HTRB reliability test method of power device

Abstract

The invention relates to the technical field of power semiconductor testing, in particular to an HTRB reliability testing method for a power device, which comprises the following steps of: selecting a device to be tested, building a main testing circuit, and ensuring that the device can keep a stable working state in a testing process; at a preset temperature, the voltage of the leakage current detection resistor is acquired by switching different sampling protection circuits; the open-loop sampling protection circuit and the closed-loop sampling protection circuit cooperatively work, the open-loop sampling holding circuit is used for rapidly capturing signal changes, the closed-loop sampling protection circuit is used for ensuring high-precision acquisition of key data, and it is ensured that the two circuits can cooperatively work and exert respective advantages; control logic is set in a computer program, so that the two circuits are dynamically switched or used in parallel when needed, it is ensured that the control logic can correctly process output of the two circuits, and data fusion or selection is carried out when necessary.

Description

Technical Field

[0001] The invention relates to the technical field of power semiconductor testing, and in particular to a HTRB reliability testing method for a power device. Background Art

[0002] HTRB testing is an important means to evaluate the reliability of power devices under high temperature reverse bias conditions. HTRB testing is applicable to a variety of power devices, such as diodes, triodes, MOSFET tubes, IGBTs, etc. After the device is developed, the process is finalized and packaged, the power device is heated up, and then the voltage across the device is adjusted through the circuit. When the temperature and voltage reach the set conditions, the device is placed in a long-term steady-state mode and then tested.

[0003] A Chinese patent with publication number CN115524595A discloses an HTRB reliability test device and method for a power device, including a main test circuit, an IGBT control circuit and a sampling protection circuit. The main test circuit includes a power device under test, a leakage current detection resistor, a first voltmeter connected to the leakage current detection resistor, an IGBT control switch and a voltage source. One end of the sampling protection circuit is connected to the first voltmeter, the other end of the sampling protection circuit is connected to one end of the IGBT control circuit, and the other end of the IGBT control circuit is connected to the IGBT control switch; the voltage of the leakage current detection resistor connected to the power device under test is collected by the sampling protection circuit. The sampling protection circuit can collect the voltage of the leakage current detection resistor, and transmit it to the IGBT control circuit after amplification to realize the circuit rapid protection function.

[0004] In the current existing technology, the sampling protection circuit uses an amplifier to amplify and transmit the signal to the IGBT control circuit. Although the amplifier can protect the circuit, the output impedance of some amplifiers is low and may not be able to effectively solve the problem of low output impedance, resulting in signal distortion or reduced signal gain. In addition, when multiple resistors are used, the smaller the resistance, the higher the power consumption, and the larger the output current of the amplifier, which may have an adverse effect on the performance and life of the amplifier and fail to protect the safety of the test circuit.

[0005] To this end, the present invention provides a HTRB reliability testing method for a power device. Summary of the invention

[0006] To this end, the technical problem to be solved by the present invention is to overcome the low output impedance of some amplifiers in the prior art, which may not be able to effectively solve the problem of low output impedance, resulting in signal distortion or reduced signal gain. In addition, when multiple resistors are used, the smaller the resistance, the higher the power consumption, and the greater the output current of the amplifier, which may have an adverse effect on the performance and life of the amplifier and fail to protect the safety of the test circuit.

[0007] In order to solve the above technical problems, the present invention provides a HTRB reliability test method for a power device, comprising the following steps:

[0008] A1: Select the device to be tested and build the main test circuit to ensure that the device can maintain a stable working state during the test;

[0009] A2: Under the preset temperature, the voltage of the leakage current detection resistor is collected by switching different sampling protection circuits;

[0010] A3: Based on the voltage of the leakage current detection resistor, the device parameters are continuously monitored in a high temperature reverse bias environment, and the voltage of the power device under test and the voltage of the leakage current detection resistor are measured through the MOSFET control circuit;

[0011] A4: Evaluate the performance of the power device and determine its reliability based on the tested voltage.

[0012] In one embodiment of the present invention, the sampling protection circuit in A2 includes an open-loop sampling protection circuit and a closed-loop sampling protection circuit; the open-loop sampling protection circuit and the closed-loop sampling protection circuit work in coordination.

[0013] In one embodiment of the present invention, the open-loop sampling protection circuit includes an analog switch S1, a holding capacitor C1 and an operational amplifier O1. The analog switch S1 adopts MOSFET to control the sampling and holding of the signal; the holding capacitor C1 is used to charge to the level of the input voltage during the sampling period and maintain the voltage during the holding period; the operational amplifier O1 adopts a voltage follower to increase the input impedance of the circuit and reduce the output impedance; the open-loop sampling protection circuit also includes a control system for controlling the on-off state of the analog switch.

[0014] In one embodiment of the present invention, the closed-loop sampling protection circuit includes an analog switch S2, a holding capacitor C2 and an operational amplifier O2; in the sampling stage, the analog switch S2 is closed, and the input signal charges the holding capacitor C2 to the level of the input signal through S2, and the operational amplifier O2 works as a voltage follower to transfer the voltage on the capacitor C2 to the output terminal Vout; in the holding stage, the analog switch S2 is disconnected, and the charge on the holding capacitor C2 remains unchanged, thereby keeping the output signal Vout unchanged.

[0015] In one embodiment of the present invention, one end of the sampling protection circuit is connected to the main test circuit; the other end of the sampling protection circuit is connected to one end of the MOSFET control circuit; the main test circuit includes a power device under test, an ammeter, a leakage current detection resistor, a first voltmeter, a second voltmeter, a first capacitor, a second capacitor, a switch and a voltage source, and the leakage current detection resistor is connected to the power device under test to detect the leakage current passing through the power device under test under high temperature and reverse bias conditions.

[0016] In one embodiment of the present invention, one end of the switch is connected to a leakage current detection resistor, and the other end of the switch is connected to the positive electrode of a voltage source, so as to control the on-off of the current in the main test circuit; the first capacitor and the second capacitor are used for filtering, stabilizing the voltage and protecting the circuit; one end of the power device under test is connected to an ammeter, and the other end of the power device under test is connected to a ground wire; one end of the ammeter away from the power device under test is connected to the leakage current detection resistor; the first voltmeter is connected in parallel to the leakage current detection resistor, and the second voltmeter is connected in parallel to the power device under test; one end of the first capacitor and one end of the second capacitor are respectively connected to the other end of the leakage current detection resistor, and the other end of the first capacitor and the other end of the second capacitor are respectively connected to ground wires; the negative electrode of the voltage source is grounded.

[0017] In one embodiment of the present invention, the MOSFET control circuit includes an A / D analog-to-digital converter, a DSP digital processor, a D / A digital-to-analog converter, a level conversion circuit and a drive circuit, and the other end of the MOSFET control circuit is connected to one end of the switch; the output end of the A / D analog-to-digital converter is connected to the DSP digital processor, the output end of the DSP digital processor is connected to the input end of the D / A digital-to-analog converter, the output end of the D / A digital-to-analog converter is connected to the input end of the level conversion circuit, and the output end of the level conversion circuit is connected to the input end of the drive circuit.

[0018] In one embodiment of the present invention, the A / D analog-to-digital converter is used to receive the voltage signal collected by the sampling protection circuit and convert the voltage signal into a digital signal; the DSP digital processor is used to receive the digital signal output by the A / D analog-to-digital converter and output a PWM signal for controlling the switch according to the control requirements; the D / A digital-to-analog converter is used to convert the PWM signal output by the DSP digital processor into an analog signal; the level conversion circuit is used to perform level conversion on the analog signal output by the D / A digital-to-analog converter; the drive circuit is used to generate a drive signal for controlling the switch according to the analog signal after the level conversion, and output the drive signal to the switch.

[0019] In one embodiment of the present invention, judging the reliability of the power device in A4 comprises the following steps:

[0020] B1: Leakage current analysis: by analyzing the change of leakage current, we can understand the stability and reliability of the device under high temperature and reverse bias conditions;

[0021] B2: Breakdown voltage analysis, by measuring the breakdown voltage of the device under high temperature and reverse bias, to understand the voltage resistance and stability;

[0022] B3: Temperature impact analysis, by simulating the temperature environment under actual working conditions and observing the performance changes of the device under different temperatures, to evaluate the sensitivity and adaptability to temperature;

[0023] B4: Life prediction: by statistics and comparison of test data, life curve fitting and prediction are performed to evaluate the service life of the device under a specific working environment.

[0024] In one embodiment of the present invention, the reliability is judged using the HV-H3TRB model, which introduces the voltage acceleration factor into the traditional Peck model to describe the effects of temperature and humidity on device reliability, so as to more accurately predict the life of the device under specific conditions.

[0025] In one embodiment of the present invention,

[0026] The above technical solution of the present invention has the following advantages compared with the prior art:

[0027] The HTRB reliability test method for a power device described in the present invention uses an open-loop sampling protection circuit and a closed-loop sampling protection circuit to work together, uses the open-loop sampling and holding circuit to quickly capture signal changes, and uses the closed-loop sampling protection circuit to ensure high-precision collection of key data, ensuring that the two circuits can work together and give full play to their respective advantages; by setting control logic in a computer program, the two circuits can be dynamically switched or used in parallel when necessary, which can be achieved through a microcontroller, FPGA or other programmable logic devices, ensuring that the control logic can correctly process the outputs of the two circuits and perform data fusion or selection when necessary.

[0028] The HTRB reliability test method of a power device disclosed in the present invention comprises the following steps: a main test circuit, a sampling protection circuit and a MOSFET control circuit cooperate to collect the voltage of a leakage current detection resistor connected to the power device under test through the sampling protection circuit at a preset temperature; a drive signal is generated through the MOSFET control circuit according to the voltage of the leakage current detection resistor; a switch is controlled to be turned on or off according to the drive signal, and the switching speed of the switch is controlled; a result of the influence of the voltage on the leakage of the power device under test is obtained according to the voltage of the power device under test and the voltage of the leakage current detection resistor when the switch is turned on or off; the power device under test in the main test circuit under high temperature is tested through the sampling protection circuit, and the collected voltage signal is transmitted to the MOSFET control circuit; a DSP digital processor is used in the MOSFET control circuit to output a PWM signal for controlling the main test circuit through a control algorithm; after digital-to-analog conversion and level conversion, the drive circuit generates a drive signal according to the PWM signal, and then controls the switch in the main test circuit to be turned on or off, thereby achieving PWM control of the power supply, and then simulating the reliability test of the HTRB of the power device under test under high temperature; and according to the test result, the performance of the power device is evaluated and the reliability of the power device is judged.

[0029] The HTRB reliability test method of a power device described in the present invention analyzes the change of leakage current to understand the stability and reliability of the device under high temperature and reverse bias conditions when judging the reliability of the power device. If the leakage current is stable at a low level, it means that the quality of the device is good; if the leakage current gradually increases, it means that the device has defects or performance degradation; by measuring the breakdown voltage of the device under high temperature and reverse bias, its withstand voltage capability and stability are understood; if the breakdown voltage is maintained at a high level, it means that the device has good withstand voltage performance; if the breakdown voltage decreases, it may indicate that the device has problems such as insulation layer damage or material aging; by simulating the temperature environment under actual working conditions and observing the performance changes of the device at different temperatures, its sensitivity and adaptability to temperature can be evaluated; if the device can still maintain stable performance under high temperature environment, it means that it has good thermal stability and reliability; otherwise, it is necessary to further improve the design or material selection to improve its reliability; by statistics and comparison of test data, the life curve can be fitted and predicted to evaluate the service life of the device under a specific working environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings.

[0031] Figure 1 It is a flow chart of the HTRB reliability test method of the power device in the present invention;

[0032] Figure 2 is a flow chart of a method for determining the reliability of a power device in the present invention;

[0033] Figure 3 It is a structural schematic diagram of the HTRB reliability main test circuit of the power device in the present invention;

[0034] Figure 4 It is a structural schematic diagram of the HTRB reliability sampling protection circuit of the power device in the present invention;

[0035] Figure 5 It is a structural schematic diagram of the HTRB reliability MOSFET control circuit of the power device in the present invention. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0037] See also Figure 1 - Figure 5 The present invention provides a HTRB reliability test method for a power device, comprising the following steps:

[0038] A1: Select the device to be tested and build the main test circuit to ensure that the device can maintain a stable working state during the test;

[0039] A2: Under the preset temperature, the voltage of the leakage current detection resistor is collected by switching different sampling protection circuits;

[0040] A3: Based on the voltage of the leakage current detection resistor, the device parameters are continuously monitored in a high temperature reverse bias environment, and the voltage of the power device under test and the voltage of the leakage current detection resistor are measured through the MOSFET control circuit;

[0041] A4: Evaluate the performance of the power device and determine its reliability based on the tested voltage.

[0042] When the test method provided by the present invention is used, a device to be tested is selected, a main test circuit is built, and it is ensured that the device can maintain a stable working state during the test process; then, at a preset temperature, the voltage of the leakage current detection resistor connected to the power device to be tested is collected through a sampling protection circuit; according to the voltage of the leakage current detection resistor, a drive signal is generated through a MOSFET control circuit; according to the drive signal, the switch is controlled to be turned on or off, and the switching speed of the switch is controlled; according to the voltage of the power device to be tested and the voltage of the leakage current detection resistor when the switch is turned on or off, a test result of the voltage on the leakage of the power device to be tested is obtained; the power device to be tested in the main test circuit under high temperature is tested through the sampling protection circuit, and the collected voltage signal is transmitted to the MOSFET control circuit, and a DSP digital processor is used in the MOSFET control circuit to output a PWM signal for controlling the main test circuit through a control algorithm, and after digital-to-analog conversion and level conversion, the drive circuit generates a drive signal according to the PWM signal, and then controls the switch in the main test circuit to be turned on or off, thereby achieving PWM control of the power supply, and then simulating the reliability test of the HTRB of the power device to be tested under high temperature, and according to the test result, the performance of the power device is evaluated and the reliability of the power device is judged.

[0043] Furthermore, if Figure 1 and Figure 4 As shown, the sampling protection circuit in A2 includes an open-loop sampling protection circuit and a closed-loop sampling protection circuit; the open-loop sampling protection circuit and the closed-loop sampling protection circuit work in coordination.

[0044] When the sampling protection circuit provided by the present invention is used, since the open-loop sampling and holding circuit has no feedback loop, its response speed is relatively fast and is suitable for application scenarios with high speed requirements. However, since it lacks a feedback mechanism to correct errors, the accuracy of the open-loop sampling and protection circuit is relatively low; the closed-loop sampling and holding circuit can provide higher sampling accuracy and stability by introducing a feedback loop, but the response speed may be slightly slower; therefore, the advantages of the open-loop and closed-loop sampling and protection circuits are simultaneously utilized to work in coordination, the open-loop sampling and holding circuit is used to quickly capture signal changes, and the closed-loop sampling and protection circuit is used to ensure high-precision acquisition of key data, ensuring that the two circuits can work in coordination and give play to their respective advantages; by setting control logic in a computer program, the two circuits can be dynamically switched or used in parallel when needed, which can be achieved through a microcontroller, FPGA or other programmable logic device, ensuring that the control logic can correctly process the outputs of the two circuits and perform data fusion or selection when necessary.

[0045] Embodiment 1:

[0046] The open-loop sampling protection circuit includes an analog switch S1, a holding capacitor C1 and an operational amplifier O1. The analog switch S1 adopts MOSFET to control the sampling and holding of the signal; the holding capacitor C1 is used to charge to the level of the input voltage during the sampling period and maintain the voltage during the holding period; the operational amplifier O1 adopts a voltage follower to increase the input impedance and reduce the output impedance of the circuit; the open-loop sampling protection circuit also includes a control system for controlling the on-off state of the analog switch.

[0047] When the open-loop sampling protection circuit provided by the present invention is in use, the analog switch S1 is one of the core components of the sampling protection circuit, which is used to control the sampling and holding of the signal. When the analog switch S1 is closed, the signal is sampled; when the analog switch S1 is disconnected, the circuit holds the output signal; the holding capacitor C1 is another key component, which is used to store the sampled signal charge and maintain the charge in the holding stage to keep the output signal stable; the operational amplifier O1, in the open-loop sampling protection circuit, the operational amplifier is used as a voltage follower or buffer to increase the input impedance of the circuit and reduce the output impedance, thereby improving the performance of the circuit; finally, the on-off state of the analog switch S1 and the entire sampling and holding process are controlled by the control system control logic; since the open-loop sampling protection circuit has no feedback loop, its acquisition time is relatively short, but the accuracy may not be as high as that of the closed-loop sampling and holding circuit.

[0048] Embodiment 2:

[0049] The closed-loop sampling protection circuit includes an analog switch S2, a holding capacitor C2 and an operational amplifier O2; in the sampling stage, the analog switch S2 is closed, and the input signal charges the holding capacitor C2 to the level of the input signal through S2, and the operational amplifier O2 works as a voltage follower to transfer the voltage on the capacitor C2 to the output terminal Vout; in the holding stage, the analog switch S2 is disconnected, and the charge on the holding capacitor C2 remains unchanged, thereby keeping the output signal Vout unchanged.

[0050] When the closed-loop sampling protection circuit provided by the present invention is used, the analog switch S2 is used to control the sampling and holding state of the signal; the holding capacitor C2 stores the charge during the sampling period and keeps the signal unchanged during the holding stage; the operational amplifier O2 is used as a voltage follower or a buffer to increase the input impedance of the circuit and reduce the output impedance, thereby improving the circuit performance; in the closed-loop circuit, the operational amplifier O2 also participates in the feedback loop to further improve the sampling accuracy; in the sampling stage, the analog switch S2 is closed, and the input signal charges the holding capacitor C2 to the level of the input signal through S2, and the operational amplifier O2 works as a voltage follower to transfer the voltage on the capacitor C2 to the output terminal Vout; in the holding stage, the analog switch S2 is disconnected, and the charge on the holding capacitor C2 remains unchanged, thereby keeping the output signal Vout unchanged.

[0051] Furthermore, if Figure 1 , Figure 3 and Figure 4 As shown, one end of the sampling protection circuit is connected to the main test circuit; the other end of the sampling protection circuit is connected to one end of the MOSFET control circuit; the main test circuit includes a power device under test, an ammeter, a leakage current detection resistor, a first voltmeter, a second voltmeter, a first capacitor, a second capacitor, a switch and a voltage source, and the leakage current detection resistor is connected to the power device under test to detect the leakage current passing through the power device under test under high temperature and reverse bias conditions;

[0052] One end of the switch is connected to the leakage current detection resistor, and the other end of the switch is connected to the positive electrode of the voltage source, which is used to control the current on and off in the main test circuit; the first capacitor and the second capacitor are used for filtering, stabilizing the voltage and protecting the circuit; one end of the power device under test is connected to the ammeter, and the other end of the power device under test is grounded; the end of the ammeter away from the power device under test is connected to the leakage current detection resistor; the first voltmeter is connected in parallel to the leakage current detection resistor, and the second voltmeter is connected in parallel to the power device under test; one end of the first capacitor and one end of the second capacitor are respectively connected to the other end of the leakage current detection resistor, and the other end of the first capacitor and the other end of the second capacitor are respectively grounded; the negative electrode of the voltage source is grounded.

[0053] When the main test circuit provided by the present invention is used, the main test circuit is the core part of the HTRB reliability test device of the power device, and is mainly used to simulate the performance of the power device under actual working conditions; the power device under test is the object under test in the main test circuit, and is used to evaluate its reliability under high temperature and reverse bias conditions; the leakage current detection resistor is connected to the power device under test, and is used to detect the leakage current flowing through the power device under test; the first voltmeter is connected in parallel to the leakage current detection resistor, and is used to measure the voltage across the leakage current detection resistor; the switch is connected between the leakage current detection resistor and the voltage source, and is controlled by the MOSFET The circuit control is used to open or close the test circuit; the voltage source provides the power required for the test; the second voltmeter is connected in parallel to the power device under test to measure the voltage across the power device under test; the ammeter is connected in series to one end of the power device under test to measure the current flowing through the power device under test; the first capacitor and the second capacitor are respectively connected to the other end of the leakage current detection resistor to filter and stabilize the circuit; the main test circuit is an indispensable part of the HTRB reliability test of the power device. It provides an important basis for evaluating the performance and reliability of the power device by accurately simulating the high temperature and reverse bias environment under actual working conditions.

[0054] Furthermore, if Figure 1 and Figure 5 As shown, the MOSFET control circuit includes an A / D analog-to-digital converter, a DSP digital processor, a D / A digital-to-analog converter, a level conversion circuit and a driving circuit, and the other end of the MOSFET control circuit is connected to one end of the switch; the output end of the A / D analog-to-digital converter is connected to the DSP digital processor, the output end of the DSP digital processor is connected to the input end of the D / A digital-to-analog converter, the output end of the D / A digital-to-analog converter is connected to the input end of the level conversion circuit, and the output end of the level conversion circuit is connected to the input end of the driving circuit;

[0055] The A / D analog-to-digital converter is used to receive the voltage signal collected by the sampling protection circuit and convert the voltage signal into a digital signal; the DSP digital processor is used to receive the digital signal output by the A / D analog-to-digital converter and output a PWM signal for controlling the switch according to the control requirements; the D / A digital-to-analog converter is used to convert the PWM signal output by the DSP digital processor into an analog signal; the level conversion circuit is used to perform level conversion on the analog signal output by the D / A digital-to-analog converter; the drive circuit is used to generate a drive signal for controlling the switch according to the analog signal after the level conversion, and output the drive signal to the switch.

[0056] When the MOSFET control circuit provided by the present invention is used, the voltage signal collected by the sampling protection circuit is received through the A / D analog-to-digital converter, and the voltage signal is converted into a digital signal; the digital signal output by the A / D analog-to-digital converter is received through the DSP digital processor, and a PWM signal for controlling the switch is output according to the control requirement; the PWM signal output by the DSP digital processor is converted into an analog signal through the D / A digital-to-analog converter; the analog signal output by the D / A digital-to-analog converter is converted into a level through the level conversion circuit; the driving circuit is used to generate a driving signal for controlling the switch according to the analog signal after the level conversion, and the driving signal is output to the switch.

[0057] Furthermore, if Figure 2 As shown, the reliability of the power device in A4 includes the following steps:

[0058] B1: Leakage current analysis: by analyzing the change of leakage current, we can understand the stability and reliability of the device under high temperature and reverse bias conditions;

[0059] B2: Breakdown voltage analysis, by measuring the breakdown voltage of the device under high temperature and reverse bias, to understand the voltage resistance and stability;

[0060] B3: Temperature impact analysis, by simulating the temperature environment under actual working conditions and observing the performance changes of the device under different temperatures, to evaluate the sensitivity and adaptability to temperature;

[0061] B4: Life prediction: by statistics and comparison of test data, life curve fitting and prediction are performed to evaluate the service life of the device under a specific working environment.

[0062] When judging the reliability of a power device, the present invention analyzes the change in leakage current to understand the stability and reliability of the device under high temperature and reverse bias conditions. If the leakage current is stable at a relatively low level, it means that the quality of the device is good; if the leakage current gradually increases, it means that the device has defects or performance degradation; by measuring the breakdown voltage of the device under high temperature and reverse bias, its voltage resistance and stability are understood; if the breakdown voltage remains at a relatively high level, it means that the device has good voltage resistance; if the breakdown voltage decreases, it may indicate that the device has problems such as insulation layer damage or material aging; by simulating the temperature environment under actual working conditions and observing the performance changes of the device at different temperatures, its sensitivity and adaptability to temperature can be evaluated; if the device can still maintain stable performance under high temperature environment, it means that it has good thermal stability and reliability; otherwise, it is necessary to further improve the design or material selection to improve its reliability; by statistics and comparison of test data, the life curve can be fitted and predicted to evaluate the service life of the device under a specific working environment.

[0063] Furthermore, if Figure 1 As shown, the reliability judgment adopts the HV-H3TRB model, which introduces the voltage acceleration factor into the traditional Peck model to describe the impact of temperature and humidity on device reliability, so as to more accurately predict the life of the device in a specific environment.

[0064] When the reliability judgment provided by the present invention is used, the Peck model is an empirical model used to describe the influence of temperature and humidity on device reliability; in the H3TRB test, the model is used to evaluate the reliability of power semiconductor devices under high temperature and high humidity conditions; and the HV-H3TRB model is an improved version of the Peck model, which is suitable for high-voltage power devices with a bias voltage greater than 100V. It introduces a voltage acceleration factor into the traditional Peck model to more accurately predict the life of the device under specific conditions.

[0065] Working principle: Select the device to be tested and build the main test circuit to ensure that the device can maintain a stable working state during the test process; then, at a preset temperature, collect the voltage of the leakage current detection resistor connected to the power device to be tested through the sampling protection circuit; generate a drive signal through the MOSFET control circuit according to the voltage of the leakage current detection resistor; control the switch to be turned on or off according to the drive signal, and control the switching speed of the switch; according to the voltage of the power device to be tested and the voltage of the leakage current detection resistor when the switch is turned on or off, obtain the effect of the voltage on the leakage of the power device to be tested; detect the power device to be tested in the main test circuit under high temperature through the sampling protection circuit, and transmit the collected voltage signal to the MOSFET control circuit, and use the DSP digital processor in the MOSFET control circuit to output the PWM signal for controlling the main test circuit through the control algorithm, after digital-to-analog conversion and level conversion, the drive circuit generates a drive signal according to the PWM signal, and then controls the switch in the main test circuit to be turned on or off, thereby achieving PWM control of the power supply, and then simulates the reliability test of the HTRB of the power device to be tested under high temperature, and evaluates the performance of the power device according to the test results, and judges the reliability of the power device;

[0066] Since the open-loop sampling and holding circuit has no feedback loop, its response speed is fast and it is suitable for application scenarios with high speed requirements. However, because it lacks a feedback mechanism to correct errors, the accuracy of the open-loop sampling and protection circuit is relatively low. The closed-loop sampling and holding circuit can provide higher sampling accuracy and stability by introducing a feedback loop, but the response speed may be slightly slower. Therefore, the advantages of open-loop and closed-loop sampling and protection circuits are used to work together. The open-loop sampling and holding circuit is used to quickly capture signal changes, while the closed-loop sampling and protection circuit is used to ensure high-precision acquisition of key data, ensuring that the two circuits can work together and give full play to their respective advantages. By setting control logic in the computer program, the two circuits can be dynamically switched or used in parallel when necessary. This can be achieved through a microcontroller, FPGA or other programmable logic device to ensure that the control logic can correctly process the outputs of the two circuits and perform data fusion or selection when necessary.

[0067] When judging the reliability of power devices, the stability and reliability of the device under high temperature and reverse bias conditions can be understood by analyzing the changes in leakage current. If the leakage current is stable at a low level, it means that the quality of the device is good; if the leakage current gradually increases, it means that the device has defects or performance degradation; by measuring the breakdown voltage of the device under high temperature and reverse bias, its voltage resistance and stability can be understood; if the breakdown voltage remains at a high level, it means that the device has good voltage resistance; if the breakdown voltage decreases, it may indicate that the device has problems such as insulation layer damage or material aging; by simulating the temperature environment under actual working conditions and observing the performance changes of the device at different temperatures, its sensitivity and adaptability to temperature can be evaluated; if the device can still maintain stable performance in a high temperature environment, it means that it has good thermal stability and reliability; otherwise, it is necessary to further improve the design or material selection to improve its reliability; through statistics and comparison of test data, the life curve can be fitted and predicted to evaluate the service life of the device under a specific working environment.

[0068] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A HTRB reliability test method for a power device, characterized in that: The following steps are involved: A1: Select the device to be tested and build the main test circuit to ensure that the device can maintain a stable working state during the test; A2: Under the preset temperature, the voltage of the leakage current detection resistor is collected by switching different sampling protection circuits; A3: Based on the voltage of the leakage current detection resistor, the device parameters are continuously monitored in a high temperature reverse bias environment, and the voltage of the power device under test and the voltage of the leakage current detection resistor are measured through the MOSFET control circuit; A4: Evaluate the performance of the power device and determine its reliability based on the tested voltage.

2. The HTRB reliability testing method for a power device according to claim 1, characterized in that: The sampling protection circuit in A2 includes an open-loop sampling protection circuit and a closed-loop sampling protection circuit; the open-loop sampling protection circuit and the closed-loop sampling protection circuit work in coordination.

3. The HTRB reliability testing method for a power device according to claim 2, characterized in that: The open-loop sampling protection circuit includes an analog switch S1, a holding capacitor C1 and an operational amplifier O1. The analog switch S1 adopts MOSFET to control the sampling and holding of the signal; the holding capacitor C1 is used to charge to the level of the input voltage during the sampling period and maintain the voltage during the holding period; the operational amplifier O1 adopts a voltage follower to increase the input impedance and reduce the output impedance of the circuit; the open-loop sampling protection circuit also includes a control system for controlling the on-off state of the analog switch.

4. The HTRB reliability testing method for a power device according to claim 2, characterized in that: The closed-loop sampling protection circuit includes an analog switch S2, a holding capacitor C2 and an operational amplifier O2; in the sampling stage, the analog switch S2 is closed, and the input signal charges the holding capacitor C2 to the level of the input signal through S2, and the operational amplifier O2 works as a voltage follower to transfer the voltage on the capacitor C2 to the output terminal Vout; in the holding stage, the analog switch S2 is disconnected, and the charge on the holding capacitor C2 remains unchanged, thereby keeping the output signal Vout unchanged.

5. The HTRB reliability testing method for a power device according to claim 2, characterized in that: One end of the sampling protection circuit is connected to the main test circuit; the other end of the sampling protection circuit is connected to one end of the MOSFET control circuit; the main test circuit includes a power device under test, an ammeter, a leakage current detection resistor, a first voltmeter, a second voltmeter, a first capacitor, a second capacitor, a switch and a voltage source, and the leakage current detection resistor is connected to the power device under test to detect the leakage current passing through the power device under test under high temperature and reverse bias conditions.

6. The HTRB reliability testing method for a power device according to claim 5, characterized in that: One end of the switch is connected to the leakage current detection resistor, and the other end of the switch is connected to the positive electrode of the voltage source, which is used to control the current on and off in the main test circuit; the first capacitor and the second capacitor are used for filtering, stabilizing the voltage and protecting the circuit; one end of the power device under test is connected to the ammeter, and the other end of the power device under test is grounded; the end of the ammeter away from the power device under test is connected to the leakage current detection resistor; the first voltmeter is connected in parallel to the leakage current detection resistor, and the second voltmeter is connected in parallel to the power device under test; one end of the first capacitor and one end of the second capacitor are respectively connected to the other end of the leakage current detection resistor, and the other end of the first capacitor and the other end of the second capacitor are respectively grounded; the negative electrode of the voltage source is grounded.

7. The HTRB reliability testing method for a power device according to claim 5, characterized in that: The MOSFET control circuit comprises an A / D analog-to-digital converter, a DSP digital processor, a D / A digital-to-analog converter, a level conversion circuit and a driving circuit. The other end of the MOSFET control circuit is connected to one end of the switch; the output end of the A / D analog-to-digital converter is connected to the DSP digital processor, the output end of the DSP digital processor is connected to the input end of the D / A digital-to-analog converter, the output end of the D / A digital-to-analog converter is connected to the input end of the level conversion circuit, and the output end of the level conversion circuit is connected to the input end of the driving circuit.

8. The HTRB reliability testing method for a power device according to claim 7, characterized in that: The A / D analog-to-digital converter is used to receive the voltage signal collected by the sampling protection circuit and convert the voltage signal into a digital signal; the DSP digital processor is used to receive the digital signal output by the A / D analog-to-digital converter and output a PWM signal for controlling the switch according to the control requirements; the D / A digital-to-analog converter is used to convert the PWM signal output by the DSP digital processor into an analog signal; the level conversion circuit is used to perform level conversion on the analog signal output by the D / A digital-to-analog converter; the drive circuit is used to generate a drive signal for controlling the switch according to the analog signal after the level conversion, and output the drive signal to the switch.

9. The HTRB reliability testing method for a power device according to claim 1, characterized in that: Determining the reliability of the power device in A4 includes the following steps: B1: Leakage current analysis: by analyzing the change of leakage current, we can understand the stability and reliability of the device under high temperature and reverse bias conditions; B2: Breakdown voltage analysis, by measuring the breakdown voltage of the device under high temperature and reverse bias, to understand the voltage resistance and stability; B3: Temperature impact analysis, by simulating the temperature environment under actual working conditions and observing the performance changes of the device under different temperatures, to evaluate the sensitivity and adaptability to temperature; B4: Life prediction: by statistics and comparison of test data, life curve fitting and prediction are performed to evaluate the service life of the device under a specific working environment.

10. The HTRB reliability testing method for a power device according to claim 9, characterized in that: The reliability judgment adopts the HV-H3TRB model, which introduces the voltage acceleration factor into the traditional Peck model to describe the influence of temperature and humidity on the reliability of the device, so as to more accurately predict the life of the device in a specific environment.

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