering circuit and a second capacitor; The first input pad and the second input pad of the first operational amplifier are connected to the second pad of the second resistor and the second pad of the third resistor through the second differential trace, the first input pad of the first operational amplifier is connected to the first end of the first filter circuit, the second end of the first filter circuit is connected to the ground pad, the second input pad of the first operational amplifier is connected to the first end of the second filter circuit, the second end of the second filter circuit is connected to the output pad of the first operational amplifier, the first power pad of the first operational amplifier is connected to the power pad and to the first pad of the second capacitor, the second pad of the second capacitor is connected to the ground pad through the second copper-plated area, the second power pad of the first operational amplifier is connected to the ground pad, and the output pad of the first operational amplifier is connected to the receiving pad; The first filter circuit is located on a side of the first operational amplifier away from the second filter circuit, the second capacitor is located on a side of the first operational amplifier away from the receiving pad, and the second capacitor is arranged along the first direction.

5. The PCB board of the sampling circuit according to claim 4, characterized in that: The first filtering circuit includes a fourth resistor and a third capacitor; The first pad of the fourth resistor is connected to the first pad of the third capacitor and to the first input pad of the first operational amplifier, the second pad of the fourth resistor is connected to the second pad of the third capacitor and to the second power pad of the first operational amplifier, the second pad of the fourth resistor, the second pad of the third capacitor and the ground pad are connected through the second copper-plated area, and a plurality of vias are provided to connect to the ground plane of the PCB board.

6. The PCB board of the sampling circuit according to claim 5, characterized in that: The third capacitor is located at a side of the fourth resistor away from the first operational amplifier, and the third capacitor and the fourth resistor are arranged along the second direction.

7. The PCB board of the sampling circuit according to claim 4, characterized in that: The second filtering circuit includes a fifth resistor and a fourth capacitor; The first pad of the fifth resistor is connected to the first pad of the fourth capacitor and to the second input pad of the first operational amplifier, and the second pad of the fifth resistor is connected to the second pad of the fourth capacitor and to the output pad of the first operational amplifier.

8. The PCB board of the sampling circuit according to claim 7, characterized in that: The fourth capacitor is located at a side of the fifth resistor away from the first operational amplifier, and the fourth capacitor and the fifth resistor are arranged along the second direction.

9. The PCB board of the sampling circuit according to claim 1, characterized in that: It also includes a third filtering circuit, a first end of the third filtering circuit is connected to the output end of the sampling module, a second end of the third filtering circuit is connected to the receiving pad, and a third end of the third filtering circuit is connected to the ground pad.

10. The PCB board of the sampling circuit according to claim 9, characterized in that: The third filtering circuit includes a sixth resistor and a fifth capacitor; the first pad of the sixth resistor is connected to the output end of the sampling module, the second pad of the sixth resistor is connected to the first pad of the fifth capacitor, the second pad of the fifth capacitor is connected to the ground pad through the third copper-plated area, and is connected to the ground plane of the PCB board through a via; The sixth resistor is located at a side of the fifth capacitor away from the receiving pad, and the sixth resistor and the fifth capacitor are arranged along the second direction.

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