IGBT (Insulated Gate Bipolar Translator) test circuit and test device

Abstract

The utility model provides an IGBT test circuit and a test device, a power supply anode and a power supply cathode of the test circuit are respectively connected to a black meter pen jack and a red meter pen jack, the black meter pen jack is connected to a first grid jack through a first switch, and the red meter pen jack is connected to a second grid jack through a second switch. The G pole of the IGBT is connected to the first grid jack and the second grid jack through two lines, the C pole and the E pole of the IGBT are connected to the black meter pen jack and the red meter pen jack respectively, and the condition of the IGBT can be known by closing or turning off the first switch and the second switch and observing the deflection condition of a meter head pointer in the circuit. Meanwhile, the test circuit further comprises a three-gear switch, so that whether the fly-wheel diode is abnormal or not can be known under the condition that the on-off test jacks are not exchanged. According to the testing device of the utility model, the jacks of the testing circuit are integrated in the front panel, so that IGBT testing can be rapidly completed through single-person and single-hand operation, operation steps are simplified, and diagnosis and maintenance speed is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of IGBT detection, in particular to an IGBT test circuit and a test device. Background Art

[0002] IGBT stands for Insulated Gate Bipolar Transistor. It is a device composed of MOSFET and bipolar transistor. Its input pole is MOSFET and its output pole is PNP transistor. It combines the advantages of these two devices. It has the advantages of low driving power and fast switching speed of MOSFET devices, and the advantages of low saturation voltage and large capacity of bipolar devices. It is increasingly used in modern power electronics technology and occupies a dominant position in high-frequency and medium-power applications.

[0003] An IGBT has three pins: the G (gate), C (collector), and E (emitter). Its operating principle is to control the output current through the input voltage. IGBTs have a junction capacitance between the G and E pins, and a junction capacitance between the C and E pins. The charging, charge retention, and discharge characteristics of the junction capacitance between the G and E pins can be used to effectively detect IGBT failure.

[0004] The existing method for testing IGBTs using a multimeter requires first setting the multimeter to the resistance measurement position. Connect the black test lead (positive) and the red test lead (negative) to the C and E terminals of the IGBT, respectively. Then, using a wire or a finger, temporarily connect the G and C pins. This applies voltage to the G pin, turning on the IGBT, and the multimeter pointer deflects from infinite resistance to several hundred kilo-ohms. After removing the temporary connection, the multimeter pointer remains in place because the IGBT remains in the ON state. This indicates a healthy IGBT, while a defective IGBT cannot remain in the ON state. Then, move the wire or finger between the G and E pins to make a temporary connection. This releases the internal charge, causing the multimeter pointer to deflect to infinite resistance. The IGBT's condition can be determined by whether the pointer deflects normally or returns to zero.

[0005] The existing method requires temporary connections using wires or fingers, making it inconvenient to operate. Furthermore, when testing the freewheeling diode in parallel with the C and E poles of an IGBT, it is necessary to first connect the freewheeling diode forward and then reverse the polarity, swapping the positive and negative poles, to test the reverse cutoff characteristics of the freewheeling diode. This process requires swapping test leads, making the operation cumbersome and affecting test efficiency. Utility Model Content

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides an IGBT test circuit, comprising a power supply, wherein the positive electrode of the power supply is connected to the black test lead jack, and the negative electrode of the power supply is connected to the red test lead jack via a pointer meter head; the black test lead jack is further connected to the first grid jack via a first branch circuit, and the first branch circuit is connected in series with a first switch and a first resistor; the red test lead jack is further connected to the second grid jack via a second branch circuit, and the second branch circuit is connected in series with a second switch and a second resistor;

[0007] The G pole of the IGBT to be tested is connected to the first gate jack and the second gate jack through two lines respectively, and the C pole and E pole of the IGBT to be tested are connected to the black test lead jack and the red test lead jack respectively.

[0008] Optionally, the IGBT test circuit further includes a three-position switch, the switch base of the three-position switch includes six contacts, a first contact and a third contact are respectively provided on the left and right sides of the second contact, and a fourth contact and a sixth contact are respectively provided on the left and right sides of the fifth contact; the first contact is connected to the sixth contact via a wire, and the third contact is connected to the fourth contact via a wire;

[0009] The second contact is equipped with a first metal contact and a second metal contact facing the left and right sides respectively, and the fifth contact is equipped with a third metal contact and a fourth metal contact facing the left and right sides respectively; when the switch handle is toggled, the first metal contact and the third metal contact move synchronously, and the second metal contact and the fourth metal contact move synchronously, and the switching states of the first and third metal contacts are opposite to the switching states of the second and fourth metal contacts.

[0010] Optionally, the second contact is connected to the first on-off test jack, and the fifth contact is connected to the second on-off test jack; the third contact is connected to the positive pole of the power supply, and the sixth contact is connected to the negative pole of the power supply through a light-emitting diode. The C pole and E pole of the IGBT to be tested are respectively connected to the first on-off test jack and the second on-off test jack. The positive and reverse directions of the current passing through the IGBT are changed by the three-position switch to determine whether the freewheeling diode connected in parallel between the C pole and the E pole of the IGBT is abnormal.

[0011] Optionally, a buzzer is further included, and the buzzer is connected in parallel with the light emitting diode.

[0012] Optionally, the pointer meter is a DC ammeter.

[0013] Optionally, the voltage value of the power supply is 5-20V.

[0014] The utility model also provides an IGBT testing device, comprising the IGBT testing circuit.

[0015] Optionally, the front panel of the testing device is provided with the black test lead jack, the red test lead jack, the first grid jack, the second grid jack, the first switch, the second switch, and the pointer header, the pointer header is located in the upper area of the front panel, the first switch and the second switch are symmetrical on the left and right and are arranged below the pointer header, the first grid jack and the second grid jack are respectively arranged below the first switch and the second switch, and the black test lead jack and the red test lead jack are respectively arranged below the first grid jack and the second grid jack.

[0016] Optionally, the front panel of the testing device is also provided with the first on-off test jack, the second on-off test jack, and a three-position switch. The first on-off test jack and the second on-off test jack are respectively arranged below the black test lead jack and the red test lead jack, and the three-position switch is arranged between the first on-off test jack and the second on-off test jack.

[0017] Optionally, the testing device is further provided with an opening for revealing the brightness of the light-emitting diode and the audio of the buzzer.

[0018] As described above, the present invention provides an IGBT test circuit and test device, wherein the positive and negative poles of the power supply of the test circuit are connected to the black test lead jack and the red test lead jack respectively, the black test lead jack is connected to the first gate jack via a first switch, and the red test lead jack is connected to the second gate jack via a second switch. The G pole of the IGBT to be tested is connected to the first gate jack and the second gate jack respectively via two lines, and the C pole and the E pole are connected to the black test lead jack and the red test lead jack respectively. By closing or closing the first switch and the second switch, the deflection of the meter pointer connected to the circuit is observed to know whether the IGBT is good or bad. At the same time, the test circuit also includes a three-position switch, which can change the positive and negative direction of the current passing through the IGBT, so as to know whether the freewheeling diode is abnormal without exchanging the on-off test jacks. The test device of the present invention integrates the various jacks of the test circuit into the front panel, and a single person can quickly complete the judgment of the quality of the IGBT module with one hand, simplifying the operation steps and improving the diagnosis and maintenance speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Shown is a schematic diagram of a circuit for testing the quality of an IGBT in the first embodiment of the present invention.

[0020] Figure 2 It shows a schematic diagram of the principle of measuring the quality of IGBT in the first embodiment of the present utility model.

[0021] Figure 3 Shown is a schematic diagram of a circuit for detecting a freewheeling diode in an IGBT in the first embodiment of the present invention.

[0022] Figure 4Shown is a schematic structural diagram of the testing device in Example 2 of the present utility model.

[0023] Component number description

[0024] Black test lead jack 11; red test lead jack 12; first grid jack 13; second grid jack 14; first switch 15; first resistor 16; second switch 17; second resistor 18; pointer meter 19; freewheeling diode 101; three-position switch 20; first continuity test jack 21; second continuity test jack 22; LED 23; buzzer 24; first metal contact 201; second metal contact 202; third metal contact 203; fourth metal contact 204. DETAILED DESCRIPTION

[0025] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different perspectives and applications without departing from the spirit of the present invention.

[0026] For ease of explanation, when describing the embodiments of the present invention, cross-sectional views of device structures may be partially enlarged and not to scale. These schematic views are merely illustrative and should not limit the scope of protection of the present invention. Furthermore, in actual production, three-dimensional dimensions, including length, width, and depth, should be included.

[0027] For ease of description, spatially relative terms such as "under," "below," "below," "below," "above," and "on" may be used herein to describe the relationship of one element or feature to other elements or features shown in the drawings. It will be understood that these spatially relative terms are intended to encompass orientations of the device in use or operation in addition to the orientation depicted in the drawings. Additionally, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may be present. As used herein, "between" is inclusive of both endpoints.

[0028] In the context of the present application, a structure described as a first feature being "above" a second feature may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where an additional feature is formed between the first and second features, such that the first and second features may not be in direct contact.

[0029] It should be noted that the illustrations provided in this embodiment are only used to schematically illustrate the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0030] Example 1

[0031] like Figure 1 As shown, this embodiment provides an IGBT test circuit, including:

[0032] A power supply, wherein the positive electrode of the power supply is connected to the black test lead jack 11, and the negative electrode of the power supply is connected to the red test lead jack 12 via the pointer meter head 19. The black test lead jack 11 is further connected to the first grid jack 13 via a first branch circuit, and the first branch circuit is connected in series with a first switch 15 and a first resistor 16. The red test lead jack 12 is further connected to the second grid jack 14 via a second branch circuit, and the second branch circuit is connected in series with a second switch 17 and a second resistor 18;

[0033] The G pole of the IGBT to be tested is connected to the first gate jack 13 and the second gate jack 14 through two lines, and the C pole and E pole of the IGBT to be tested are connected to the black test lead jack 11 and the red test lead jack 12 respectively. Figure 2 As shown, closing the first switch 15 and closing the second switch 17 is equivalent to temporarily connecting the G and C pins with a wire or a finger. Voltage is now input to the G pin, turning on the IGBT and causing the pointer to deflect. Closing the first switch 15 and closing the second switch 17 is equivalent to temporarily connecting the G and E pins with a wire or a finger. The internal charge is released, and the pointer returns to its original position. The quality of the IGBT can be determined by whether the pointer deflects normally or returns to zero.

[0034] Specifically, the pointer meter 19 is a DC ammeter, similar to the meter of a pointer multimeter. It uses a sensitive magnetoelectric DC ammeter as the meter. When a small current passes through the meter, a current indication is provided. Because the meter cannot pass large currents, in actual applications, it is necessary to connect some resistors in parallel or series to shunt or reduce the voltage to meet the measurement requirements. For the parallel or series resistor form, please refer to the internal circuit of the multimeter and will not be described in detail here.

[0035] Furthermore, if Figure 3As shown, the IGBT test circuit further includes a three-position switch 20. The switch base of the three-position switch 20 includes six contacts. The second contact is connected to the first on-off test jack 21, the fifth contact is connected to the second on-off test jack 22, the left and right sides of the second contact are respectively provided with a first contact and a third contact, and the left and right sides of the fifth contact are respectively provided with a fourth contact and a sixth contact; the first contact is connected to the sixth contact via a wire, and the third contact is connected to the fourth contact via a wire;

[0036] The second contact is equipped with a first metal contact piece 201 and a second metal contact piece 202 facing the left and right sides respectively. The fifth contact is equipped with a third metal contact piece 203 and a fourth metal contact piece 204 facing the left and right sides respectively. The first metal contact piece 201 and the third metal contact piece 203 move synchronously, and the second metal contact piece 202 and the fourth metal contact piece 204 move synchronously. The switching states of the first and third metal contacts 203 are opposite to the switching states of the second and fourth metal contacts 204.

[0037] The third contact is connected to the positive pole of the power supply, and the sixth contact is connected to the negative pole of the power supply through the light-emitting diode 23. The C pole and E pole of the IGBT to be tested are respectively connected to the first on-off test jack 21 and the second on-off test jack 22. The positive and negative directions of the current flowing into the IGBT are changed by the three-position switch 20 to judge whether the freewheeling diode 101 connected in parallel between the C pole and the E pole of the IGBT is abnormal. When the first and third metal contacts 201 and 203 are closed, the current direction flowing into the freewheeling diode 101 is forward, the freewheeling diode 101 is turned on, and the light-emitting diode 23 emits light; when the second and fourth metal contacts 202 and 204 are closed, the current direction flowing into the freewheeling diode 101 is reverse, the freewheeling diode 101 is cut off, and the light-emitting diode 23 does not emit light. In this way, the working status of the freewheeling diode 101 can be known without swapping the on-off test jacks.

[0038] Furthermore, the IGBT test circuit further includes a buzzer 24 , which is connected in parallel with the light emitting diode 23 . The buzzer 24 can cooperate with the light emitting diode 23 to emit light and make sounds to prompt the tester.

[0039] Furthermore, the voltage of the power supply is 5-20V, which is sufficient to turn on the IGBT. It should be understood that the power supply connected to the pointer meter 19 and the power supply connected to the three-position switch 20 can be the same power supply or each can use a separate power supply.

[0040] Example 2

[0041] Based on the test circuit in the above embodiment 1, this embodiment provides a test device, such as Figure 4As shown, the test device includes the test circuit in the above-mentioned embodiment 1, and the front panel of the test device is provided with the black test lead jack 11, the red test lead jack 12, the first grid jack 13, the second grid jack 14, the first switch 15, the second switch 17, and the pointer header 19. The pointer header 19 is located above the front panel, the first switch 15 and the second switch 17 are symmetrical and arranged below the pointer header 19, the first grid jack 13 and the second grid jack 14 are respectively arranged below the first switch 15 and the second switch 17, and the black test lead jack 11 and the red test lead jack 12 are respectively arranged below the first grid jack 13 and the second grid jack 14.

[0042] Furthermore, the front panel of the testing device is also provided with the first on-off test jack 21, the second on-off test jack 22, and a three-position switch 20. The first on-off test jack 21 and the second on-off test jack 22 are respectively arranged below the black test lead jack 11 and the red test lead jack 12, and the three-position switch 20 is arranged between the first on-off test jack 21 and the second on-off test jack 22.

[0043] Furthermore, the testing device is also provided with an opening for revealing the light of the light emitting diode 23 and the audio of the buzzer 24 .

[0044] In summary, the present invention provides an IGBT test circuit and test device, in which the positive and negative poles of the power supply of the test circuit are connected to the black test lead jack and the red test lead jack respectively, the black test lead jack is connected to the first gate jack via a first switch, and the red test lead jack is connected to the second gate jack via a second switch. The G pole of the IGBT to be tested is connected to the first gate jack and the second gate jack respectively through two lines, and the C pole and the E pole are connected to the black test lead jack and the red test lead jack respectively. By closing or closing the first switch and the second switch, the deflection of the meter pointer connected to the circuit is observed to know the quality of the IGBT. At the same time, the test circuit also includes a three-position switch, which can change the positive and negative direction of the current passing through the IGBT, so as to know whether the freewheeling diode is abnormal without swapping the on-off test jacks. The test device of the present invention integrates the various jacks of the test circuit into the front panel, and a single person can quickly complete the quality judgment of the IGBT module with one hand, simplifying the operation steps and improving the diagnosis and maintenance speed.

[0045] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed in the present invention are intended to be covered by the claims of the present invention.

Claims

1. An IGBT test circuit, characterized in that: The device comprises a power supply, wherein the positive electrode of the power supply is connected to the black test lead jack, and the negative electrode of the power supply is connected to the red test lead jack via a pointer meter head. The black test lead jack is further connected to the first grid jack via a first branch circuit, wherein the first branch circuit is connected in series with a first switch and a first resistor; the red test lead jack is further connected to the second grid jack via a second branch circuit, wherein the second branch circuit is connected in series with a second switch and a second resistor; The G pole of the IGBT to be tested is connected to the first gate jack and the second gate jack through two lines respectively, and the C pole and E pole of the IGBT to be tested are connected to the black test lead jack and the red test lead jack respectively.

2. The IGBT test circuit according to claim 1, wherein: The IGBT test circuit also includes a three-position switch, the switch base of the three-position switch includes six contacts, a first contact and a third contact are respectively provided on the left and right sides of the second contact, and a fourth contact and a sixth contact are respectively provided on the left and right sides of the fifth contact; the first contact is connected to the sixth contact via a wire, and the third contact is connected to the fourth contact via a wire; The second contact is equipped with a first metal contact and a second metal contact facing the left and right sides respectively, and the fifth contact is equipped with a third metal contact and a fourth metal contact facing the left and right sides respectively; when the switch handle is toggled, the first metal contact and the third metal contact move synchronously, and the second metal contact and the fourth metal contact move synchronously, and the switching states of the first and third metal contacts are opposite to the switching states of the second and fourth metal contacts.

3. The IGBT test circuit according to claim 2, wherein: The second contact is connected to the first on-off test jack, and the fifth contact is connected to the second on-off test jack; the third contact is connected to the positive pole of the power supply, and the sixth contact is connected to the negative pole of the power supply through a light-emitting diode. The C pole and E pole of the IGBT to be tested are respectively connected to the first on-off test jack and the second on-off test jack. The positive and reverse directions of the current passing through the IGBT are changed by the three-position switch to determine whether the freewheeling diode connected in parallel between the C pole and the E pole of the IGBT is abnormal.

4. The IGBT test circuit according to claim 3, wherein: The device further comprises a buzzer, which is connected in parallel with the light emitting diode.

5. The IGBT test circuit according to claim 4, wherein: The pointer meter is a DC ammeter.

6. The IGBT test circuit according to claim 4, wherein: The voltage value of the power supply is 5-20V.

7. An IGBT testing device, characterized in that: The IGBT test circuit comprises any one of claims 4 to 6.

8. The IGBT testing device according to claim 7, wherein: The front panel of the testing device is provided with the black test lead jack, the red test lead jack, the first grid jack, the second grid jack, the first switch, the second switch, and the pointer header. The pointer header is located in the upper area of the front panel, the first switch and the second switch are symmetrical on the left and right and are arranged below the pointer header, the first grid jack and the second grid jack are respectively arranged below the first switch and the second switch, and the black test lead jack and the red test lead jack are respectively arranged below the first grid jack and the second grid jack.

9. The IGBT testing device according to claim 8, wherein: The front panel of the testing device is also provided with the first on-off test jack, the second on-off test jack, and a three-position switch. The first on-off test jack and the second on-off test jack are respectively arranged below the black test lead jack and the red test lead jack, and the three-position switch is arranged between the first on-off test jack and the second on-off test jack.

10. The IGBT testing device according to claim 7, wherein: The testing device is further provided with an opening for revealing the brightness of the light emitting diode and the audio of the buzzer.

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