Testing machine and grounding terminal connectivity detection device
By setting a detection point at the ground terminal between the tester and the device under test and using the detection module and current limiting module to record the voltage, the problem of insufficient ground terminal connection conductivity detection in traditional testers is solved, and more accurate automated testing is achieved.
Patent Information
- Application Number
- CN202422484824.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-14
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2034-10-14
AI Technical Summary
Traditional testers do not detect the continuity between the measurement line and the ground terminal of the device under test, resulting in inaccurate test results.
A detection point is set between the ground terminal of the device under test and the local ground terminal of the resource board in the test machine. The reference voltage and the measured voltage are recorded by the detection module, and the connectivity of the ground terminal is automatically detected in combination with the output voltage of the current limiting module.
The test accuracy is improved, manual intervention is reduced, measurement errors are reduced, and automatic ground terminal connectivity detection is achieved.
Smart Images
Figure CN223401031U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor testing technology, and in particular to a testing machine and a ground terminal connectivity detection device. Background Art
[0002] Semiconductor automated testing refers to the use of automatic test equipment (ATE) to inspect various parameters of devices under test (DUTs), eliminating defective products and controlling the quality of semiconductors before they leave the factory. Due to the voltage difference between the ground terminal of the tester and the DUT, traditional testers connect the ground terminal of the DUT to the test board inside the machine via a measuring line. This voltage difference is then compensated for using a compensation circuit to reduce measurement errors. The connection and continuity between the measuring line and the DUT are generally not checked. Manually verifying contact based on test results can easily lead to inaccurate test results. Utility Model Content
[0003] Based on this, it is necessary to provide a testing machine and a ground terminal connectivity detection device that can improve test accuracy in order to address the above problems.
[0004] A first aspect of the present application provides a ground terminal connectivity detection device, comprising:
[0005] A detection module connected to a detection point, wherein the detection point is provided on a cable between a ground terminal of the device under test and a local ground terminal of a resource board in the test machine;
[0006] a current limiting module, connecting the detection point and the detection module;
[0007] In which, when the detection module does not output the voltage to the detection point through the current limiting module, the detection module records the reference voltage of the detection point; when the detection module outputs the voltage to the detection point through the current limiting module, the detection module records the measured voltage of the detection point; the reference voltage and the measured voltage are used to detect whether the ground terminal of the device under test is connected to the local ground terminal of the resource board.
[0008] In one embodiment, the ground terminal connectivity detection device further includes a switch K1 , and the detection module is connected to the detection point via the switch K1 .
[0009] In one embodiment, the detection module includes a voltage detection unit and a voltage source, the voltage detection unit is connected to the switch K1, and the voltage source is connected to the current limiting module.
[0010] In one embodiment, the current limiting module includes a current limiting element and a switch K2 , wherein the current limiting element and the switch K2 are connected in series, one end of the current limiting element is connected to the voltage source, and the other end is connected to the detection point.
[0011] In one embodiment, the ground terminal connectivity detection device further includes a switching switch K3, a switching switch K4, and a switching switch K5, wherein the switching switch K3 is connected in series to a first cable between the detection point and the ground terminal of the device under test, the switching switch K4 is connected in series to a second cable between the detection point and the voltage difference compensation circuit in the resource board, a first end of the switching switch K5 is connected to a side where the second cable is connected to the voltage difference compensation circuit, and a second end of the switching switch K5 is connected to a local ground terminal of the resource board.
[0012] In one embodiment, when the switch K3 is disconnected, the switch K4 is closed, the switch K5 is closed, the switch K2 is disconnected, and the switch K1 is closed, the voltage detection unit records a first reference voltage of the detection point; when the switch K3 is disconnected, the switch K4 is closed, the switch K5 is closed, the switch K1 is closed, and the switch K2 is closed, and the voltage source outputs a voltage to the detection point through the current limiting element, the voltage detection unit records a first measured voltage of the detection point; the first reference voltage and the first measured voltage are used to detect whether the detection point is connected to the local ground terminal of the resource board;
[0013] When the switching switch K3 is closed, the switching switch K4 is disconnected, the switching switch K2 is disconnected, and the switching switch K1 is closed, the voltage detection unit records the second reference voltage of the detection point; when the switching switch K3 is closed, the switching switch K4 is disconnected, the switching switch K1 is closed, and the switching switch K2 is closed, and the voltage source outputs a voltage to the detection point through the current limiting element, the voltage detection unit records the second measured voltage of the detection point; the second reference voltage and the second measured voltage are used to detect whether the detection point is connected to the ground terminal of the device under test.
[0014] A second aspect of the present application provides a testing machine, comprising a voltage difference compensation circuit and the above-mentioned ground terminal connectivity detection device connected in series.
[0015] In one embodiment, the voltage difference compensation circuit includes a follower circuit and a PE chip, and the follower circuit is connected to a local ground terminal of a resource board, the ground terminal connectivity detection device, and the PE chip.
[0016] In one embodiment, the follower circuit includes an operational amplifier, a resistor R2 and a resistor R3, the first end of the resistor R2 is connected to the ground terminal connectivity detection device and the non-inverting input terminal of the operational amplifier, the second end of the resistor R2 is connected to the local ground terminal, the inverting input terminal of the operational amplifier is connected to the output terminal of the operational amplifier, the output terminal of the operational amplifier is connected to the first end of the resistor R3, and the second end of the resistor R3 is connected to the PE chip.
[0017] In one embodiment, the follower circuit further includes a capacitor C1 , a first end of the capacitor C1 is connected to the second end of the resistor R3 and the PE chip, and a second end of the capacitor C1 is connected to a local ground.
[0018] In one embodiment, the voltage difference compensation circuit and the ground terminal connectivity detection device are arranged on a resource board, and the device to be tested is arranged on a carrier board; or
[0019] The voltage difference compensation circuit, the switch K4 and the switch K5 in the ground terminal connectivity detection device are set on the resource board, and the device to be tested and the detection module, current limiting module, switch K1 and switch K3 in the ground terminal connectivity detection device are set on the carrier board.
[0020] The aforementioned tester and ground terminal connectivity detection device has a probe point set on the cable between the ground terminal of the device under test and the local ground terminal of the resource board in the tester. The detection module is connected to the probe point, and the current limiting module is connected to the probe point and the detection module. When the detection module outputs voltage to the probe point without passing through the current limiting module, the detection module records the reference voltage at the probe point. When the detection module outputs voltage to the probe point through the current limiting module, the detection module records the measured voltage at the probe point. The reference voltage and measured voltage are combined to detect whether the ground terminal of the device under test is connected to the local ground terminal of the resource board, thereby improving the accuracy of subsequent testing operations. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 is a structural block diagram of a ground terminal connectivity detection device in one embodiment;
[0022] Figure 2 1. It is a structural principle diagram of a ground terminal continuity detection device and a voltage difference compensation circuit in one embodiment;
[0023] Figure 3 FIG. 4 is a structural schematic diagram of a ground terminal connectivity detection device and a voltage difference compensation circuit in another embodiment. DETAILED DESCRIPTION
[0024] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.
[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.
[0026] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if there is transmission of electrical signals or data between the connected circuits, modules, units, etc.
[0027] As used herein, the singular forms "a," "an," and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include," "comprising," "having," and the like specify the presence of stated features, integers, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, components, parts, or combinations thereof. Furthermore, the term "and / or" as used in this specification includes any and all combinations of the relevant listed items.
[0028] In one embodiment, Figure 1 As shown, a ground terminal connectivity detection device 100 is provided, comprising a detection module 110 and a current limiting module 120. The detection module 110 is connected to a detection point DETECT POINT, and the current limiting module 120 is connected to the detection point DETECT POINT and the detection module 110. The detection point DETECT POINT is located on a cable between the ground terminal DUT_GND of the device under test (DUT) and the local ground terminal of a resource board in a tester. When the detection module 110 outputs a voltage to the detection point DETECT POINT without passing through the current limiting module 120, the detection module 110 records a reference voltage at the detection point DETECT POINT. When the detection module 110 outputs a voltage to the detection point DETECT POINT through the current limiting module 120, the detection module 110 records a measured voltage at the detection point DETECT POINT. The reference voltage and the measured voltage are used to detect whether the ground terminal DUT_GND of the device under test (DUT) is connected to the local ground terminal of the resource board.
[0029] Specifically, the device under test (DUT) can be a device such as a semiconductor chip, and the ground terminal (DUT_GND) is a ground terminal near the device under test (DUT). The ground terminal connectivity detection device (100) can also be connected to the voltage difference compensation circuit in the resource board. The ground terminal connectivity detection device (100) and the voltage difference compensation circuit can both be set on the resource board of the tester. The port on the resource board, the ground terminal connectivity detection device (100), and the voltage difference compensation circuit are connected via a cable. The port on the resource board is connected to a carrier board on which the device under test (DUT) is set via a cable, and then connected to the ground terminal (DUT_GND) of the device under test (DUT) via the carrier board. It can be understood that in other embodiments, the ground terminal connectivity detection device (100) can also be partially set on the resource board and partially set outside the resource board (for example, set on the carrier board).
[0030] After recording the reference voltage and measured voltage, the detection module 110 can analyze whether the ground terminal DUT_GND of the device under test (DUT) is connected to the local ground terminal of the resource board through an internal control unit. Alternatively, the detection module 110 can send the reference voltage and measured voltage to an external FPGA, which can analyze whether the ground terminal DUT_GND of the device under test (DUT) is connected to the local ground terminal of the resource board through the FPGA (not shown). The FPGA can be the FPGA of the resource board. The voltage reading and output of the detection module 110, as well as the various switches and the PE chip, are all controlled by the FPGA.
[0031] In one embodiment, Figure 2 As shown, the ground terminal continuity detection device 100 further includes a switch K1, through which the detection module 110 is connected to the detection point DETECT POINT. The detection module 110 may include a voltage detection unit and a voltage source. The voltage detection unit is connected to the switch K1, and the voltage source is connected to the current limiting module 120. The voltage detection unit may utilize an analog-to-digital converter (ADC), and the voltage source may utilize a digital-to-analog converter (DAC). The switch K1 controls the connection between the analog-to-digital converter (ADC) and the detection point DETECT POINT. When the switch K1 is closed, the analog-to-digital converter (ADC) reads the voltage at the detection point DETECT POINT.
[0032] The current limiting module 120 may specifically include a current limiting element and a switching switch K2. After the current limiting element is connected in series with the switching switch K2, one end is connected to the digital-to-analog converter DAC, and the other end is connected to the detection point DETECT POINT. The current limiting element may be a current limiting resistor R1, or it may be other devices with current limiting function. The positional relationship between the current limiting resistor R1 and the switching switch K2 is not unique. The current limiting resistor R1 may be connected to the detection point DETECT POINT and the switching switch K2, and the switching switch K2 is then connected to the digital-to-analog converter DAC; or the switching switch K2 may be connected to the detection point DETECT POINT and the current limiting resistor R1, and the current limiting resistor R1 is then connected to the digital-to-analog converter DAC. When the switching switch K2 is disconnected and the switching switch K1 is closed, the analog-to-digital converter ADC records the reference voltage of the detection point DETECT POINT; when the switching switch K1 is closed, the switching switch K2 is closed, and the digital-to-analog converter DAC outputs the voltage to the detection point DETECT POINT through the current limiting element, the analog-to-digital converter ADC records the measured voltage of the detection point DETECT POINT.
[0033] Further, continue to refer to Figure 2 The ground terminal connectivity detection device may further include a switch K3, a switch K4, and a switch K5. Switch K3 is connected in series to a first cable A between the detection point DETECT POINT and the ground terminal DUT_GND of the device under test (DUT). Switch K4 is connected in series to a second cable B between the detection point DETECT POINT and the voltage differential compensation circuit 200 in the resource board. A first end of switch K5 is connected to the side of the second cable B connected to the voltage differential compensation circuit 200, and a second end of switch K5 is connected to the local ground terminal of the resource board. The resource board may be a digital board or other type of board. For example, in the case of a digital board, the local ground terminal is the digital ground terminal DGND. Switch switching control can be used to detect whether the first cable A and the second cable B are connected, thereby determining whether the ground terminal DUT_GND of the device under test (DUT) is connected to the local ground terminal of the resource board.
[0034] Specifically, when the switching switch K3 is disconnected, the switching switch K4 is closed, the switching switch K5 is closed, the switching switch K2 is disconnected, and the switching switch K1 is closed, the voltage detection unit records the first reference voltage of the detection point DETECT POINT; when the switching switch K3 is disconnected, the switching switch K4 is closed, the switching switch K5 is closed, the switching switch K1 is closed, and the switching switch K2 is closed, and the voltage source outputs voltage to the detection point DETECT POINT through the current limiting element, the voltage detection unit records the first measured voltage of the detection point DETECT POINT; the first reference voltage and the first measured voltage are used to detect whether the detection point DETECT POINT is connected to the local ground terminal of the resource board.
[0035] like Figure 2 As shown, when switch K3 is open, switch K4 is closed, switch K5 is closed, and switch K2 is open, and switch K1 is closed, the first reference voltage recorded by the analog-to-digital converter (ADC) controlled by the FPGA is close to 0mV. When switch K3 is open, switch K4 is closed, switch K5 is closed, switch K1 is closed, and switch K2 is closed, the digital-to-analog converter (DAC) outputs a voltage of a set amplitude (e.g., 100mV) through a current-limiting element to the detection point (DETECTPOINT), ensuring that the voltage output by the analog-to-digital converter (DAC) controlled by the FPGA is not directly transmitted to the local ground terminal of the resource board. At this time, the FPGA controls the analog-to-digital converter (ADC) to record the first measured voltage. The analog-to-digital converter (ADC) can transmit the recorded first reference voltage and the first measured voltage to the FPGA, and the FPGA combines the first reference voltage and the first measured voltage to detect whether the detection point (DETECTPOINT) is connected to the local ground terminal of the resource board.
[0036] Furthermore, when the switching switch K3 is closed, the switching switch K4 is disconnected, the switching switch K2 is disconnected, and the switching switch K1 is closed, the voltage detection unit records the second reference voltage of the detection point DETECT POINT; when the switching switch K3 is closed, the switching switch K4 is disconnected, the switching switch K1 is closed, and the switching switch K2 is closed, and the voltage source outputs voltage to the detection point DETECT POINT through the current limiting element, the voltage detection unit records the second measured voltage of the detection point DETECT POINT; the second reference voltage and the second measured voltage are used to detect whether the detection point DETECT POINT is connected to the ground terminal DUT_GND of the device under test DUT.
[0037] Continue to refer to Figure 2 When switch K3 is closed, switch K4 is open, switch K2 is open, and switch K1 is closed, the FPGA controls the analog-to-digital converter (ADC) to record a second reference voltage close to 0mV. When switch K3 is closed, switch K4 is open, switch K1 is closed, and switch K2 is closed, the voltage source outputs a voltage to the detection point (DETECT POINT) through the current-limiting element, ensuring that the voltage output by the analog-to-digital converter (DAC) controlled by the FPGA is not directly transmitted to the ground terminal (DUT_GND) of the device under test (DUT). At this time, the FPGA controls the analog-to-digital converter (ADC) to record the second measurement voltage. The analog-to-digital converter (ADC) can transmit the recorded second reference voltage and second measurement voltage to the FPGA (not shown in the figure). The FPGA combines the second reference voltage and the second measurement voltage to detect whether the detection point (DETECT POINT) is connected to the ground terminal (DUT_GND) of the device under test (DUT).
[0038] In one embodiment, Figure 2 As shown, a tester is also provided, comprising a voltage differential compensation circuit 200 and the aforementioned ground terminal continuity detection device 100, connected in series. The voltage differential compensation circuit 200 includes a follower circuit 210 and a PE chip. The follower circuit 210 is connected to the local ground terminal of the resource board, the ground terminal continuity detection device 100, and the PE chip. The PE chip receives the voltage value transmitted by the follower circuit 210 and performs voltage differential compensation. This function is not controlled by the FPGA.
[0039] Follower circuit 210 may include an operational amplifier U1, a resistor R2, and a resistor R3. The first end of resistor R2 is connected to the ground terminal continuity detection device 100 and the non-inverting input terminal + of the operational amplifier U1, specifically connected to the switch K4 and the switch K5 in the ground terminal continuity detection device 100. The second end of resistor R2 is connected to the local ground terminal, and resistor R2 and the switch K5 are in a parallel relationship. The inverting input terminal - of the operational amplifier U1 is connected to the output terminal of the operational amplifier U1, and the output terminal of the operational amplifier U1 is connected to the first end of resistor R3. The second end of resistor R3 is connected to the PE chip. Furthermore, follower circuit 210 also includes a capacitor C1. The first end of capacitor C1 is connected to the second end of resistor R3 and the PE chip, and the second end of capacitor C1 is connected to the local ground terminal.
[0040] Among them, Figure 2 As shown, the voltage difference compensation circuit 200 and the ground terminal connectivity detection device 100 may be arranged on a resource board, and the device under test DUT may be arranged on a carrier board; Figure 3 As shown, the voltage difference compensation circuit 200, the switching switch K4 and the switching switch K5 in the ground terminal continuity detection device 100 can also be set on the resource board, and the device under test DUT and the detection module 110, the current limiting module 120, the switching switch K1 and the switching switch K3 in the ground terminal continuity detection device 100 can be set on the carrier board.
[0041] The FPGA can also connect to the analog-to-digital converter (ADC) and the digital-to-analog converter (DAC) to control the output voltage of the DAC and receive voltage data read by the ADC. Switches K1, K2, K3, K4, and K5 can be manual switches or controlled switches such as relays. Taking controlled switches as an example, the FPGA can also connect switches K1, K2, K3, K4, and K5 to perform on-off control. By controlling the on-off state of switches K3, K4, and K5, it is possible to detect whether the first cable A and the second cable B are connected. Switch K4 is also used to shut down the tester during calibration, disconnecting it from the outside world and providing isolation.
[0042] When the test machine is installed and the DUT test has not yet started, the connectivity between the ground terminal DUT_GND of the DUT and the local ground terminal of the resource board is checked. After the ground terminal connectivity test is completed, voltage difference compensation and subsequent measurement processes are performed.
[0043] When performing a ground terminal connectivity test, first, switch K3 is opened, switch K4 is closed, switch K5 is closed, switch K2 is opened, and switch K1 is closed, and the analog-to-digital converter (ADC) reads a first reference voltage at the detection point DETECTPOINT. Switch K3 is opened, switch K4 is closed, switch K5 is closed, switch K1 is closed, and switch K2 is closed, and the digital-to-analog converter (DAC) outputs a voltage, and the analog-to-digital converter (ADC) reads a first measured voltage at the detection point DETECTPOINT. Then, switch K3 is closed, switch K4 is opened, switch K2 is opened, and switch K1 is closed, and the analog-to-digital converter (ADC) reads a second reference voltage at the detection point DETECTPOINT. Switch K3 is closed, switch K4 is opened, switch K1 is closed, and switch K2 is closed, and the digital-to-analog converter (DAC) outputs a voltage, and the analog-to-digital converter (ADC) reads a second measured voltage at the detection point DETECTPOINT.
[0044] When the DUT ground terminal (DUT_GND) or the resource board's local ground terminal is disconnected, the measured voltage at the detection point (DETECT POINT) will be 100mV due to the high input resistance of the analog-to-digital converter (ADC). When the difference between the first reference voltage and the first measurement voltage is greater than a set threshold (e.g., 90mV), the FPGA determines that the resource board's local ground terminal is disconnected. Otherwise, the resource board's local ground terminal is connected to the detection point (DETECT POINT). When the difference between the second reference voltage and the second measurement voltage is greater than a set threshold (e.g., 90mV), the FPGA determines that the DUT ground terminal (DUT_GND) is disconnected. Otherwise, the DUT ground terminal (DUT_GND) is connected to the detection point (DETECT POINT).
[0045] After the ground terminal connectivity test is completed, when using the PE chip in the voltage difference compensation circuit 200 to perform voltage difference compensation, the ground terminal DUT_GND of the device under test (DUT) is brought back through a cable. The follower circuit 210 introduces the ground terminal DUT_GND of the device under test (DUT) into the PE chip. The PE chip then compensates for the voltage difference between the ground terminal DUT_GND and the digital ground terminal DGND. During voltage difference compensation, switch K3 is closed, switch K4 is closed, switch K5 is open, switch K1 is open, and switch K2 is open. Because the voltage difference is small and the resistance of resistor R2, which is set between the non-inverting input terminal of operational amplifier U1 and the ground, is large, the resistance of switches K3 and K4 can be ignored, and the PE chip can accurately compensate for the voltage difference.
[0046] The above-mentioned test machine and ground terminal continuity detection device have the following advantages:
[0047] 1) Low cost: DAC and ADC in the resource board are used, and detection can be achieved by simply adding switches and resistors.
[0048] 2) Automated testing, eliminating the need for manual testing using additional instruments.
[0049] 3) It does not affect the function and performance. When not in use, the control switch is disconnected. When in use, the internal resistance is high. The output voltage of the digital-to-analog converter DAC also passes through the current-limiting resistor R1, and will not raise the voltage of the ground terminal DUT_GND of the device under test DUT.
[0050] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.
[0051] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.
Claims
1. A ground terminal connectivity detection device, characterized in that: include: A detection module connected to a detection point, wherein the detection point is provided on a cable between a ground terminal of the device under test and a local ground terminal of a resource board in the test machine; a current limiting module, connecting the detection point and the detection module; In which, when the detection module does not output the voltage to the detection point through the current limiting module, the detection module records the reference voltage of the detection point; when the detection module outputs the voltage to the detection point through the current limiting module, the detection module records the measured voltage of the detection point; the reference voltage and the measured voltage are used to detect whether the ground terminal of the device under test is connected to the local ground terminal of the resource board.
2. The ground terminal connectivity detection device according to claim 1, characterized in that: It also includes a switch K1, and the detection module is connected to the detection point through the switch K1.
3. The ground terminal continuity detection device according to claim 2, characterized in that: The detection module includes a voltage detection unit and a voltage source. The voltage detection unit is connected to the switch K1 , and the voltage source is connected to the current limiting module.
4. The ground terminal continuity detection device according to claim 3, characterized in that: The current limiting module includes a current limiting element and a switch K2 . The current limiting element and the switch K2 are connected in series, one end of which is connected to the voltage source, and the other end is connected to the detection point.
5. The ground terminal continuity detection device according to claim 4, characterized in that: It also includes a switching switch K3, a switching switch K4 and a switching switch K5, wherein the switching switch K3 is connected in series to the first cable between the detection point and the ground terminal of the device under test, the switching switch K4 is connected in series to the second cable between the detection point and the voltage difference compensation circuit in the resource board, the first end of the switching switch K5 is connected to the side where the second cable is connected to the voltage difference compensation circuit, and the second end of the switching switch K5 is connected to the local ground terminal of the resource board.
6. The ground terminal continuity detection device according to claim 5, characterized in that: When the switch K3 is disconnected, the switch K4 is closed, the switch K5 is closed, the switch K2 is disconnected, and the switch K1 is closed, the voltage detection unit records the first reference voltage of the detection point; When the switch K3 is disconnected, the switch K4 is closed, the switch K5 is closed, the switch K1 is closed, and the switch K2 is closed, and the voltage source outputs voltage to the detection point through the current limiting element, the voltage detection unit records the first measured voltage of the detection point; the first reference voltage and the first measured voltage are used to detect whether the detection point is connected to the local ground terminal of the resource board; When the switch K3 is closed, the switch K4 is open, the switch K2 is open, and the switch K1 is closed, the voltage detection unit records the second reference voltage of the detection point; When the switching switch K3 is closed, the switching switch K4 is open, the switching switch K1 is closed, and the switching switch K2 is closed, and the voltage source outputs voltage to the detection point through the current limiting element, the voltage detection unit records the second measured voltage of the detection point; the second reference voltage and the second measured voltage are used to detect whether the detection point is connected to the ground terminal of the device under test.
7. A testing machine, characterized in that: The invention comprises a voltage difference compensation circuit connected in series and the ground terminal connectivity detection device according to any one of claims 1 to 6.
8. The testing machine according to claim 7, characterized in that: The voltage difference compensation circuit includes a follower circuit and a PE chip. The follower circuit is connected to the local ground terminal of the resource board, the ground terminal connectivity detection device and the PE chip.
9. The testing machine according to claim 8, characterized in that: The follower circuit includes an operational amplifier, a resistor R2 and a resistor R3, the first end of the resistor R2 is connected to the ground terminal connectivity detection device and the non-inverting input terminal of the operational amplifier, the second end of the resistor R2 is connected to the local ground terminal, the inverting input terminal of the operational amplifier is connected to the output terminal of the operational amplifier, the output terminal of the operational amplifier is connected to the first end of the resistor R3, and the second end of the resistor R3 is connected to the PE chip.
10. The testing machine according to claim 9, characterized in that: The follower circuit further includes a capacitor C1 , a first end of the capacitor C1 is connected to the second end of the resistor R3 and the PE chip, and a second end of the capacitor C1 is connected to a local ground end.
11. The testing machine according to claim 7, characterized in that: The voltage difference compensation circuit and the ground terminal connectivity detection device are arranged on a resource board, and the device to be tested is arranged on a carrier board; or The voltage difference compensation circuit, the switch K4 and the switch K5 in the ground terminal connectivity detection device are set on the resource board, and the device to be tested and the detection module, current limiting module, switch K1 and switch K3 in the ground terminal connectivity detection device are set on the carrier board.