Repeated avalanche energy test circuit and system based on 555 timer

Abstract

The utility model discloses a repeated avalanche energy test circuit and system based on a 555 timer, and relates to the technical field of repeated avalanche energy, and the repeated avalanche energy test system comprises a signal driving module, a power supply module, a load adjusting module, a waveform sampling module, a waveform monitoring module, and a temperature monitoring module. Wherein the signal driving module is electrically connected with the power supply module, the load adjusting module, the waveform sampling module, the waveform monitoring module and the temperature monitoring module in sequence; according to the utility model, the square wave generator composed of the 555 timer generates a pulse signal and transmits the pulse signal to the tested element, and the switching frequency of the tested element is controlled by the preceding stage generator, so that the composed repeated avalanche energy test circuit is simple in structure and convenient to debug; and different switching frequencies can be set and the real-time temperature of the tested element can be monitored according to requirements, so that different test frequency requirements can be met, and the service life and the reliability of the designed product can be quickly judged.

Description

Technical Field

[0001] The utility model relates to the technical field of repetitive avalanche energy, in particular to a repetitive avalanche energy test circuit and system composed of a 555 timer. Background Technique

[0002] Repetitive avalanche energy test is a test method for evaluating the durability and reliability of semiconductor devices (such as MOSFETs, IGBTs) under high-stress conditions. In this test, the device will experience multiple avalanche events to measure and analyze its energy absorption capacity, thermal stability and long-term reliability. With the continuous improvement of the requirements for product reliability in recent years, the market's requirements for the performance of semiconductor devices have become more stringent. This not only requires the product to be able to match the circuit in performance and meet the standard of single avalanche energy, but also puts forward higher requirements for the repetitive avalanche energy generated by the product under long-term load conditions.

[0003] At present, the repetitive avalanche test systems on the market are usually integrated into the equipment by equipment manufacturers, and there are still the following defects:

[0004] 1. Existing systems usually can only display and test a fixed number of inductance values, lacking flexibility and unable to meet the adjustment of different test requirements;

[0005] 2. Only fixed current and voltage inputs can be used during the test, which limits the comprehensive evaluation of the device performance under different working conditions;

[0006] 3. Existing systems cannot monitor the test temperature of the device in real time, which makes it impossible to ensure that the junction temperature of the device remains within a safe range under high-stress test conditions, and may lead to inaccurate test results or device damage;

[0007] 4. The system cannot set the turn-on and turn-off times of the device and cannot simulate the dynamic changes in the real working environment;

[0008] 5. When it is necessary to flexibly and quickly compare the product performance under different test conditions, the fixed settings of the existing system make this process slow and cumbersome, and it is difficult to meet the requirements of efficient testing.

[0009] For the problems in the related technology, no effective solution has been proposed yet. Content of the Utility Model

[0010] The purpose of the utility model is to provide a new type of dual-channel input control optocoupler device to solve the problems proposed in the above background technique.

[0011] To achieve the above object, the present utility model provides the following technical solutions: A repetitive avalanche energy test circuit composed of a 555 timer, the repetitive avalanche energy test circuit comprising: a square wave generator U1, a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a capacitor C2, a diode D1, an inductor L1, and a device under test U2;

[0012] Wherein, the first pin of the square wave generator U1 is respectively connected to one end of the capacitor C1, one end of the capacitor C2, and the second pin of the device under test U2 and grounded. The other end of the capacitor C1 is respectively connected to the second pin of the square wave generator U1, the sixth pin of the square wave generator U1, and one end of the resistor R2. The other end of the resistor R2 is respectively connected to the seventh pin of the square wave generator U1 and one end of the resistor R1. The other end of the resistor R1 is respectively connected to the fourth pin of the square wave generator U1 and the eighth pin of the square wave generator U1 and connected to 10V. The third pin of the square wave generator U1 is respectively connected to one end of the resistor R3 and the negative electrode of the diode D1. The positive electrode of the diode D1 is respectively connected to the first pin of the device under test U2 and the other end of the resistor R3. The third pin of the device under test U2 is connected to one end of the inductor L1, and the other end of the inductor L1 is connected to the power supply VCC. The other end of the capacitor C2 is connected to the fifth pin of the square wave generator U1.

[0013] Preferably, the execution actions of the repetitive avalanche energy test circuit include:

[0014] Using the square wave generator U1 composed of a 555 timer to output a square wave signal to the device under test U2 to drive the device under test U2 into a working state;

[0015] Connecting the inductor L1 as a load to the power supply VCC, and continuously turning on or off the device under test U2 through the square wave signal, so that the two ends of the device under test U2 experience breakdown to form a repetitive avalanche breakdown phenomenon;

[0016] Calculating the repetitive avalanche energy generated in the repetitive avalanche breakdown phenomenon and evaluating the durability of the device under test U2 under repetitive avalanche conditions.

[0017] Preferably, the connecting the inductor L1 as a load to the power supply VCC and continuously turning on or off the device under test U2 through the square wave signal includes:

[0018] Connecting the inductor L1 as a load to the power supply VCC, turning on the device under test U2 through the square wave signal. When the device under test U2 is turned on, the inductor L1 is charged and stores energy, and a maximum current value is generated;

[0019] Turn off the device under test U2 through a square wave signal. When the device under test U2 is turned off instantaneously, the inductor L1 starts to discharge, and at the same time, a breakdown voltage is generated across the device under test U2.

[0020] The breakdown voltage generated across the device under test U2 gradually decreases to the theoretical voltage value within a preset time period, and at the same time, a switching cycle of the device under test U2 is completed.

[0021] Preferably, calculating the repetitive avalanche energy generated in the repetitive avalanche breakdown phenomenon and evaluating the durability of the device under test U2 under repetitive avalanche conditions includes:

[0022] Calculating the repetitive avalanche energy generated in the repetitive avalanche breakdown phenomenon based on the maximum current and the breakdown voltage generated across the device under test U2;

[0023] Converting the repetitive avalanche energy and collecting the surface temperature of the device under test U2 in combination with the temperature measurement module;

[0024] Generating a limit value of the repetitive avalanche energy in combination with the converted repetitive avalanche energy and the surface temperature of the device under test U2, and evaluating the durability of the device under test U2 based on the limit value of the repetitive avalanche energy.

[0025] Preferably, the diode D1 is used to increase the turn-off speed of the device under test U2 and release the charge controlled by the device under test U2;

[0026] The resistor R1, the resistor R2, and the resistor R3 are all used to reduce waveform resonance interference and make the waveform closer to the theoretical waveform.

[0027] Preferably, the inductor L1 is an air core inductor.

[0028] Preferably, the present invention also discloses a repetitive avalanche energy test system composed of a 555 timer. The repetitive avalanche energy test system includes a signal driving module, a power supply module, a load adjustment module, a waveform sampling module, a waveform monitoring module, and a temperature monitoring module;

[0029] Among them, the signal driving module is electrically connected to the power supply module, the load adjustment module, the waveform sampling module, the waveform monitoring module, and the temperature monitoring module in sequence;

[0030] The signal driving module is used to generate a square wave signal through a square wave oscilloscope and transmit it to the device under test to drive the device under test to start working;

[0031] The power supply module is used to provide a DC power supply to the device under test and supply power to the device under test at the same time;

[0032] The load adjustment module is used to provide an inductive load and test the response of the device under test under different inductance conditions;

[0033] The waveform sampling module is used to collect the current waveform flowing through the component under test and transmit it to the waveform monitoring module for waveform monitoring;

[0034] The waveform monitoring module is used to monitor in real time the current waveform passing through the component under test and the voltage waveform across the component under test;

[0035] The temperature monitoring module is used to detect in real time the temperature on the surface of the component under test.

[0036] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0037] 1. The repetitive avalanche energy test circuit and system composed of a 555 timer generate a pulse signal through the square wave generator composed of the 555 timer and transmit it to the component under test, so that the switching frequency of the component under test is controlled by the previous-stage generator. As a result, the composed repetitive avalanche energy test circuit has a simple structure and is convenient to debug, and can set different switching frequencies according to requirements and monitor the real-time temperature of the component under test to meet different test frequency requirements, thereby quickly judging the working life and reliability of the designed product, providing important reference significance for R & D personnel;

[0038] 2. The repetitive avalanche energy test circuit and system composed of a 555 timer make the frequency and duty cycle adjustable through the square wave signal generator composed of the 555 timer, and the output voltage range of the signal generator is relatively wide, which can meet different turn-on voltage requirements. At the same time, the signal generator and the component under test are connected through a resistor and a diode, so as to be able to accelerate the turn-off speed of the component under test, quickly release the charge of the control electrode of the component under test, and then make the component under test enter avalanche breakdown faster. The use of the resistor can reduce the waveform resonance interference at the GATE pole of the MOS device when it is turned on, making the waveform closer to the theoretical waveform;

[0039] 3. For the repetitive avalanche energy test circuit and system composed of a 555 timer, different repetitive avalanche energy values can be obtained by adjusting different inductance values and charging currents. The waveform monitoring of the component under test is obtained through an oscilloscope, so as to be able to calculate the repetitive avalanche energy EAR value. The temperature of the component under test is obtained through temperature monitoring devices such as a dot thermometer or an infrared thermal imager, ensuring that the junction temperature of the component under test when in repetitive avalanche breakdown does not exceed the upper limit value of the device itself. It plays a promoting role whether it is for device R & D personnel to evaluate the performance of newly developed products or for hardware circuit personnel to evaluate the reliable state of the whole machine circuit. Description of the Drawings

[0040] Figure 1 is the circuit diagram of the repetitive avalanche energy test circuit composed of a 555 timer according to an embodiment of the present utility model;

[0041] Figure 2 It is the schematic diagram of a repetitive avalanche energy test system composed of a 555 timer according to an embodiment of the present invention.

[0042] In the figure: 1. Signal driving module; 2. Power supply module; 3. Load regulation module; 4. Waveform sampling module; 5. Waveform monitoring module; 6. Temperature monitoring module; 7. Component under test. Specific implementation manners

[0043] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0044] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0045] In the description of this patent, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "setting" should be understood in a broad sense. For example, it can be fixedly connected and set, or detachably connected and set, or integrally connected and set. For those of ordinary skill in the art, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0046] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "several" means two or more, unless otherwise specifically and clearly defined.

[0047] Embodiment

[0048] Please refer to Figure 1As shown, a technical solution of a novel dual-channel input control optocoupler device provided by the present utility model: The present invention will be further described in conjunction with the accompanying drawings and specific embodiments. As Figure 1 As shown, a repetitive avalanche energy test circuit composed of a 555 timer according to an embodiment of the present invention, the repetitive avalanche energy test circuit includes: a square wave generator U1, a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a capacitor C2, a diode D1, an inductor L1, and a device under test U2.

[0049] Among them, the first pin of the square wave generator U1 is respectively connected to one end of the capacitor C1, one end of the capacitor C2, and the second pin of the device under test U2 and grounded. The other end of the capacitor C1 is respectively connected to the second pin of the square wave generator U1, the sixth pin of the square wave generator U1, and one end of the resistor R2. The other end of the resistor R2 is respectively connected to the seventh pin of the square wave generator U1 and one end of the resistor R1. The other end of the resistor R1 is respectively connected to the fourth pin of the square wave generator U1 and the eighth pin of the square wave generator U1 and connected to 10V. The third pin of the square wave generator U1 is respectively connected to one end of the resistor R3 and the negative electrode of the diode D1. The positive electrode of the diode D1 is respectively connected to the first pin of the device under test U2 and the other end of the resistor R3. The third pin of the device under test U2 is connected to one end of the inductor L1. The other end of the inductor L1 is connected to the power supply VCC. The other end of the capacitor C2 is connected to the fifth pin of the square wave generator U1.

[0050] Among them, the execution actions of the repetitive avalanche energy test circuit include:

[0051] Using the square wave generator U1 composed of a 555 timer to output a square wave signal to the device under test U2 to drive the device under test U2 into a working state.

[0052] It should be noted that in addition to using the square wave generator U1 to output a square wave signal, a square wave signal with adjustable frequency and duty cycle can also be provided by writing a program with a single-chip microcomputer to drive the switch of the device under test; or directly using a ready-made signal generator on the market to provide a square wave signal with adjustable frequency and duty cycle to drive the switch of the device under test.

[0053] Connect the inductor L1 (the inductor L1 is an air-core inductor) as a load to the power supply VCC, and continuously turn on or off the device under test U2 through the square wave signal, so that repetitive avalanche breakdown phenomena occur across the device under test U2.

[0054] Among them, connecting the inductor L1 as a load to the power supply VCC and continuously turning on or off the device under test U2 through the square wave signal includes:

[0055] Connect the inductor L1 as a load to the power supply VCC, turn on the device under test U2 through a square wave signal. When the device under test U2 is turned on, the inductor L1 charges and stores energy, and generates a maximum current value.

[0056] Turn off the device under test U2 through a square wave signal. When the device under test U2 is turned off instantaneously, the inductor L1 starts to discharge, and at the same time, a breakdown voltage is generated across the device under test U2.

[0057] The breakdown voltage generated across the device under test U2 gradually decreases to the theoretical voltage value within a preset time period, and at the same time, a switching cycle of the device under test U2 is completed.

[0058] Calculate the repetitive avalanche energy generated in the repetitive avalanche breakdown phenomenon, and evaluate the durability of the device under test U2 under repetitive avalanche conditions.

[0059] Among them, the diode D1 is used to improve the turn-off speed of the device under test U2 and release the charge controlled by the device under test U2; the resistors R1, R2, and R3 are all used to reduce waveform resonance interference, making the waveform closer to the theoretical waveform.

[0060] Among them, by adjusting the resistance values of the resistors R1 and R2 and the capacitance value of the capacitor C1, the frequency of the square wave signal is adjusted. The corresponding relationship of the resistors R1, R2, and the capacitor C1 is:

[0061]

[0062] In the formula, R1 represents the resistance value of the resistor R1; R2 represents the resistance value of the resistor R2; C1 represents the capacitance value of the capacitor C1; f represents the corresponding relationship of the resistors R1, R2, and the capacitor C1.

[0063] Among them, calculating the repetitive avalanche energy generated in the repetitive avalanche breakdown phenomenon and evaluating the durability of the device under test U2 under repetitive avalanche conditions include:

[0064] Calculate the repetitive avalanche energy generated in the repetitive avalanche breakdown phenomenon based on the maximum current value and the breakdown voltage generated across the device under test U2.

[0065] Among them, the calculation formula for the repetitive avalanche energy is:

[0066]

[0067] In the formula, E AR represents the repetitive avalanche energy; I AR represents the repetitive avalanche current; V BR represents the avalanche breakdown voltage value generated after the device under test is turned off; t AV represents the avalanche time.

[0068] Convert the repetitive avalanche energy and collect the surface temperature of the device under test U2 in combination with the temperature measurement module.

[0069] It should be noted that by externally connecting an oscilloscope to measure the current value IAR flowing through the device under test, the voltage value VBR across the device under test U2, and the input signal, and simultaneously monitoring the surface temperature of the device under test U2 through a thermometer, the limit value of the repetitive avalanche energy of the device under test U2 can be effectively compared.

[0070] Generate the limit value of the repetitive avalanche energy by combining the converted repetitive avalanche energy and the surface temperature of the device under test U2, and evaluate the durability of the device under test U2 based on the limit value of the repetitive avalanche energy.

[0071] Among them, since the load uses an inductor L1, after introducing the inductive load, the calculation formula for the repetitive avalanche energy is converted, and the converted calculation formula is:

[0072]

[0073] I AR represents the repetitive avalanche current; V BR represents the avalanche breakdown voltage value generated after the device under test is turned off; V DD represents the working voltage value at both ends of the device under test after the avalanche turn-off ends; t AV represents the avalanche time; E AR represents the repetitive avalanche energy.

[0074] It should be noted that through the square wave generator U1 composed of a 555 timer, a square wave signal with adjustable frequency and duty cycle is generated and given to the device under test U2 to make the device under test U2 in a working state. A hollow inductor L1 is used as the load of the device under test U2 and connected to the power supply VCC. When the device under test U2 is turned on, the power supply VCC charges and stores energy in the inductor L1, and the current reaches a maximum of IAR. When the device under test U2 is turned off instantaneously, the inductor L1 discharges instantaneously, and a breakdown voltage VBR exceeding the BVDSS of the device under test U2 itself will be generated across the device under test U2 and maintained for a period of tAV, and then the voltage across the device under test U2 drops to the normal VCC voltage value. By continuously switching the device under test U2 through a signal, a breakdown process will be repeatedly formed across the device under test U2, which is called repetitive avalanche breakdown, and the energy generated during the process is the repetitive avalanche energy EAR.

[0075] Taking the Jiejie JMSH0406AGQ as an example, test the repetitive avalanche energy across this MOSFET. The inductor L in the circuit uses a 0.1mH hollow inductor.

[0076] Specifically, the repetitive avalanche energy actually flowing through the MOS is calculated based on the waveform conforming to the theoretical waveform requirements and in combination with the corresponding parameters (f = 10 KHz, VBR = 62.1 V, IAR = 1.73 A, tAV = 2.642 μs, VDD = 2 V). The calculation formula is as follows:

[0077]

[0078] In the formula, E AR represents the repetitive avalanche energy actually flowing through the MOS.

[0079] As Figure 2 shown, according to another embodiment of the present invention, a repetitive avalanche energy test system based on a 555 timer is further provided. The repetitive avalanche energy test system includes a signal driving module 1, a power supply module 2, a load adjusting module 3, a waveform sampling module 4, a waveform monitoring module 5, and a temperature monitoring module 6;

[0080] Among them, the signal driving module 1 is electrically connected to the power supply module 2, the load adjusting module 3, the waveform sampling module 4, the waveform monitoring module 5, and the temperature monitoring module 6 in sequence;

[0081] The signal driving module 1 is used to generate a square wave signal through the square wave generator U1 composed of a 555 timer and transmit it to the device under test 7 to drive the device under test 7 to start working;

[0082] The power supply module 2 is used to provide a DC power supply to the device under test 7 and supply power to the device under test 7 at the same time (used to provide an adjustable DC power supply to the device under test 7 and supply power to the device under test 7 through the load);

[0083] The load adjusting module 3 is used to provide an inductive load and test the response of the device under test under different inductance conditions (used to connect the air-core inductor L1 as the load to the power supply VCC and test the response of the device under test 7 under different conditions);

[0084] The waveform sampling module 4 is used to collect the current waveform flowing through the device under test and transmit it to the waveform monitoring module for waveform monitoring (used to non-contact sample the current waveform flowing through the device under test 7 and transmit it to the waveform monitoring module 5 for waveform monitoring);

[0085] The waveform monitoring module 5 is used to real-time monitor the current waveform passing through the device under test 7 and the voltage waveform across the device under test 7 through an oscilloscope;

[0086] The temperature monitoring module 6 is used to real-time detect the temperature on the surface of the device under test (used to real-time detect the surface temperature rise of the device under test 7 to ensure that the device under test 7 fails due to insufficient repetitive avalanche tolerance rather than failure caused by the product operating beyond the junction temperature);

[0087] In addition, the repetitive avalanche energy test system based on the 555 timer provided by the present invention further includes a normally closed switch module (not shown in the figure). The normally closed switch module is normally in a normally closed state and can disconnect the entire test circuit when receiving an action signal sent by the control circuit.

[0088] In summary, by means of the above technical solutions of the present invention, the present invention generates a pulse signal through a square wave generator composed of a 555 timer and transmits it to the device under test, enabling the switching frequency of the device under test to be controlled by the pre-stage generator. As a result, the composed repetitive avalanche energy test circuit has a simple structure and is convenient to debug. Moreover, it can set different switching frequencies according to requirements and monitor the real-time temperature of the device under test to meet different test frequency requirements, and then quickly judge the working life and reliability of the designed product, providing important reference significance for R & D personnel; the present invention makes the frequency and duty cycle adjustable through the square wave signal generator composed of a 555 timer, and the output voltage range of the signal generator is relatively wide, which can meet different turn-on voltage requirements. At the same time, the signal generator and the device under test are connected through a resistor and a diode, which can accelerate the turn-off speed of the device under test, quickly release the charge of the control electrode of the device under test, and then enable the device under test to enter avalanche breakdown faster. Combining the use of the resistor can reduce the waveform resonance interference at the GATE electrode of the MOS device when it is turned on, making the waveform closer to the theoretical waveform; different repetitive avalanche energy values in the present invention can be obtained by adjusting different inductance values and charging currents. The waveform monitoring of the device under test is obtained through an oscilloscope, so that the repetitive avalanche energy EAR value can be calculated. The temperature of the device under test is obtained through a temperature monitoring device such as a dot thermometer or an infrared thermal imager to ensure that the junction temperature of the device under test during repetitive avalanche breakdown does not exceed the upper limit value of the device itself. Whether it is for device R & D personnel to evaluate the performance of newly developed products or for hardware circuit personnel to evaluate the reliable state of the whole machine circuit, it has played a promoting role.

[0089] The above shows and describes the basic principles, main features and advantages of the present utility model. Those skilled in the art should understand that the present utility model is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present utility model and are not used to limit the present utility model. Without departing from the spirit and scope of the present utility model, the present utility model will have various changes and improvements, and these changes and improvements all fall within the scope of the present utility model claimed. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents.

Claims

1. A repetitive avalanche energy test circuit composed of a 555 timer, characterized in that The repetitive avalanche energy test circuit includes: a square wave generator U1, a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a capacitor C2, a diode D1, an inductor L1, and a device under test U2; Among them, the first pin of the square wave generator U1 is respectively connected to one end of the capacitor C1, one end of the capacitor C2, and the second pin of the device under test U2 and grounded. The other end of the capacitor C1 is respectively connected to the second pin of the square wave generator U1, the sixth pin of the square wave generator U1, and one end of the resistor R2. The other end of the resistor R2 is respectively connected to the seventh pin of the square wave generator U1 and one end of the resistor R1. The other end of the resistor R1 is respectively connected to the fourth pin of the square wave generator U1 and the eighth pin of the square wave generator U1 and connected to 10V. The third pin of the square wave generator U1 is respectively connected to one end of the resistor R3 and the negative electrode of the diode D1. The positive electrode of the diode D1 is respectively connected to the first pin of the device under test U2 and the other end of the resistor R3. The third pin of the device under test U2 is connected to one end of the inductor L1, and the other end of the inductor L1 is connected to the power supply VCC. The other end of the capacitor C2 is connected to the fifth pin of the square wave generator U1.

2. The repetitive avalanche energy test circuit composed of a 555 timer according to claim 1, characterized in that, The execution actions of the repetitive avalanche energy test circuit include: Using the square wave generator U1 composed of a 555 timer to output a square wave signal to the device under test U2 to drive the device under test U2 into the working state; Connecting the inductor L1 as a load to the power supply VCC, and continuously turning on or off the device under test U2 through the square wave signal, so that the two ends of the device under test U2 experience breakdown to form a repetitive avalanche breakdown phenomenon; Calculating the repetitive avalanche energy generated in the repetitive avalanche breakdown phenomenon and evaluating the durability of the device under test U2 under repetitive avalanche conditions.

3. The repetitive avalanche energy test circuit composed of a 555 timer according to claim 2, wherein The connecting the inductor L1 as a load to the power supply VCC and continuously turning on or off the device under test U2 through the square wave signal includes: Connecting the inductor L1 as a load to the power supply VCC, turning on the device under test U2 through the square wave signal. When the device under test U2 is turned on, the inductor L1 is charged and stores energy, and generates a maximum current value; Turning off the device under test U2 through the square wave signal. When the device under test U2 is turned off instantaneously, the inductor L1 starts to discharge, and at the same time, a breakdown voltage is generated across the two ends of the device under test U2; The breakdown voltage generated across the two ends of the device under test U2 gradually drops to the theoretical voltage value within a preset time period, and at the same time, a switching cycle of the device under test U2 is completed.

4. The repetitive avalanche energy test circuit composed of a 555 timer according to claim 3, characterized in that, The calculating the repetitive avalanche energy generated in the repetitive avalanche breakdown phenomenon and evaluating the durability of the device under test U2 under repetitive avalanche conditions includes: Calculating the repetitive avalanche energy generated in the repetitive avalanche breakdown phenomenon based on the maximum current value and the breakdown voltage generated across the two ends of the device under test U2; Converting the repetitive avalanche energy, and collecting the surface temperature of the device under test U2 in combination with the temperature measurement module; Generating a limit value of the repetitive avalanche energy in combination with the converted repetitive avalanche energy and the surface temperature of the device under test U2, and evaluating the durability of the device under test U2 based on the limit value of the repetitive avalanche energy.

5. The repetitive avalanche energy test circuit composed of a 555 timer according to claim 4, characterized in that, The diode D1 is used to improve the turn-off speed of the device under test U2 and release the charge controlled by the device under test U2; The resistor R1, the resistor R2, and the resistor R3 are all used to reduce waveform resonance interference, making the waveform closer to the theoretical waveform.

6. The repetitive avalanche energy test circuit composed of a 555 timer according to claim 5, characterized in that The inductor L1 is an air-core inductor.

7. A repetitive avalanche energy test system composed of a 555 timer, which is used to implement the repetitive avalanche energy test circuit composed of a 555 timer described in any one of claims 1-6, characterized in that, The repetitive avalanche energy test system includes a signal driving module, a power supply module, a load adjusting module, a waveform sampling module, a waveform monitoring module, and a temperature monitoring module; Among them, the signal driving module is electrically connected to the power supply module, the load adjusting module, the waveform sampling module, the waveform monitoring module, and the temperature monitoring module in sequence; The signal driving module is used to generate a square wave signal through a square wave oscilloscope and transmit it to the device under test to drive the device under test to start working; The power supply module is used to provide a DC power supply to the device under test and supply power to the device under test at the same time; The load adjusting module is used to provide an inductive load and test the response of the device under test under different inductance conditions; The waveform sampling module is used to collect the current waveform flowing through the device under test and transmit it to the waveform monitoring module for waveform monitoring; The waveform monitoring module is used to monitor in real time the current waveform passing through the device under test and the voltage waveform across the device under test; The temperature monitoring module is used to detect in real time the temperature on the surface of the device under test.

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