Kelvin detection circuit and test method

Abstract

The present invention relates to a Kelvin detection circuit and a test method. In the present invention, multiple circuit arms correspond to ports of a device under test one by one, and each circuit arm is composed of two sub-circuits, the output connection ends of the two sub-circuits are connected to the same port of the device under test, and the other ends are open ends; the open ends of the two sub-circuits correspond to the driving end and the sensing end of the Kelvin detection circuit respectively; the switch circuit is arranged on a test board adapter board, and is used to select two circuit arms in the detection stage, and short-circuit the two sub-circuits in each selected circuit arm, and then connect the selected two circuit arms to the same port of the device under test to form a test loop.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor integrated circuit testing, and in particular to a Kelvin detection circuit and a testing method. Background Art

[0002] During the chip test process, due to the various transfers between the output end of the voltage and current (VI) source and the end of the device under test, these transfers and routings will cause considerable resistance. When the current is large, the impact of these resistances on the test is particularly important. For the above reasons, the Kelvin structure of the VI source is extremely important for chip testing. It is of great significance to detect the four-wire Kelvin connection of the VI source in advance to ensure the accuracy and reliability of the test results. At present, for the VI source with a built-in Kelvin detection circuit, although there is no need to add an additional detection circuit, for the test with high requirements for Kelvin contact resistance, due to the existence of various external transfer links, it is impossible to measure a relatively accurate contact resistance. For the VI source without an internal Kelvin detection circuit, the current mainstream solution is to ensure the correctness of the Kelvin connection by adding an external Kelvin detection circuit on the test board. However, this solution usually requires the use of VI sources and relay control bits on each test board, making the limited test resources even more scarce. In addition, especially for the probe card (ProberCard) in wafer testing, the test board area itself is limited, and the additional Kelvin detection circuit will inevitably increase the difficulty of Prober Card layout and wiring. Summary of the invention

[0003] Based on this, it is necessary to provide a Kelvin detection circuit and a test method to address the problem that the current Kelvin detection circuit requires more control bits and has complex wiring.

[0004] The present invention provides a Kelvin detection circuit, comprising:

[0005] A multi-channel circuit arm, corresponding to the ports of the device under test one by one, each of the circuit arms is composed of two sub-circuits, the output connection ends of the two sub-circuits are connected to the same port of the device under test, and the other ends are open ends; the open ends of the two sub-circuits correspond to the driving end and the sensing end of the Kelvin detection circuit respectively; and

[0006] The switch circuit is arranged on the test board adapter board, and is used to select two circuit arms during the detection stage, and short-circuit the two sub-circuits in each selected circuit arm, and then connect the selected two circuit arms to the same port of the device under test to form a test loop.

[0007] In one embodiment, the Kelvin detection circuit includes two circuit arms, one of which is an H-end circuit arm and the other is an L-end circuit arm. The H-end circuit arm includes an H-end driving subcircuit and an H-end sensing subcircuit, and the L-end circuit arm includes an L-end driving subcircuit and an L-end sensing subcircuit.

[0008] In one embodiment, the switch circuit comprises:

[0009] a first switch branch, wherein a first end of the first switch branch is connected to a sensing end of the H-end sensing subcircuit, a second end of the first switch branch is connected to an output end of the H-end sensing subcircuit, a third end of the first switch branch is connected to the H-end driving subcircuit, and a fourth end of the first switch branch is connected to the L-end driving subcircuit, and is used to short-circuit the H-end driving subcircuit and the H-end sensing subcircuit, disconnect the sensing end and the output end of the H-end sensing subcircuit, and connect the L-end driving subcircuit to the output end of the H-end sensing subcircuit when detecting the contact resistance of the H-end of the device under test;

[0010] a second switch branch, one end of which is connected to the L-end driving subcircuit and the other end of which is connected to the sensing end of the L-end sensing subcircuit, and is used to short-circuit the L-end driving subcircuit and the L-end sensing subcircuit when detecting the contact resistance of the H / L end of the device under test; and

[0011] A third switch branch, a first end of which is connected to the sensing end of the L-end sensing subcircuit, a second end of which is connected to the output end of the L-end sensing subcircuit, a third end of which is connected to the H-end driving subcircuit, and a fourth end of which is connected to the sensing end of the H-end sensing subcircuit, is used to short-circuit the H-end driving subcircuit and the H-end sensing subcircuit, disconnect the connection between the sensing end and the output end of the L-end sensing subcircuit, and connect the H-end driving subcircuit to the output end of the L-end sensing subcircuit when detecting the contact resistance of the L-end of the device under test.

[0012] In one embodiment, the first switch branch includes a first double-pole double-throw switch;

[0013] The first double-pole double-throw switch includes four static contacts, two moving contacts and two switch blades, wherein the first static contact is connected to the sensing end of the H-end sensing subcircuit, the second static contact is connected to the L-end driving subcircuit, the third static contact is connected to the H-end driving subcircuit, the fourth static contact is suspended, the first moving contact is connected to the output end of the H-end sensing subcircuit, the second moving contact is connected to the sensing end of the H-end sensing subcircuit, and the first moving contact controls the first switch blade to switch between the first static contact and the second static contact, and the second moving contact controls the second switch blade to switch between the third static contact and the fourth static contact.

[0014] In one embodiment, the third switch branch includes a second double-pole double-throw switch;

[0015] The second double-pole double-throw switch includes four static contacts, two moving contacts and two switch blades, wherein the first static contact is connected to the sensing end of the L-end sensing subcircuit, the second static contact and the third static contact are both connected to the H-end driving subcircuit, the fourth static contact is suspended, the first moving contact is connected to the output end of the L-end sensing subcircuit, the second moving contact is connected to the sensing end of the H-end sensing subcircuit, and the first moving contact controls the third switch blade to switch between the first static contact and the second static contact, and the second moving contact controls the fourth switch blade to switch between the third static contact and the fourth static contact.

[0016] In one embodiment, the Kelvin detection circuit further includes:

[0017] an ammeter, connected in series in the test loop, for detecting a test current in the test loop; and

[0018] A voltmeter is respectively connected to the two output terminals in the test loop and is used to test the test voltage between the two output terminals.

[0019] Based on the same inventive concept, the present invention further provides a testing method based on the Kelvin detection circuit described in any of the above embodiments, comprising:

[0020] Using a switch circuit, short-circuiting the two sub-circuits of the two circuit arms respectively, and connecting the short-circuited four sub-circuits to the same port of the device under test to form a test loop;

[0021] An input voltage is provided to the test loop, a test voltage between the output terminals of the two sub-circuits corresponding to the same port is detected, and an open circuit connection state between the output terminals of the two sub-circuits is determined according to the test voltage.

[0022] In one embodiment, the testing method further comprises:

[0023] The test current of the test loop is detected, and the contact resistance at the port is calculated according to the test voltage and the test current obtained by the detection.

[0024] In one embodiment, the switch circuit comprises:

[0025] a first double-pole double-throw switch, wherein the first static contact is connected to the sensing end of the H-end sensing subcircuit, the second static contact is connected to the L-end driving subcircuit, the third static contact is connected to the H-end driving subcircuit, the fourth static contact is suspended, the first moving contact is connected to the output end of the H-end sensing subcircuit, the second static contact is connected to the sensing end of the H-end sensing subcircuit, and the first moving contact controls the first switch to switch between the first static contact and the second static contact, and the second moving contact controls the second switch to switch between the third static contact and the fourth static contact;

[0026] a second double-pole double-throw switch, wherein the first static contact is connected to the sensing end of the L-end sensing subcircuit, the second static contact and the third static contact are both connected to the H-end driving subcircuit, the fourth static contact is suspended, the first moving contact is connected to the output end of the L-end sensing subcircuit, the second moving contact is connected to the sensing end of the H-end sensing subcircuit, and the first moving contact controls the third switch to switch between the first static contact and the second static contact, and the second moving contact controls the fourth switch to switch between the third static contact and the fourth static contact;

[0027] and a third switch, which is arranged in series between the L-terminal driving sub-circuit and the sensing end of the L-terminal sensing sub-circuit.

[0028] In one embodiment, detecting the contact resistance at the H-terminal port of the device under test includes:

[0029] Throwing the first switch toward the second static contact of the first double-pole double-throw switch, and throwing the second switch toward the third static contact of the first double-pole double-throw switch, so that the H-end driving subcircuit and the H-end sensing subcircuit are short-circuited, the sensing end and the output end of the H-end sensing subcircuit are disconnected, and the L-end driving subcircuit is connected to the output end of the H-end sensing subcircuit, and the third switch is closed to short-circuit the L-end driving subcircuit and the L-end sensing subcircuit, thereby forming the test loop;

[0030] The input voltage is provided to the test loop, the detection voltage and the detection current are detected and obtained, and the contact resistance at the H-terminal port of the device under test is determined according to the detection voltage and the detection current.

[0031] In one embodiment, the test voltage is obtained by using a voltmeter, and the test current is obtained by using an ammeter.

[0032] In summary, the present invention provides a Kelvin detection circuit and test method. In the present invention, multiple circuit arms correspond one-to-one to the ports of the device under test, and each circuit arm is composed of two sub-circuits, the output connection ends of the two sub-circuits are connected to the same port of the device under test, and the other end is an open end; the open ends of the two sub-circuits correspond to the driving end and the sensing end of the Kelvin detection circuit respectively; the switch circuit is arranged on the test board adapter board, which is used to select the two circuit arms in the detection stage, and short-circuit the two sub-circuits in each selected circuit arm, and then connect the selected two circuit arms to the same port of the device under test to form a test loop. In the present invention, the switch circuit is arranged on the test board adapter board, and the space on the test board adapter board and the spare relay control bit resources can be used for detection, without occupying the area of ​​the test board or the test resources on the test board. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the structure of a Kelvin detection circuit provided by an embodiment of the present invention;

[0034] Figure 2 An exemplary Kelvin detection principle diagram provided for an embodiment of the present invention;

[0035] Figure 3 A schematic flow chart of a testing method based on a Kelvin detection circuit provided by the present invention. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific implementation disclosed below.

[0037] See also Figure 1 An embodiment of the present invention provides a Kelvin detection circuit, including a multi-channel circuit arm 100 and a switch circuit 200.

[0038] The multi-channel circuit arm 100 corresponds one-to-one to the port of the device under test, and each circuit arm is composed of two sub-circuits, the output connection ends of the two sub-circuits are connected to the same port of the device under test, and the other ends are open ends; the open ends of the two sub-circuits correspond to the driving end and the sensing end of the Kelvin detection circuit respectively.

[0039] The switch circuit 200 is arranged on the test board adapter board, and is used to select two circuit arms during the detection stage, and short-circuit the two sub-circuits in each selected circuit arm, and then connect the selected two circuit arms to the same port of the device under test to form a test loop.

[0040] It is understood that for VI sources without built-in Kelvin detection circuits, please refer to Figure 1 , the multiple groups of relays shown in the schematic diagram of the VI source external Kelvin detection can realize the external VI source Kelvin detection. The detection circuit consists of four input terminals, FH, SH, FL and SL, which are connected to the four-wire output inside the VI source, and FH', SH', FL' and SL' are four output terminals, which are connected to the DUT (device under test). In this structure, there is a switching relay between FH and SH to short-circuit the FH and SH of the VI source in advance, and there is a switching relay between FL and SL to short-circuit the FL and SL of the VI source in advance; there are switching relays between FH and SH', and between SL and SL', which can cut off SH and SH', and SL and SL' respectively; there are switching relays between FH and SL', and between SH' and FL', which can realize the Kelvin detection of the High and Low ends of the DUT, and measure the Kelvin contact resistance value relatively accurately. However, this solution usually requires the occupation of the VI source and relay control bits on each DUT test board, making the originally few test resources even more tense.

[0041] In the present invention, the switch circuit 200 is arranged on the test board adapter board. In the detection stage, the two sub-circuits of two of the circuit arms are short-circuited respectively, and the four short-circuited sub-circuits are connected to the same port of the device under test to form a test loop. The space on the test board adapter board and the spare relay control bit resources can be used for detection, without occupying the area of ​​the test board or the test resources on the test board.

[0042] In one embodiment, the Kelvin detection circuit includes two circuit arms, one of which is an H-end circuit arm and the other is an L-end circuit arm. The H-end circuit arm includes an H-end driving subcircuit 110 and an H-end sensing subcircuit 120, and the L-end circuit arm includes an L-end driving subcircuit 130 and an L-end sensing subcircuit 140.

[0043] It can be understood that the H-end circuit arm and the L-end circuit arm form a four-wire connection method, which is conducive to eliminating the influence of resistance in the test circuit, thereby ensuring accuracy when measuring low resistance.

[0044] In one embodiment, the switch circuit 200 includes a first switch branch 210 , a second switch branch 220 and a third switch branch 230 .

[0045] The first switch branch 210 has a first end connected to the sensing end of the H-end sensing sub-circuit 120, a second end connected to the output end of the H-end sensing sub-circuit 120, a third end connected to the H-end driving sub-circuit 110, and a fourth end connected to the L-end driving sub-circuit 130, and is used to short-circuit the H-end driving sub-circuit 110 and the H-end sensing sub-circuit 120, disconnect the connection between the sensing end and the output end of the H-end sensing sub-circuit 120, and connect the L-end driving sub-circuit 130 to the output end of the H-end sensing sub-circuit 120 when detecting the contact resistance of the H-end of the device under test.

[0046] One end of the second switch branch 220 is connected to the L-end driving subcircuit 130, and the other end is connected to the sensing end of the L-end sensing subcircuit 140, and is used to short-circuit the L-end driving subcircuit 130 and the L-end sensing subcircuit 140 when detecting the contact resistance of the H / L end of the device under test.

[0047] The third switch branch 230 has a first end connected to the sensing end of the L-end sensing sub-circuit 140, a second end connected to the output end of the L-end sensing sub-circuit 140, a third end connected to the H-end driving sub-circuit 110, and a fourth end connected to the sensing end of the H-end sensing sub-circuit 120, and is used to short-circuit the H-end driving sub-circuit 110 and the H-end sensing sub-circuit 120, disconnect the connection between the sensing end and the output end of the L-end sensing sub-circuit 140, and connect the H-end driving sub-circuit 110 to the output end of the L-end sensing sub-circuit 140 when detecting the contact resistance of the L end of the device under test.

[0048] In one embodiment, the first switch branch 210 includes a first double-pole double-throw switch K1.

[0049] The first double-pole double-throw switch K1 includes four static contacts, two moving contacts and two switch blades, wherein the first static contact P11 is connected to the sensing end FH of the H-end sensing subcircuit 120, the second static contact P12 is connected to the L-end driving subcircuit 130, the third static contact P13 is connected to the H-end driving subcircuit 110, the fourth static contact P14 is suspended, the first moving contact P15 is connected to the output end SH' of the H-end sensing subcircuit 120, the second moving contact P16 is connected to the sensing end SH of the H-end sensing subcircuit 120, and the first moving contact P15 controls the first switch blade to switch between the first static contact P11 and the second static contact P12, and the second moving contact P16 controls the second switch blade to switch between the third static contact P13 and the fourth static contact P14.

[0050] When used for forming a DUT test circuit, the first moving contact P15 of the first double-pole double-throw switch K1 controls the first switch to be connected to the first static contact P11 of the first double-pole double-throw switch K1, and the second moving contact P16 of the first double-pole double-throw switch K1 controls the second switch to be connected to the fourth static contact P14 of the first double-pole double-throw switch K1. During the connection state of the test port, the first moving contact P15 of the first double-pole double-throw switch K1 controls the first switch to be connected to the second static contact P12 of the first double-pole double-throw switch K1, and the second moving contact P16 of the first double-pole double-throw switch K1 controls the second switch to be connected to the third static contact P13 of the first double-pole double-throw switch K1, and the H-end driving subcircuit 110 is short-circuited with the H-end sensing subcircuit 120, and is connected to the output terminal FH' of the H-end driving subcircuit 110. In addition, the L-terminal driving subcircuit 130 and the L-terminal sensing subcircuit 140 are short-circuited through the second switch branch 220 and connected to the output terminal SH' of the H-terminal sensing subcircuit 120, and then a small voltage is applied and measured. If the output terminal FH' and the output terminal SH' are short-circuited, a voltage value close to zero is measured; if the output terminal FH' and the output terminal SH' are open-circuited, the applied voltage value is measured.

[0051] Furthermore, if it is necessary to quantitatively test the Kelvin contact resistance, the FVMI pressure measurement method (or FIMV flow measurement method) can be used. That is, a small voltage V1 is applied, and the current I1 is measured back to calculate the Kelvin contact resistance R H =V1 / I1, that is, the connection status of the High end of the DUT and the Kelvin contact resistance value are obtained.

[0052] In one embodiment, the third switch branch 230 includes a second double-pole double-throw switch K2.

[0053] The second double-pole double-throw switch K2 includes four static contacts, two moving contacts and two switch blades, wherein the first static contact P21 is connected to the sensing end SL of the L-end sensing subcircuit 140, the second static contact P21 and the third static contact P23 are both connected to the H-end driving subcircuit 110, the fourth static contact P24 is suspended, the first moving contact P25 is connected to the output end SL' of the L-end sensing subcircuit 140, the second moving contact P26 is connected to the sensing end SH of the H-end sensing subcircuit 120, and the first moving contact P25 controls the third switch blade to switch between the first static contact P21 and the second static contact P22, and the second moving contact P26 controls the fourth switch blade to switch between the third static contact K and the fourth static contact P24.

[0054] When used for forming a DUT test circuit, the first moving contact P25 of the second double-pole double-throw switch K2 is connected to the first static contact P21 through the third switch, and the second moving contact P26 of the second double-pole double-throw switch K2 controls the fourth switch to connect to the fourth static contact P24. During the connection state of the test port, the first moving contact P25 of the second double-pole double-throw switch K2 is connected to the second static contact P22 through the third switch, and the second moving contact P26 of the second double-pole double-throw switch K2 controls the fourth switch to connect to the third static contact P23. At this time, the H-end driving subcircuit 110 is short-circuited with the H-end sensing subcircuit 120 and connected to the output terminal SL' of the L-end sensing subcircuit 140. In addition, the L-end driving subcircuit 130 and the L-end sensing subcircuit 140 are short-circuited through the second switch branch 220 and connected to the output terminal FL' of the L-end driving subcircuit 130, and then a small voltage is applied and measured back. If the output terminal FL' and the output terminal SL' are short-circuited, a voltage value close to zero is measured; if the output terminal FL' and the output terminal SL' are open-circuited, the applied voltage value is measured.

[0055] Furthermore, if it is necessary to quantitatively test the Kelvin contact resistance, the FVMI (or FIMV) method can be used. That is, a small voltage V2 is applied, and the current I2 is measured back to calculate the Kelvin contact resistance R L =V2 / I2, that is, the connection status of the Low end of the DUT and the Kelvin contact resistance value are obtained.

[0056] In one embodiment, the Kelvin detection circuit further includes an ammeter (not shown) and a voltmeter (not shown).

[0057] The ammeter is connected in series in the test loop and is used to detect the test circuit in the test loop.

[0058] The voltmeter is connected to the two output terminals in the test loop respectively, and is used for testing the test voltage between the two output terminals.

[0059] Based on the Kelvin detection circuit described in any of the above embodiments, the embodiment of the present invention further provides a testing method, see Figure 3 , the test method comprises:

[0060] Step S310, using the switch circuit 200, selecting two circuit arms, and short-circuiting the two sub-circuits in each of the selected circuit arms, and then connecting the two selected circuit arms to the same port of the device under test to form a test loop;

[0061] Step S320, providing an input voltage for the test loop, detecting a test voltage between the output ends of the two sub-circuits corresponding to the same port, and determining an open circuit connection state between the output ends of the two sub-circuits according to the test voltage.

[0062] The above method can be used to detect the connection status of each port of the DUT device. In the present invention, the switch circuit 200 is set on the test board adapter board. In the detection stage, the two sub-circuits of two of the circuit arms are short-circuited respectively, and the four short-circuited sub-circuits are connected to the same port of the device under test to form a test loop. The space on the test board adapter board and the spare relay control bit resources can be used for detection, without occupying the area of ​​the test board or the test resources on the test board.

[0063] In one embodiment, the method further comprises:

[0064] The test current of the test loop is detected, and the contact resistance at the port is calculated according to the test voltage and the test current obtained by the detection.

[0065] In one embodiment, the Kelvin detection circuit includes two circuit arms, one of which is an H-end circuit arm and the other is an L-end circuit arm, the H-end circuit arm includes an H-end driving subcircuit 110 and an H-end sensing subcircuit 120, and the L-end circuit arm includes an L-end driving subcircuit 130 and an L-end sensing subcircuit 140. It can be understood that the H-end circuit arm and the L-end circuit arm form a four-wire connection, which is conducive to eliminating the influence of resistance in the test circuit, thereby ensuring accuracy when measuring low resistance.

[0066] In one embodiment, the switch circuit 200 includes a first double-pole double-throw switch K1 , a second double-pole double-throw switch K2 , and a third switch K3 .

[0067] The first double-pole double-throw switch K1 includes four static contacts, two moving contacts and two switch blades, wherein the first static contact P11 is connected to the sensing end FH of the H-end sensing subcircuit 120, the second static contact P12 is connected to the L-end driving subcircuit 130, the third static contact P13 is connected to the H-end driving subcircuit 110, the fourth static contact P14 is suspended, the first moving contact P15 is connected to the output end SH' of the H-end sensing subcircuit 120, the second moving contact P16 is connected to the sensing end SH of the H-end sensing subcircuit 120, and the first moving contact P15 controls the first switch blade to switch between the first static contact P11 and the second static contact P12, and the second moving contact P16 controls the second switch blade to switch between the third static contact P13 and the fourth static contact P14.

[0068] When used for forming a DUT test circuit, the first moving contact P15 of the first double-pole double-throw switch K1 controls the first switch to be connected to the first static contact P11 of the first double-pole double-throw switch K1, and the second moving contact P16 of the first double-pole double-throw switch K1 controls the second switch to be connected to the fourth static contact P14 of the first double-pole double-throw switch K1. During the connection state of the test port, the first moving contact P15 of the first double-pole double-throw switch K1 controls the first switch to be connected to the second static contact P12 of the first double-pole double-throw switch K1, and the second moving contact P16 of the first double-pole double-throw switch K1 controls the second switch to be connected to the third static contact P13 of the first double-pole double-throw switch K1, and the H-end driving subcircuit 110 is short-circuited with the H-end sensing subcircuit 120, and is connected to the output terminal FH' of the H-end driving subcircuit 110. In addition, the L-terminal driving subcircuit 130 and the L-terminal sensing subcircuit 140 are short-circuited through the second switch branch 220 and connected to the output terminal SH' of the H-terminal sensing subcircuit 120, and then a small voltage is applied and measured. If the output terminal FH' and the output terminal SH' are short-circuited, a voltage value close to zero is measured; if the output terminal FH' and the output terminal SH' are open-circuited, the applied voltage value is measured.

[0069] The second double-pole double-throw switch K2 includes four static contacts, two moving contacts and two switch blades, wherein the first static contact P21 is connected to the sensing end SL of the L-end sensing subcircuit 140, the second static contact P21 and the third static contact P23 are both connected to the H-end driving subcircuit 110, the fourth static contact P24 is suspended, the first moving contact P25 is connected to the output end SL' of the L-end sensing subcircuit 140, the second moving contact P26 is connected to the sensing end SH of the H-end sensing subcircuit 120, and the first moving contact P25 controls the third switch blade to switch between the first static contact P21 and the second static contact P22, and the second moving contact P26 controls the fourth switch blade to switch between the third static contact K and the fourth static contact P24.

[0070] When used for forming a DUT test circuit, the first moving contact P25 of the second double-pole double-throw switch K2 is connected to the first static contact P21 through the third switch, and the second moving contact P26 of the second double-pole double-throw switch K2 controls the fourth switch to connect to the fourth static contact P24. During the connection state of the test port, the first moving contact P25 of the second double-pole double-throw switch K2 is connected to the second static contact P22 through the third switch, and the second moving contact P26 of the second double-pole double-throw switch K2 controls the fourth switch to connect to the third static contact P23. At this time, the H-end driving subcircuit 110 is short-circuited with the H-end sensing subcircuit 120 and connected to the output terminal SL' of the L-end sensing subcircuit 140. In addition, the L-end driving subcircuit 130 and the L-end sensing subcircuit 140 are short-circuited through the second switch branch 220 and connected to the output terminal FL' of the L-end driving subcircuit 130, and then a small voltage is applied and measured back. If the output terminal FL' and the output terminal SL' are short-circuited, a voltage value close to zero is measured; if the output terminal FL' and the output terminal SL' are open-circuited, the applied voltage value is measured.

[0071] The third switch K3 is arranged in series between the L-end driving sub-circuit 130 and the sensing end of the L-end sensing sub-circuit 140 .

[0072] In one embodiment, detecting the contact resistance at the H-terminal port of the device under test includes:

[0073] Throwing the first switch toward the second static contact P12 of the first double-pole double-throw switch, and throwing the second switch toward the third static contact P13 of the first double-pole double-throw switch, so that the H-end driving subcircuit 110 and the H-end sensing subcircuit 120 are short-circuited, the sensing end and the output end of the H-end sensing subcircuit 120 are disconnected, and the L-end driving subcircuit 130 is connected to the output end of the H-end sensing subcircuit 120, and the third switch is closed to short-circuit the L-end driving subcircuit 130 and the L-end sensing subcircuit 140, thereby forming the test loop;

[0074] The input voltage is provided to the test loop, the detection voltage and the detection current are detected and obtained, and the contact resistance at the H-terminal port of the device under test is determined according to the detection voltage and the detection current.

[0075] In this embodiment, when the Kelvin contact resistance is quantitatively tested, the FVMI pressure measurement method (or FIMV flow measurement method) is used. That is, a small voltage V1 is applied, and the current I1 is measured back to calculate the Kelvin contact resistance R H=V1 / I1, that is, the connection condition of the High end of the DUT and the Kelvin contact resistance value are obtained. Similarly, the connection condition of the Low end of the DUT and the Kelvin contact resistance value can be obtained, and the details are not repeated here.

[0076] In one embodiment, the test voltage is obtained by using a voltmeter, and the test current is obtained by using an ammeter.

[0077] In summary, the present invention provides a Kelvin detection circuit and test method. In the present invention, multiple circuit arms correspond one-to-one to the ports of the device under test, and each circuit arm is composed of two sub-circuits, the output connection ends of the two sub-circuits are connected to the same port of the device under test, and the other end is an open end; the open ends of the two sub-circuits correspond to the driving end and the sensing end of the Kelvin detection circuit respectively; the switch circuit 200 is arranged on the test board adapter board, which is used to select the two circuit arms in the detection stage, and short-circuit the two sub-circuits in each selected circuit arm, and then connect the selected two circuit arms to the same port of the device under test to form a test loop. In the present invention, the switch circuit 200 is arranged on the test board adapter board, and the space on the test board adapter board and the spare relay control bit resources can be used for detection, without occupying the area of ​​the test board or the test resources on the test board.

[0078] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0079] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A Kelvin detection circuit, characterized in that: include: A multi-channel circuit arm, corresponding to the ports of the device under test one by one, each of the circuit arms is composed of two sub-circuits, the output connection ends of the two sub-circuits are connected to the same port of the device under test, and the other ends are open ends; the open ends of the two sub-circuits correspond to the driving end and the sensing end of the Kelvin detection circuit respectively; as well as A switch circuit is provided on the test board adapter board, and is used to select two circuit arms during the detection phase, and short-circuit the two sub-circuits in each of the selected circuit arms, and then connect the two selected circuit arms to the same port of the device under test to form a test loop; The Kelvin detection circuit comprises two circuit arms, one of which is an H-end circuit arm and the other is an L-end circuit arm, the H-end circuit arm comprises an H-end driving subcircuit and an H-end sensing subcircuit, and the L-end circuit arm comprises an L-end driving subcircuit and an L-end sensing subcircuit; The switch circuit comprises: a first switch branch, a first end of which is connected to the sensing end of the H-end sensing subcircuit, a second end of which is connected to the output end of the H-end sensing subcircuit, a third end of which is connected to the H-end driving subcircuit, and a fourth end of which is connected to the L-end driving subcircuit, and is used to short-circuit the H-end driving subcircuit and the H-end sensing subcircuit, disconnect the connection between the sensing end and the output end of the H-end sensing subcircuit, and connect the L-end driving subcircuit to the output end of the H-end sensing subcircuit when detecting the contact resistance of the H-end of the device under test; a second switch branch, one end of which is connected to the L-end driving subcircuit and the other end of which is connected to the sensing end of the L-end sensing subcircuit, and is used to short-circuit the L-end driving subcircuit and the L-end sensing subcircuit when detecting the contact resistance of the H / L end of the device under test; and A third switch branch, a first end of which is connected to the sensing end of the L-end sensing subcircuit, a second end of which is connected to the output end of the L-end sensing subcircuit, a third end of which is connected to the H-end driving subcircuit, and a fourth end of which is connected to the sensing end of the H-end sensing subcircuit, is used to short-circuit the H-end driving subcircuit and the H-end sensing subcircuit, disconnect the connection between the sensing end and the output end of the L-end sensing subcircuit, and connect the H-end driving subcircuit to the output end of the L-end sensing subcircuit when detecting the contact resistance of the L-end of the device under test.

2. The Kelvin detection circuit according to claim 1, characterized in that: The first switch branch includes a first double-pole double-throw switch; The first double-pole double-throw switch includes four static contacts, two moving contacts and two switch blades, wherein the first static contact is connected to the sensing end of the H-end sensing subcircuit, the second static contact is connected to the L-end driving subcircuit, the third static contact is connected to the H-end driving subcircuit, the fourth static contact is suspended, the first moving contact is connected to the output end of the H-end sensing subcircuit, the second moving contact is connected to the sensing end of the H-end sensing subcircuit, and the first moving contact controls the first switch blade to switch between the first static contact and the second static contact, and the second moving contact controls the second switch blade to switch between the third static contact and the fourth static contact.

3. The Kelvin detection circuit according to claim 1, characterized in that: The third switch branch includes a second double-pole double-throw switch; The second double-pole double-throw switch includes four static contacts, two moving contacts and two switch blades, wherein the first static contact is connected to the sensing end of the L-end sensing subcircuit, the second static contact and the third static contact are both connected to the H-end driving subcircuit, the fourth static contact is suspended, the first moving contact is connected to the output end of the L-end sensing subcircuit, the second moving contact is connected to the sensing end of the H-end sensing subcircuit, and the first moving contact controls the third switch blade to switch between the first static contact and the second static contact, and the second moving contact controls the fourth switch blade to switch between the third static contact and the fourth static contact.

4. The Kelvin detection circuit according to claim 1, characterized in that: Also includes: An ammeter, connected in series in the test loop, for detecting a test circuit in the test loop; as well as A voltmeter is respectively connected to the two output terminals in the test loop and is used to test the test voltage between the two output terminals.

5. A testing method based on the Kelvin detection circuit according to any one of claims 1 to 4, characterized in that: include: Using a switch circuit, two circuit arms are selected, two sub-circuits in each of the selected circuit arms are short-circuited respectively, and the four short-circuited sub-circuits are connected to the same port of the device under test to form a test loop; An input voltage is provided to the test loop, a test voltage between the output terminals of the two sub-circuits corresponding to the same port is detected, and an open circuit connection state between the output terminals of the two sub-circuits is determined according to the test voltage.

6. The testing method according to claim 5, characterized in that: Also includes: The test current of the test loop is detected, and the contact resistance at the port is calculated according to the test voltage and the test current obtained by the detection.

7. The testing method according to claim 5, characterized in that: The Kelvin detection circuit includes two circuit arms, one of which is an H-end circuit arm and the other is an L-end circuit arm. The H-end circuit arm includes an H-end driving subcircuit and an H-end sensing subcircuit, and the L-end circuit arm includes an L-end driving subcircuit and an L-end sensing subcircuit.

8. The testing method according to claim 7, characterized in that: The switch circuit comprises: a first double-pole double-throw switch, wherein the first static contact is connected to the sensing end of the H-end sensing subcircuit, the second static contact is connected to the L-end driving subcircuit, the third static contact is connected to the H-end driving subcircuit, the fourth static contact is suspended, the first moving contact is connected to the output end of the H-end sensing subcircuit, the second static contact is connected to the sensing end of the H-end sensing subcircuit, and the first moving contact controls the first switch to switch between the first static contact and the second static contact, and the second moving contact controls the second switch to switch between the third static contact and the fourth static contact; a second double-pole double-throw switch, wherein the first static contact is connected to the sensing end of the L-end sensing subcircuit, the second static contact and the third static contact are both connected to the H-end driving subcircuit, the fourth static contact is suspended, the first moving contact is connected to the output end of the L-end sensing subcircuit, the second moving contact is connected to the sensing end of the H-end sensing subcircuit, and the first moving contact controls the third switch to switch between the first static contact and the second static contact, and the second moving contact controls the fourth switch to switch between the third static contact and the fourth static contact; and a third switch, which is arranged in series between the L-terminal driving sub-circuit and the sensing end of the L-terminal sensing sub-circuit.

9. The testing method according to claim 8, characterized in that: Detecting the contact resistance at the H-terminal port of the device under test, comprising: Throwing the first switch toward the second static contact of the first double-pole double-throw switch, and throwing the second switch toward the third static contact of the first double-pole double-throw switch, so that the H-end driving subcircuit and the H-end sensing subcircuit are short-circuited, the sensing end and the output end of the H-end sensing subcircuit are disconnected, and the L-end driving subcircuit is connected to the output end of the H-end sensing subcircuit, and the third switch is closed to short-circuit the L-end driving subcircuit and the L-end sensing subcircuit, thereby forming the test loop; The input voltage is provided to the test loop, a detection voltage and a detection current are detected and obtained, and the contact resistance at the H-terminal port of the device under test is determined according to the detection voltage and the detection current.

10. The testing method according to claim 6, characterized in that: The test voltage is obtained by using a voltmeter, and the test current is obtained by using an ammeter.

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