Electrostatic discharge test circuit, circuit board and test equipment

Abstract

The utility model relates to the technical field of electromagnetic compatibility testing, in particular to an electrostatic discharge testing circuit, a circuit board and testing equipment. The electrostatic discharge test circuit comprises a first switch module, an energy storage module, a second switch module and a test port, wherein the test port is in contact with a tested signal line of a circuit board to be tested. The first switch module is connected with a power supply. And the first switch module is switched on when receiving the charging signal, so that the power supply can charge the energy storage module through the first switch module. And the second switch module is switched on when receiving the trigger signal, so that the energy storage module outputs a test signal to the tested signal line through the test port. According to the circuit, a single excitation function is realized through trigger signal control of the second switch module, an electrostatic discharge test can be excited in a single time by providing a single trigger signal, and the problem that interference pulses are continuously output in a traditional test instrument is avoided; based on the single excitation function, the response condition of the circuit board to be tested under the electrostatic discharge impact can be analyzed more accurately.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromagnetic compatibility testing, in particular to an electrostatic discharge test circuit, a circuit board and a test device. BACKGROUND

[0002] The electrostatic discharge (ESD) test is an important link in the production process of electronic products, which is used to evaluate the stability and reliability of the product when encountering static electricity impact. In the electrostatic discharge immunity experiment of the national standard GB / T17626.2, the test instrument outputs a simulated electrostatic discharge interference to the circuit board of the electronic device, and observes the response of the circuit board, so as to realize the electrostatic discharge interference test of the electronic instrument. However, the test instrument in the related art usually uses high-frequency oscillation principle to output a pulse of sinusoidal interference waveform to test the circuit board. Due to the continuous high-frequency oscillation, the interference of the probe of the instrument is large when it is close to the circuit board to be tested, and the electrostatic discharge pulse is continuously generated during the test process, which cannot be excited single time as needed, and the interference pulse is continuously output during the test process. Therefore, if the electronic instrument is unqualified, the electronic instrument to be tested will be triggered when the probe is close to the sensitive signal line, and only regional positioning can be realized, that is, only the approximate region of the sensitive signal line can be determined, and the specific signal line cannot be accurately positioned, resulting in that the subsequent rectification of the instrument needs to check or process all signal lines in this region, and the engineering personnel can only judge and check the sensitive signal line according to experience, which is time-consuming and laborious. In addition, the test instrument in the related art is large in size and is not convenient to carry and move. CONTENT OF THE UTILITY MODEL

[0003] The technical problem of the prior art electrostatic discharge interference test instrument cannot accurately position the sensitive signal line is mainly solved by the embodiments of the present application.

[0004] To solve the above technical problems, one technical scheme adopted by the embodiments of the present application is to provide an electrostatic discharge test circuit, which comprises a first switch module, an energy storage module, a second switch module and a test port, the test port is used to contact a test signal line of a circuit board to be tested; the first switch module is used to connect a power supply, and in combination with the power supply, a charging circuit of the energy storage module is formed, and the second switch module, in combination with the test port and the test signal line, forms a discharge circuit of the energy storage module; the first switch module is used to receive a charging signal, and turns on when the charging signal is received, so that the power supply charges the energy storage module through the first switch module; the second switch module is used to receive a trigger signal, and turns on when the trigger signal is received, so that the energy storage module outputs a test signal to the test signal line through the test port.

[0005] The first switch module and the second switch module are arranged to realize accurate control of the charging process and the discharging process, which helps to ensure the accuracy and reliability of the test, and the single-shot function is realized through the trigger signal control of the second switch module, so that the engineering personnel can single-shot excite the electrostatic discharge test by providing a single trigger signal when needed, avoiding the problem of continuous output of interference pulses in the traditional test instrument. Based on the single-shot test function, the response of the to-be-tested circuit board under the electrostatic discharge impact can be more accurately analyzed. Based on this, the engineering personnel can test the multiple test signal lines in the to-be-tested circuit board one by one by using the trigger signal and the test port, quickly locate the specific sensitive signal line according to the response of the to-be-tested circuit board, thereby more accurately locating the specific test signal line, and thus more conveniently performing the electrostatic discharge test, improving the test efficiency and controlling the test cost. In addition, the circuit has the characteristics of simplicity and modularity, and the volume and weight of the traditional test instrument are relatively small, which is convenient for carrying and moving. For occasions that need to perform electrostatic discharge tests at different places, the portability is also an important advantage.

[0006] In some embodiments, the first switch module includes a charging switch, which is used to conduct when receiving the charging signal, so as to make the charging loop of the energy storage module conduct.

[0007] In some embodiments, the charging switch is a first relay, a first end of the first relay is connected to the power supply, a second end of the first relay is connected to the positive electrode of the energy storage module, a control end of the first relay is used to receive the charging signal, and a negative electrode of the energy storage module is connected to a negative electrode of the power supply.

[0008] In some embodiments, the first switch module further includes a charging current limiting resistor, which is connected in series with the charging switch, and is used to limit the current of the charging loop when the charging switch conducts.

[0009] In some embodiments, the second switch module includes a discharging switch, which is used to conduct when receiving the trigger signal, so as to make the discharging loop of the energy storage module conduct, and output a test signal to the test signal line based on the test port.

[0010] In some embodiments, the discharging switch is a second relay, a first end of the second relay is connected to the positive electrode of the energy storage module, a second end of the second relay is connected to the test port, a control end of the second relay is used to receive the trigger signal, and a negative electrode of the energy storage module is connected to a reference ground of the to-be-tested circuit board.

[0011] In some embodiments, the second switch module further comprises a discharge current-limiting resistor connected in series with the discharge switch, for limiting the current of the discharge circuit when the discharge switch is turned on.

[0012] In some embodiments, the energy storage module is an energy storage capacitor.

[0013] To solve the above technical problems, another technical solution adopted by the embodiments of the present application is to provide a circuit board comprising the electrostatic discharge test circuit as described above.

[0014] To solve the above technical problems, still another technical solution adopted by the embodiments of the present application is to provide a test device comprising the electrostatic discharge test circuit as described above.

[0015] Unlike the related art, the embodiments of the present application provide an electrostatic discharge test circuit, a circuit board and a test device. The electrostatic discharge test circuit comprises a first switch module, an energy storage module, a second switch module and a test port, the test port being used to contact a subject signal line of a circuit board under test; the first switch module is used to connect a power supply, and in combination with the power supply, forms a charging circuit of the energy storage module, and the second switch module, in combination with the test port and the subject signal line, forms a discharge circuit of the energy storage module; the first switch module is used to receive a charging signal, and when the charging signal is received, the first switch module is turned on, so that the power supply charges the energy storage module through the first switch module; the second switch module is used to receive a trigger signal, and when the trigger signal is received, the second switch module is turned on, so that the energy storage module outputs a test signal to the subject signal line through the test port. The circuit sets the first switch module and the second switch module to realize accurate control of the charging process and the discharging process, which helps to ensure the accuracy and reliability of the test, and the single-shot function is realized through the trigger signal control of the second switch module, so that the engineering personnel can single-shot excite the electrostatic discharge test by providing a single trigger signal when needed, avoiding the problem of continuous output of interference pulses in traditional test instruments, and based on the single-shot excitation function, the response of the circuit board under test under the electrostatic discharge impact can be more accurately analyzed. Based on this, the engineering personnel can use the trigger signal and the test port to test the multiple subject signal lines in the circuit board under test one by one, thereby more accurately positioning the specific subject signal line, quickly positioning the specific sensitive signal line in combination with the response of the circuit board under test, and thus more conveniently performing the electrostatic discharge test, improving the test efficiency and saving the test cost. In addition, the design of the circuit has the characteristics of simplicity and modularity, and the volume and weight of the traditional test instrument are relatively small, which is convenient for carrying and moving, and the portability is also an important advantage for occasions that need to perform electrostatic discharge tests at different places. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1is a structural block diagram of an electrostatic discharge test circuit provided by an embodiment of the present application.

[0017] Figure 2 is a circuit structure schematic diagram of an electrostatic discharge test circuit provided by an embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to facilitate understanding of the present application, the present application will be described in more detail below in combination with the drawings and specific embodiments. It should be noted that when one element is described as being "connected" to another element, it can be directly connected to the other element or one or more intermediate elements can be present therebetween. The terms "first", "second", and the like used in the present specification are only for the purpose of description and should not be understood as indicating or implying relative importance. Unless otherwise defined, all technical and scientific terms used in the present specification have the same meaning as understood by those skilled in the art to which the present application belongs. The terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used in the present specification includes any and all combinations of one or more related listed items.

[0019] Electrostatic discharge test is a common test item before electronic products are shipped, which is used to evaluate the stability and reliability of the products when encountering electrostatic shock. When the electronic product test is unqualified, professional analysis equipment needs to be used to assist in locating the problem and finding the specific disturbed signal line. At present, the detection instruments using high-frequency oscillation principle are commonly used in the market, which can output sinusoidal interference waveform to apply specific interference signal to the circuit board, and engineering personnel can observe the response of the circuit board. Due to the continuous high-frequency oscillation, the interference of the probe of the instrument is large when it is close to the circuit board to be tested, and the electrostatic discharge pulse will continuously generate during the test process. The interference pulse cannot be triggered and excited once as needed, and it is continuously output during the test process. Therefore, only the approximate area of the sensitive signal line triggering the action can be determined, and the specific signal line cannot be accurately positioned, resulting in that all signal lines in this area need to be investigated or processed when the electronic product or the circuit board to be tested is subsequently rectified. Engineering personnel can only judge and investigate the sensitive signal line according to experience, which is time-consuming and laborious.

[0020] To solve the above problems, the embodiment of the application creatively proposes a solution concept. By setting an energy storage module in cooperation with a switch module to cooperate with the control of the trigger signal to realize the single excitation function, the engineering personnel can single excitation electrostatic discharge test by providing a single trigger signal when needed. Thus, the engineering personnel can use the trigger signal and the test port to test the multiple test signal lines in the circuit board one by one, quickly locate the specific sensitive signal line in combination with the response of the circuit board under test, avoid the problem of continuously outputting interference pulses in the traditional test instrument, and more accurately locate the specific unqualified test signal line to improve the test efficiency and reduce the test cost.

[0021] Based on the above solution concept of the embodiment, the embodiment is further described in combination with a specific scenario. The embodiment of the application provides an electrostatic discharge test circuit. Please refer to Figure 1 The electrostatic discharge test circuit 100 includes a first switch module 11, an energy storage module 12, a second switch module 13, and a test port 14. The test port 14 is used to contact the test signal line 20 of the circuit board under test. The first switch module 11 is used to connect the power supply 30 and form a charging loop of the energy storage module 12 in combination with the power supply 30. The second switch module 13 forms a discharge loop of the energy storage module 13 in combination with the test port 14 and the test signal line 20. The first switch module 11 is used to receive a charging signal and turn on when the charging signal is received, so that the power supply 30 charges the energy storage module 12 through the first switch module 11. The second switch module 13 is used to receive a trigger signal and turn on when the trigger signal is received, so that the energy storage module 12 outputs a test signal to the test signal line 20 through the test port.

[0022] It should be noted that in the embodiment of the application, the above-mentioned power supply 30 can be a power supply capable of providing direct current to the energy storage module 12. According to the needs of the actual application scenario, the voltage output of the power supply 30 can be defined between 20V-200V. Further, the voltage output can be set to support manual adjustment by engineering personnel to adapt to the actual needs in different scenarios. The above-mentioned energy storage module 12 can be an energy storage capacitor or other forms of energy storage elements. In the following, the energy storage capacitor is taken as an example for description.

[0023] It can be understood that the charging signal is used to control the power supply 30 to charge the energy storage module 12. In the embodiment of the present application, the charging signal can be manually controlled by an engineer or automatically controlled by a software program. When the first switch module 11 is turned on based on the charging signal, the power supply 30 charges the energy storage capacitor. When the energy storage capacitor is fully charged, the charging signal is stopped, and the first switch module 11 is turned off and remains in the off state until the next charging signal is received. In the embodiment of the present application, the time required for the energy storage capacitor to be fully charged is relatively short, for example, it can be fully charged within one second. Therefore, the on time of the first switch module is usually not more than one second.

[0024] After the energy storage capacitor completes the power supply process, when it is necessary to test the circuit board under test, the engineer contacts the test port 14 of the circuit with the signal line 20 under test of the circuit board under test, that is, an electrical circuit path is formed between the test port 14 and the signal line 20 under test. Then, the second switch module 13 is turned on by providing a trigger signal, and then the energy storage capacitor outputs a test signal to the signal line 20 under test through the test port 14 to simulate the influence of an electrostatic discharge interference pulse on the signal line 20 under test, and a single signal test is completed. It can be understood that based on the above circuit, if continuous testing is required, the engineer can control the on and off of the first switch module 11 and the second switch module 13 to achieve continuous testing. For example, a trigger signal can be continuously provided at a suitable frequency to cause the energy storage capacitor to provide a test signal of a corresponding frequency to the signal line 20 under test through the test port 14 to test the signal line 20 under test. For another example, a charging signal and / or a trigger signal can be periodically provided by a software program or a control circuit to test the signal line 20 under test. The specific control method is not limited in the embodiment of the present application.

[0025] In some embodiments, the first switch module 11 in the electrostatic discharge test circuit includes a charging switch that can be turned on when a charging signal is received to turn on a charging loop of the energy storage capacitor, and the power supply 30 charges the energy storage capacitor. The second switch module 13 in the electrostatic discharge test circuit includes a discharge switch that can be turned on when a trigger signal is received to turn on a discharge loop of the energy storage capacitor to output a test signal to the signal line 20 under test based on the test port to test the signal line 20 under test.

[0026] The scheme sets the charging switch and the discharging switch to realize the precise control of the charging and discharging process of the energy storage capacitor, which helps to ensure the accuracy and reliability of the test, and the single-shot function can be realized by the trigger signal control, so that the engineering personnel can single-shot the electrostatic discharge test by providing a single trigger signal when needed, avoiding the problem of continuous output of interference pulses in the traditional test instrument. The test function based on single-shot can more accurately analyze the response of the circuit board under test under the electrostatic discharge impact. Therefore, the engineering personnel can test the multiple test signal lines in the circuit board under test one by one by using the trigger signal and the test port, quickly locate the specific sensitive signal line according to the response of the circuit board under test, thereby more accurately locating the specific test signal line, and more conveniently performing the electrostatic discharge test, improving the test efficiency and controlling the test cost.

[0027] Please combine Figure 2 , Figure 2 The circuit structure diagram of the electrostatic discharge test circuit provided in the embodiment of the present application is shown in the figure, wherein the energy storage module 12 is schematically shown as an energy storage capacitor Cd, and the power supply is schematically shown as VCC. Figure 2 As shown in the figure, the first switch module 11 can further include a charging current limiting resistor Rc, which is connected in series with the charging switch. When the charging switch is turned on, the power supply VCC charges the energy storage capacitor Cd through the charging switch and the charging current limiting resistor Rc. The charging current limiting resistor Rc can limit the current of the charging circuit to ensure the stability of the circuit. The second switch module 13 can further include a discharging current limiting resistor Rd, which is connected in series with the discharging switch. When the discharging switch receives a trigger signal, it is turned on, and the energy storage capacitor Cd outputs a test signal to the test signal line through the test port 14, simulating the influence of the electrostatic discharge interference pulse on the test signal line, and completing the single-shot signal test.

[0028] In the embodiment of the present application, the parameters of the devices in the circuit can be set according to the standard of the national standard, for example, the specification of the discharging current limiting resistor Rd can be set to 330R; for example, the specification of the energy storage capacitor Cd can be set to 150Pf, and the like.

[0029] It can be understood that the electrostatic discharge test circuit provided in the embodiment of the present application is used for electrostatic discharge test of the test signal line in the circuit board under test, and the test is performed by applying a test signal to the test signal line to simulate the influence of the electrostatic discharge interference pulse on the test signal line. Therefore, in the embodiment of the present application, a relay is selected as the charging switch and the discharging switch. The relay is a trigger device that can produce a reproducible and fast-rising discharge current, and has sufficient voltage resistance and single contact (to avoid the double discharge of the rising part), which can ensure the output effect of the test signal.

[0030] Please combineFigure 2 The charging switch can be a first relay LS1, and the charging signal controls the action of the first relay LS1. The discharging switch can be a second relay LS2, and the trigger signal controls the action of the second relay LS2. Specifically, as shown in the figure, the first end LS1_3 of the first relay LS1 is connected to the power supply VCC, the second end LS1_4 of the first relay LS1 is connected to the positive electrode of the energy storage capacitor Cd, further connected to the positive electrode of the energy storage capacitor Cd through the charging current limiting resistor Rc, and the negative electrode of the energy storage capacitor Cd is connected to the negative electrode of the power supply VCC. The control end (LS1_1 and LS1_2) of the first relay LS1 controls the conduction of the first relay LS1 based on the charging signal, thereby controlling the power supply VCC to charge the energy storage capacitor Cd. The first end LS2_3 of the second relay LS2 is connected to the positive electrode of the energy storage capacitor Cd, further connected to the positive electrode of the energy storage capacitor Cd through the discharging current limiting resistor Rd, and the second end LS2_4 of the second relay LS2 is connected to the test port 14. The control end (LS2_1 and LS2_2) of the second relay LS2 controls the conduction of the second relay LS2 based on the trigger signal, thereby controlling the energy storage capacitor Cd to output the test signal to the test signal line through the test port 14, simulating the influence of the electrostatic discharge interference pulse on the test signal line, and completing a single signal test.

[0031] The embodiments of the present application use a relay as a switch trigger device (charging switch and discharging switch), which not only has better repeatability of the measured discharge pulse in its rising part, but also has better reproducibility of the test results using actual test devices, and has a relatively simple circuit structure, is easy to use, and is easy to promote.

[0032] In some embodiments, the above electrostatic discharge test circuit can be used with test instruments in related technologies. For example, the test instruments in related technologies can be used to find the approximate range of devices that cause test failure, and then the circuit of the present application can be used to test the signal lines in this range one by one to accurately locate the specific sensitive signal line, thereby improving the efficiency of engineers in locating problems and saving test costs. In addition, the electrostatic discharge test circuit provided by the embodiments of the present application requires a low voltage, which is convenient for realizing the miniaturization of the device and has great advantages in portability, can be easily moved in different test scenes, and optimizes the use experience of engineers.

[0033] The embodiments of the present application provide a circuit board, which is provided with the above-mentioned electrostatic discharge test circuit. The circuit board can be a whole board or can be spliced by multiple boards. The circuit board has the corresponding functions and advantages of the above-mentioned electrostatic discharge test circuit. The technical details not described in detail in the circuit board embodiment can be referred to the electrostatic discharge test circuit provided by the embodiments of the present application.

[0034] The test device provided by the embodiment of the present application comprises the electrostatic discharge test circuit. The test device has the functions and advantages of the electrostatic discharge test circuit. The technical details not described in the embodiment of the test device can be referred to the electrostatic discharge test circuit provided by the embodiment of the present application.

[0035] It should be noted that the preferred embodiments of the present application are given in the specification and drawings of the present application, but the present application can be implemented in many different forms, and is not limited to the embodiments described in the specification. The embodiments are not additional limitations on the content of the present application, and the purpose of providing the embodiments is to make the understanding of the disclosed content of the present application more thorough and comprehensive. Furthermore, the above technical features continue to combine with each other to form various embodiments not listed above, which are considered to be within the scope of the present application. Furthermore, for those skilled in the art, the above description can be improved or transformed, and all these improvements and transformations should be within the protection scope of the appended claims of the present application.

Claims

1. An electrostatic discharge test circuit, characterized by, The first switch module, the energy storage module, the second switch module and the test port, the test port is used for contacting the test signal line of the circuit board to be tested; The first switch module is used for connecting the power supply, and the power supply is combined to form the charging circuit of the energy storage module, and the second switch module is combined with the test port and the test signal line to form the discharge circuit of the energy storage module; The first switch module is used for receiving a charging signal and conducting when receiving the charging signal, so that the power supply charges the energy storage module through the first switch module. The second switch module is used for receiving a trigger signal and conducting when receiving the trigger signal, so that the energy storage module outputs a test signal to the test signal line through the test port.

2. The electrostatic discharge test circuit of claim 1, wherein, The first switch module includes a charging switch, which is used for conducting when receiving the charging signal, so that the charging circuit of the energy storage module is turned on.

3. The electrostatic discharge test circuit of claim 2, wherein, The charging switch is a first relay, the first end of the first relay is connected to the power supply, the second end of the first relay is connected to the positive electrode of the energy storage module, the control end of the first relay is used for receiving the charging signal, and the negative electrode of the energy storage module is connected to the negative electrode of the power supply.

4. The electrostatic discharge test circuit of claim 2, wherein, The first switch module further includes a charging current limiting resistor, which is connected in series with the charging switch, and is used for limiting the current of the charging circuit when the charging switch is turned on.

5. The electrostatic discharge test circuit of claim 1, wherein, The second switch module includes a discharge switch, which is used for conducting when receiving the trigger signal, so that the discharge circuit of the energy storage module is turned on, and the test signal is output to the test signal line based on the test port.

6. The electrostatic discharge test circuit of claim 5, wherein, The discharge switch is a second relay, the first end of the second relay is connected to the positive electrode of the energy storage module, the second end of the second relay is connected to the test port, the control end of the second relay is used for receiving the trigger signal, and the negative electrode of the energy storage module is connected to the reference ground of the circuit board to be tested.

7. The electrostatic discharge test circuit of claim 5, wherein, The second switch module further includes a discharge current limiting resistor, which is connected in series with the discharge switch, and is used for limiting the current of the discharge circuit when the discharge switch is turned on.

8. The electrostatic discharge test circuit of claim 1, wherein, The energy storage module is an energy storage capacitor.

9. A circuit board, characterized by The electrostatic discharge test circuit includes the electrostatic discharge test circuit according to any one of claims 1-8.

10. A test apparatus, characterized by, The electrostatic discharge test circuit includes the electrostatic discharge test circuit according to any one of claims 1-8.

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