Multi-channel current testing device

Abstract

The utility model discloses a multi-channel current testing device which comprises a current testing assembly, a multi-channel switching assembly and a control circuit. Wherein the multi-channel switching assembly is respectively connected with the current testing assembly and the N tested units, the control circuit is respectively connected with the current testing assembly and the multi-channel switching assembly, and the current testing assembly is used for testing the current of the N tested units. When current testing of a large number of channels needs to be carried out, the control circuit can control work of the multi-channel switching assembly so as to switch the testing channels connected between the current testing assembly and the N tested units, and then the current testing assembly can test the current of the tested units of the multiple connected testing channels. Therefore, current testing of a large number of channels can be realized.

Description

Technical Field

[0001] The utility model relates to the technical field of current testing, in particular to a multi-channel current testing device. Background Art

[0002] In semiconductor chip leakage current testing, a picoammeter with a voltage source is often used for measurement. The picoammeter detects the leakage current of the semiconductor chip by applying a specified voltage and measuring the leakage current of the unit under test, which is usually between fA (femtoampere) and nA (nanoampere).

[0003] However, high-precision picoammeters are expensive and bulky, and it is not possible to implement current testing of a large number of channels by simply increasing the number of picoammeters. Therefore, it is urgent to propose a test device that can implement current testing of a large number of channels. Utility Model Content

[0004] The main purpose of the utility model is to provide a multi-channel current testing device, aiming to propose a testing device that can realize current testing of a large number of channels.

[0005] To achieve the above object, the utility model provides a multi-channel current testing device, comprising:

[0006] A current test component, wherein the current test component is used to test the test current of N units under test;

[0007] A multi-channel switching component, the multi-channel switching component is connected to the current test component and the N units under test respectively; the multi-channel switching component is used to switch the test channels between the current test component and the N units under test;

[0008] A control circuit, wherein the control circuit is connected to the current testing component and the multi-channel switching component respectively; the control circuit is used to control the operation of the current testing component, and the control circuit is also used to control the operation of the multi-channel switching component.

[0009] Optionally, the multi-channel switching component includes:

[0010] A switch circuit, the switch circuit is connected to the current test component and the N units under test respectively; the switch circuit is used to switch the test channel between the current test component and the N units under test;

[0011] A driving circuit, wherein the driving circuit is connected to the switch circuit and the control circuit respectively; the driving circuit is used to receive a control signal output by the control circuit and drive the switch circuit to operate according to the control signal.

[0012] Optionally, the current testing assembly includes M picoammeters; each of the picoammeters includes a voltage source and a current testing circuit;

[0013] The voltage source is connected to the control circuit and the switch circuit respectively; the voltage source is used to provide power for the unit under test to generate a test current;

[0014] The current test circuit is connected to the control circuit, the switch circuit and the voltage source respectively; the current test circuit is used to receive the test current and output a current test signal according to the test current;

[0015] The control circuit is also used to control the operation of the voltage source and the current test circuit, and to receive the current test signal and operate according to the current test signal.

[0016] Optionally, the test channel includes a first channel and a second channel; and the switch circuit includes:

[0017] A power supply switch circuit, the power supply switch circuit is respectively connected to the M voltage sources and the N power supply input terminals of the units under test; the power supply switch circuit is used to switch the first channel between the M voltage sources and the power supply input terminals of the N units under test;

[0018] A test switch circuit, wherein the test switch circuit is respectively connected to the M groups of current test circuits and the output ends of the N units under test; the test switch circuit is used to switch the second channel between the M groups of current test circuits and the output ends of the N units under test.

[0019] Optionally, the multi-channel current testing device also includes a multi-core probe card, which includes a first connection end, a second connection end and a test end; the first connection end of the multi-core probe card is connected to the power supply switch circuit; the second connection end of the multi-core probe card is connected to the test switch circuit; and the test end of the multi-core probe card is connected to N of the units under test.

[0020] Optionally, the multi-channel current testing device further includes:

[0021] a first coaxial cable, the first coaxial cable comprising an inner conductor and an outer shielding layer, the inner conductor of the first coaxial cable being used to connect the positive electrodes of the M voltage sources with the first end of the power supply switch circuit, and the outer shielding layer of the first coaxial cable being used to connect the negative electrodes of the M voltage sources;

[0022] a second coaxial cable, the second coaxial cable comprising an inner conductor, an intermediate conductor layer and an outer shielding layer, the inner conductor of the second coaxial cable being used to connect the first end of the M groups of current test circuits with the first end of the test switch circuit, the intermediate conductor layer of the second coaxial cable being used to connect the second end of the M groups of current test circuits with the outer shielding layer of the first coaxial cable, and the outer shielding layer of the second coaxial cable being grounded;

[0023] a third coaxial cable, the third coaxial cable comprising an inner conductor and an outer shielding layer, the inner conductor of the third coaxial cable being used to connect the second end of the power switch circuit with the first connection end of the multi-core probe card, and the outer shielding layer of the third coaxial cable being connected to the outer shielding layer of the first coaxial cable;

[0024] A multi-core shielded cable, the multi-core shielded cable includes a multi-core inner conductor and an outer shielding layer, the multi-core inner conductor of the multi-core shielded cable is used to connect the second end of the test switch circuit with the second connection end of the multi-core probe card; the outer shielding layer of the multi-core shielded cable is grounded.

[0025] Optionally, the power supply switch circuit includes a common electrode, and the common electrode is used to connect the power input terminals of the N units under test; the power supply switch circuit also includes M power supply switches and a power supply grounding switch;

[0026] The M power switches each include a first connection terminal, a second connection terminal, a controlled terminal and a ground terminal; the first connection terminals of the M power switches are respectively connected to the M voltage sources in a one-to-one correspondence; the second connection terminals of the M power switches are each connected to the common electrode; the controlled terminals of the M power switches are each connected to the driving circuit; and the ground terminals of the M power switches are each grounded;

[0027] The power supply grounding switch includes a first connection end, a grounding end and a controlled end; the first connection end of the power supply grounding switch is connected to the common electrode; the grounding end of the power supply grounding switch is grounded; and the controlled end of the power supply grounding switch is connected to the driving circuit.

[0028] Optionally, the test switch circuit includes M groups of test sub-switch circuits, and the first ends of the M groups of test sub-switch circuits are connected to the M current test circuits in a one-to-one correspondence; wherein each group of the test sub-switch circuits includes an isolation switch circuit and a gating switch circuit;

[0029] The isolation switch circuit includes a first switch and a second switch; the first switch includes a first connection end, a second connection end, a controlled end and a ground end; the second switch includes a first connection end, a ground end and a controlled end; the first connection end of the first switch is connected to the first end of the test sub-switch circuit; the second connection end of the first switch is connected to the first connection end of the second switch; the controlled end of the first switch and the controlled end of the second switch are connected to the driving circuit; the ground end of the first switch and the ground end of the second switch are grounded;

[0030] The gating switch circuit includes K gating switches; the K gating switches each include a first connection end, a second connection end, a controlled end and a ground end; the first connection ends of the K gating switches are respectively connected to the K units under test in a one-to-one correspondence; the second connection ends of the K gating switches are each connected to the second connection end of the first switch; the controlled ends of the K gating switches are each connected to the driving circuit; and the ground ends of the K gating switches are each grounded.

[0031] Optionally, the power supply switch circuit further includes M groups of filter circuits; the input ends of the M groups of filter circuits are connected one-to-one with the M voltage sources; and the output ends of the M groups of filter circuits are connected one-to-one with the first connection ends of the M groups of power switches.

[0032] Optionally, each group of the filtering circuits includes a first resistor, a first capacitor, a second resistor and a second capacitor;

[0033] Among them, one end of the first resistor is connected to the input end of the filter circuit; the other end of the first resistor, one end of the first capacitor and one end of the second resistor are connected; the other end of the second resistor, one end of the second capacitor are connected to the output end of the filter circuit; the other end of the first capacitor and the other end of the second capacitor are grounded.

[0034] The technical solution of the utility model adopts a multi-channel current testing device, including a current testing component, a multi-channel switching component and a control circuit. Among them, when a large number of channels of current testing are required, N units under test can be connected to the multi-channel switching component, and the multi-channel switching component can be connected to the current testing component, and the control circuit can control the multi-channel switching component to switch the test channel between the current testing component and the N units under test. When the test channel between the current current testing component and the current unit under test is connected, the control circuit can control the current testing component to perform a current test on the current unit under test, and when the test of the current unit under test is completed, the control can control the multi-channel switching component to switch the next test channel between the next current testing component and the next unit under test to perform a current test on the next unit under test. In this way, the utility model can expand the test channel between the current testing component and the N units under test. If the current testing component includes M picoammeters, each picoammeter is connected to K test channels in the multi-channel switching component, then (M*K) units under test can be tested for current, wherein N, M, and K are all positive integers greater than or equal to 1. In this way, the utility model can realize leakage current testing of a large number of channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0036] Figure 1 This is a structural schematic diagram of an embodiment of a multi-channel current testing device of the utility model;

[0037] Figure 2 This is a structural schematic diagram of another embodiment of the multi-channel current testing device of the utility model;

[0038] Figure 3 It is a structural schematic diagram of another embodiment of the multi-channel current testing device of the utility model;

[0039] Figure 4 This is a structural schematic diagram of another embodiment of the multi-channel current testing device of the utility model;

[0040] Figure 5 An electronic circuit for testing a switch circuit of an embodiment of a multi-channel current testing device of the utility model;

[0041] Figure 6 The electronic circuit is a power supply switch circuit of an embodiment of the multi-channel current testing device of the utility model.

[0042] Description of Figure Numbers:

[0043]

[0044]

[0045] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0047] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0048] In addition, the descriptions of "first", "second", etc. in the present utility model are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0049] In the prior art, high-precision picoammeters are expensive and large in size, and it is not possible to implement current testing of a large number of channels by simply increasing the number of picoammeters. Therefore, it is urgent to propose a testing device that can implement current testing of a large number of channels.

[0050] To achieve the above object, the utility model provides a multi-channel current testing device.

[0051] In one embodiment of the present invention, Figure 1 As shown, the multi-channel current test device includes:

[0052] A current testing component 200, the current testing component 200 is used to test the test current of N units under test;

[0053] A multi-channel switching component 300, the multi-channel switching component 300 is connected to the current test component 200 and the N units under test respectively; the multi-channel switching component 300 is used to switch the test channels between the current test component 200 and the N units under test;

[0054] The control circuit 100 is connected to the current test component 200 and the multi-channel switching component 300 respectively; the control circuit 100 is used to control the operation of the current test component 200, and the control circuit 100 is also used to control the operation of the multi-channel switching component 300.

[0055] It should be noted that N is a positive integer greater than or equal to 1. This embodiment can be used for current testing of multiple units under test, such as semiconductor testing, wafer testing, fully automatic probe station testing, manual station testing, and pA level leakage current testing.

[0056] In this embodiment, when a large number of channels need to be tested for current, N units under test can be connected to the multi-channel switching component 300, and the multi-channel switching component 300 can be connected to the current test component 200. The control circuit 100 can control the multi-channel switching component 300 to switch the test channel between the current test component 200 and the N units under test. When the test channel between the current current test component 200 and the current unit under test is connected, the control circuit 100 can control the current test component 200 to perform a current test on the current unit under test. When the test of the current unit under test is completed, the control can control the multi-channel switching component 300 to switch the next test channel between the next current test component 200 and the next unit under test to be connected, so as to perform a current test on the next unit under test. In this way, the utility model can expand the test channel between the current test component 200 and the N units under test. If the current test component 200 includes M picoammeters, each picoammeter is connected to K test channels in the multi-channel switching component 300, then the current test can be performed on (M*K) units under test, where M and K are both positive integers greater than or equal to 1, and N is a positive integer less than or equal to (M*K). When the number of units under test is greater than N, batch testing can be performed, which is not limited here. In this way, this embodiment can implement current testing of a large number of channels.

[0057] It should be noted that if Figure 3 and Figure 5As shown, when M is 4 and K is 8, that is, the current test component 200 includes 4 high-precision picoammeters, 32 test channels can be set in the multi-channel switching component 300, and each high-precision picoammeter corresponds to 8 test channels, and the current test can be performed on the 32 units under test. At this time, the 32 units under test can be connected to the 32 test channels, and each high-precision picoammeter can be connected to the 8 test channels. When it is necessary to test the unit under test of the first test channel Anode1, the first picoammeter can be switched to be connected to the first test channel Anode1 for current testing. When it is necessary to test the units under test of the second test channel Anode2, the third test channel Anode3 and the fourth test channel Anode4, the first picoammeter can be switched to be connected to the second test channel Anode2, the third test channel Anode3 and the fourth test channel Anode4, respectively, and each test is performed three times to perform current testing. When it is necessary to test the units under test of the first test channel Anode1, the ninth test channel Anode9, the seventeenth test channel Anode17 and the twenty-fifth test channel Anode25, the first picoammeter can be switched to connect to the first test channel Anode1, the second picoammeter to connect to the ninth test channel Anode9, the third picoammeter to connect to the seventeenth test channel Anode17, and the fourth picoammeter to connect to the twenty-fifth test channel Anode25, and a current test can be performed at the same time to complete the test. It should be noted that M is 4 and K is 8 only for the purpose of illustration, and the values ​​of M and K are not limited thereto. In this way, the present embodiment can implement current testing of at least (M*K) test channels.

[0058] It should be noted that, in this embodiment, the multi-channel switching component 300 can be quickly controlled by the control circuit 100 to switch the test channel for testing, which solves the problem of slow current testing of a large number of channels and has the advantage of high efficiency. Moreover, in this embodiment, the multi-channel switching component 300 switches the test channel, which can also ensure that the difference in current test results between each test channel is small, solves the problem of large difference in current test results between a large number of channels, and the current test result obtained is of high accuracy.

[0059] It should be noted that the control circuit 100 may include a host computer, an IO card and an IO box, wherein the host computer is respectively connected to the current test component 200 and the IO card, the IO card is connected to the IO box, and the IO box is connected to the multi-channel switching component 300. Among them, the host computer can output a control signal when triggered by the user, and the control signal can control the operation of the current test component 200 and the multi-channel switching component 300. The user can also operate the received current test data through the host computer to obtain the analysis result. The host computer can be a computer, which outputs a digital signal through the IO card, and the IO box realizes the isolation level conversion of the digital signal output by the IO card, and can output the converted signal to the multi-channel switching component 300, and can provide the power required by the multi-channel switching component 300.

[0060] In the present utility model, when a large number of channels of current testing are required, N units under test can be connected to the multi-channel switching component 300, and the multi-channel switching component 300 can be connected to the current test component 200, and the control circuit 100 can control the multi-channel switching component 300 to switch the test channel between the current test component 200 and the N units under test. When the test channel between the current current test component 200 and the current unit under test is connected, the control circuit 100 can control the current test component 200 to perform a current test on the current unit under test, and when the test of the current unit under test is completed, the control can control the multi-channel switching component 300 to switch the next test channel between the next current test component 200 and the next unit under test to be connected, so as to perform a current test on the next unit under test. In this way, the present utility model can expand the test channel between the current test component 200 and the N units under test. If the current test component 200 includes M picoammeters, each picoammeter is connected to K test channels in the multi-channel switching component 300, then (M*K) units under test can be tested for current. In this way, the utility model can realize current testing of a large number of channels.

[0061] Further, in an embodiment of the present invention, if Figure 2 As shown, the multi-channel switching component 300 includes:

[0062] A switch circuit 310, the switch circuit 310 is connected to the current test component 200 and the N units under test respectively; the switch circuit 310 is used to switch the test channel between the current test component 200 and the N units under test;

[0063] The driving circuit 320 is connected to the switch circuit 310 and the control circuit 100 respectively; the driving circuit 320 is used to receive the control signal output by the control circuit 100 and drive the switch circuit 310 to work according to the control signal.

[0064] In this embodiment, the drive circuit 320 may include a voltage conversion circuit, a signal conditioning circuit and a relay drive circuit 320. Among them, the voltage conversion circuit can be connected to the input power supply voltage and the relay drive circuit 320 respectively, such as connecting the power supply provided by the IO box, and the voltage conversion circuit is used to convert the input power supply voltage and output it to the relay drive circuit 320, so as to provide the required power supply for the relay drive circuit 320 to drive the switch circuit 310. The signal conditioning circuit can be connected to the control circuit 100 and the relay drive circuit 320 respectively, and is used to output the input control signal to the relay drive circuit 320 after amplification, filtering and conversion, so as to convert it into a signal recognizable by the relay drive circuit 320. The relay drive circuit 320 is used to drive the switch circuit 310 to work according to the control signal, such as outputting a high level or a low level to drive the electronic switch of the switch circuit 310 to turn on or off. The switch circuit 310 may include a switch matrix, and the switch matrix controls the test channels between the multiple picoammeters and the N units under test in the switching current test component 200. In this way, the driving circuit 320 of this embodiment can accurately drive the switching circuit 310 to switch the test channel according to the control signal, thereby realizing current testing of a large number of channels, ensuring that the difference in test results between each test channel is small, and the obtained current test results are more accurate.

[0065] Further, in an embodiment of the present invention, if Figure 2 As shown, the current test assembly 200 includes M picoammeters; each picoammeter includes a voltage source and a current test circuit;

[0066] The voltage source is connected to the control circuit 100 and the switch circuit 310 respectively; the voltage source is used to provide power for the unit under test to generate a test current;

[0067] The current test circuit is connected to the control circuit 100, the switch circuit 310 and the voltage source respectively; the current test circuit is used to receive the test current and output a current test signal according to the test current;

[0068] The control circuit 100 is further used to control the operation of the voltage source and the current test circuit, and to receive a current test signal and operate according to the current test signal.

[0069] In this embodiment, when performing a leakage current test on the unit under test, the control circuit 100 can control the voltage sources of the M picoammeters to output a power supply voltage respectively, and the power supply voltage can be output to the N units under test via the switch circuit 310, and then the N units under test can generate a test current under the action of the power supply voltage, and the test current can be output to the current test circuit via the switch circuit 310. In this way, the current test circuit of this embodiment can receive the test current and output a current test signal according to the test current, and the control circuit 100 can receive the current test signal and analyze and obtain the current test result. In this embodiment, since M picoammeters are included, this embodiment can simultaneously perform current tests on the units under test of M test channels.

[0070] It should be noted that the picoammeter of this embodiment can be a 6487 picoammeter, which has multiple current measurement ranges and high-speed automatic ranges, and can measure currents ranging from 20fA to 20mA, and can measure at a speed of up to 1000 readings per second, and the output range of the voltage source is from 200μV to 505V. Thus, in this embodiment, the multi-channel current test device has a wide current test range, can be applied to current tests of multiple types of units under test, and has fast current measurement speed and high accuracy.

[0071] Further, in an embodiment of the present invention, if Figure 2 As shown, the test channel includes a first channel and a second channel; the switch circuit 310 includes:

[0072] A power supply switch circuit 311, the power supply switch circuit 311 is connected to the M voltage sources 210 and the power supply input terminals of the N units under test respectively; the power supply switch circuit 311 is used to switch the first channel between the M voltage sources 210 and the power supply input terminals of the N units under test;

[0073] The test switch circuit 312 is connected to the M groups of current test circuits 220 and the output ends of the N units under test respectively; the test switch circuit 312 is used to switch the second channel between the M groups of current test circuits 220 and the output ends of the N units under test.

[0074] In this embodiment, when the leakage current test of the unit under test is performed, the control circuit 100 can control the M voltage sources 210 to output the power supply voltage respectively, and the power supply voltage can be output to the N units under test through the first channel between the power supply switch circuits 311, then the N units under test can generate a test current under the action of the power supply voltage, and the test current can be output to the current test circuit through the second channel between the test switch circuits 312. In this way, the current test of this embodiment can receive the test current, and output a current test signal according to the test current, and the control circuit 100 can receive the current test signal and analyze and obtain the current test result. In this embodiment, since the power supply switch circuit 311 and the test switch circuit 312 are included, the first channel corresponding to the M voltage sources 210 and the second channel corresponding to the M groups of current test circuits 220 can be controlled respectively. In this way, precise control of the first channel and the second channel is achieved, mutual interference between the power supply circuit and the test circuit can be avoided, which is safer, and when a fault occurs, it is also more conducive to fault troubleshooting and positioning.

[0075] Further, in an embodiment of the present invention, if Figure 2 As shown, the multi-channel current testing device also includes a multi-core probe card 400, which includes a first connection end, a second connection end and a test end; the first connection end of the multi-core probe card 400 is connected to the power supply switch circuit 311; the second connection end of the multi-core probe card 400 is connected to the test switch circuit 312; and the test end of the multi-core probe card 400 is connected to N units under test.

[0076] In this embodiment, the multi-core probe card 400 has multiple core wires and can connect multiple channels at the same time. In this way, the connection between the multi-channel switching component 300 and N units under test can be facilitated, reducing the number and clutter of connecting wires. In this embodiment, the multi-core probe card 400 adopts an integrated design, which can ensure the stability and reliability of the connection between each test channel, and the multi-core probe card 400 can be freely configured and expanded as needed.

[0077] Further, in an embodiment of the present invention, if Figure 4 As shown, D1, D2 to DN are respectively the first unit under test, the second unit under test to the Nth unit under test, and the multi-channel current testing device also includes:

[0078] A first coaxial cable, the first coaxial cable comprising an inner conductor and an outer shielding layer, the inner conductor of the first coaxial cable is used to connect the positive electrodes of the M voltage sources 210 and the first end of the power supply switch circuit 311, and the outer shielding layer of the first coaxial cable is used to connect the negative electrodes of the M voltage sources 210;

[0079] A second coaxial cable, the second coaxial cable includes an inner conductor, an intermediate conductor layer and an outer shielding layer, the inner conductor of the second coaxial cable is used to connect the first end of the M-group current test circuit 220 and the first end of the test switch circuit 312, the intermediate conductor layer of the second coaxial cable is used to connect the second end of the M-group current test circuit 220 and the outer shielding layer of the first coaxial cable, and the outer shielding layer of the second coaxial cable is grounded;

[0080] A third coaxial cable, the third coaxial cable comprising an inner conductor and an outer shielding layer, the inner conductor of the third coaxial cable being used to connect the second end of the power supply switch circuit 311 with the first connection end of the multi-core probe card 400, and the outer shielding layer of the third coaxial cable being connected to the outer shielding layer of the first coaxial cable;

[0081] The multi-core shielded cable includes a multi-core inner conductor and an outer shielding layer. The multi-core inner conductor of the multi-core shielded cable is used to connect the second end of the test switch circuit 312 with the second connection end of the multi-core probe card 400; the outer shielding layer of the multi-core shielded cable is grounded.

[0082] It should be noted that the coaxial cable in this embodiment includes an inner conductor, an inner insulating layer, an outer shielding layer, an outer insulating layer and an outer sheath. The inner conductor can be made of copper or aluminum and is used to transmit the current of the signal. The inner insulating layer can be composed of materials such as plastic or foamed polyethylene to isolate the inner conductor and prevent interference between the signal and the external environment. The outer shielding layer can be composed of a metal grid or copper foil to shield external electromagnetic interference and protect the signal from external interference. The outer insulating layer is a second layer of insulating material outside the outer shielding layer, and forms an insulating isolation layer with the outer shielding layer to protect the outer shielding layer from the external environment. The outer sheath is the outermost protective layer and can be made of durable plastic or rubber material to protect the cable from mechanical damage and environmental influences. Among them, the second coaxial cable is a three-coaxial cable, and between the inner insulating layer and the outer shielding layer, it also includes an intermediate conductor layer and an intermediate insulating layer. A multi-core shielded cable is a cable for transmitting multi-channel signals, including an inner conductor, an insulating layer, an outer shielding layer and an outer sheath. In this embodiment, the first coaxial cable, the second coaxial cable, the third coaxial cable and the multi-core shielded cable are used to connect the lines, which can protect the current loop from external noise interference to the greatest extent and improve the accuracy of small current testing.

[0083] It should be noted that the interface between the M groups of current test circuits 220 and the second coaxial cable, the interface between the second coaxial cable and the test switch circuit 312, the interface between the test switch circuit 312 and the multi-core shielded cable, the interface between the multi-core shielded cable and the multi-core probe card 400, the interface between the multi-core probe card 400 and the third coaxial cable, the interface between the third coaxial cable and the power supply switch circuit 311, the interface between the power supply switch circuit 311 and the first coaxial cable, and the interface between the first coaxial cable and the M voltage sources 210 can all be processed for anti-interference so as to better cope with various complex environments encountered in industrial production.

[0084] Further, in an embodiment of the present invention, if Figure 3 and Figure 6 As shown, the power supply switch circuit 311 includes a common electrode, and the common electrode is used to connect the power input terminals of N units under test; the power supply switch circuit 311 also includes M power supply switches and a power supply grounding switch S50;

[0085] The M power switches each include a first connection terminal, a second connection terminal, a controlled terminal and a ground terminal; the first connection terminals of the M power switches are respectively connected to the M voltage sources 210 in a one-to-one correspondence; the second connection terminals of the M power switches are connected to a common electrode; the controlled terminals of the M power switches are connected to a driving circuit; and the ground terminals of the M power switches are grounded;

[0086] The power supply grounding switch S50 includes a first connection end, a grounding end and a controlled end; the first connection end of the power supply grounding switch S50 is connected to the common electrode; the grounding end of the power supply grounding switch S50 is grounded; and the controlled end of the power supply grounding switch S50 is connected to the driving circuit.

[0087] In this embodiment, the first connection end of the first power switch S41 is connected to the first voltage source, the first connection end of the second power switch is connected to the second voltage source, until the first connection end of the Mth power switch S4M is connected to the Mth voltage source.

[0088] In this embodiment, when performing a leakage current test on the unit under test, the control circuit 100 can control the M voltage sources 210 to output a power supply voltage respectively, and the power supply voltage can be output to the N units under test via the M power supply switches and the common electrode corresponding to the M voltage sources 210, and then the N units under test can generate a test current under the action of the power supply voltage, and the test current can be output to the current test circuit via the test switch circuit 312. In this way, the current test of this embodiment can receive the test current and output a current test signal according to the test current, and the control circuit 100 can receive the current test signal and analyze and obtain the current test result.

[0089] It should be noted that when each power supply switch is actuated, the power supply grounding switch S50 also actuates synchronously. Specifically, when the first connection end of the power supply switch is switched from being connected to the second connection end to being connected to the ground end, the first connection end of the power supply grounding switch S50 is also connected to the ground end. When the first connection end of the power supply switch is switched from being connected to the ground end to being connected to the second connection end, the first connection end of the power supply grounding switch S50 is also disconnected from the ground end. For example, when the first connection end of the first power supply switch S41 is switched from being connected to the second connection end to being connected to the ground end, the power supply grounding switch S50 is synchronously switched to being connected to the first connection end and the ground end; when the first connection end of the first power supply switch S41 is switched from being connected to the ground end to being connected to the second connection end, the power supply grounding switch S50 is synchronously switched to being disconnected from the first connection end and the ground end. In this way, the power supply grounding switch S50 will not affect the normal current test, and the residual charge in the line can be released in time after the current test is completed.

[0090] Further, in an embodiment of the present invention, if Figure 3 and Figure 5 As shown, the test switch circuit 312 includes M groups of test sub-switch circuits, and the first ends of the M groups of test sub-switch circuits are connected to the M current test circuits one by one; wherein each group of test sub-switch circuits includes an isolation switch circuit 3121 and a gate switch circuit 3122;

[0091] The isolation switch circuit 3121 includes a first switch and a second switch; the first switch includes a first connection end, a second connection end, a controlled end and a ground end; the second switch includes a first connection end, a ground end and a controlled end; the first connection end of the first switch is connected to the first end of the test sub-switch circuit; the second connection end of the first switch is connected to the first connection end of the second switch; the controlled end of the first switch and the controlled end of the second switch are connected to the driving circuit; the ground end of the first switch and the ground end of the second switch are grounded;

[0092] The gating switch circuit 3122 includes K gating switches; the K gating switches each include a first connection end, a second connection end, a controlled end and a ground end; the first connection ends of the K gating switches are respectively connected to the K units under test in a one-to-one correspondence; the second connection ends of the K gating switches are each connected to the second connection end of the first switch; the controlled ends of the K gating switches are each connected to the driving circuit; and the ground ends of the K gating switches are each grounded.

[0093] In this embodiment, the first end of the first group of test sub-switch circuits is connected to the first current test circuit, the first end of the second group of test sub-switch circuits is connected to the second current test circuit, until the first end of the Mth group of test sub-switch circuits is connected to the Mth current test circuit.

[0094] In this embodiment, when the leakage current test of the unit under test is performed, the control circuit 100 can control the M voltage sources 210 to output the power supply voltage respectively, and the power supply voltage can be output to the N units under test through the power supply switch circuit 311, and then the N units under test can generate a test current under the action of the power supply voltage, and the test current can be output to the current test circuit through the gate switch circuit and the isolation switch circuit of the test switch circuit 312. In this way, the current test of this embodiment can receive the test current and output a current test signal according to the test current, and the control circuit 100 can receive the current test signal and analyze and obtain the current test result.

[0095] It should be noted that when the first switch is in action, the corresponding second switch also acts synchronously. Specifically, when the first connection end of the first switch is switched from being connected to the second connection end to being connected to the ground end, the first connection end of the second switch is also connected to the ground end. When the first connection end of the first switch is switched from being connected to the ground end to being connected to the second connection end, the first connection end of the second switch is also disconnected from the ground end. For example, when the first connection end of the first first switch S11 is switched from being connected to the second connection end to being connected to the ground end, the first second switch S21 is also synchronously switched to being connected to the first connection end and the ground end. When the first connection end of the first first switch S11 is switched from being connected to the ground end to being connected to the second connection end, the first second switch S21 is synchronously switched to being disconnected from the first connection end and the ground end. In this way, the second switch will not affect the normal current test, and the residual charge in the circuit can be released in time after the current test is completed. In this embodiment, the synchronous action of the switch can be completed by a relay, which can ensure that multiple switches are operated at the same time, thereby ensuring the synchronization of the switching of multiple switches. The control unit can centrally control multiple switches through relays, which can implement a unified control strategy and simplify management.

[0096] Further, in an embodiment of the present invention, if Figure 3 As shown, the power switch circuit 311 also includes M groups of filter circuits; the input ends of the M groups of filter circuits are connected one-to-one with the M voltage sources 210; the output ends of the M groups of filter circuits are connected one-to-one with the first connection ends of the M groups of power switches.

[0097] In this embodiment, the input end of the first group of filter circuits is connected to the first voltage source, the input end of the second group of filter circuits is connected to the second voltage source, until the input end of the M-th group of filter circuits is connected to the M-th voltage source 210. The output end of the first group of filter circuits is connected to the first connection end of the first group of power switches, the output end of the second group of filter circuits is connected to the first connection end of the second group of power switches, until the output end of the M-th group of filter circuits is connected to the first connection end of the M-th group of power switches.

[0098] In this embodiment, the power supply voltage output by the voltage source can be filtered through the filtering circuit. The noise, interference and fluctuation of the voltage source output can be reduced or eliminated through the filtering circuit, thereby providing a stable power supply voltage for the generation of the test current to improve the stability of the generated test current.

[0099] Further, in an embodiment of the present invention, if Figure 6 As shown, each filter circuit includes a first resistor R1, a first capacitor C1, a second resistor R2 and a second capacitor C2;

[0100] Among them, one end of the first resistor R1 is connected to the input end of the filter circuit; the other end of the first resistor R1, one end of the first capacitor C1 and one end of the second resistor R2 are connected; the other end of the second resistor R2, one end of the second capacitor C2 are connected to the output end of the filter circuit; the other end of the first capacitor C1 and the other end of the second capacitor C2 are grounded.

[0101] In this embodiment, each group of filtering circuits may use two groups of RC low-pass filters for filtering, which can effectively filter out the high-frequency components of the power supply voltage output by the voltage source.

[0102] The above description is only an optional embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A multi-channel current testing device, characterized in that: include: A current test component, wherein the current test component is used to test the test current of N units under test; A multi-channel switching component, the multi-channel switching component is connected to the current test component and the N units under test respectively; the multi-channel switching component is used to switch the test channels between the current test component and the N units under test; A control circuit, wherein the control circuit is connected to the current testing component and the multi-channel switching component respectively; the control circuit is used to control the operation of the current testing component, and the control circuit is also used to control the operation of the multi-channel switching component.

2. The multi-channel current testing device according to claim 1, characterized in that: The multi-channel switching component comprises: A switch circuit, the switch circuit is connected to the current test component and the N units under test respectively; the switch circuit is used to switch the test channel between the current test component and the N units under test; A driving circuit, wherein the driving circuit is connected to the switch circuit and the control circuit respectively; the driving circuit is used to receive a control signal output by the control circuit and drive the switch circuit to operate according to the control signal.

3. The multi-channel current testing device according to claim 2, characterized in that: The current testing assembly includes M picoammeters; each of the picoammeters includes a voltage source and a current testing circuit; The voltage source is connected to the control circuit and the switch circuit respectively; the voltage source is used to provide power for the unit under test to generate a test current; The current test circuit is connected to the control circuit, the switch circuit and the voltage source respectively; the current test circuit is used to receive the test current and output a current test signal according to the test current; The control circuit is also used to control the operation of the voltage source and the current test circuit, and to receive the current test signal and operate according to the current test signal.

4. The multi-channel current testing device according to claim 3, characterized in that: The test channel includes a first channel and a second channel; the switch circuit includes: A power supply switch circuit, the power supply switch circuit is respectively connected to the M voltage sources and the N power supply input terminals of the units under test; the power supply switch circuit is used to switch the first channel between the M voltage sources and the power supply input terminals of the N units under test; A test switch circuit, wherein the test switch circuit is respectively connected to the M groups of current test circuits and the output ends of the N units under test; the test switch circuit is used to switch the second channel between the M groups of current test circuits and the output ends of the N units under test.

5. The multi-channel current testing device according to claim 4, characterized in that: The multi-channel current testing device also includes a multi-core probe card, which includes a first connection end, a second connection end and a test end; the first connection end of the multi-core probe card is connected to the power supply switch circuit; the second connection end of the multi-core probe card is connected to the test switch circuit; and the test end of the multi-core probe card is connected to N of the units under test.

6. The multi-channel current testing device according to claim 5, characterized in that: The multi-channel current testing device also includes: a first coaxial cable, the first coaxial cable comprising an inner conductor and an outer shielding layer, the inner conductor of the first coaxial cable being used to connect the positive electrodes of the M voltage sources with the first end of the power supply switch circuit, and the outer shielding layer of the first coaxial cable being used to connect the negative electrodes of the M voltage sources; a second coaxial cable, the second coaxial cable comprising an inner conductor, an intermediate conductor layer and an outer shielding layer, the inner conductor of the second coaxial cable being used to connect the first end of the M groups of current test circuits with the first end of the test switch circuit, the intermediate conductor layer of the second coaxial cable being used to connect the second end of the M groups of current test circuits with the outer shielding layer of the first coaxial cable, and the outer shielding layer of the second coaxial cable being grounded; a third coaxial cable, the third coaxial cable comprising an inner conductor and an outer shielding layer, the inner conductor of the third coaxial cable being used to connect the second end of the power switch circuit with the first connection end of the multi-core probe card, and the outer shielding layer of the third coaxial cable being connected to the outer shielding layer of the first coaxial cable; A multi-core shielded cable, the multi-core shielded cable includes a multi-core inner conductor and an outer shielding layer, the multi-core inner conductor of the multi-core shielded cable is used to connect the second end of the test switch circuit with the second connection end of the multi-core probe card; the outer shielding layer of the multi-core shielded cable is grounded.

7. The multi-channel current testing device according to claim 4, characterized in that: The power supply switch circuit includes a common electrode, and the common electrode is used to connect the power input terminals of the N units under test; the power supply switch circuit also includes M power supply switches and a power supply grounding switch; The M power switches each include a first connection terminal, a second connection terminal, a controlled terminal and a ground terminal; the first connection terminals of the M power switches are respectively connected to the M voltage sources in a one-to-one correspondence; the second connection terminals of the M power switches are each connected to the common electrode; the controlled terminals of the M power switches are each connected to the driving circuit; and the ground terminals of the M power switches are each grounded; The power supply grounding switch includes a first connection end, a grounding end and a controlled end; the first connection end of the power supply grounding switch is connected to the common electrode; the grounding end of the power supply grounding switch is grounded; and the controlled end of the power supply grounding switch is connected to the driving circuit.

8. The multi-channel current testing device according to claim 4, characterized in that: The test switch circuit includes M groups of test sub-switch circuits, and the first ends of the M groups of test sub-switch circuits are connected to the M current test circuits in a one-to-one correspondence; wherein each group of the test sub-switch circuits includes an isolation switch circuit and a gate switch circuit; The isolation switch circuit includes a first switch and a second switch; the first switch includes a first connection end, a second connection end, a controlled end and a ground end; the second switch includes a first connection end, a ground end and a controlled end; the first connection end of the first switch is connected to the first end of the test sub-switch circuit; the second connection end of the first switch is connected to the first connection end of the second switch; the controlled end of the first switch and the controlled end of the second switch are connected to the driving circuit; the ground end of the first switch and the ground end of the second switch are grounded; The gating switch circuit includes K gating switches; the K gating switches each include a first connection end, a second connection end, a controlled end and a ground end; the first connection ends of the K gating switches are respectively connected to the K units under test in a one-to-one correspondence; the second connection ends of the K gating switches are each connected to the second connection end of the first switch; the controlled ends of the K gating switches are each connected to the driving circuit; and the ground ends of the K gating switches are each grounded.

9. The multi-channel current testing device according to claim 7, characterized in that: The power supply switch circuit also includes M groups of filter circuits; the input ends of the M groups of filter circuits are connected one-to-one with the M voltage sources; the output ends of the M groups of filter circuits are connected one-to-one with the first connection ends of the M groups of power supply switches.

10. The multi-channel current testing device according to claim 9, characterized in that: Each group of the filtering circuits includes a first resistor, a first capacitor, a second resistor and a second capacitor; Among them, one end of the first resistor is connected to the input end of the filter circuit; the other end of the first resistor, one end of the first capacitor and one end of the second resistor are connected; the other end of the second resistor, one end of the second capacitor are connected to the output end of the filter circuit; the other end of the first capacitor and the other end of the second capacitor are grounded.

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