PCB-based impedance measurement circuit, device and system

Abstract

The embodiment of the utility model provides an impedance measurement circuit, device and system based on a PCB, and belongs to the technical field of circuit testing. The circuit comprises a constant current source output module, an amplification module, a first circuit arm module, a second circuit arm module, a third circuit arm module, a fourth circuit arm module, a first interface and a second interface, and the first circuit arm module, the second circuit arm module, the third circuit arm module and the fourth circuit arm module are combined to form a Kelvin bridge circuit. The first interface is electrically connected with the control module, the second interface is electrically connected with the to-be-tested circuit board, and the control module is used for collecting a target voltage and determining a target resistance value of a wire in the to-be-tested circuit board according to the target voltage. According to the embodiment of the invention, the accuracy and test efficiency of impedance measurement of the PCB can be improved.

Description

Technical Field

[0001] This application relates to the technical field of circuit testing, and particularly to an impedance measurement circuit, device, and system based on a printed circuit board (PCB). Background Art

[0002] During the large-scale mass production of printed circuit boards (PCBs), in order to ensure the quality of the products, it is particularly important to measure the trace impedance of the PCB. Accurate impedance measurement is related to the performance stability of the PCB. At present, the trace impedance test of the PCB requires manual operation, which has measurement errors and low test efficiency.

[0003] Therefore, how to improve the accuracy and test efficiency of PCB impedance measurement has become a technical problem to be solved urgently. Summary of the Utility Model

[0004] The main purpose of the embodiments of this application is to propose an impedance measurement circuit, device, and system based on a PCB, aiming to improve the accuracy and test efficiency of PCB impedance measurement.

[0005] To achieve the above object, a first aspect of the embodiments of this application proposes an impedance measurement circuit based on a PCB. The impedance measurement circuit is electrically connected to a circuit board under test and a control module. The impedance measurement circuit includes: a constant current source output module, an amplification module, a first circuit arm module, a second circuit arm module, a third circuit arm module, a fourth circuit arm module, a first interface, and a second interface;

[0006] The first circuit arm module is electrically connected to the constant current source output module and the first interface, and the second circuit arm module is electrically connected to the constant current source output module and the first interface; the third circuit arm module is electrically connected to the first interface, the second interface, and the amplification module, and the fourth circuit arm module is electrically connected to the first interface, the second interface, and the amplification module; the first interface is electrically connected to the control module, and the second interface is electrically connected to the circuit board under test; wherein, the first circuit arm module, the second circuit arm module, the third circuit arm module, and the fourth circuit arm module are combined to form a Kelvin bridge circuit;

[0007] The constant current source output module is used to provide power; the amplification module is used to amplify the voltage generated by the traces on the circuit board under test when powered on to obtain a target voltage; the control module is used to collect the target voltage and determine the target resistance value of the traces in the circuit board under test according to the target voltage.

[0008] In some embodiments, the impedance measurement circuit further includes a diode rectification module;

[0009] The diode rectification module is electrically connected to the first circuit arm module and the second circuit arm module, and the diode rectification module is used to rectify the currents of the first circuit arm module and the second circuit arm module.

[0010] In some embodiments, the first circuit arm module includes a first resistor and a tenth resistor, the second circuit arm module includes a seventh resistor, the third circuit arm module includes a second resistor, a fourth resistor and an eighth resistor, the fourth circuit arm module includes a third resistor, a fifth resistor and a ninth resistor, and the amplification module includes an operational amplifier, a first capacitor, a first diode, a second diode and a sixth resistor;

[0011] The first resistor is electrically connected to the first interface and the tenth resistor, the second resistor is electrically connected to the first interface, the inverting input terminal of the operational amplifier and the fourth resistor, the third resistor is electrically connected to the first interface, the non-inverting input terminal of the operational amplifier and the fifth resistor, the output terminal of the operational amplifier is electrically connected to the sixth resistor, the input terminal of the first diode and the output terminal of the second diode, the first capacitor is electrically connected to the output terminal of the first diode and the input terminal of the second diode, the eighth resistor is electrically connected to the fourth resistor and the second interface, and the ninth resistor is electrically connected to the fifth resistor and the second interface.

[0012] In some embodiments, the diode rectification module includes a third diode and a fourth diode;

[0013] The input terminal of the third diode is electrically connected to the output terminal of the fourth diode and the seventh resistor, and the output terminal of the third diode is electrically connected to the input terminal of the fourth diode and the first resistor.

[0014] In some embodiments, the amplification module further includes a second capacitor and a third capacitor;

[0015] The second capacitor is electrically connected to the first capacitor and the input terminal of the second diode, and the third capacitor is electrically connected to the output terminal of the first diode.

[0016] In some embodiments, the constant current source output module includes a current source, a fourth capacitor, a fifth capacitor, a fifth diode, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor and a fifteenth resistor;

[0017] The current source is electrically connected to the eleventh resistor, the twelfth resistor, the thirteenth resistor and the fifth diode, the thirteenth resistor is electrically connected to the fourth capacitor, and the fourteenth resistor is electrically connected to the eleventh resistor, the twelfth resistor, the fifteenth resistor and the fifth capacitor.

[0018] To achieve the above object, a second aspect of the embodiments of the present application provides an impedance measurement device based on a PCB, where the impedance measurement device includes: the impedance measurement circuit based on a PCB described in the first aspect above, a control module, and an analog-to-digital conversion module;

[0019] The control module is electrically connected to the analog-to-digital conversion module, the analog-to-digital conversion module is electrically connected to the impedance measurement circuit, and the impedance measurement circuit is electrically connected to the circuit board to be measured;

[0020] The analog-to-digital conversion module collects the target voltage output by the impedance measurement circuit and converts the target voltage into a target digital signal; the control module calculates the target resistance value of the circuit board to be measured according to the target digital signal.

[0021] In some embodiments, the impedance measurement device further includes a switch matrix module;

[0022] The switch matrix module is electrically connected to the control module, the analog-to-digital conversion module, and multiple impedance measurement circuits; the switch matrix module has multiple channels, and each channel is electrically connected to an impedance measurement circuit;

[0023] The control module outputs a control signal, and the switch matrix module switches channels according to the control signal to collect the target voltage output by the impedance measurement circuit.

[0024] In some embodiments, the impedance measurement device further includes a test probe module;

[0025] The test probe module is electrically connected to the impedance measurement circuit and the switch matrix module.

[0026] To achieve the above object, a third aspect of the embodiments of the present application provides an impedance measurement system based on a PCB, where the impedance measurement system includes:

[0027] The impedance measurement device based on a PCB described in the second aspect above;

[0028] An upper computer, the upper computer is communicatively connected to the impedance measurement device, and the upper computer is configured to obtain the target resistance value output by the impedance measurement device, obtain a test result according to the target resistance value, and save the test result.

[0029] The impedance measurement circuit, device, and system based on PCB proposed in this application form a Kelvin bridge circuit through the combination of the first circuit arm module, the second circuit arm module, the third circuit arm module, and the fourth circuit arm module, and precisely measure the trace impedance in the way of the Kelvin bridge to reduce measurement errors. Moreover, the impedance of the traces in the circuit board to be measured is extremely small, so an amplification module is required to amplify the weak voltage signal generated by the traces in the circuit board to be measured, thereby further improving the accuracy of trace impedance measurement. Through the control module, the target voltage obtained after amplification is collected, and the impedance of the traces in the circuit board to be measured is calculated, so as to obtain the target resistance value, improve the test efficiency, and thus improve the accuracy and test efficiency of PCB impedance measurement. Description of the Drawings

[0030] Figure 1 is the block diagram of the impedance measurement circuit based on PCB provided by an embodiment of this application;

[0031] Figure 2 is the circuit schematic diagram of the impedance measurement circuit based on PCB provided by an embodiment of this application;

[0032] Figure 3 is the circuit schematic diagram of the impedance measurement circuit based on PCB provided by another embodiment of this application;

[0033] Figure 4 is the block diagram of the impedance measurement device based on PCB provided by an embodiment of this application;

[0034] Figure 5 is the block diagram of the impedance measurement device based on PCB provided by another embodiment of this application. Detailed Embodiments

[0035] In order to make the objectives, technical solutions, and advantages of this application clearer, the following further elaborates on this application in combination with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0036] It should be noted that although functional module division is performed in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order from the module division in the device or the order in the flowchart. Terms such as "first" and "second" in the specification, claims, and the above accompanying drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein are for the purpose of describing embodiments of this application only and are not intended to limit this application.

[0038] First, several nouns involved in this application are parsed as follows:

[0039] Trace: In a PCB (Printed Circuit Board), it refers to the signal line connecting device pins.

[0040] Trace impedance: It refers to the resistance characteristics of the signal line on a PCB. During the manufacturing and testing processes of a PCB, the control and testing of trace impedance are very important.

[0041] Kelvin bridge: It is a circuit used to measure resistance. The Kelvin bridge can specifically be a Kelvin four - wire bridge. According to the functions and potential levels, these four wires are respectively called the high - potential application line (HF), the low - potential application line (LF), the high - potential detection line (HS), and the low - potential detection line (LS). The Kelvin four - wire bridge is based on the four - wire measurement principle and uses two additional leads to eliminate the influence of resistance wires and contact resistance, providing more accurate resistance measurement results. When the bridge reaches the balanced state, the voltage difference across the bridge circuit is zero. At this time, there is a proportional relationship among the resistances in the bridge circuit, so that the resistance value of the resistance to be measured can be calculated.

[0042] The impedance measurement circuit, device, and system based on a PCB provided by the embodiments of this application will be specifically described through the following embodiments. First, the impedance measurement circuit based on a PCB in the embodiments of this application is described.

[0043] Figure 1 is a module block diagram of the impedance measurement circuit 100 based on a PCB provided by the embodiments of this application. The impedance measurement circuit 100 is electrically connected to a circuit board under test ( Figure 1 not shown in the figure) and a control module ( Figure 1 not shown in the figure). The impedance measurement circuit 100 includes: a constant - current source output module 10, an amplification module 20, a first circuit arm module 30, a second circuit arm module 40, a third circuit arm module 50, a fourth circuit arm module 60, a first interface 70, and a second interface 80.

[0044] The first circuit arm module 30 is electrically connected to the constant current source output module 10 and the first interface 70, and the second circuit arm module 40 is electrically connected to the constant current source output module 10 and the first interface 70; the third circuit arm module 50 is electrically connected to the first interface 70, the second interface 80 and the amplification module 20, and the fourth circuit arm module 60 is electrically connected to the first interface 70, the second interface 80 and the amplification module 20; the first interface 70 is electrically connected to the control module, and the second interface 80 is electrically connected to the circuit board under test. Among them, the first circuit arm module 30, the second circuit arm module 40, the third circuit arm module 50 and the fourth circuit arm module 60 are combined to form a Kelvin bridge circuit.

[0045] The constant current source output module 10 is used to provide power; the amplification module 20 is used to amplify the voltage generated by the trace when the circuit board under test is powered on to obtain the target voltage; the control module is used to collect the target voltage and determine the target resistance value of the trace in the circuit board under test according to the target voltage.

[0046] The beneficial effects of the embodiments of the present application include but are not limited to: a Kelvin bridge circuit is formed by combining the first circuit arm module 30, the second circuit arm module 40, the third circuit arm module 50 and the fourth circuit arm module 60, and the Kelvin bridge method is used to accurately measure the trace impedance and reduce the measurement error. Moreover, the impedance of the trace in the circuit board under test is extremely small, so it is necessary to amplify the weak voltage signal generated by the trace in the circuit board under test through the amplification module 20 to further improve the accuracy of the trace impedance measurement. Through the control module, the target voltage obtained after amplification is collected, the impedance of the trace in the circuit board under test is calculated, and thus the target resistance value is obtained, improving the test efficiency. In summary, the embodiments of the present application can improve the accuracy and test efficiency of the impedance measurement of the PCB.

[0047] It should be noted that the circuit board under test is a PCB. Specifically, the second interface 80 is electrically connected to the trace under test in the circuit board under test, and the impedance of the trace under test is measured to obtain the corresponding target resistance value.

[0048] Specifically, the current provided by the constant current source output module 10 has a preset current value, and the preset current value can be any value in the range of 1 - 100 mA, such as 40 mA.

[0049] Specifically, the amplification module 20 can be a differential amplifier. The amplification module 20 has a preset amplification factor. For example, the amplification factor is 100 times.

[0050] It should be noted that the target voltage is the amplified voltage. Therefore, the target voltage needs to be divided by the amplification factor to obtain the actual voltage of the trace in the circuit board under test. Divide the actual voltage of the trace in the circuit board under test by the current value to calculate the resistance value of the trace in the circuit board under test, which is also the target resistance value. For example, if the amplification factor is 100, the current value is 40 mA, and the target voltage is 40 mV, then the target resistance value Rx = 40 / (100 * 40) = 100 mΩ.

[0051] In some embodiments, a probe is used to connect to the test point in the circuit board under test, so as to measure the impedance of the trace in the circuit board under test. It should be noted that the impedance of the trace in the circuit board under test is extremely small. For example, the impedance of the trace is generally a few ohms. Therefore, compared with the impedance of the test lead, the contact resistance between the probe and the test point can no longer be ignored. If the conventional two-wire test method is still used, it will surely lead to an increase in the test error of the resistance. In view of this situation, the embodiment of the present application adopts the Kelvin connection method for testing to improve the accuracy of the impedance measurement of the PCB.

[0052] In some embodiments, the control module connects to the first interface 70 through a probe. The probe tip length is less than a preset probe tip length threshold, so that the probe tip is as short as possible, avoiding a large resistance value at the contact point between the probe tip and the above-mentioned circuit, so as to improve the accuracy of the measurement result.

[0053] In some embodiments, the impedance measurement circuit 100 further includes a diode rectification module (not shown in the figure). The diode rectification module is electrically connected to the first circuit arm module 30 and the second circuit arm module 40, and the diode rectification module is used to rectify the current of the first circuit arm module 30 and the second circuit arm module 40.

[0054] The advantage of this embodiment is that by rectifying the current of the first circuit arm module 30 and the second circuit arm module 40 through the diode rectification module, the stability of the circuit is improved, thereby improving the reliability of the test result.

[0055] Please refer to Figure 1 and Figure 2 , in some embodiments, the first circuit arm module 30 includes a first resistor R1 and a tenth resistor R10, the second circuit arm module 40 includes a seventh resistor R7, the third circuit arm module 50 includes a second resistor R2, a fourth resistor R4 and an eighth resistor R8, the fourth circuit arm module 60 includes a third resistor R3, a fifth resistor R5 and a ninth resistor R9, and the amplification module 20 includes an operational amplifier U1, a first capacitor C1, a first diode D1, a second diode D2 and a sixth resistor R6;

[0056] The first resistor R1 is electrically connected to the first interface J1 and the tenth resistor R10. The second resistor R2 is electrically connected to the first interface J1, the inverting input terminal of the operational amplifier U1, and the fourth resistor R4. The third resistor R3 is electrically connected to the first interface J1, the non-inverting input terminal of the operational amplifier U1, and the fifth resistor R5. The output terminal of the operational amplifier U1 is electrically connected to the sixth resistor R6, the input terminal of the first diode D1, and the output terminal of the second diode D2. The first capacitor C1 is electrically connected to the output terminal of the first diode D1 and the input terminal of the second diode D2. The eighth resistor R8 is electrically connected to the fourth resistor R4 and the second interface J2. The ninth resistor R9 is electrically connected to the fifth resistor R5 and the second interface J2.

[0057] The advantage of this embodiment is that it can improve the accuracy and test efficiency of PCB impedance measurement.

[0058] It should be noted that in Figure 2 , VB+ represents the positive pole of the first regulated power supply, and the input voltage of VB+ can be +12V. VB- represents the negative pole of the first regulated power supply, and the input voltage of VB- can be -12V. HF represents the high-potential application line, LF represents the low-potential application line, HS represents the high-potential detection line, and LS represents the low-potential detection line. HF_X represents the first end of the constant current source, and the first end of the constant current source can be connected to the constant current source output module 10. LF_X represents the second end of the constant current source, and the second end of the constant current source can be connected to the constant current source output module 10 or grounded. The first interface J1 has a first end, a second end, a third end, and a fourth end. The second interface J2 has a first end and a second end.

[0059] In some embodiments, it should be noted that Figure 2 in the second circuit arm module 40 of

[0060] further includes a seventeenth resistor R17. One end of the seventeenth resistor R17 is electrically connected to the seventh resistor R7, and the other end is grounded.

[0061] Please refer to Figure 2 , in some embodiments, the diode rectification module includes a third diode D3 and a fourth diode D4;

[0062] The input terminal of the third diode D3 is electrically connected to the output terminal of the fourth diode D4 and the seventh resistor R7. The output terminal of the third diode D3 is electrically connected to the input terminal of the fourth diode D4 and the first resistor R1.

[0063] The advantage of this embodiment is that the diode rectification module rectifies the currents of the first circuit arm module 30 and the second circuit arm module 40, improving the stability of the circuit and thus the reliability of the test results.

[0064] Please refer toFigure 2 In some embodiments, the amplification module 20 further includes a second capacitor C2 and a third capacitor C3. The second capacitor C2 is electrically connected to the input terminal of the first capacitor C1 and the second diode D2, and the third capacitor C3 is electrically connected to the output terminal of the first diode D1.

[0065] In some embodiments, it should be noted that the distance between the second capacitor C2 and the operational amplifier U1 is less than a preset first distance threshold, and the distance between the third capacitor C3 and the operational amplifier U1 is less than a preset second distance threshold. The first distance threshold and the second distance threshold can be preset length values. For example, both the first distance threshold and the second distance threshold are 1 mm.

[0066] The advantage of this embodiment is that by setting the first distance threshold and the second distance threshold, the second capacitor C2 and the third capacitor C3 are as close as possible to the operational amplifier U1, thereby shortening the length of the connection lines in the circuit and improving the accuracy of the test results.

[0067] Please refer to Figure 1 and Figure 3 In some embodiments, the constant current source output module 10 includes a current source U2, a fourth capacitor C4, a fifth capacitor C5, a fifth diode D5, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, and a fifteenth resistor R15;

[0068] The current source U2 is electrically connected to the eleventh resistor R11, the twelfth resistor R12, the thirteenth resistor R13, and the fifth diode D5. The thirteenth resistor R13 is electrically connected to the fourth capacitor C4, and the fourteenth resistor R14 is electrically connected to the eleventh resistor R11, the twelfth resistor R12, the fifteenth resistor R15, and the fifth capacitor C5.

[0069] The advantage of this embodiment is that a constant current is given by the constant current source output module 10 to energize the circuit board under test, so as to measure the trace impedance.

[0070] It should be noted that in Figure 3 , HF_X represents the first terminal of the constant current source, which means it is interconnected with HF_X in Figure 2 . VB2 represents the second regulated power supply, and the input voltage of the second regulated power supply can be +15V.

[0071] Specifically, the current source U2 can be an LT3092 chip.

[0072] In some embodiments, it should be noted that Figure 3 the constant current source output module 10 in

[0073] Please refer to Figure 4 , the embodiment of the present application further provides an impedance measurement device based on a PCB. The impedance measurement device includes: the above-mentioned impedance measurement circuit 100 based on a PCB, a control module 200, and an analog-to-digital conversion module 300;

[0074] The control module 200 is electrically connected to the analog-to-digital conversion module 300, the analog-to-digital conversion module 300 is electrically connected to the impedance measurement circuit 100, and the impedance measurement circuit 100 is electrically connected to the circuit board under test 400;

[0075] The analog-to-digital conversion module 300 collects the target voltage output by the impedance measurement circuit 100 and converts the target voltage into a target digital signal; the control module 200 calculates the target resistance value of the circuit board under test 400 according to the target digital signal.

[0076] The advantage of this embodiment is that through the impedance measurement circuit 100, the Kelvin bridge method is used to accurately measure the trace impedance and reduce the measurement error. After the analog-to-digital conversion of the target voltage, the control module 200 calculates the impedance of the traces in the circuit board under test 400 according to the target digital signal, so as to obtain the target resistance value, improve the test efficiency, and thus improve the accuracy and test efficiency of the impedance measurement of the PCB.

[0077] Specifically, the control module 200 can be an MCU (Microcontroller Unit, micro control unit, or single-chip microcomputer).

[0078] Specifically, the control module 200 and the analog-to-digital conversion module 300 are connected through a bus interface, and the bus interface can be of types such as SPI, I2C, EMI F, etc.

[0079] The specific implementation manner of this impedance measurement device based on a PCB is basically the same as that of the above-mentioned specific embodiment of the impedance measurement circuit 100 based on a PCB, and will not be elaborated here.

[0080] Please refer to Figure 5 , in some embodiments, the impedance measurement device further includes a switch matrix module 500. The switch matrix module 500 is electrically connected to the control module 200, the analog-to-digital conversion module 300, and a plurality of impedance measurement circuits 100; the switch matrix module 500 has a plurality of channels, and each channel is electrically connected to an impedance measurement circuit 100; the control module 200 outputs a control signal, and the switch matrix module 500 switches channels according to the control signal to collect the target voltage output by the impedance measurement circuit 100.

[0081] The advantage of this embodiment is that the control module 200 outputs a control signal to the switch matrix module 500, and the switch matrix module 500 switches different channels, so as to switch the impedance measurement circuits 100 connected to different channels, so as to obtain the trace impedance of different printed circuit boards to be measured, realizing automated testing, and can be effectively applied to the testing of a large number of PCB products.

[0082] In some embodiments, the impedance measurement device further includes a test probe module (not shown in the figure). The test probe module is electrically connected to the impedance measurement circuit based on the PCB and the switch matrix module 500.

[0083] Specifically, the test probe module may include a test mold and a test probe board. The switch matrix module 500 is connected to the test mold, the test mold is connected to the test probe board, and the test probe board is connected to the first interface J1 in the above-mentioned impedance measurement circuit.

[0084] The embodiment of the present application also provides an impedance measurement system for a PCB, and the impedance measurement system includes: the above-mentioned impedance measurement device based on the PCB; a host computer, the host computer is communicatively connected to the impedance measurement device, and the host computer is used to obtain the target resistance value output by the impedance measurement device, and obtain a test result according to the target resistance value, and save the test result.

[0085] The advantage of this embodiment is that by communicatively connecting the host computer to the impedance measurement device and controlling the test process of the impedance measurement device, the errors caused by manual input and judgment of data are reduced, and the accuracy of the test result is improved.

[0086] Specifically, the host computer may be a PC (Personal Computer, personal computer) or a server, etc.

[0087] It should be noted that the impedance measurement device based on the PCB may include a host computer communication interface, such as an RS232 communication interface, an Ethernet communication interface, etc. Through the host computer communication interface, the test data can be automatically uploaded to the host computer and the test data can be archived and recorded, realizing the function of automated testing.

[0088] The embodiments described in the embodiments of the present application are for more clearly illustrating the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art know that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

[0089] Those skilled in the art can understand that the technical solutions shown in the figure do not constitute a limitation on the embodiments of the present application, and may include more or fewer modules than shown in the figure.

[0090] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0091] Those of ordinary skill in the art can understand that all or some of the functional modules / units in the systems and devices disclosed above can be implemented as software, firmware, hardware, and their appropriate combinations.

[0092] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of this application and the above-mentioned drawings are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of this application described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0093] It should be understood that in this application, "at least one (item)" means one or more, and "a plurality" means two or more. "And / or" is used to describe the association relationship of associated objects and indicates that three relationships can exist. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist at the same time. Among them, A and B can be singular or plural. The character " / " generally means that the associated objects before and after are in an "or" relationship. "At least one (one) of the following" or its similar expression refers to any combination of these items, including any combination of single item (one) or plural items (ones). For example, at least one (one) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0094] In several embodiments provided by the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the above-mentioned units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. The displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical or other forms.

[0095] The units described above as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place, or can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0096] In addition, in each embodiment of the present application, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0097] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in each embodiment of the present application. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs that can store programs.

[0098] The preferred embodiments of the embodiments of the present application have been described above with reference to the accompanying drawings, and thus do not limit the scope of the rights of the embodiments of the present application. Any modifications, equivalent replacements, and improvements made by those skilled in the art without departing from the scope and essence of the embodiments of the present application shall be within the scope of the rights of the embodiments of the present application.

Claims

1. An impedance measurement circuit based on PCB, characterized in that: The impedance measurement circuit is electrically connected to the circuit board to be tested and the control module, and the impedance measurement circuit includes: a constant current source output module, an amplification module, a first circuit arm module, a second circuit arm module, a third circuit arm module, a fourth circuit arm module, a first interface and a second interface; The first circuit arm module is electrically connected to the constant current source output module and the first interface, and the second circuit arm module is electrically connected to the constant current source output module and the first interface; the third circuit arm module is electrically connected to the first interface, the second interface and the amplification module, and the fourth circuit arm module is electrically connected to the first interface, the second interface and the amplification module; the first interface is electrically connected to the control module, and the second interface is electrically connected to the circuit board to be tested; wherein the first circuit arm module, the second circuit arm module, the third circuit arm module and the fourth circuit arm module are combined to form a Kelvin bridge circuit; The constant current source output module is used to provide power; the amplification module is used to amplify the voltage generated by the wiring of the circuit board to be tested when power is turned on to obtain a target voltage; the control module is used to collect the target voltage and determine the target resistance value of the wiring in the circuit board to be tested based on the target voltage.

2. The PCB-based impedance measurement circuit according to claim 1, characterized in that: The impedance measurement circuit also includes a diode rectifier module; The diode rectifier module is electrically connected to the first circuit arm module and the second circuit arm module, and is used for rectifying the current of the first circuit arm module and the second circuit arm module.

3. The PCB-based impedance measurement circuit according to claim 2, characterized in that: The first circuit arm module includes a first resistor and a tenth resistor, the second circuit arm module includes a seventh resistor, the third circuit arm module includes a second resistor, a fourth resistor and an eighth resistor, the fourth circuit arm module includes a third resistor, a fifth resistor and a ninth resistor, and the amplification module includes an operational amplifier, a first capacitor, a first diode, a second diode and a sixth resistor; The first resistor is electrically connected to the first interface and the tenth resistor, the second resistor is electrically connected to the first interface, the inverting input terminal of the operational amplifier and the fourth resistor, the third resistor is electrically connected to the first interface, the non-inverting input terminal of the operational amplifier and the fifth resistor, the output terminal of the operational amplifier is electrically connected to the sixth resistor, the input terminal of the first diode and the output terminal of the second diode, the first capacitor is electrically connected to the output terminal of the first diode and the input terminal of the second diode, the eighth resistor is electrically connected to the fourth resistor and the second interface, and the ninth resistor is electrically connected to the fifth resistor and the second interface.

4. The PCB-based impedance measurement circuit according to claim 3, characterized in that: The diode rectifier module includes a third diode and a fourth diode; An input end of the third diode is electrically connected to an output end of the fourth diode and the seventh resistor, and an output end of the third diode is electrically connected to an input end of the fourth diode and the first resistor.

5. The PCB-based impedance measurement circuit according to claim 3, characterized in that: The amplification module also includes a second capacitor and a third capacitor; The second capacitor is electrically connected to the first capacitor and the input end of the second diode, and the third capacitor is electrically connected to the output end of the first diode.

6. The PCB-based impedance measurement circuit according to claim 1, characterized in that: The constant current source output module includes a current source, a fourth capacitor, a fifth capacitor, a fifth diode, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor and a fifteenth resistor; The current source is electrically connected to the eleventh resistor, the twelfth resistor, the thirteenth resistor and the fifth diode, the thirteenth resistor is electrically connected to the fourth capacitor, and the fourteenth resistor is electrically connected to the eleventh resistor, the twelfth resistor, the fifteenth resistor and the fifth capacitor.

7. An impedance measurement device based on PCB, characterized in that: The impedance measurement device comprises: the PCB-based impedance measurement circuit, a control module and an analog-to-digital conversion module according to any one of claims 1 to 5; The control module is electrically connected to the analog-to-digital conversion module, the analog-to-digital conversion module is electrically connected to the impedance measurement circuit, and the impedance measurement circuit is electrically connected to the circuit board to be tested; The analog-to-digital conversion module collects the target voltage output by the impedance measurement circuit and converts the target voltage into a target digital signal; the control module calculates the target resistance value of the circuit board to be tested according to the target digital signal.

8. The PCB-based impedance measurement device according to claim 7, characterized in that: The impedance measurement device also includes a switch matrix module; The switch matrix module is electrically connected to the control module, the analog-to-digital conversion module and a plurality of impedance measurement circuits; the switch matrix module has a plurality of channels, each channel being electrically connected to an impedance measurement circuit; The control module outputs a control signal, and the switch matrix module switches channels according to the control signal to collect a target voltage output by the impedance measurement circuit.

9. The PCB-based impedance measurement device according to claim 8, characterized in that: The impedance measurement device also includes a test probe module; The test probe module is electrically connected to the impedance measurement circuit and the switch matrix module.

10. A PCB-based impedance measurement system, characterized in that: The impedance measurement system comprises: The PCB-based impedance measurement device according to any one of claims 7 to 9; A host computer is communicatively connected to the impedance measuring device, and is used to obtain a target resistance value output by the impedance measuring device, obtain a test result according to the target resistance value, and save the test result.

Images