An avalanche energy measuring circuit and a measuring method thereof

Abstract

This application provides an avalanche energy measurement circuit and method thereof. The avalanche energy measurement circuit includes a generating circuit, an integrating circuit, and a calculation circuit. The generating circuit causes the device under test (DUT) to undergo avalanche breakdown, forming a discharge loop between the DUT and the generating circuit. During the discharge loop, the integrating circuit acquires the voltage and current of the DUT, performs a first integral operation on the voltage and current to obtain a first integral result, and performs a second integral operation on the current to obtain a second integral result. After the discharge loop is complete, the calculation circuit calculates the avalanche energy of the DUT based on the energy calculation formula, using the first integral result, the second integral result, and the equivalent resistance of the generating circuit. The second integral result and the equivalent resistance are used to correct the calculation result of the energy calculation formula. This application effectively improves the accuracy of measuring the avalanche energy of the DUT.

Description

[0001] The present application relates to the technical field of power electronic device testing, and particularly relates to an avalanche energy measurement circuit and a measurement method thereof. <BACKGROUND>

[0002] Power semiconductor devices are mainly used for electric energy conversion and circuit control of power electronic devices, which include but are not limited to MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), IGBT (Insulated Gate Bipolar Transistor), triode and thyristor. In actual application, not only the main circuit of the power semiconductor device has inductance, but also the internal part has stray inductance. When the power semiconductor device is turned off, the release path of the electric energy is disconnected, so that the inductance generates a high voltage applied to the power semiconductor device, and when the high voltage exceeds a certain value, the power semiconductor device enters an avalanche breakdown state. Generally, the index for measuring the performance of the power semiconductor device in the avalanche breakdown state is the avalanche energy (the maximum energy that can be consumed by the power semiconductor device in the avalanche breakdown state), and if the avalanche energy exceeds a certain value, the power semiconductor device will be completely damaged. Therefore, it is necessary to study the avalanche energy of the power semiconductor device, which has extremely important significance for analyzing the reasons for the avalanche failure of the power semiconductor device, optimizing the avalanche energy of the power semiconductor device from the circuit structure, and providing a reference for users to select the power semiconductor device and manufacturers to develop a new generation of power semiconductor devices with excellent avalanche energy characteristics.

[0003] In the related art, since the data manual of the power semiconductor device does not provide related data of the avalanche energy, in order to focus on the avalanche energy when using the power semiconductor device, the avalanche energy of the power semiconductor device needs to be measured by an avalanche energy test device. When the avalanche energy test device measures the avalanche energy of the power semiconductor device, an oscilloscope or a high-speed analog-to-digital conversion chip needs to be used to collect the voltage and current of the power semiconductor device, so as to calculate the avalanche energy of the power semiconductor device according to the collected voltage and current. However, the avalanche energy test device still has many disadvantages when measuring the avalanche energy of the power semiconductor device, such as: high cost, not easy to implement; large-capacity storage chips are needed to cache data; the calculation accuracy of the avalanche energy is low, which is limited by the sampling accuracy of the analog-to-digital conversion chip (usually only 8 bits, and the sampling accuracy is very limited).

[0004] Therefore, it is necessary to improve the circuit structure of the above-mentioned avalanche energy test device. <SUMMARY>​

[0005] The application provides an avalanche energy measurement circuit and a measurement method thereof, and aims to solve the problem of low precision in measuring the avalanche energy of a power semiconductor device by using an avalanche energy test device in the prior art.

[0006] To solve the above technical problem, a first aspect of an embodiment of the application provides an avalanche energy measurement circuit for measuring the avalanche energy of a device under test, the avalanche energy measurement circuit comprising a generation circuit, an integration circuit and a calculation circuit, the generation circuit being connected to the device under test, the integration circuit being connected to the device under test and the calculation circuit; wherein:

[0007] The generation circuit is configured to cause the device under test to undergo avalanche breakdown, wherein the device under test and the generation circuit form a discharge loop after the avalanche breakdown occurs;

[0008] The integration circuit is configured to collect the voltage and current of the device under test during the discharge of the discharge loop, and perform first integration operation on the voltage and current to obtain a corresponding first integration operation result, and perform second integration operation on the current to obtain a corresponding second integration operation result;

[0009] The calculation circuit is configured to obtain the first integration operation result and the second integration operation result after the discharge of the discharge loop is completed, and perform operation on the first integration operation result, the second integration operation result and a preset equivalent resistance of the generation circuit according to a preset energy calculation formula to obtain the avalanche energy of the device under test, wherein the second integration operation result and the equivalent resistance are used to correct the calculation result of the energy calculation formula.

[0010] A second aspect of an embodiment of the application provides an avalanche energy measurement method, which is implemented based on an avalanche energy measurement circuit for measuring the avalanche energy of a device under test, the avalanche energy measurement circuit comprising a generation circuit, an integration circuit and a calculation circuit, wherein the generation circuit is connected to the device under test, and the integration circuit is connected to the device under test and the calculation circuit;

[0011] The avalanche energy measurement method comprises:

[0012] The generation circuit causes the device under test to undergo avalanche breakdown, wherein the device under test and the generation circuit form a discharge loop after the avalanche breakdown occurs;

[0013] The integration circuit collects the voltage and current of the device under test during the discharge of the discharge loop, and performs first integration operation on the voltage and current to obtain a corresponding first integration operation result, and performs second integration operation on the current to obtain a corresponding second integration operation result;

[0014] The computing circuit obtains the first integral operation result and the second integral operation result after the discharge of the discharge loop, and performs operation on the first integral operation result, the second integral operation result and the preset equivalent resistance of the generating circuit according to a preset energy calculation formula to obtain the avalanche energy of the measured device, wherein the second integral operation result and the equivalent resistance are used to correct the calculation result of the energy calculation formula.

[0015] From the above description, compared with the related art, the beneficial effects of the present application are that:

[0016] The generating circuit, the integral circuit and the computing circuit jointly constitute an avalanche energy measurement circuit, and the generating circuit is connected to the measured device, and the integral circuit is connected to the measured device and the computing circuit. In actual application, the generating circuit can cause the measured device to undergo avalanche breakdown, and after the avalanche breakdown occurs, the measured device forms a discharge loop with the generating circuit; the integral circuit can collect the voltage and current of the measured device during the discharge of the discharge loop, and perform first integral operation on the voltage and current to obtain the corresponding first integral operation result, and perform second integral operation on the current to obtain the corresponding second integral operation result; the computing circuit can obtain the first integral operation result and the second integral operation result after the discharge of the discharge loop, and perform operation on the first integral operation result, the second integral operation result and the preset equivalent resistance of the generating circuit according to a preset energy calculation formula to obtain the avalanche energy of the measured device, and wherein the second integral operation result and the equivalent resistance are used to correct the calculation result of the energy calculation formula.

[0017] It can be understood that the avalanche energy refers to the maximum energy that the measured device undergoing avalanche breakdown can consume, i.e. the energy consumed on the measured device, but in the actual measurement of the avalanche energy, the equivalent resistance of the generating circuit also causes energy loss, thereby bringing errors to the measurement of the avalanche energy. For this, the present application introduces an energy loss compensation function of the equivalent resistance of the generating circuit in the measurement process of the avalanche energy, i.e. the second integral operation result and the equivalent resistance of the generating circuit are used to correct the calculation of the avalanche energy of the measured device by the computing circuit, the purpose being to eliminate the measurement errors caused by the energy loss of the equivalent resistance of the generating circuit, thereby effectively improving the precision in measuring the avalanche energy of the measured device. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the related art or the embodiments of the present application, the drawings required to be used in the description of the related art or the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and not all embodiments. Those skilled in the art can obtain other drawings according to these drawings without creating any creative labor.

[0019] Figure 1 A module block diagram of an avalanche energy measurement circuit provided by an embodiment of the present application;

[0020] Figure 2 A circuit structure schematic diagram of an avalanche energy measurement circuit provided by an embodiment of the present application;

[0021] Figure 3 A timing diagram of an avalanche energy measurement circuit provided by an embodiment of the present application;

[0022] Figure 4 A flowchart of an avalanche energy measurement method provided by an embodiment of the present application.

CONCRETE EMBODIMENT

[0023] In order to make the purpose, technical solutions and advantages of the present application more obvious and easy to understand, the present application will be described clearly and completely below in combination with the embodiments of the present application and the corresponding drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. It should be understood that the embodiments of the present application described below are only used to explain the present application and do not limit the present application, i.e. all other embodiments obtained by those skilled in the art without creative labor based on the embodiments of the present application belong to the scope of protection of the present application. In addition, the technical features involved in the embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0024] Figure 1 A module block diagram of an avalanche energy measurement circuit provided by an embodiment of the present application, which is used for measuring the avalanche energy of a device under test DUT and includes a generation circuit 10, an integration circuit 20 and a calculation circuit 30, wherein the generation circuit 10 is connected to the device under test DUT, the integration circuit 20 is connected to the device under test DUT and the calculation circuit 30. In the embodiment of the present application, the device under test DUT can include but is not limited to MOSFET, IGBT, triode and thyristor.

[0025] Specifically, the generation circuit 10 is used for causing the device under test DUT to occur avalanche breakdown, wherein the device under test DUT and the generation circuit 10 constitute a discharge loop after the occurrence of avalanche breakdown; the integration circuit 20 is used for collecting the voltage Vds and the current Ids of the device under test DUT in the process of discharging of the discharge loop, and performing first integration operation on the voltage Vds and the current Ids to obtain a corresponding first integration operation result, and performing second integration operation on the current Ids to obtain a corresponding second integration operation result; the calculation circuit 30 is used for obtaining the first integration operation result and the second integration operation result after the discharge of the discharge loop is completed, and calculating the first integration operation result, the second integration operation result and the preset equivalent resistance R of the generation circuit 10 according to a preset energy calculation formula to obtain the avalanche energy of the device under test DUT.eq to obtain the avalanche energy of the device under test DUT, wherein the second integral operation result and the equivalent resistance R eq to correct the calculation result of the energy calculation formula, that is, to correct the calculation of the avalanche energy of the device under test DUT by the calculation circuit 30.

[0026] In actual application, the occurrence circuit 10 first works to make the device under test DUT occur avalanche breakdown, at this time, the avalanche test of the device under test DUT is formally started, and after the avalanche breakdown occurs, the device under test DUT will form a discharge loop with the occurrence circuit 10, which will continue to discharge, when the discharge of the discharge loop is completed, that is, when the current (equivalent to the current Ids of the device under test DUT) in the discharge loop is consumed, the avalanche test of the device under test DUT is ended. The integral circuit 20 will collect the voltage Vds and the current Ids of the device under test DUT in the process of discharging the discharge loop, and perform first integral operation on the collected voltage Vds and current Ids to obtain the corresponding first integral operation result, and perform second integral operation on the collected current Ids to obtain the corresponding second integral operation result. The calculation circuit 30 will obtain the first integral operation result and the second integral operation result from the integral circuit 20 after the discharge of the discharge loop is completed, and calculate the avalanche energy of the device under test DUT according to the preset energy calculation formula. eq to obtain the avalanche energy of the device under test DUT. It can be seen that the occurrence circuit 10, the integral circuit 20 and the calculation circuit 30 work in sequence in time sequence.

[0027] It can be understood that the avalanche energy refers to the maximum energy that the device under test DUT can consume in avalanche breakdown, that is, the energy consumed on the device under test DUT, but in the actual measurement of the avalanche energy, the equivalent resistance R eq of the occurrence circuit 10 will also cause energy loss, thereby causing error in the measurement of the avalanche energy. In view of this, the energy loss compensation function of the equivalent resistance R eq of the occurrence circuit 10 is introduced in the measurement process of the avalanche energy, that is, the second integral operation result and the equivalent resistance R eq of the occurrence circuit 10 are used to correct the calculation of the avalanche energy of the device under test DUT by the calculation circuit 30, so as to eliminate the measurement error caused by the energy loss of the equivalent resistance R eq of the occurrence circuit 10, thereby effectively improving the precision in measuring the avalanche energy of the device under test DUT.

[0028] In some embodiments, the first integration operation performed by the integration circuit 20 is ∫(Vds x Ids)dt, i.e., the integration of the product of the voltage Vds and the current Ids of the device under test DUT with respect to time t; and the second integration operation performed by the integration circuit 20 is ∫Ids 2 dt, i.e., the integration of the self-product (square) of the current Ids of the device under test DUT with respect to time t. Based on this, the energy calculation formula used by the calculation circuit 30 is E = ∫(Vds x Ids)dt - R eq ×∫Ids 2 dt, i.e., the first integration operation minus the product of the second integration operation and the equivalent resistance R eq , wherein E represents the avalanche energy of the device under test DUT.

[0029] It can be understood that both the first integration operation and the second integration operation are expressed in the form of a formula without introducing specific numerical values, so that the result of the first integration operation can also be represented by ∫(Vds x Ids)dt, and the result of the second integration operation can also be represented by ∫Ids 2 dt. In the energy calculation formula, we can call R eq ×∫Ids 2 dt a correction factor for correcting the calculation result of the energy calculation formula, and the correction factor needs to be subtracted when measuring the avalanche energy of the device under test DUT, the purpose of which is to eliminate the measurement error caused by the energy loss of the equivalent resistance R eq of the generation circuit 10.

[0030] In some embodiments, please further refer to Figure 2 , Figure 2 the circuit structure diagram of the avalanche energy measurement circuit provided by the embodiments of the present application. The integration circuit 20 includes a voltage follower 21, a current follower 22, a first multiplier 23, a second multiplier 24, a first switch S1, a second switch S2, a first integrator 25, and a second integrator 26, wherein the input terminals of the voltage follower 21 and the current follower 22 are connected to the device under test DUT, the output terminal of the voltage follower 21 is connected to the input terminal of the first multiplier 23, the output terminal of the current follower 22 is connected to the input terminals of the first multiplier 23 and the second multiplier 24, the output terminal of the first multiplier 23 is connected to the input terminal of the first integrator 25 through the first switch S1, the output terminal of the second multiplier 24 is connected to the input terminal of the second integrator 26 through the second switch S2, and the output terminals of the first integrator 25 and the second integrator 26 are connected to the calculation circuit 30.

[0031] Specifically, voltage follower 21 is used to acquire the voltage Vds of the device under test (DUT) during the discharge process in the discharge circuit; current follower 22 is used to acquire the current Ids of the DUT during the discharge process in the discharge circuit; first multiplier 23 is used to perform a first multiplication operation (i.e., Vds × Ids) on voltage Vds and current Ids to obtain the corresponding first multiplication result (also represented by Vds × Ids); second multiplier 24 is used to perform a second multiplication operation (i.e., Ids × Ids) on current Ids. 2 To obtain the corresponding result of the second multiplication operation (also from Ids) 2 The first integrator 25 is used to perform a first integration operation (i.e., ∫(Vds×Ids)dt) on the result of the first multiplication operation when the first switch S1 is closed to obtain the first integration result (also represented by ∫(Vds×Ids)dt); the second integrator 26 is used to perform a second integration operation (i.e., ∫Ids) on the result of the second multiplication operation when the second switch S2 is closed. 2 dt) to obtain the result of the second integral operation (also by ∫Ids) 2 dt represents.

[0032] Understandably, during the discharge process in the discharge circuit, the current Ids of the device under test (DUT) flows through the shunt R1 (see below) and is followed by the current follower 22, while the voltage Vds of the DUT is followed by the voltage follower 21 after being divided by the voltage divider (the voltage divider network is not in the circuit). Figure 2 As shown in the diagram, it can employ a voltage divider network commonly used in this field. The voltage follower 21 and current follower 22, after passing through the first multiplier 23, yield the first multiplication result (i.e., Vds × Ids). The current follower 22, after passing through the second multiplier 24, yields the second multiplication result (i.e., Ids). 2 After the first switch S1 is closed under the control of the controller 31 (see below), the first multiplier 23 can obtain the first integral result (i.e., ∫(Vds×Ids)dt) through the first integrator 25. After the second switch S2 is closed under the control of the controller 31, the second multiplier 24 can obtain the second integral result (i.e., ∫Ids) through the second integrator 26. 2 dt).

[0033] As one implementation method, please refer to [the relevant documentation]. Figure 2, the integral circuit 20 comprises a voltage follower 21, a current follower 22, a first multiplier 23, a second multiplier 24, a first switch S1, a second switch S2, a first integrator 25 and a second integrator 26, and further comprises a level detector 27, an input end of the level detector 27 being connected to the device under test DUT, and an output end of the level detector 27 being connected to the calculation circuit 30. Specifically, the level detector 27 is configured to detect the level state of the voltage Vds of the device under test DUT in real time, and determine whether the discharging of the discharging loop is completed according to the level state, and send a signal to the calculation circuit 30 after the discharging of the discharging loop is completed so as to make the calculation circuit 30 obtain the first integral operation result and the second integral operation result. It can be understood that the calculation circuit 30 needs to obtain the first integral operation result and the second integral operation result from the integral circuit 20 after the discharging of the discharging loop is completed, and thus needs to be informed that the discharging of the discharging loop is completed after the discharging of the discharging loop is completed, and the level detector 27 in the embodiment sends a signal to the calculation circuit 30 after determining that the discharging of the discharging loop is completed, and the signal is just used to inform the calculation circuit 30 that the discharging of the discharging loop is completed, i.e., the calculation circuit 30 only obtains the first integral operation result and the second integral operation result from the integral circuit 20 after receiving the signal.

[0034] Exemplarily, the level detector 27 adopts a comparator COMP, in which case one input end of the comparator COMP is connected to a reference voltage Vref, another input end of the comparator COMP is connected to the device under test DUT, and an output end of the comparator COMP is connected to the calculation circuit 30. In actual application, the comparator COMP can obtain the voltage Vds of the device under test DUT in real time, and compare the obtained voltage Vds with the reference voltage Vref, and the comparison manner can include but is not limited to difference and ratio, and the comparison result can indicate the level state of the voltage Vds of the device under test DUT, so as to determine whether the discharging of the discharging loop is completed, so as to achieve the purpose of informing the calculation circuit 30 when the discharging of the discharging loop is completed.

[0035] In some embodiments, still referring to Figure 2 , the calculation circuit 30 comprises a controller 31, an analog-to-digital converter 32, a first sample-and-hold 33, a second sample-and-hold 34, a third switch S3 and a fourth switch S4, wherein the controller 31 is connected to the analog-to-digital converter 32, the analog-to-digital converter 32 is connected to the first sample-and-hold 33 and the second sample-and-hold 34, the first sample-and-hold 33 is connected to the integral circuit 20 through the third switch S3, and the second sample-and-hold 34 is connected to the integral circuit 20 through the fourth switch S4.

[0036] Specifically, the first sample-and-hold circuit 33 is used to acquire the first integral result (i.e., ∫(Vds×Ids)dt) when the third switch S3 is closed; the second sample-and-hold circuit 34 is used to acquire the second integral result (i.e., ∫Ids) when the fourth switch S4 is closed. 2 dt); The analog-to-digital converter 32 is used to convert the first integral operation result and the second integral operation result into analog and then transmit them to the controller 31; The controller 31 is used to close the third switch S3 and the fourth switch S4 after the discharge of the discharge circuit is completed, and to open the third switch S3 and the fourth switch S4 after the first sample-and-hold circuit 33 obtains the first integral operation result and the second sample-and-hold circuit 34 obtains the second integral operation result, and according to the energy calculation formula (i.e., E=∫(Vds×Ids)dt-R), eq ×∫Ids 2 dt) is related to the first integral result, the second integral result, and the equivalent resistance R of the generator circuit 10. eq The calculation is performed to obtain the avalanche energy of the device under test (DUT) (i.e., ∫(Vds×Ids)dt-R). eq ×∫Ids 2 It is understandable that after the first sample-and-hold circuit 33 obtains the first integral result and the second sample-and-hold circuit 34 obtains the second integral result, the third switch S3 and the fourth switch S4 need to be closed under the control of the controller 31 in order to avoid affecting the sampling accuracy of the first sample-and-hold circuit 33 and the second sample-and-hold circuit 34.

[0037] The controller 31 can be, but is not limited to, a microcontroller, ARM, FPGA / CPLD, DSP, PLC, or other control chip. In the avalanche energy measurement circuit, it mainly plays a central control role, such as controlling the closing and closing of the first switch S1, the second switch S2, the third switch S3, the fourth switch S4, and the fifth switch S5 (see below), generating a pulse signal Vgs (see below) and transmitting it to the gate of the device under test (DUT) to control the DUT's on / off state. The equivalent resistance R of the generating circuit 10... eq Alternatively, the settings can be pre-configured by the measurement personnel in the controller 31. For the analog-to-digital converter 32, a high-precision, low-speed analog-to-digital converter chip can be used.

[0038] As one implementation method, please refer to [the relevant documentation]. Figure 2In addition to the controller 31, analog-to-digital converter 32, first sample-and-hold circuit 33, second sample-and-hold circuit 34, third switch S3, and fourth switch S4, the computing circuit 30 also includes a display 35. The display 35 is connected to the controller 31 and is used to display the avalanche energy of the device under test (DUT) output by the controller 31. The display 35 can be a communication interface such as RS232, RS485, RS422, USB, or Ethernet port, or it can be a display device such as a digital tube or LED light, or even a display screen composed of many display devices, such as an LED display screen.

[0039] In some implementations, see still Figure 2 The generating circuit 10 includes a power supply VDD, a fifth switch S5, a diode D1, an inductor L1, and a shunt R1. The positive terminal of the power supply VDD is connected to one end of the fifth switch S5, and the negative terminal is connected to the anode of the diode D1. The other end of the fifth switch S5 and the cathode of the diode D1 are respectively connected to one end of the inductor L1. The other end of the inductor L1 is connected to the drain of the device under test (DUT). The source of the DUT is connected to the negative terminal of the power supply VDD through the shunt R1. The gate of the DUT receives a pulse signal Vgs, which drives the DUT to turn it on or off. The shunt R1 can be, but is not limited to, a Rogowski coil, a resistor, a fluxgate magnetometer, or a Hall effect sensor.

[0040] Specifically, when the generating circuit 10 is working, the fifth switch S5 within the generating circuit 10 needs to be closed under the control of the controller 31, while the device under test (DUT) continuously switches between on and off under the drive of the pulse signal Vgs. When the DUT is on, the power supply VDD charges the inductor L1; when the DUT is off, since the DUT has not yet been avalanche breakdown, that is, the discharge circuit mentioned above has not yet been formed, the voltage across the inductor L1 will continue to rise; when the voltage across the inductor L1 rises to the avalanche breakdown voltage of the DUT, the DUT undergoes avalanche breakdown, and the inductor L1, the DUT, the shunt R1, and the diode D1 form the discharge circuit mentioned above.

[0041] It should be noted that the above implementation methods are only preferred implementations of the embodiments of this application, and are not the only limitation on the specific circuit configuration and corresponding control logic of the generating circuit 10, the integrating circuit 20 and the calculating circuit 30; those skilled in the art can make flexible settings based on the embodiments of this application and according to the actual application scenario.

[0042] In summary, this application provides an avalanche energy measurement circuit that introduces the equivalent resistance R of the generating circuit 10 during the avalanche energy measurement process.eq The energy loss compensation function is achieved by integrating the second integral calculation result with the equivalent resistance R of the generator circuit 10. eq The product is used to correct the calculation circuit 30's calculation of the avalanche energy of the device under test (DUT), with the aim of eliminating the effect caused by the equivalent resistance R of the generating circuit 10. eq The measurement error caused by energy loss is effectively reduced, thus improving the accuracy of avalanche energy measurement of the device under test (DUT). The integrator circuit 20 in this avalanche energy measurement circuit can accurately integrate the voltage Vds and current Ids of the DUT. The analog-to-digital converter 32 in the calculation circuit 30 uses a high-precision, low-speed analog-to-digital converter chip, which can further improve the measurement accuracy of avalanche energy. At the same time, this avalanche energy measurement circuit also has excellent characteristics such as low cost and ease of implementation.

[0043] In addition, the timing diagram of this avalanche energy measurement circuit can be found in [reference needed]. Figure 3 Where IL represents the current in inductor L1. The operation of this avalanche energy measurement circuit is as follows: the fifth switch S5 is closed under the control of the controller 31, and the first switch S1 and the second switch S2 are normally closed under the control of the controller 31, so that the capacitor in the integrator circuit 20 ( Figure 2(Not shown in the text) Discharge; Controller 31 transmits a single-pulse signal Vgs to the gate of the device under test (DUT). Avalanche breakdown occurs in the DUT at the falling edge of the single-pulse signal Vgs; First switch S1 and second switch S2 are normally open under the control of controller 31, so that the integrator circuit 20 integrates the voltage Vds and current Ids of the DUT; After the DUT finishes avalanche (i.e., the discharge circuit is completed), the voltage Vds of the DUT returns to a low level. Comparator COMP generates a signal indicating that the discharge circuit has completed by comparing the reference voltage Vref with the voltage Vds of the DUT, and transmits this signal to controller 31; After receiving this signal, controller 31 controls the third switch S3 and the fourth switch S4 to close at the rising edge of the output of comparator COMP. The first sample-and-hold circuit 33 samples the current voltage of the first integrator 25 (i.e., the first integration result), and the second sample-and-hold circuit 34 samples the current voltage of the second integrator 26 (i.e., the second integration result). After the first sample-and-hold circuit 33 and the second sample-and-hold circuit 34 have completed sampling, the third switch S3 and the fourth switch S4 are opened under the control of the controller 31. The controller 31 controls the analog-to-digital converter 32 to perform analog-to-digital conversion on the voltages output by the first sample-and-hold circuit 33 and the second sample-and-hold circuit 34 (i.e., the first integration result and the second integration result) and transmit them to itself, so that it can calculate the avalanche energy of the device under test (DUT) according to the preset energy calculation formula, and transmit the calculated avalanche energy to the display 35 so that the display 35 can display the avalanche energy of the device under test (DUT).

[0044] Figure 4 This is a flowchart illustrating the avalanche energy measurement method provided in this application embodiment. This application embodiment also provides an avalanche energy measurement method, which is implemented based on the aforementioned avalanche energy measurement circuit provided in this application embodiment. This avalanche energy measurement method includes the following steps 401 to 403.

[0045] Step 401: The generating circuit causes the device under test to undergo avalanche breakdown.

[0046] In this embodiment of the application, when measuring the avalanche energy of the device under test (DUT), the DUT needs to first undergo avalanche breakdown through the generating circuit 10. At this time, the avalanche test of the DUT officially begins. After the avalanche breakdown occurs, the DUT and the generating circuit 10 form a discharge circuit. This discharge circuit will continue to discharge. When the discharge circuit is completed, that is, when the current in the discharge circuit (equivalent to the current Ids of the DUT) is exhausted, the avalanche test of the DUT ends.

[0047] Step 402: During the discharge process in the discharge circuit, the integrator circuit collects the voltage and current of the device under test, performs a first integration operation on the voltage and current to obtain the corresponding first integration operation result, and performs a second integration operation on the current to obtain the corresponding second integration operation result.

[0048] In this embodiment of the application, after the avalanche test of the device under test (DUT) officially begins, that is, during the discharge process in the discharge circuit, the integrator circuit 20 will collect the voltage Vds and current Ids of the DUT, and perform a first integration operation on the collected voltage Vds and current Ids to obtain the corresponding first integration operation result, and perform a second integration operation on the collected current Ids to obtain the corresponding second integration operation result, so that the subsequent calculation circuit 30 can use these two integration operation results to calculate the avalanche energy.

[0049] Step 403: After the discharge circuit completes the discharge, the calculation circuit obtains the first integral calculation result and the second integral calculation result, and calculates the first integral calculation result, the second integral calculation result and the equivalent resistance preset by the generating circuit according to the preset energy calculation formula to obtain the avalanche energy of the device under test.

[0050] In this embodiment, after the avalanche test of the device under test (DUT) is completed, i.e. after the discharge circuit is fully discharged, the calculation circuit 30 obtains the first integration result and the second integration result from the integrator circuit 20, and compares the first integration result and the second integration result with the equivalent resistance R preset by the generator circuit 10 according to the preset energy calculation formula. eq The avalanche energy of the device under test (DUT) is calculated. The result of the second integral operation is compared with the equivalent resistance R. eq The calculation results are used to correct the energy calculation formula, that is, to correct the calculation circuit 30 for the avalanche energy of the device under test (DUT).

[0051] It is understandable that avalanche energy refers to the maximum energy that the device under test (DUT) can dissipate when an avalanche breaks down, i.e., the energy consumed by the DUT. However, in the actual measurement of avalanche energy, the equivalent resistance R of the generating circuit 10 is... eq This also leads to energy loss, thus introducing errors in the measurement of avalanche energy. To address this, this embodiment introduces the equivalent resistance R of the generating circuit 10 during the avalanche energy measurement process. eq The energy loss compensation function is achieved by integrating the second integral calculation result with the equivalent resistance R of the generator circuit 10. eq The purpose of correcting the calculation of avalanche energy of the device under test (DUT) by the calculation circuit 30 is to eliminate the influence of the equivalent resistance R of the generation circuit 10. eq This effectively reduces measurement errors caused by energy loss, thereby improving the accuracy of avalanche energy measurement of the device under test (DUT).

[0052] It should be noted that the various embodiments in this application are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For product-related embodiments, since they are similar to method-related embodiments, the descriptions are relatively simple, and relevant parts can be referred to the descriptions of the method-related embodiments.

[0053] It should also be noted that, in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0054] The above description of the disclosed embodiments enables those skilled in the art to implement or use the content of this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined in this application may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An avalanche energy measurement circuit for measuring the avalanche energy of a device under test, characterized in that, The system includes a generating circuit, an integrating circuit, and a calculating circuit. The generating circuit is connected to the device under test (DUT), and the integrating circuit is connected to both the DUT and the calculating circuit. The generating circuit is used to cause the device under test to undergo avalanche breakdown, wherein after the avalanche breakdown occurs, the device under test and the generating circuit form a discharge circuit; The integrator circuit is used to acquire the voltage and current of the device under test during the discharge process of the discharge circuit, and to perform a first integration operation on the voltage and the current to obtain a corresponding first integration operation result, and to perform a second integration operation on the current to obtain a corresponding second integration operation result. The calculation circuit is used to obtain the first integral calculation result and the second integral calculation result after the discharge circuit is completed, and to calculate the avalanche energy of the device under test by performing calculations on the first integral calculation result, the second integral calculation result and the equivalent resistance of the generating circuit according to the preset energy calculation formula. The second integral calculation result and the equivalent resistance are used to correct the calculation result of the energy calculation formula.

2. The avalanche energy measurement circuit as described in claim 1, characterized in that, The first integral operation is Where Vds represents the voltage of the device under test, Ids represents the current of the device under test, and t represents time.

3. The avalanche energy measurement circuit as described in claim 2, characterized in that, The second integral operation is .

4. The avalanche energy measurement circuit as described in claim 3, characterized in that, The energy calculation formula is as follows: Where E represents the avalanche energy of the device under test, and R eq This represents the equivalent resistance.

5. The avalanche energy measurement circuit as described in claim 1, characterized in that, The integrating circuit includes a voltage follower, a current follower, a first multiplier, a second multiplier, a first switch, a second switch, a first integrator, and a second integrator. The input terminals of the voltage follower and the current follower are connected to the device under test. The output terminal of the voltage follower is connected to the input terminal of the first multiplier. The output terminal of the current follower is connected to the input terminals of the first multiplier and the second multiplier. The output terminal of the first multiplier is connected to the input terminal of the first integrator via the first switch. The output terminal of the second multiplier is connected to the input terminal of the second integrator via the second switch. The output terminals of the first integrator and the second integrator are connected to the calculation circuit. Wherein: The voltage follower is used to acquire the voltage of the device under test during the discharge process of the discharge circuit; the current follower is used to acquire the current of the device under test during the discharge process of the discharge circuit; the first multiplier is used to perform a first multiplication operation on the voltage and the current to obtain a corresponding first multiplication operation result; the second multiplier is used to perform a second multiplication operation on the current to obtain a corresponding second multiplication operation result; the first integrator is used to perform a first integration operation on the first multiplication operation result when the first switch is closed to obtain a first integration operation result; the second integrator is used to perform a second integration operation on the second multiplication operation result when the second switch is closed to obtain a second integration operation result.

6. The avalanche energy measurement circuit as described in claim 5, characterized in that, The integration circuit further includes a level detector, the input of which is connected to the device under test and the output of which is connected to the computing circuit. The level detector is used to detect the voltage level of the device under test and to determine whether the discharge of the discharge circuit is complete based on the voltage level. After the discharge of the discharge circuit is completed, the level detector sends a signal to the computing circuit so that the computing circuit can obtain the first integration result and the second integration result.

7. The avalanche energy measurement circuit as described in claim 1, characterized in that, The computing circuit includes a controller, an analog-to-digital converter (ADC), a first sample-and-hold circuit, a second sample-and-hold circuit, a third switch, and a fourth switch. The controller is connected to the ADC, the ADC is connected to the first sample-and-hold circuit and the second sample-and-hold circuit, the first sample-and-hold circuit is connected to the integrator circuit via the third switch, and the second sample-and-hold circuit is connected to the integrator circuit via the fourth switch; wherein: The first sample-and-hold circuit is used to acquire the first integral calculation result when the third switch is closed; the second sample-and-hold circuit is used to acquire the second integral calculation result when the fourth switch is closed; the analog-to-digital converter is used to convert the first integral calculation result and the second integral calculation result into analog and then transmit them to the controller; the controller is used to close the third switch and the fourth switch after the discharge circuit is completed, and to open the third switch and the fourth switch after the first sample-and-hold circuit acquires the first integral calculation result and the second sample-and-hold circuit acquires the second integral calculation result, and to calculate the avalanche energy of the device under test according to the energy calculation formula using the first integral calculation result, the second integral calculation result and the equivalent resistance.

8. The avalanche energy measurement circuit as described in claim 7, characterized in that, The computing circuit also includes a display connected to the controller, the display being used to display the avalanche energy of the device under test output by the controller.

9. The avalanche energy measurement circuit as described in claim 1, characterized in that, The generating circuit includes a power supply, a fifth switch, a diode, an inductor, and a shunt. The positive terminal of the power supply is connected to one end of the fifth switch, and the negative terminal is connected to the anode of the diode. The other end of the fifth switch and the cathode of the diode are respectively connected to one end of the inductor. The other end of the inductor is connected to the drain of the device under test (DUT). The source of the DUT is connected to the negative terminal of the power supply through the shunt. The gate of the DUT is used to receive a pulse signal, which is used to drive the DUT to turn it on or off. When the device under test (DUT) is turned on, the power supply charges the inductor; when the DUT is turned off, the voltage across the inductor continuously increases; when the voltage across the inductor increases to the avalanche breakdown voltage of the DUT, the DUT undergoes avalanche breakdown, and the inductor, the DUT, the shunt, and the diode form the discharge circuit.

10. An avalanche energy measurement method, implemented based on an avalanche energy measurement circuit, wherein the avalanche energy measurement circuit is used to measure the avalanche energy of the device under test, characterized in that... The avalanche energy measurement circuit includes a generating circuit, an integrating circuit, and a calculating circuit, wherein the generating circuit is connected to the device under test, and the integrating circuit is connected to the device under test and the calculating circuit. The avalanche energy measurement method includes: The generating circuit causes the device under test to undergo avalanche breakdown, wherein after the avalanche breakdown occurs, the device under test and the generating circuit form a discharge circuit; The integrator circuit acquires the voltage and current of the device under test during the discharge process of the discharge circuit, performs a first integration operation on the voltage and the current to obtain a corresponding first integration operation result, and performs a second integration operation on the current to obtain a corresponding second integration operation result. The calculation circuit obtains the first integral calculation result and the second integral calculation result after the discharge circuit is completed, and performs calculations on the first integral calculation result, the second integral calculation result and the equivalent resistance of the generating circuit according to the preset energy calculation formula to obtain the avalanche energy of the device under test. The second integral calculation result and the equivalent resistance are used to correct the calculation result of the energy calculation formula.

Images