An automated testing system and method for MOSFET SOA curves

Abstract

This invention proposes an automated testing system and method for MOSFET SOA curves. The system includes: a host computer, a signal generator, a DC power supply, and an SOA test board. The SOA test board is connected to the host computer, the signal generator, and the DC power supply, respectively. The signal generator is connected to the host computer. The host computer is used to control the operation of the testing system and collect test data. The signal generator is used to control the on-time (Ton) and drain current (Id) of the driving MOSFET on the SOA test board. The DC power supply is used to power the testing system. The SOA test board is used to connect the MOSFET under test and test its SOA curve. This invention achieves automated testing of MOSFET SOA curves, eliminating tedious manual testing operations, simplifying the testing method, shortening the testing time, and improving testing efficiency.

Description

Technical Field

[0001] This invention relates to the field of MOSFET testing technology, and more specifically to an automated testing system and method for MOSFET SOA curves. Background Technology

[0002] MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) are widely used in circuit design in products such as servers, desktops, and laptops. For example, MOSFETs are involved in DC-DC (Direct-to-Direct-Voltage Conversion) circuit design and Hot Swap (Hot-Swap) circuit design.

[0003] MOSFETs have a parameter called SOA (Safe Operating Area), which is defined as the ability of a MOSFET to withstand a single pulse of current. This parameter is often represented by a two-dimensional graph of the drain-source voltage (Vds) and drain current (Id) of the MOSFET over a single pulse duration. The voltage and current during normal operation of a MOSFET should not exceed this limit; otherwise, there is a risk of burning out the MOSFET. Especially in high-current applications, circuit design should strictly adhere to the SOA curve.

[0004] Currently, MOSFET manufacturers provide SOA (Solution-of-Age) curves in their datasheets to guide engineers in circuit design. The MOSFET SOA curve consists of the drain current Id and drain-to-source voltage Vds of the MOSFET during a specific on-time. When selecting a MOSFET, especially for high-current applications, directly referencing the SOA curves in the manufacturer's datasheets, which haven't been tested and verified, carries a certain risk. Furthermore, MOSFET SOA curves require numerous test points, necessitating testing Id at different on-times and for different Vds. This testing is labor-intensive and tedious, and manual testing is prone to errors or omissions. Additionally, existing SOA testing equipment is quite expensive, making SOA testing impractical for many engineers. Summary of the Invention

[0005] To address the above problems, the present invention aims to provide an automated testing system and method for MOSFET SOA curves, which realizes automated testing of MOSFET SOA curves, eliminates tedious manual testing operations, simplifies the testing method, shortens the testing time, and improves testing efficiency.

[0006] To achieve the above objectives, this invention provides the following technical solution: an automated MOSFET SOA curve testing system, comprising: a host computer, a signal generator, a DC power supply, and an SOA test board; the SOA test board is connected to the host computer, the signal generator, and the DC power supply, respectively, and the signal generator is connected to the host computer; the host computer is used to control the operation of the test system and collect test data; the signal generator is used to control the on-time Ton and drain current Id of the driving MOSFET on the SOA test board; the DC power supply is used to power the test system; the SOA test board is used to connect the MOSFET under test and test the SOA curve of the MOSFET under test.

[0007] Furthermore, the SOA test board includes a VDD power supply, a MOSFET under test, a driving MOSFET, a first control module, a second control module, a monitoring chip, and a detection resistor. The VDD power supply is connected to ground after being connected in series with the MOSFET under test, the driving MOSFET, and the detection resistor. The first control module is connected to the host computer and the MOSFET under test, the second control module is connected to the signal generator and the driving MOSFET, and the monitoring chip is connected in parallel with the detection resistor and connected to the host computer.

[0008] Furthermore, the DC power supply supplies power to the VDD power supply through the power line; the signal generator is connected to the second control module through a coaxial cable, and the second control module controls the on-time Ton and drain current Id of the driving MOSFET, thereby controlling the on-time Ton and drain current Id of the MOSFET under test.

[0009] Furthermore, the host computer is connected to the signal generator via a GPIB cable to control the start or stop of the signal generator's operation, and to control the pulse width and amplitude of the signal generator's output signal; the host computer is connected to the I2C header of the monitoring chip via a USB-to-I2C cable to monitor and read the voltage and current values ​​of the detection resistor; the host computer is connected to the first control module via a USB-to-UART cable to control the Vds voltage of the MOSFET under test.

[0010] Furthermore, the first control module includes a CPLD, a switching channel control circuit, and a programmable Zener diode. The host computer is connected to the CPLD via a USB-to-UART cable. The CPLD is connected to the programmable Zener diode via the switching channel control circuit. The programmable Zener diode is connected to the MOSFET under test. The CPLD selects the resistor connected to the programmable Zener diode via the switching channel control circuit to control the voltage change of the programmable Zener diode, thereby controlling the Vds voltage of the MOSFET under test.

[0011] Furthermore, the second control module employs an operational amplifier; the operational amplifier is used to receive square waves with different pulse widths and voltage amplitudes emitted by the signal generator, amplify them, and send them to the driving MOSFET. The on-time Ton of the driving MOSFET is controlled by square waves with different pulse widths, and the Vgs voltage of the driving MOSFET is controlled by square waves with different voltage amplitudes, thereby controlling the drain current Id of the driving MOSFET.

[0012] Furthermore, the monitoring chip is used to collect the voltage and current of the detection resistor and store the collected data in the built-in register; the host computer is used to read the current register of the monitoring chip through the I2C interface, determine the drain current Id of the MOSFET under test, generate the measured SOA curve based on the read current value, and compare it with the corresponding current data given in the manufacturer's datasheet to determine the accuracy of the SOA curve in the datasheet.

[0013] Accordingly, this invention also discloses an automated testing method for MOSFET SOA curves, comprising the following steps:

[0014] S1: Connect the DC power supply, host computer, signal generator, and SOA test board, and start the DC power supply to output voltage;

[0015] S2: The host computer sends a command to control the Vds voltage, conduction time Ton, and drain current Id of the MOSFET under test; S3: The host computer controls the signal generator to output a square wave pulse to the driving MOSFET to start the test;

[0016] S4: The host computer reads the drain current Id collected by the monitoring chip, executes the preset test procedure, records the drain current Id of the test PASS, and plots the curves of Ton, Vds and Id.

[0017] S5: When the conduction time Ton is constant, use the preset test procedure to test the Id current corresponding to different Vds, and plot the curves of Ton, Vds and Id;

[0018] S6: Change the on-time Ton, use the preset test procedure to test the Id current corresponding to different Vds, and plot the curves of Ton, Vds and Id;

[0019] S7: The host computer records all test data and completes the plotting of the SOA curve of the MOSFET under test.

[0020] Furthermore, step S2 includes:

[0021] The host computer controls the signal generator and sets the square wave pulse width, which is the on-time Ton of the MOSFET under test;

[0022] The host computer controls the CPLD to select the resistor connected to the programmable Zener diode and determine the voltage of the programmable Zener diode, which is the Vds voltage of the MOSFET under test.

[0023] The host computer controls the signal generator and sets the square wave pulse voltage amplitude, which is the drain current Id of the MOSFET under test.

[0024] Furthermore, the pre-defined test process includes:

[0025] During the conduction of the MOSFET under test, if the drain current Id collected by the monitoring chip does not show a sudden increase, the test is considered PASS. At this time, keep the Vds voltage and conduction time Ton unchanged, increase the drain current Id by 10% based on the previously tested value, and repeat step S3. If the test is PASS after increasing the drain current Id, the host computer records the current drain current Id value to plot the measured SOA curve of the MOSFET under test. If a sudden increase in current occurs after increasing the drain current Id, the MOSFET under test is damaged and the test is considered FAIL. The preset LED is lit by the CPLD to notify the tester to replace the MOSFET under test, and the host computer plots the measured SOA curve of the MOSFET under test using the drain current Id value of the previous PASS test.

[0026] If the recorded current value shows a sudden increase during the conduction of the MOSFET under test, it indicates that the MOSFET under test is damaged and is considered a test failure. At this time, keep the Vds voltage and conduction time Ton of the MOSFET under test unchanged, reduce the drain current Id by 10% based on the previously tested drain current Id, and repeat the operation of step S3 until the test can pass. Find the drain current Id value that the MOSFET under test can withstand under the current Vds voltage and conduction time Ton, and record this drain current Id value for plotting the measured SOA curve of the MOSFET under test.

[0027] Compared with the prior art, the advantages of this invention are as follows:

[0028] 1. This invention can verify MOSFET SOA from different manufacturers and models, providing a basis for MOSFET selection and circuit design, effectively ensuring the reliability of circuit design, improving product quality, and building a good reputation for the company.

[0029] 2. This invention realizes an automated testing process for MOSFET SOA, which can avoid omissions and errors caused by manual testing, save testing time and manpower, and improve testing efficiency.

[0030] 3. This invention saves on the purchase cost and time cost of professional SOA testing equipment.

[0031] Therefore, it is evident that the present invention has outstanding substantive features and significant progress compared with the prior art, and the beneficial effects of its implementation are also obvious. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0033] Figure 1 This is a system structure diagram of Embodiment 1 of the present invention.

[0034] Figure 2 This is a flowchart of the method in Embodiment 2 of the present invention.

[0035] Figure 3 This is a flowchart of the method in Embodiment 3 of the present invention. Detailed Implementation

[0036] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1:

[0038] like Figure 1 As shown, this embodiment provides an automated MOSFET SOA curve testing system, including: a host computer, a signal generator, a DC power supply, and an SOA test board; the SOA test board is connected to the host computer, the signal generator, and the DC power supply, and the signal generator is connected to the host computer. The host computer is used to control the operation of the test system and collect test data; the signal generator is used to control the on-time Ton and drain current Id of the driving MOSFET on the SOA test board; the DC power supply is used to power the test system; the SOA test board is used to connect the MOSFET under test and test the SOA curve of the MOSFET under test.

[0039] The SOA test board includes a VDD power supply, a MOSFET under test (DUT), a driving MOSFET, a first control module, a second control module, a monitoring chip, and a sensing resistor Rsense. The VDD power supply is connected to ground in series with the DUT, driving MOSFET, and sensing resistor. The first control module is connected to both the host computer and the DUT, while the second control module is connected to both the signal generator and the driving MOSFET. The monitoring chip is connected in parallel with the sensing resistor Rsense and is also connected to the host computer. A DC power supply powers the VDD power supply via a power line. The signal generator is connected to the second control module via a coaxial cable. The second control module controls the on-time (Ton) and drain current (Id) of the driving MOSFET, thereby controlling the on-time (Ton) and drain current (Id) of the DUT.

[0040] Specifically, the host computer is connected to the signal generator via a GPIB cable to control the start or stop of the signal generator's operation, and to control the pulse width and amplitude of the output signal of the signal generator; the host computer is connected to the I2C header of the monitoring chip via a USB to I2C cable to monitor and read the voltage and current values ​​of the sensing resistor Rsense; the host computer is connected to the first control module via a USB to UART cable to control the Vds voltage of the MOSFET under test.

[0041] The first control module includes a CPLD, a switching channel control circuit, and a programmable Zener diode. The host computer is connected to the CPLD via a USB-to-UART cable. The CPLD is connected to the programmable Zener diode via the switching channel control circuit. The programmable Zener diode is connected to the MOSFET under test. The CPLD selects the resistor connected to the programmable Zener diode via the switching channel control circuit to control the voltage change of the programmable Zener diode, thereby controlling the Vds voltage of the MOSFET under test.

[0042] The second control module uses an operational amplifier. The operational amplifier is used to receive square waves with different pulse widths and voltage amplitudes emitted by the signal generator. After amplification, the square waves are sent to the driving MOSFET. The conduction time Ton of the driving MOSFET is controlled by square waves with different pulse widths, and the Vgs voltage of the driving MOSFET is controlled by square waves with different voltage amplitudes, thereby controlling the drain current Id of the driving MOSFET.

[0043] As an example, the specific content and principles of this system are as follows:

[0044] 1) First control module: It consists of a CPLD and a programmable Zener diode. The CPLD GPIO selects the resistor connected to the programmable Zener diode through the channel of the control switch, realizes the voltage change of the Zener diode, and thus controls the Vds voltage of the MOSFET under test.

[0045] 2) Second Control Module: The signal generator emits square waves with different pulse widths and voltage amplitudes, which are then amplified by operational amplifiers and fed to the driving MOSFET. Square waves with different pulse widths control the on-time (Ton) of the driving MOSFET, while square waves with different voltage amplitudes control the Vgs of the driving MOSFET, and consequently, the Id of the driving MOSFET (Id is positively correlated with Vgs). Because the driving MOSFET and the MOSFET under test are connected in series, the signal generator can adjust the on-time (Ton) and drain current (Id) of the MOSFET under test by emitting square waves with different pulse widths and voltage amplitudes. If the square wave pulse voltage amplitude of the signal generator is too high, resulting in an excessively large Id, the MOSFET under test will not be able to withstand the voltage and will burn out.

[0046] 3) Monitoring Chip: Used to acquire the Rsense voltage and Id current during actual testing. The host computer reads the current register of the monitoring chip via the I2C interface, which allows it to determine the magnitude of the actual drain current Id through the MOSFET under test under certain Ton and Vds conditions. The host computer reads and records this current value, generates the measured SOA curve, and compares it with the corresponding current data given in the manufacturer's datasheet to determine the accuracy of the SOA curve in the datasheet.

[0047] Example 2:

[0048] Based on Example 1, such as Figure 2 As shown, this invention also discloses an automated testing method for MOSFET SOA curves, comprising the following steps:

[0049] S1: Connect the DC power supply, host computer, signal generator, and SOA test board, and start the DC power supply to output voltage.

[0050] S2: The host computer sends commands to control the Vds voltage, conduction time Ton, and drain current Id of the MOSFET under test.

[0051] Specifically, the host computer controls the signal generator to set the square wave pulse width, which is the conduction time Ton of the MOSFET under test; the host computer controls the CPLD to select the resistor connected to the programmable Zener diode and determine the voltage of the programmable Zener diode, which is the Vds voltage of the MOSFET under test; the host computer controls the signal generator to set the square wave pulse voltage amplitude, which is the drain current Id of the MOSFET under test.

[0052] S3: The host computer control signal generator outputs a square wave pulse to the drive MOSFET to start the test.

[0053] S4: The host computer reads the drain current Id collected by the monitoring chip, executes the preset test procedure, records the drain current Id of the test pass, and plots the curves of Ton, Vds and Id.

[0054] S5: When the conduction time Ton is constant, use the preset test procedure to test the Id current corresponding to different Vds, and plot the curves of Ton, Vds and Id.

[0055] S6: Change the on-time Ton, use the preset test procedure to test the Id current corresponding to different Vds, and plot the curves of Ton, Vds and Id.

[0056] In the above steps, the preset test process includes:

[0057] During the conduction of the MOSFET under test, if the drain current Id collected by the monitoring chip does not show a sudden increase, the test is considered PASS. At this time, keeping the Vds voltage and conduction time Ton unchanged, the drain current Id is increased by 10% based on the previously tested drain current Id, and the operation of step S3 is repeated. If the test is PASS after increasing the drain current Id, the host computer records the current drain current Id value to plot the measured SOA curve of the MOSFET under test. If a sudden increase in current occurs after increasing the drain current Id, the MOSFET under test is damaged and the test is considered FAIL. The preset LED is lit by the CPLD to notify the tester to replace the MOSFET under test, and the host computer plots the measured SOA curve of the MOSFET under test using the drain current Id value of the previous PASS test.

[0058] If the recorded current value shows a sudden increase during the conduction of the MOSFET under test, it indicates that the MOSFET under test is damaged and is considered a test failure. At this time, keep the Vds voltage and conduction time Ton of the MOSFET under test unchanged, reduce the drain current Id by 10% based on the previously tested drain current Id, and repeat the operation of step S3 until the test can pass. Find the drain current Id value that the MOSFET under test can withstand under the current Vds voltage and conduction time Ton, and record this drain current Id value for plotting the measured SOA curve of the MOSFET under test.

[0059] S7: The host computer records all test data and completes the plotting of the SOA curve of the MOSFET under test.

[0060] Example 3:

[0061] Based on the above embodiments, such as Figure 3 As shown, this invention also discloses an automated testing method for MOSFET SOA curves, comprising the following steps:

[0062] 1. According to Figure 1 The diagram shows how to correctly connect the DC power supply, host computer, signal generator, and SOA test board.

[0063] The specific connection method is as follows:

[0064] (1) The DC power supply is connected to the SOA test board through the power cord to provide power to the system.

[0065] (2) The host computer and the monitoring chip are connected via a USB-to-I2C cable to monitor and record the current.

[0066] (3) The host computer is connected to the signal generator via a GPIB cable to control the operation of the signal generator.

[0067] (4) The host computer and the CPLD are connected via a serial cable to enable the CPLD to send and receive commands.

[0068] 2. The host computer should pre-store the SOA curve data from the MOSFET datasheet to be tested, so as to compare the test data.

[0069] 3. Turn on the DC power supply and output voltage to power the entire test system.

[0070] 4. The host computer's USB0 interface is connected to the signal generator via a GPIB cable.

[0071] At this point, the on-time (Ton) of the MOSFET under test is set. The host computer, based on the SOA curve data from the MOSFET's datasheet, controls the signal generator to set the square wave pulse width, which is the MOSFET's on-time (Ton). Testing typically starts with the shortest on-time, such as 10µs.

[0072] 5. The host computer's USB2 interface is connected to the CPLD UART interface of the SOA test board via a USB-to-UART cable. Based on the SOA curve data from the MOSFET's datasheet, the host computer starts testing from the minimum Vds voltage, for example, 0.01V, and instructs the CPLD control switch to select the resistor connected to the Zener diode to determine its voltage.

[0073] The Vds voltage can be set in the following four steps:

[0074] A: 0.01V <Vds<0.1V,Vds step=0.01V;

[0075] B: 0.1V <Vds<1V,Vds step=0.1V;

[0076] C:1V <Vds<10V,Vds step=1V;

[0077] D: 10V <Vds<100V,Vds step=10V。

[0078] 6. The host computer's USB0 interface is connected to the signal generator via a GPIB cable.

[0079] At this point, the drain current Id is set. Specifically, the square wave pulse voltage amplitude of the signal generator is amplified by an operational amplifier and drives the MOSFET gate. The host computer, based on the SOA curve data from the MOSFET's datasheet, finds the Id corresponding to the set Vds and Ton; based on the Vgs vs. Id curve data from the datasheet, it finds the corresponding Vgs voltage, which is the output voltage after amplification by the operational amplifier. This allows the calculation of the required square wave pulse voltage amplitude from the signal generator. The host computer can then control the voltage amplitude of the signal generator's square wave pulse, thereby controlling Id.

[0080] After setting Ton, Vds, and Id, the host computer instructs the signal generator to output a square wave pulse to start the test.

[0081] 8. The host computer's USB1 interface is connected to the monitoring chip's I2C interface via a USB-to-I2C cable. During the test, USB1 accesses the monitoring chip every 1µs to read and record the value of the current register.

[0082] (1) During the MOSFET's conduction period, if the recorded current values ​​are stable, for example, within 10µs, the current in the monitoring chip's current register remains at 10A without any sudden increase in current, such as 50A or 100A, it indicates that the MOSFET under test is intact and undamaged. We define this as a test pass. Keep Vds and Ton unchanged, increase Id by 10% based on the previous test values, and repeat step 7.

[0083] A. If the MOSFET is not damaged after increasing Id during the test, the host computer records the Id value and uses it to plot the measured SOA curve of the MOSFET under test.

[0084] B. If the MOSFET is damaged after increasing the Id value during the test, we define this as a test failure. The CPLD illuminates the LED to notify the tester to replace the MOSFET under test. The host computer uses the Id value from the previous successful test (the current value before increasing the test Id) to plot the measured SOA curve of the MOSFET under test.

[0085] (2) If the recorded current value shows a sudden increase during MOSFET conduction, it indicates that the MOSFET under test is damaged. We define this as test failure. Keep Vds and Ton constant, reduce Id by 10%, 20%, 30%... based on the previously tested value, and repeat step 7 until the test passes. Find the Id current value that the MOSFET under test can withstand under the given Vds and Ton conditions, and record it. Plot the measured SOA curve of the MOSFET under test.

[0086] 9. After performing steps 4-8, the Id current test was completed at Ton = 10µs and Vds = 0.01V. Next, repeat steps 5-8, keeping Ton constant and increasing Vds stepwise, testing the corresponding Id current. Once the corresponding Id current has been measured at all Vds test points, the SOA curve of the MOSFET under test at Ton = 10µs is complete.

[0087] 10. After completing the above operations, repeat steps 4-8 to test the SOA curve data when Ton = 100us, 500us, 1ms... Finally, draw a complete curve and compare it with the SOA curve in the datasheet of the MOSFET under test.

[0088] 11. After all tests are completed, the host computer stops sending commands, completes the plotting of the test data curves, shuts off the DC power output, and the test ends.

[0089] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only 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.

[0090] The automated MOSFET SOA curve testing system and method provided by this invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make several improvements and modifications to this invention without departing from the principles of this invention, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. An automated testing system for MOSFET SOA curves, characterized in that, include: The system consists of a host computer, a signal generator, a DC power supply, and an SOA test board. The SOA test board is connected to the host computer, the signal generator, and the DC power supply, respectively. The signal generator is connected to the host computer. The host computer is used to control the operation of the testing system and collect test data; A signal generator is used to control the on-time Ton and drain current Id of the driving MOSFET on the SOA test board. A DC power supply is used to power the test system; SOA test board: used to connect the MOSFET under test and test the SOA curve of the MOSFET under test; The SOA test board includes a VDD power supply, a MOSFET under test, a driving MOSFET, a first control module, a second control module, a monitoring chip, and a detection resistor. The VDD power supply is connected in series with the MOSFET under test, the driving MOSFET and the detection resistor, and then grounded. The first control module is connected to the host computer and the MOSFET under test respectively. The second control module is connected to the signal generator and the driving MOSFET respectively. The monitoring chip is connected in parallel with the detection resistor and is connected to the host computer. The DC power supply supplies power to the VDD power supply through a power line; the signal generator is connected to the second control module through a coaxial cable, and the second control module controls the on-time Ton and drain current Id of the driving MOSFET, thereby controlling the on-time Ton and drain current Id of the MOSFET under test. The host computer is connected to the signal generator via a GPIB cable to control the start or stop of the signal generator and to control the pulse width and amplitude of the output signal of the signal generator. The host computer is connected to the I2C header of the monitoring chip via a USB to I2C cable to monitor and read the voltage and current values ​​of the sensing resistor. The host computer is connected to the first control module via a USB-to-UART cable to control the Vds voltage of the MOSFET under test.

2. The MOSFET SOA curve automated testing system according to claim 1, characterized in that: The first control module includes a CPLD, a switching channel control circuit, and a programmable Zener diode. The host computer is connected to the CPLD via a USB-to-UART cable. The CPLD is connected to the programmable Zener diode via the switching channel control circuit. The programmable Zener diode is connected to the MOSFET under test. The CPLD selects the resistor connected to the programmable Zener diode via the switching channel control circuit to control the voltage change of the programmable Zener diode, thereby controlling the Vds voltage of the MOSFET under test.

3. The MOSFET SOA curve automated testing system according to claim 1, characterized in that: The second control module uses an operational amplifier; the operational amplifier is used to receive square waves with different pulse widths and voltage amplitudes emitted by the signal generator, amplify them and send them to the driving MOSFET. The on-time Ton of the driving MOSFET is controlled by square waves with different pulse widths, and the Vgs voltage of the driving MOSFET is controlled by square waves with different voltage amplitudes, thereby controlling the drain current Id of the driving MOSFET.

4. The MOSFET SOA curve automated testing system according to claim 1, characterized in that: The monitoring chip is used to collect the voltage and current of the detection resistor and store the collected data in a built-in register; The host computer is used to read the current register of the monitoring chip through the I2C interface, determine the drain current Id of the MOSFET under test, generate the measured SOA curve based on the read current value, and compare it with the corresponding current data given in the manufacturer's datasheet to determine the accuracy of the SOA curve in the datasheet.

5. An automated testing method for MOSFET SOA curves using an automated testing system for MOSFET SOA curves according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1: Connect the DC power supply, host computer, signal generator, and SOA test board, and start the DC power supply to output voltage; S2: The host computer sends commands to control the Vds voltage, conduction time Ton, and drain current Id of the MOSFET under test; S3: The host computer control signal generator outputs a square wave pulse to the drive MOSFET to start the test; S4: The host computer reads the drain current Id collected by the monitoring chip, executes the preset test procedure, records the drain current Id of the test PASS, and plots the curves of Ton, Vds and Id. S5: When the conduction time Ton is constant, use the preset test procedure to test the Id current corresponding to different Vds, and plot the curves of Ton, Vds and Id; S6: Change the on-time Ton, use the preset test procedure to test the Id current corresponding to different Vds, and plot the curves of Ton, Vds and Id; S7: The host computer records all test data and completes the plotting of the SOA curve of the MOSFET under test.

6. The automated testing method for MOSFET SOA curves according to claim 5, characterized in that, Step S2 includes: The host computer controls the signal generator and sets the square wave pulse width, which is the on-time Ton of the MOSFET under test; The host computer controls the CPLD to select the resistor connected to the programmable Zener diode and determine the voltage of the programmable Zener diode, which is the Vds voltage of the MOSFET under test. The host computer controls the signal generator and sets the square wave pulse voltage amplitude, which is the drain current Id of the MOSFET under test.

7. The automated testing method for MOSFET SOA curves according to claim 5, characterized in that, The preset test process includes: During the conduction of the MOSFET under test, if the drain current Id collected by the monitoring chip does not show a sudden increase, the test is considered PASS. At this time, keep the Vds voltage and conduction time Ton unchanged, increase the drain current Id by 10% based on the previously tested value, and repeat step S3. If the test is PASS after increasing the drain current Id, the host computer records the current drain current Id value to plot the measured SOA curve of the MOSFET under test. If a sudden increase in current occurs after increasing the drain current Id, the MOSFET under test is damaged and the test is considered FAIL. The preset LED is lit by the CPLD to notify the tester to replace the MOSFET under test, and the host computer plots the measured SOA curve of the MOSFET under test using the drain current Id value of the previous PASS test. If the recorded current value shows a sudden increase during the conduction of the MOSFET under test, it indicates that the MOSFET under test is damaged and is considered a test failure. At this time, keep the Vds voltage and conduction time Ton of the MOSFET under test unchanged, reduce the drain current Id by 10% based on the previously tested drain current Id, and repeat the operation of step S3 until the test can be passed. Find the drain current Id value that the MOSFET under test can withstand under the current Vds voltage and conduction time Ton, and record this drain current Id value for plotting the measured SOA curve of the MOSFET under test.

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