Method, device and system for calculating safe working area of MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) and storage medium

Abstract

The invention discloses a safe working area calculation method, device and system of an MOSFET and a storage medium, and relates to the technical field of semiconductors. The method comprises the following steps: acquiring MOSFET temperature sensitive parameters; obtaining a relation curve between the MOSFET temperature sensitive parameter and the MOSFET junction temperature; acquiring transient thermal impedance of the MOSFET under different duty ratios and different pulse widths; calculating the maximum allowable power loss of the MOSFET under different pulse widths of the single pulse; calculating a safe working area SOA curve coordinate of the MOSFET; and automatically calculating, drawing, storing and outputting a safe working area SOA diagram of the MOSFET on the basis of Qt Widgets. According to the SOA calculation method for the safe working area of the MOSFET, the thermal performance and the electrical performance of the MOSFET are comprehensively considered, the safe working area of the MOSFET is determined through a series of experiments and calculation steps, and the accuracy of a calculation result is improved.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor technology, and in particular, relates to a method, device, system and storage medium for calculating a safe operating area of ​​a MOSFET. Background Art

[0002] SOA (Safe Operating Area) is a graphic that describes the safe operating area of ​​MOSFET. The graphic shows the current and voltage combination range in which the MOSFET can operate reliably to ensure that the device will not be overloaded or damaged.

[0003] At present, the safe operating area SOA curve of MOSFET cannot be directly drawn through the point-by-point testing method. The safe operating area curves provided in the product specifications of various manufacturers are calculated through the relationship between thermal resistance test data, power, temperature, voltage, current, and on-resistance to obtain the corresponding voltage and current data, and then drawn through third-party software.

[0004] The drawing of the safe operating area SOA curve of MOSFET involves complex calculations and model simulations of multiple physical parameters, including transient thermal resistance, power dissipation, temperature effects, and electrical characteristics of the device. These calculations require corresponding mathematical models and test data to support them, so the calculation process is relatively complex and time-consuming. At the same time, the drawing of the safe operating area SOA curve of MOSFET usually requires the help of third-party software, and the calculation process and graphic drawing cannot be completed automatically. In order to calculate and draw the safe operating area SOA curve of MOSFET more simply and automatically, and display the curve with a more intuitive visual interface, a safe operating area implementation method of MOSFET was developed based on the thermal resistance test system and Qt Widgets Qt C++ user interface application. Summary of the invention

[0005] The purpose of this application is to provide a method, device, system and storage medium for calculating the safe operating area of ​​MOSFET, which comprehensively considers the thermal performance and electrical performance of MOSFET and improves the accuracy, applicability, calculation efficiency, controllability and safety of the calculation of the safe operating area of ​​MOSFET.

[0006] In order to achieve the above objectives, the solution of this application is:

[0007] In a first aspect, an embodiment of the present application provides a method for calculating a safe operating area of ​​a MOSFET, comprising:

[0008] Obtain MOSFET temperature sensitive parameters and obtain the MOSFET temperature sensitive parameters and MOSFET junction temperature T through the thermal resistance test system J The relationship curve of

[0009] Through the thermal resistance test system, the transient thermal impedance Z of MOSFET under different duty cycles and pulse widths is obtained. thJC And through the transient thermal impedance Z of MOSFET at different duty ratios and pulse widths thJC , calculate the maximum allowable power loss P of MOSFET under different pulse widths of a single pulse D :

[0010] Get the rated parameters of MOSFET, according to the maximum allowable power loss P of MOSFET under different pulse widths of single pulse D The safe operating area curve coordinates of the MOSFET are calculated based on the rated parameters of the MOSFET; the rated parameters of the MOSFET include the maximum allowable junction temperature on-resistance Maximum allowable continuous current value I DMAX The maximum permissible pulse current value I DMMAX Ratio n, maximum allowable voltage value V DSMAX , Maximum allowable junction temperature T JMAX , Shell temperature T C , Steady-state thermal impedance R thJC ;

[0011] The SOA diagram is drawn according to the coordinates of the safe operating area curve of the MOSFET to form a complete safe operating area of ​​the MOSFET.

[0012] According to the above method of the embodiment of the present application, the following additional technical features may also be provided:

[0013] Furthermore, the temperature sensitive parameters of MOSFET are obtained, including:

[0014] When the MOSFET includes a body diode, and the forward voltage drop of the body diode varies linearly with temperature, the temperature sensitive parameters include the forward voltage drop of the body diode, V F ;

[0015] When the MOSFET does not include a body diode or the forward voltage drop of the body diode varies nonlinearly with temperature, the temperature sensitive parameters include the on-state drain-source voltage V DSON and threshold voltage V GSTH .

[0016] Furthermore, the MOSFET temperature sensitive parameters and the MOSFET junction temperature T J The relationship curve includes:

[0017] Place the MOSFET in a temperature-controlled constant temperature environment and set the ambient temperature T A The temperature rises from room temperature 25℃ to the preset temperature 80℃, and then starts to cool down after reaching the preset temperature. The temperature sensitive parameters of MOSFET are recorded every time the temperature drops to a fixed value until the ambient temperature TA From the preset temperature to the normal temperature of 25°C, the MOSFET temperature sensitive parameters and MOSFET junction temperature T J relationship curve.

[0018] Furthermore, the transient thermal impedance Z of MOSFET under different duty cycles and pulse widths is obtained. thJC ,include:

[0019] Based on the JEDEC standard, the ambient temperature of the MOSFET is maintained at 25°C through the thermal resistance test system, and the pulse heating method is used to set the heating current I H With the measured current I M It works by switching an electronic switch, with a preset fixed heating time for each heating. The measured current I M Measure the temperature sensitive parameters of MOSFET once, and compare the temperature sensitive parameters of MOSFET with the junction temperature T J The MOSFET junction temperature is obtained by the relationship curve. After the measurement is completed, heating is continued for a preset fixed heating time and the measurement current I is applied again. M Measure temperature sensitive parameters; repeat the work in this way. During the whole test process, the thermal resistance test system compares the MOSFET junction temperature measured each time with the previously measured junction temperature. When the thermal resistance test system detects that 8 consecutive junction temperatures are within the range of ±5% of its junction temperature average, and the junction temperature range of the MOSFET at the final thermal equilibrium is 100±10℃, it is judged that all test conditions for thermal equilibrium are met, and the steady-state thermal resistance R is calculated. thJC , the formula is as follows:

[0020]

[0021] P H =U H *I H

[0022] Among them, T J Indicates the MOSFET junction temperature, T C Indicates the MOSFET case temperature, P H It represents the heating power when MOSFET reaches thermal equilibrium, I H Indicates the heating current when MOSFET reaches thermal equilibrium; U H Indicates the voltage value when MOSFET reaches thermal equilibrium;

[0023] If the junction temperature does not reach the junction temperature range of the MOSFET's final thermal equilibrium, the heating current I H When the MOSFET reaches thermal equilibrium, the heating current I is cut off through the thermal resistance test system. HMOSFET automatically cools down; the heating current I H Switch to measure current I M , continuously measure the transient voltage value of the temperature sensitive parameter during the cooling process of MOSFET, and obtain the transient response curve of the temperature sensitive parameter during the cooling process of MOSFET; through the relationship curve between the temperature sensitive parameter of MOSFET and the junction temperature T of MOSFET, obtain the transient temperature response curve of MOSFET, and compare the transient temperature response curve with the heating power P H Perform normalized calculations to obtain single pulse transient thermal impedance and single pulse transient thermal impedance curves; repeat the above tests and calculations by changing the power pulse width and duty cycle to obtain the transient thermal impedance Z of MOSFET under different duty cycles and pulse widths. thJC .

[0024] Furthermore, the maximum allowable power loss P of MOSFET under different pulse widths of a single pulse is calculated. D ,include:

[0025] Through the transient thermal impedance Z of MOSFET at different duty ratios and pulse widths thJC , combined with the maximum allowable junction temperature T JMAX , calculate the maximum allowable power loss P of MOSFET under different pulse widths of a single pulse D , the formula is as follows:

[0026]

[0027] Among them, P D Indicates the maximum allowable power loss, T JMAX Indicates the maximum junction temperature, T C Indicates the shell temperature, Z thJC Represents transient thermal impedance.

[0028] Furthermore, the safe operating area SOA curve coordinates of the MOSFET are calculated, including:

[0029] Set the horizontal axis of the MOSFET safe operating area SOA curve coordinate to the drain-source voltage V DS , the vertical axis is the leakage current I D , MOSFET maximum allowable continuous current value I DMAX The maximum allowable junction temperature on-resistance Maximum allowable junction temperature T JMAX , Steady-state thermal impedance R thJC Decision, I DMAX The calculation formula is as follows:

[0030]

[0031] According to I DMAXCalculate the maximum allowable pulse current value I of MOSFET DMMAX , the formula is as follows:

[0032] I DMMAX =Int(n×I DMAX )

[0033] Among them, I DMMAX Indicates the maximum allowable pulse current value of MOSFET, the value range of n is 2-4;

[0034] Calculate the current and voltage coordinates of a single pulse with different pulse widths. The formula is as follows:

[0035]

[0036] Among them, P D It represents the maximum allowable power loss of MOSFET under different pulse widths of a single pulse, I DMAX Indicates the maximum allowable continuous current value of MOSFET, I DMMAX Indicates the maximum allowable pulse current value of MOSFET, V DSMAX Indicates the maximum allowable voltage value of MOSFET, T JMAX Indicates the maximum allowable junction temperature, T C Indicates the shell temperature, R thJC represents the steady-state thermal impedance of the MOSFET, Z thJC represents the transient thermal impedance of MOSFET, Indicates the maximum allowable junction temperature on-resistance of MOSFET; V DS represents the drain-source voltage, I D Represents the drain current.

[0037] Furthermore, an SOA diagram is drawn according to the safe operating area curve coordinates of the MOSFET to form a complete MOSFET safe operating area, including automatic calculation, drawing, storage and output of the MOSFET safe operating area SOA diagram based on Qt Widgets.

[0038] In a second aspect, an embodiment of the present application provides a safe operating area calculation device for a MOSFET, comprising:

[0039] The parameter acquisition module is configured to obtain the temperature sensitive parameters of the MOSFET and obtain the temperature sensitive parameters of the MOSFET and the MOSFET junction temperature T through the thermal resistance test system. J The relationship curve of

[0040] The power loss module is configured to obtain the transient thermal impedance Z of the MOSFET at different duty cycles and pulse widths through the thermal resistance test system. thJC And through the transient thermal impedance Z of MOSFET at different duty ratios and pulse widthsthJC , calculate the maximum allowable power loss P of MOSFET under different pulse widths of a single pulse D ;

[0041] The curve coordinate module is configured to obtain the rated parameters of the MOSFET according to the maximum allowable power loss P of the MOSFET under different pulse widths of a single pulse. D The safe operating area curve coordinates of the MOSFET are calculated based on the rated parameters of the MOSFET; the rated parameters of the MOSFET include the maximum allowable junction temperature on-resistance Maximum allowable continuous current value I DMAX The maximum permissible pulse current value I DMMAX Ratio n, maximum allowable voltage value V DSMAX , Maximum allowable junction temperature T JMAX , Shell temperature T C , Steady-state thermal impedance R thJC ;

[0042] The curve drawing module is configured to draw a SOA diagram according to the safe operating area curve coordinates of the MOSFET to form a complete safe operating area of ​​the MOSFET.

[0043] In a third aspect, an embodiment of the present application provides a safe operating area calculation system for a MOSFET, the system comprising a processor and a memory, the memory storing a computer program, the computer program being loaded and executed by the processor to implement a safe operating area calculation method and a calculation device for a MOSFET as provided in the first and second aspects of the embodiments of the present application.

[0044] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, it is used to implement a safe operating area calculation method and a calculation device for a MOSFET as described in the first aspect and the second aspect of the embodiment of the present application.

[0045] Compared with the prior art, the safe operating area calculation method, device, system and storage medium of MOSFET provided by the embodiments of the present application have the following beneficial technical effects:

[0046] The embodiment of the present application more accurately and flexibly calculates the power loss and safety margin of MOSFET under different working conditions by comprehensively considering the type of MOSFET temperature sensitive parameters, the relationship between MOSFET temperature sensitive parameters and MOSFET junction temperature, and transient thermal impedance under different duty cycles and pulse widths; ensures that the output MOSFET safe working area is the device design limit value, thereby giving the application end correct application guidance, avoiding device damage due to overvoltage, overcurrent or overheating, and improving the overall reliability and stability of the circuit;

[0047] The embodiment of the present application obtains MOSFET temperature-sensitive parameters (including body diode forward voltage drop, on-state drain-source voltage and threshold voltage), and uses a thermal resistance test system to obtain the relationship curve between MOSFET temperature-sensitive parameters and MOSFET junction temperature and transient thermal impedance under different duty cycles and pulse widths, thereby providing a more accurate data basis for subsequent power loss calculation and safe operating area curve drawing, taking into account the performance changes of MOSFET under different temperatures and working conditions, so as to more accurately evaluate its safe operating range.

[0048] The embodiments of the present application are not only applicable to MOSFETs that include a body diode and whose forward voltage drop varies linearly with temperature, but also to MOSFETs that do not include a body diode or whose forward voltage drop varies nonlinearly with temperature. This wide applicability enables the method to be applied to more types of MOSFET devices.

[0049] The embodiment of the present application utilizes the relationship curve between the temperature sensitive parameters of MOSFET and the junction temperature of MOSFET and the transient thermal impedance under different duty cycles and different pulse widths to more efficiently calculate the maximum allowable power loss of MOSFET under different pulse widths of a single pulse, avoiding the tedious iterative calculation and trial-and-error process in the traditional method, improving the calculation efficiency, and also providing specific steps for calculating the steady-state thermal resistance and transient thermal impedance, making the calculation process clearer and controllable.

[0050] The embodiments of the present application illustrate the safe operating area of ​​MOSFET and display the complex electrical and thermal performance parameters in an intuitive graphical manner, which is convenient for engineers to quickly refer to and judge during the design process, reduce circuit failures and device damage caused by improper design, and thus reduce trial and error costs and development cycles; by calculating the thermal resistance and power loss of MOSFET under different working conditions, it is helpful to combine circuit design requirements and optimize the heat dissipation design of the circuit to ensure that the device can still maintain good performance under long-term high-load operation, and can optimize the energy efficiency of the circuit while ensuring circuit reliability, reduce power consumption and heat generation; it is not only suitable for conventional circuit design, but also for specific application scenarios that require high reliability, high stability and high energy efficiency; by real-time monitoring of the working status and temperature of MOSFET, its working point can be dynamically adjusted to adapt to changes in different loads and working environments.

[0051] Based on Qt widgets, the SOA diagram of MOSFET's safe operating area is automatically calculated, drawn, stored and output, which reduces the difficulty of realizing the SOA curve of MOSFET's safe operating area. Users only need to input key parameter data in the calculation device, and the system can accurately and automatically calculate and draw the SOA diagram of the safe operating area, and store it through the storage medium; based on Qtwidgets, the curve appearance can be customized conveniently and flexibly, and users can customize the graphical interface according to personal preferences; a variety of SOA customizations can be achieved, such as dynamic coordinate SOA, SOA drawing of different lines, etc.; SOA curves in various formats can be exported, such as vectorized PDF files, rasterized images PNG, JPG and BMP, which are convenient for electronic engineers to refer to. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A schematic diagram showing a flow chart of a method for calculating a safe operating area of ​​a MOSFET according to an embodiment of the present application is shown;

[0053] Figure 2 A structural block diagram of a device for calculating a safe operating area of ​​a MOSFET according to an embodiment of the present application is shown;

[0054] Figure 3 A structural block diagram of a computer device according to an embodiment of the present application is shown;

[0055] Figure 4 A curve diagram showing the relationship between the temperature sensitive parameters of the MOSFET and the junction temperature of the MOSFET according to the embodiment of the present application is shown;

[0056] Figure 5 The safe operating area SOA diagram of the MOSFET of the embodiment of the present application is shown. DETAILED DESCRIPTION

[0057] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It is understandable that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some but not all structures related to the present application are shown in the accompanying drawings. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0058] The terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0059] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0060] like Figure 1 As shown, the embodiment of the present application provides a method for calculating the safe operating area of ​​MOSFET, comprising the following steps:

[0061] Step 101, obtaining MOSFET temperature sensitive parameters.

[0062] When obtaining MOSFET temperature sensitive parameters, several MOSFET temperature sensitive parameters concerned in the embodiments of the present application include: body diode forward voltage drop V F , On-state drain-source voltage V DSON and threshold voltage V GSTH , these parameters will change with temperature, thus affecting the performance of MOSFET.

[0063] Specifically, the MOSFET body diode forward voltage drop V F The method for obtaining the voltage V includes: short-circuiting the gate and drain of the MOSFET, connecting the anode and cathode of the MOSFET body diode to the positive and negative poles of the test bench respectively, applying a measurement current (usually about 10mA) to the body diode, making the current reach a level that the device allows for measurement (to avoid excessive current damaging the device), and then recording the body diode voltage drop at this time, which is the body diode forward voltage drop V F .

[0064] MOSFET on-state drain-source voltage V DSON The acquisition method includes: applying a fixed voltage to the gate and source of the MOSFET to turn the device on, applying a small test current between the drain and source (the pulse width is generally less than 200μs to avoid self-heating effect), and measuring the on-state voltage between the drain and source.

[0065] MOSFET threshold voltage V GSTHThe acquisition method includes: using a specific test circuit or test instrument, which can measure the drain current of MOSFET at different gate-source voltages, gradually increasing the gate-source voltage, and monitoring the drain current. When the drain current reaches a set current value (such as 100μA~500μA), the gate-source voltage at this time is recorded. This data is the MOSFET threshold voltage.

[0066] Step 102, obtaining MOSFET temperature sensitive parameters and MOSFET junction temperature T J In order to obtain the temperature sensitive parameters of MOSFET (body diode forward voltage drop V F , On-state drain-source voltage V DSON , threshold voltage V GSTH ) and MOSFET junction temperature T J A series of temperature dependency tests are required to determine the relationship curve between the MOSFET and the junction temperature. These tests are designed to measure the trend of the MOSFET temperature sensitive parameters changing with junction temperature at different junction temperatures.

[0067] Body diode forward voltage drop V F , usually decreases with increasing temperature; the on-state drain-source voltage V DSON Usually increases with increasing temperature; threshold voltage V GSTH It usually decreases with increasing temperature.

[0068] The embodiment of the present application first prepares a test environment, uses an environment or heating / cooling platform that can accurately control the temperature, and designs or selects an appropriate test circuit to accurately measure the forward voltage drop V of the MOSFET body diode at different temperatures. F , On-state drain-source voltage V DSON , threshold voltage V GSTH Prepare multimeter, oscilloscope, measurement unit (SMU) or other necessary measurement equipment.

[0069] Set the test conditions, determine the temperature range to be tested, and set an appropriate temperature step between each temperature point to ensure that the details of parameter changes can be captured. After each temperature point is reached, wait for enough time to ensure that the MOSFET reaches thermal equilibrium.

[0070] Start the test, place the MOSFET in the temperature control device, and cool it down according to the set temperature range and step size. After each temperature point stabilizes, use the test circuit and measuring instruments to measure the MOSFET temperature sensitive parameters, and record the measured temperature sensitive parameters. Use chart software (such as Excel, MATLAB, Python's matplotlib, etc.) to plot the recorded data into a chart, using temperature as the horizontal axis and temperature sensitive parameters as the vertical axis to plot the MOSFET temperature sensitive parameters and the MOSFET junction temperature T J The relationship curve between them.

[0071] It should be noted that during the test, it is necessary to ensure that the MOSFET is not subjected to excessive thermal stress or electrical stress to avoid damage to the device. J When drawing a relationship curve, pay attention to choosing the appropriate coordinate axis range and scale to clearly show the changing trend of the data.

[0072] Specifically, select the temperature sensitive parameters of MOSFET, place the device in a temperature control console, heat the temperature to a certain high temperature, and then cool it down through water cooling or other means. As the temperature changes, the temperature sensitive parameters of MOSFET will also change. Every time the temperature drops by a fixed temperature value (such as 5℃ / 10℃), use appropriate current / voltage to test the temperature sensitive parameters according to circuit requirements until the temperature drops to normal temperature of 25℃.

[0073] like Figure 4 As shown in the figure, through the above high temperature to room temperature MOSFET temperature sensitive parameter test data, the MOSFET temperature sensitive parameters and MOSFET junction temperature T can be obtained. J relationship curve.

[0074] Step 103, obtaining the transient thermal impedance Z of MOSFET under different duty ratios and different pulse widths thJC .

[0075] In order to obtain the transient thermal impedance Z under different duty cycles and pulse widths through the thermal resistance test system thJC In the embodiment of the present application, a thermal resistance test system is first set up to ensure that the thermal resistance test system, temperature sensor, power supply and other equipment are ready, and the MOSFET is correctly connected to the test system to ensure that its junction temperature and shell temperature can be accurately measured, and the single pulse waveform applied by the test (such as pulse width, pulse interval, pulse frequency, etc.) is accurate and reliable.

[0076] Based on the JEDEC standard, the ambient temperature of the MOSFET is maintained at 25°C through the thermal resistance test system, and the pulse heating method is used to set the heating current I H With the measured current IM It works by switching an electronic switch, with a preset fixed heating time for each heating. The measured current I M Measure the temperature sensitive parameters of MOSFET once, and compare the temperature sensitive parameters of MOSFET with the junction temperature T J The MOSFET junction temperature is obtained by the relationship curve. After the measurement is completed, heating is continued for a preset fixed heating time and the measurement current I is applied again. M Measure temperature sensitive parameters; repeat the work in this way. During the whole test process, the thermal resistance test system compares the MOSFET junction temperature measured each time with the junction temperature measured previously. When the thermal resistance test system detects that 8 consecutive junction temperatures are within the range of ±5% of its junction temperature average, it is determined that the MOSFET has reached steady-state thermal equilibrium. The junction temperature of the MOSFET at the final thermal equilibrium needs to reach 100±10℃. If the junction temperature does not reach this temperature requirement, the heating current I can be increased appropriately. H After adjusting until all test conditions of thermal balance are met, the steady-state thermal impedance R is calculated by the following formula: thJC :

[0077]

[0078] P H =U H *I H

[0079] Among them, T J Indicates the MOSFET junction temperature, T C Indicates the MOSFET case temperature, P H It represents the heating power when MOSFET reaches thermal equilibrium, I H Indicates the heating current when MOSFET reaches thermal equilibrium; U H Indicates the voltage value when the MOSFET reaches thermal equilibrium.

[0080] When the MOSFET reaches thermal equilibrium, the heating current I is cut off through the thermal resistance test system. H MOSFET automatically cools down; the heating current I H Switch to measure current I M , continuously measure the transient voltage value of the temperature sensitive parameter during the cooling process of MOSFET, obtain the transient response curve of the temperature sensitive parameter during the cooling process of MOSFET, and compare the MOSFET temperature sensitive parameter with the MOSFET junction temperature T J The relationship curve of the transient temperature response curve of MOSFET is obtained, and the transient temperature response curve is compared with the heating power P HBy performing normalized calculation, the single pulse transient thermal impedance and single pulse transient thermal impedance curve can be obtained; then, by changing the power pulse width and duty cycle, the above test and calculation are repeated to obtain the transient thermal impedance Z of MOSFET under different duty cycles and pulse widths. thJC .

[0081] Step 104, calculate the maximum allowable power loss P of the MOSFET under different pulse widths of a single pulse D .

[0082] In the embodiment of the present application, the transient thermal impedance Z of MOSFET under different duty ratios and different pulse widths is measured. thJC , combined with the MOSFET design specification maximum allowable junction temperature T JMAX , calculate the maximum allowable power loss P of MOSFET under different pulse widths of a single pulse D , the formula is as follows:

[0083]

[0084] Among them, P D Represents power loss, T JMAX Indicates the maximum junction temperature, T C Indicates the shell temperature, Z thJC Represents transient thermal impedance.

[0085] The power loss and transient thermal impedance of MOSFET are interrelated in the thermal performance evaluation of MOSFET.

[0086] Transient thermal impedance describes how the junction temperature of a MOSFET changes with applied pulse power during a short pulse (such as a switching operation). Transient thermal impedance is essential for evaluating the reliability and life of MOSFETs in high-frequency switching applications. Transient thermal impedance helps evaluate the thermal stability of MOSFETs under pulse operating conditions and prevent performance degradation or damage due to overheating.

[0087] Step 105, calculating the coordinates of the safe operating area SOA curve of the MOSFET.

[0088] In the embodiment of the present application, the transient thermal impedance Z of MOSFET under different duty ratios and different pulse widths is measured. thJC , the maximum allowable power loss P of MOSFET under different pulse widths of a single pulse D , combined with the MOSFET's rated parameters, the maximum allowable junction temperature on-resistance Maximum allowable continuous current value I DMAX The maximum permissible pulse current value I DMMAX Ratio n, maximum allowable voltage value V DSMAX , Maximum allowable junction temperature T JMAX , Shell temperature TC , Steady-state thermal impedance R thJC Determine the coordinates of the MOSFET safe operating area SOA curve;

[0089] Set the X-axis of the MOSFET safe operating area SOA curve to the drain-source voltage V DS , the Y axis is the leakage current I D ; MOSFET maximum allowable continuous current value I DMAX The maximum allowable junction temperature on-resistance Maximum allowable junction temperature T JMAX , Steady-state thermal impedance R thJC Decision, I DMAX The calculation formula is as follows:

[0090]

[0091] According to I DMAX Calculate the maximum allowable pulse current value I of MOSFET DMMAX , the formula is as follows:

[0092] I DMMAX =Int(n×I DMAX )

[0093] Among them, I DMMAX Indicates the maximum allowable pulse current value of MOSFET, the value range of n is 2-4; V DSMAX The maximum reverse breakdown voltage of MOSFET is B VDSS Decision, V DSMAX =B VDSS ; Maximum allowable power loss P D Limited by the junction temperature, excessively high junction temperature is the root cause of MOSFET burning; calculate the current and voltage coordinates of a single pulse with different pulse widths, the formula is as follows:

[0094]

[0095] The above relationship can be used to determine the current and voltage coordinates of a single pulse with different pulse widths. The coordinate calculation example is as follows:

[0096] The parameter indicators of the embodiment products are shown in Table 1 and Table 2:

[0097] Table 1

[0098] <![CDATA[B VDSS (V)]]> <![CDATA[R DSON@TJMAX) (Oh)]]> <![CDATA[T JMAX (℃)]]> <![CDATA[T C (℃)]]> 500 3.704 150 25

[0099] Table 2

[0100] PulseWidth <![CDATA[Z thJC (℃ / W)]]> 0.01mS 0.016 1mS 0.265 10mS 0.667 DC 1.265

[0101] MOSFET maximum allowable continuous current value I DMAXThe calculation is as follows:

[0102]

[0103] Because the product is a TO-247 package, n=4, the maximum allowable pulse current value of MOSFET is I DMMAX The calculation is as follows:

[0104] I DMMAX =Int(n×I DMAX )=20A

[0105] The transient thermal impedance and maximum allowable power loss of single pulse with different pulse widths are shown in Table 3:

[0106] Table 3

[0107]

[0108]

[0109] Calculate the coordinates according to the data in Table 3 and the coordinate calculation method:

[0110] Set the X-axis of the MOSFET safe operating area SOA curve to the drain-source voltage V DS , the Y axis is the leakage current I D , RDSONLimit Line is determined, and according to Ohm's law:

[0111] When the drain-source voltage V DS =0.1V, the leakage current I D =0.027A;

[0112] When the leakage current I D =I DMMAX =20A, drain-source voltage V DS =74.08V;

[0113] The two coordinate points are calculated to be (0.1V, 0.027A) and (74.08V, 20A);

[0114] V DSMAX The maximum reverse breakdown voltage of MOSFET is B VDSS The maximum voltage value V in SOA is determined by DSMAX 500V;

[0115] According to the transient thermal impedance of a single pulse with different pulse widths, combined with the relevant parameters of MOSFET, the power loss under different pulse widths is calculated, such as the power loss under a single pulse with a pulse width of 10ms:

[0116]

[0117] When the leakage current ID =I DMMAX =20A, drain-source voltage:

[0118]

[0119] The first coordinate of 10ms is (9.37V, 20A);

[0120] When the drain-source voltage V DS =V DSMAX =500V,

[0121] Leakage Current:

[0122]

[0123] Then the second coordinate of 10ms is (500V, 0.3748A)

[0124] The voltage and current coordinates of different pulse widths 0.01ms, 1ms, 10ms, and DC are calculated in turn according to the above calculation method as shown in Table 4 below:

[0125] Table 4

[0126]

[0127]

[0128] Finally, referring to the coordinate data shown in Table 4, the safe operating area SOA diagram of the MOSFET is automatically calculated, drawn, stored and output based on Qt Widgets.

[0129] Step 106 , automatically calculating, drawing, storing and outputting a safe operating area SOA diagram of the MOSFET based on Qt Widgets.

[0130] The SOA diagram, namely the Safe Operating Area diagram, is mainly used in the field of power electronics, especially in evaluating the safe operating range of MOSFET.

[0131] The SOA graph reflects the safe operating range of the MOSFET under different operating conditions. It is drawn under static and dynamic operating conditions, taking into account factors such as the maximum withstand voltage, maximum current, and maximum power of the MOSFET. The SOA graph is represented by a current-voltage diagram to help engineers understand the operating boundaries of the device to ensure the stability and reliability of the system.

[0132] The embodiment of the present application automatically calculates, draws, stores and outputs the safe operating area SOA diagram of MOSFET based on Qt widgets, which reduces the difficulty of realizing the safe operating area SOA curve of MOSFET. The user only needs to input key parameter data in the calculation device, and the system can accurately and automatically calculate and draw the safe operating area SOA diagram, and store and save it through a storage medium; based on Qt widgets, the curve appearance can be conveniently and flexibly customized, and the user can customize the graphical interface according to personal preferences; a variety of safe operating area SOA customizations are achieved, such as dynamic coordinate safe operating area SOA, different line drawing safe operating area SOA, etc.; SOA curves in a variety of formats can be exported, such as vectorized PDF files, rasterized images PNG, JPG and BMP, which are convenient for electronic engineers to refer to.

[0133] Specifically, define the SOA form class header file through widget.h, run the main program through main.cpp, define the SOA constructor through widget.cpp, and use "date TimeEdit", "lineEdit", "label", and "tableWidget" in the widget ui to set the form interface and component properties to design the SOA visual interface.

[0134] like Figure 5 As shown, in the software design, the corresponding drain current I is calculated for different pulse widths of a single pulse. D , drain-source voltage V DS The calculation results are presented in the form of coordinate points, as shown in Table 4. Then, QCharts, the graphics view framework that comes with Qt, is combined with the QLineSeries class to add these data points to the line chart. Through a series of personalized settings, the generated line chart is finally presented in the interface in an intuitive way.

[0135] Enter the values ​​of the relevant parameters of MOSFET through the text input box "lineEdit", and the table "tableWidget" will display the transient thermal impedance of a single pulse with different pulse widths. The MOSFET safe operating area SOA curve can be obtained by starting the calculation process, and the curve will be drawn in real time and displayed in the "GraphicsView" view.

[0136] like Figure 2 As shown, the embodiment of the present application provides a safe operating area calculation device for MOSFET, including a parameter acquisition module 201, a power loss module 202, a curve coordinate module 203 and a curve drawing module 204, wherein:

[0137] The parameter acquisition module 201 is configured to acquire the temperature sensitive parameters of the MOSFET and acquire the temperature sensitive parameters of the MOSFET and the MOSFET junction temperature T through the thermal resistance test system. J The relationship curve of

[0138] The power loss module 202 is configured to obtain the transient thermal impedance Z of the MOSFET at different duty cycles and pulse widths through a thermal resistance test system. thJC And through the transient thermal impedance Z of MOSFET at different duty ratios and pulse widths thJC , calculate the maximum allowable power loss P of MOSFET under different pulse widths of a single pulse D ;

[0139] The curve coordinate module 203 is configured to obtain the rated parameters of the MOSFET according to the maximum allowable power loss P of the MOSFET under different pulse widths of a single pulse. D The safe operating area curve coordinates of the MOSFET are calculated based on the rated parameters of the MOSFET; the rated parameters of the MOSFET include the maximum allowable junction temperature on-resistance Maximum allowable continuous current value I DMAX The maximum permissible pulse current value I DMMAX Ratio n, maximum allowable voltage value V DSMAX , Maximum allowable junction temperature T JMAX , Shell temperature T C , Steady-state thermal impedance R thJC ;

[0140] The curve drawing module 204 is configured to draw a SOA diagram according to the safe operating area curve coordinates of the MOSFET to form a complete safe operating area of ​​the MOSFET.

[0141] Specifically, the embodiment of the present application performs the following actions:

[0142] Step 1: Define the SOA form class header file through widget.h;

[0143] Step 2: Run the main program through main.cpp definition;

[0144] In the main.cpp file, first include the widget.h header file to use the Widget class. Then create a QApplication instance and a Widget instance and display them. Finally, call the exec method of QApplication to start the application's event loop.

[0145] Step 3: Define the SOA constructor through widget.cpp;

[0146]

[0147] I DMMAX =Int(n×I DMAX )

[0148]

[0149] Among them, P D It represents the maximum allowable power loss of MOSFET under different pulse widths of a single pulse, I DMAX Indicates the maximum allowable continuous current value of MOSFET, I DMMAX Indicates the maximum allowable pulse current value of MOSFET, V DSMAX Indicates the maximum allowable voltage value of MOSFET, T JMAX Indicates the maximum allowable junction temperature, T C Indicates the shell temperature, R thJC represents the steady-state thermal impedance of the MOSFET, Z thJC represents the transient thermal impedance of MOSFET, Indicates the maximum allowable junction temperature on-resistance of MOSFET; V DS represents the drain-source voltage, I D Represents the drain current.

[0150] In software design, according to the above two key equations, the corresponding drain current I is calculated for different pulse widths of a single pulse. D , drain-source voltage V DS These calculation results are presented as coordinate points. Then, QCharts, a graphics view framework that comes with Qt, is combined with the QLineSeries class to add these data points to the line chart. Through a series of personalized settings, the generated line chart is finally presented in the interface in an intuitive way.

[0151] Step 4: Use controls such as "date TimeEdit", "lineEdit", "GraphicsView", "label", "tableWidget", "PushBotton" in the widget ui to set the form interface and component properties, and design the SOA visual interface.

[0152] Enter the relevant parameters V of MOSFET through the text input box "lineEdit" DSMAX ,I DMMAX , T JMAX ,n,R thJC , T C The table "tableWidget" shows the transient thermal impedance Z under different pulse widths. thJC, after clicking the “PushBotton” button, the software will start the calculation process, and the calculated SOA curve will be drawn in real time and displayed in the “GraphicsView” view.

[0153] The safe operating area calculation device of the MOSFET in the embodiment of the present application can be a computer device, or a component in the computer device, such as an integrated circuit or a chip. The computer device can be a terminal, or it can be other devices other than the terminal. Exemplarily, the computer device can be a mobile phone, a tablet computer, a laptop computer, a PDA, a vehicle-mounted computer device, a mobile Internet device (Mobile Internet Device, MID), an ultra-mobile personal computer (Ultra-Mobile Personal Computer, UMPC), a netbook or a personal digital assistant (Personal Digital Assistant, PDA), etc., and can also be a server, a network attached storage (Network Attached Storage, NAS), a personal computer (Personal Computer, PC), etc., which is not specifically limited in the embodiment of the present application.

[0154] The safe operating area calculation device of MOSFET provided in the embodiment of the present application can realize Figure 1 To avoid repetition, the various processes implemented in the embodiment of the method for calculating the safe operating area of ​​MOSFET are not described here.

[0155] The present application also provides a computer device, such as Figure 3 As shown, the computer device includes a processor 301 and a memory 302. The memory 302 stores programs or instructions that can be run on the processor 301. When the program or instruction is executed by the processor 301, each step of the safe operating area calculation method of the above-mentioned MOSFET is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0156] It should be noted that the computer device in the embodiment of the present application includes the above-mentioned mobile computer device and non-mobile computer device.

[0157] The memory 302 can be used to store software programs and various data. The memory 302 may mainly include a first storage area for storing programs or instructions and a second storage area for storing data, wherein the first storage area may store an operating system, an application program or instructions required for at least one function (such as a sound playback function, an image playback function, etc.), etc. In addition, the memory 302 may include a volatile memory or a non-volatile memory, or the memory 302 may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), a static random access memory (SRAM), a dynamic random access memory (DRAM), a synchronous dynamic random access memory (SDRAM), a double data rate synchronous dynamic random access memory (DDRSDRAM), an enhanced synchronous dynamic random access memory (ESDRAM), a synchronous link dynamic random access memory (SLDRAM) and a direct memory bus random access memory (DRRAM). The memory 302 of the embodiment of the present application includes but is not limited to these and any other suitable types of memory.

[0158] The processor 301 may include one or more processing units; optionally, the processor 301 integrates an application processor and a modem processor, wherein the application processor mainly processes operations related to an operating system, a user interface, and application programs, and the modem processor mainly processes wireless communication signals, such as a baseband processor. It is understandable that the modem processor may not be integrated into the processor 301.

[0159] An embodiment of the present application also provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, each process of the above-mentioned MOSFET safe operating area calculation method embodiment is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0160] An embodiment of the present application also provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned MOSFET safe operating area calculation method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0161] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0162] An embodiment of the present application also provides a computer program product, which is stored in a storage medium. The program product is executed by at least one processor to implement the various processes of the above-mentioned MOSFET safe operating area calculation method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0163] It should be noted that, in this article, the terms "comprises", "includes" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, features described with reference to certain examples may be combined in other examples.

[0164] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A method for calculating the safe operating area of ​​MOSFET, characterized in that: The method comprises: Obtain MOSFET temperature sensitive parameters, and obtain the MOSFET temperature sensitive parameters and the MOSFET junction temperature T through a thermal resistance test system. J The relationship curve of The transient thermal impedance Z of the MOSFET under different duty cycles and pulse widths is obtained through the thermal resistance test system. thJC The transient thermal impedance Z of the MOSFET under different duty ratios and pulse widths is thJC , calculate the maximum allowable power loss P of the MOSFET under different pulse widths of a single pulse D ; Obtain the rated parameters of the MOSFET, and calculate the maximum allowable power loss P of the MOSFET under different pulse widths of a single pulse. D and the rated parameters of the MOSFET to calculate the safe operating area curve coordinates of the MOSFET; the rated parameters of the MOSFET include the maximum allowable junction temperature on-resistance Maximum allowable continuous current value I DMAX The maximum permissible pulse current value I DMMAX Ratio n, maximum allowable voltage value V DSMAX , Maximum allowable junction temperature T JMAX , Shell temperature T C , Steady-state thermal impedance R thJC ; The SOA diagram is drawn according to the safe operating area curve coordinates of the MOSFET to form a complete MOSFET safe operating area.

2. The method for calculating the safe operating area of ​​MOSFET according to claim 1, characterized in that: The step of obtaining the temperature sensitive parameters of the MOSFET includes: When the MOSFET includes a body diode, and the forward voltage drop of the body diode varies linearly with temperature, the temperature sensitive parameter includes the forward voltage drop V F ; When the MOSFET does not include a body diode or the forward voltage drop of the body diode varies nonlinearly with temperature, the temperature sensitive parameter includes the on-state drain-source voltage V DSON and threshold voltage V GSTH .

3. The method for calculating the safe operating area of ​​MOSFET according to claim 1, characterized in that: The acquisition of MOSFET temperature sensitive parameters and MOSFET junction temperature T J The relationship curve includes: The MOSFET is placed in a temperature-controlled constant temperature environment, and the ambient temperature T A The temperature rises from room temperature 25°C to a preset temperature of 80°C, and then starts to cool down after reaching the preset temperature, and records the change of the temperature sensitive parameters of the MOSFET every time the fixed temperature value drops until the ambient temperature T A From the preset temperature to the normal temperature of 25°C, the MOSFET temperature sensitive parameters and the MOSFET junction temperature T J relationship curve.

4. The method for calculating the safe operating area of ​​MOSFET according to claim 1, characterized in that: The transient thermal impedance Z of MOSFET under different duty ratios and different pulse widths is obtained. thJC ,include: Based on the JEDEC standard, the ambient temperature of the MOSFET is maintained at 25°C by the thermal resistance test system, and the heating current I H With the measured current I M The system works by switching an electronic switch, and each heating is preset for a fixed time, using the measurement current I M Measure the temperature sensitive parameters of MOSFET once, and compare the temperature sensitive parameters of MOSFET with the junction temperature T J The MOSFET junction temperature is obtained by the relationship curve, and heating is continued after the measurement is completed. The heating is preset for a fixed time and the measurement current I is applied again. M The temperature sensitive parameter is measured; the work is repeated in this way. During the whole test process, the thermal resistance test system compares the MOSFET junction temperature measured each time with the previously measured junction temperature. When the thermal resistance test system detects that 8 consecutive junction temperatures are within the range of ±5% of the average junction temperature, and the junction temperature range of the MOSFET at the final thermal equilibrium is 100±10°C, it is judged that all the test conditions for thermal equilibrium are met, and the steady-state thermal resistance R is calculated. thJC , the formula is as follows: P H =U H *AND H Among them, T J Indicates the MOSFET junction temperature, T C Indicates the MOSFET case temperature, P H It represents the heating power when MOSFET reaches thermal equilibrium, I H Indicates the heating current when MOSFET reaches thermal equilibrium; U H Indicates the voltage value when the MOSFET reaches thermal equilibrium; If the junction temperature does not reach the junction temperature range of the MOSFET's final thermal equilibrium, the heating current I H When the MOSFET reaches thermal equilibrium, the heating current I is cut off by the thermal resistance test system. H , the MOSFET automatically cools down; the heating current I H Switch to the measurement current I M , continuously measure the transient voltage value of the temperature sensitive parameter of the MOSFET during the cooling process, and obtain the transient response curve of the temperature sensitive parameter during the cooling process of the MOSFET; obtain the transient temperature response curve of the MOSFET through the relationship curve between the MOSFET temperature sensitive parameter and the MOSFET junction temperature T, and compare the transient temperature response curve with the heating power P H Perform normalized calculations to obtain single pulse transient thermal impedance and single pulse transient thermal impedance curves; repeat the above tests and calculations by changing the power pulse width and duty cycle to obtain the transient thermal impedance Z of MOSFET under different duty cycles and pulse widths. thJC .

5. The method for calculating the safe operating area of ​​MOSFET according to claim 1, characterized in that: The calculation of the maximum allowable power loss P of MOSFET under different pulse widths of a single pulse D ,include: Through the transient thermal impedance Z of MOSFET at different duty ratios and pulse widths thJC , combined with the maximum allowable junction temperature T JMAX , calculate the maximum allowable power loss P of the MOSFET under different pulse widths of a single pulse D , the formula is as follows: Among them, P D Indicates the maximum allowable power loss, T JMAX Indicates the maximum junction temperature, T C Indicates the shell temperature, Z thJC Represents transient thermal impedance.

6. The method for calculating the safe operating area of ​​MOSFET according to claim 1, characterized in that: Calculate the safe operating area SOA curve coordinates of the MOSFET, including: The horizontal axis of the MOSFET safe operating area SOA curve coordinate is set to the drain-source voltage V DS , the vertical axis is the leakage current I D , MOSFET maximum allowable continuous current value I DMAX The maximum allowable junction temperature on-resistance Maximum allowable junction temperature T JMAX , Steady-state thermal impedance R thJC Decision, I DMAX The calculation formula is as follows: According to I DMAX Calculate the maximum allowable pulse current value I of MOSFET DMMAX , the formula is as follows: I DMMAX =Int(n×I DMAX ) Among them, I DMMAX Indicates the maximum allowable pulse current value of MOSFET, the value range of n is 2-4; Calculate the current and voltage coordinates of a single pulse with different pulse widths. The formula is as follows: Among them, P D It represents the maximum allowable power loss of MOSFET under different pulse widths of a single pulse, I DMAX Indicates the maximum allowable continuous current value of MOSFET, I DMMAX Indicates the maximum allowable pulse current value of MOSFET, V DSMAX Indicates the maximum allowable voltage value of MOSFET, T JMAX Indicates the maximum allowable junction temperature, T C Indicates the shell temperature, R thJC represents the steady-state thermal impedance of the MOSFET, Z thJC represents the transient thermal impedance of MOSFET, Indicates the maximum allowable junction temperature on-resistance of MOSFET; V DS represents the drain-source voltage, I D Represents the drain current.

7. The method for calculating the safe operating area of ​​MOSFET according to claim 1, characterized in that: The SOA diagram is drawn according to the safe operating area curve coordinates of the MOSFET to form a complete MOSFET safe operating area, including automatically calculating, drawing, storing and outputting the safe operating area SOA diagram of the MOSFET based on Qt Widgets.

8. A safe operating area calculation device for MOSFET, characterized in that: The device comprises: The parameter acquisition module is configured to acquire the temperature sensitive parameters of the MOSFET and acquire the temperature sensitive parameters of the MOSFET and the junction temperature T of the MOSFET through the thermal resistance test system. J The relationship curve of The power loss module is configured to obtain the transient thermal impedance Z of the MOSFET at different duty cycles and pulse widths through a thermal resistance test system. thIC The transient thermal impedance Z of the MOSFET under different duty ratios and pulse widths is thJC , calculate the maximum allowable power loss P of the MOSFET under different pulse widths of a single pulse D ; The curve coordinate module is configured to obtain the rated parameters of the MOSFET according to the maximum allowable power loss P of the MOSFET under different pulse widths of a single pulse. D and the rated parameters of the MOSFET to calculate the safe operating area curve coordinates of the MOSFET; the rated parameters of the MOSFET include the maximum allowable junction temperature on-resistance Maximum allowable continuous current value I DMAX The maximum permissible pulse current value I DMMAX Ratio n, maximum allowable voltage value V DSMAX , Maximum allowable junction temperature T JMAX , Shell temperature T C , Steady-state thermal impedance R thJC ; The curve drawing module is configured to draw a SOA diagram according to the safe operating area curve coordinates of the MOSFET to form a complete MOSFET safe operating area.

9. A safe operating area calculation system for MOSFET, the system comprising a processor and a memory, wherein a computer program is stored in the memory, characterized in that: The computer program is loaded and executed by the processor to implement the safe operating area calculation method of MOSFET according to any one of claims 1 to 7.

10. A computer-readable storage medium, wherein a computer program is stored in the storage medium, characterized in that: When the computer program is executed by a processor, it is used to implement the safe operating area calculation method of MOSFET according to any one of claims 1 to 7.

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