Test circuit and test method for dynamic threshold voltage of power device
Patent Information
- Application Number
- CN202310927517.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-26
- Publication Date
- 2025-01-28
Smart Images
Figure CN119375646A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electronic circuits, and in particular to a test circuit and a test method for a dynamic threshold voltage of a power device. Background Art
[0002] As a new generation of power devices, GaN devices have always attracted much attention. Due to their excellent performance, they are now increasingly used in high-frequency and high-power fields. However, due to various stress conditions encountered during the switching process, some charges are captured, resulting in current collapse, causing higher losses, making their actual performance lower than the theoretical performance, affecting reliability, and causing hidden dangers in practical applications. Research on the dynamic characteristics of GaN devices has always been the focus of technicians, and screening out problematic devices through electrical testing is even more important.
[0003] In the prior art, the dynamic characteristics of GaN devices are reflected by the threshold voltage of DC testing. However, the dynamic characteristics of GaN devices are transient phenomena, which need to be tested quickly in a very short time and with minimal errors. However, in conventional DC testing, the test time of each test item is relatively long and the error is relatively large, which cannot truly reflect the dynamic characteristics of GaN devices. In addition, conventional DC testing only considers the case of applying drain bias to GaN devices, and does not consider the case of applying gate bias to GaN devices. Summary of the invention
[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a test circuit and test method for the dynamic threshold voltage of a power device, so as to solve the problem that the existing DC test scheme cannot truly reflect the dynamic characteristics of the power device due to long test time and large error.
[0005] In order to achieve the above-mentioned object and other related objects, the present invention provides a test circuit for dynamic threshold voltage of a power device, the test circuit comprising:
[0006] An excitation and measurement module, a high voltage bias module, a low voltage bias and measurement module, a first switch device, a second switch device, a third switch device and a fourth switch device;
[0007] The first end of the excitation and measurement module is connected to the gate end of the power device to be measured and is connected to the drain end of the power device to be measured through the first switch device, and the second end is connected to the source end of the power device to be measured, and is used to apply a voltage to the gate end of the power device to be measured and measure the drain-source current of the power device to be measured to obtain the threshold voltage of the power device to be measured;
[0008] The first end of the high-voltage bias module is connected to the drain end of the power device to be tested through the second switch device, and the second end is connected to the source end of the power device to be tested, so as to apply a bias high voltage to the drain end of the power device to be tested;
[0009] The first end of the low voltage bias and measurement module is connected to the drain end of the power device to be measured through the third switch device, and the second end is connected to the source end of the power device to be measured, and is used to apply a bias low voltage to the drain end of the power device to be measured, measure the drain-source current of the power device to be measured, and feed it back to the excitation and measurement module;
[0010] The fourth switch device is connected between the drain terminal and the source terminal of the power device to be tested.
[0011] Optionally, the voltage applied by the excitation and measurement module to the gate terminal of the power device to be tested includes a zero voltage, a bias voltage and a step-by-step increasing driving voltage; when the excitation and measurement module applies a step-by-step increasing driving voltage to the gate terminal of the power device to be tested, the excitation and measurement module is also used to compare the drain-source current with a set current, and when the drain-source current reaches the set current, stop increasing the driving voltage, so as to obtain the threshold voltage of the power device to be tested based on the current driving voltage.
[0012] Optionally, the low-voltage bias and measurement module includes a low-voltage bias and measurement unit and a feedback unit, and the feedback unit is connected between the low-voltage bias and measurement unit and the third switching device; the low-voltage bias and measurement unit is used to apply a bias low voltage to the drain end of the power device to be tested and measure the drain-source current of the power device to be tested, and the feedback unit is used to feed back the measured drain-source current to the excitation and measurement module.
[0013] Optionally, the test circuit further includes: a leakage protection module connected between the second switch device and the high-voltage bias module.
[0014] Optionally, the leakage protection module includes: an inductor, a load resistor and a freewheeling diode; the inductor and the load resistor are connected in series and then connected in parallel with the freewheeling diode between the second switching device and the high-voltage bias module, wherein the positive end of the freewheeling diode is connected to the second switching device, and the negative end is connected to the high-voltage bias module.
[0015] Optionally, the power device to be tested includes a gallium nitride device; the first switch device, the second switch device, the third switch device and the fourth switch device are implemented by relays, MOS devices or gallium nitride devices, wherein when the corresponding switch device is implemented by a MOS device or a gallium nitride device, the test circuit also includes: a corresponding gate control module to control the on and off of the corresponding MOS device or gallium nitride device.
[0016] The present invention also provides a method for testing the dynamic threshold voltage of a power device, and based on the test circuit described in any one of the above items, a dynamic threshold voltage test is performed on the power device to be tested, and the test method comprises:
[0017] Before bias is applied, a threshold voltage test is performed on the power device to be tested;
[0018] After the test is completed, applying a bias to the power device to be tested;
[0019] After the bias is applied, a threshold voltage test is performed on the power device to be tested.
[0020] Optionally, the method for performing a threshold voltage test on the power device to be tested includes:
[0021] Controlling the first switch device to be turned on, short-circuiting the gate terminal and the drain terminal of the power device to be tested, and applying a driving voltage to the gate terminal of the power device to be tested through the excitation and measurement module, wherein the driving voltage is increased step by step from a preset value; measuring the drain-source current of the power device to be tested through the excitation and measurement module, and stopping the increase of the driving voltage when the drain-source current reaches a set current, so as to obtain the threshold voltage of the power device to be tested based on the current driving voltage;
[0022] Alternatively, the third switching device is controlled to be turned on, a bias low voltage is applied to the drain terminal of the power device to be tested through the low-voltage bias and measurement module, and a driving voltage is applied to the gate terminal of the power device to be tested through the excitation and measurement module, wherein the driving voltage increases step by step starting from a preset value; the drain-source current of the power device to be tested is measured by the low-voltage bias and measurement module and fed back to the excitation and measurement module, and the excitation and measurement module stops the increase of the driving voltage when the drain-source current reaches a set current, so as to obtain the threshold voltage of the power device to be tested based on the current driving voltage.
[0023] Optionally, before and after the bias is applied, the threshold voltage test of the power device to be tested is performed using the same method.
[0024] Optionally, the method for applying a bias to the power device to be tested includes:
[0025] Controlling the second switch device to be turned on, applying a zero voltage to the gate terminal of the power device to be tested through the excitation and measurement module, and applying a bias high voltage to the drain terminal of the power device to be tested through the high-voltage bias module;
[0026] Alternatively, the fourth switch device is controlled to be turned on, the drain terminal and the source terminal of the power device to be measured are short-circuited, and a bias voltage is applied to the gate terminal of the power device to be measured through the excitation and measurement module.
[0027] As described above, the test circuit and test method for the dynamic threshold voltage of a power device of the present invention complete pulse testing in a very short time through high-speed switch switching, thereby realizing the threshold voltage test of the power device to be tested before and after bias application, so as to test the transient change of the threshold voltage, that is, the dynamic threshold voltage; the present invention includes two threshold voltage testing methods and two bias application methods, which are conducive to exploring the drift of the dynamic threshold voltage of the power device to be tested under different test conditions. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 Shown is a schematic diagram of the structure of the test circuit in the present invention.
[0029] Figure 2 The waveform diagram shows the drain terminal voltage and gate terminal voltage of the power device to be tested when the second switch device is turned on.
[0030] Figure 3 and Figure 4 The waveform diagram of the gate voltage of the power device to be tested when the fourth switch device is turned on is shown, wherein: Figure 3 is the waveform corresponding to the forward bias voltage, Figure 4 This is the waveform corresponding to the reverse bias voltage.
[0031] Component number description
[0032] 100 Test Circuit
[0033] 110 Excitation and Measurement Module
[0034] 120 High Voltage Bias Module
[0035] 130 Low Voltage Bias and Measurement Module
[0036] 131 Low Voltage Bias and Measurement Unit
[0037] 132 Feedback unit
[0038] 140 Leakage protection module DETAILED DESCRIPTION
[0039] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.
[0040] See also Figures 1 to 4 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the form, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.
[0041] like Figure 1 As shown, this embodiment provides a test circuit 100 for dynamic threshold voltage of a power device, including: an excitation and measurement module 110, a high voltage bias module 120, a low voltage bias and measurement module 130, a first switch device K1, a second switch device K2, a third switch device K3 and a fourth switch device K4; further, it also includes: a leakage protection module 140. Among them:
[0042] The first end of the excitation and measurement module 110 is connected to the gate terminal of the power device DUT to be tested and to the drain terminal of the power device DUT to be tested through the first switching device K1, and the second end is connected to the source terminal of the power device DUT to be tested; it is used to apply voltage to the gate terminal of the power device DUT to be tested and measure the drain-source current of the power device DUT to be tested to obtain the threshold voltage of the power device DUT to be tested.
[0043] Specifically, the voltage applied by the excitation and measurement module 110 to the gate terminal of the power device DUT under test includes a zero voltage, a bias voltage and a step-by-step increasing driving voltage; wherein, the excitation and measurement module 110 applies a zero voltage to the gate terminal of the power device DUT under test, so as to apply a bias high voltage to both ends of the drain and source of the power device DUT under test through the high-voltage bias module 120; the excitation and measurement module 110 applies a bias voltage to the gate terminal of the power device DUT under test, so as to provide a new bias application method; the excitation and measurement module 110 applies a step-by-step increasing driving voltage to the gate terminal of the power device DUT under test, and drives the power device DUT under test to turn on, so as to obtain the threshold voltage of the power device DUT under test.
[0044] When the excitation and measurement module 110 applies a bias voltage to the gate terminal of the power device DUT to be tested, the bias voltage can be a forward bias voltage or a reverse bias voltage, which is a fixed voltage, and its voltage value is determined by the gate withstand voltage of the power device DUT to be tested; if the power device DUT to be tested is a low-voltage device, the absolute value of the bias voltage is usually a few volts, such as 7V-8V, etc.; if the power device DUT to be tested is a high-voltage device, the absolute value of the bias voltage is usually a dozen volts to several dozen volts, such as 16V-35V, etc.
[0045] When the excitation and measurement module 110 applies a step-by-step increasing driving voltage to the gate terminal of the power device DUT to be tested, the excitation and measurement module 110 is also used to compare the drain-source current and the set current, and when the drain-source current reaches the set current, stop increasing the driving voltage, so as to obtain the threshold voltage of the power device DUT to be tested based on the current driving voltage, such as using the current driving voltage as the threshold voltage of the power device DUT to be tested. It should be noted that the so-called current driving voltage refers to the voltage value maintained by the driving voltage after stopping the increase.
[0046] In a possible implementation, the excitation and measurement module 110 controls the driving voltage value to increase step by step from a preset value based on the step value. For example, the driving voltage value initially output by the excitation and measurement module 110 is the preset value; after the first comparison, the drain-source current does not reach the set current, and the output driving voltage value is the preset value + the step value; after the second comparison, the drain-source current still does not reach the set current, and the output driving voltage value is the preset value + 2 times the step value; and so on, until the drain-source current reaches the set current, at which time, the excitation and measurement module 110 controls the driving voltage value to stop increasing and remain unchanged.
[0047] In this implementation, the preset value can be zero or other values greater than zero, which is determined by the threshold voltage of the power device DUT to be tested; if the threshold voltage of the power device DUT to be tested is small, the preset value is usually designed to be zero; if the threshold voltage of the power device DUT to be tested is large, the preset value is usually designed to be a value greater than zero, so that the test time can be shortened. In addition, the size of the step value should be set according to actual needs, and there is no restriction on this.
[0048] As an example, the excitation and measurement module 110 is implemented using an SMU (Source Measure Unit). The SMU is used as a voltage source when working in the FV (Force Voltage) mode, as a current source when working in the FI (Force Current) mode, can measure voltage when working in the MV (Measure Voltage) mode, and can measure current when working in the MI (Measure Current) mode. By combining the working modes of the SMU, the SMU can have multiple functions; in this embodiment, the SMU used as the excitation and measurement module 110 mainly works in the FV mode and the MI mode, that is, the FVMI mode.
[0049] As an example, the first switch device K1 is implemented by a relay, a MOS device or a gallium nitride device to perform fast switching of the switch, thereby performing fast switching of the test circuit; wherein, when the first switch device K1 is implemented by a MOS device or a gallium nitride device, the test circuit 100 of this embodiment also includes: a corresponding first gate control module (not shown in the figure), which controls the on and off of the corresponding MOS device or gallium nitride device.
[0050] The first end of the high voltage bias module 120 is connected to the drain end of the power device DUT under test through the second switch device K2, and the second end is connected to the source end of the power device DUT under test; it is used to apply a bias high voltage to the drain end of the power device DUT under test.
[0051] As an example, the high voltage bias module 120 can be implemented by an excitation source or by an SMU, which has no substantial impact on this embodiment; when the high voltage bias module 120 is implemented by an SMU, the SMU used as the high voltage bias module 120 mainly works in the FV mode. It should be noted that the bias high voltage is a forward bias voltage, which is a fixed voltage, usually a high voltage of several hundred volts.
[0052] As an example, the second switch device K2 is implemented by a relay, a MOS device or a gallium nitride device to perform fast switching of the switch, thereby performing fast switching of the test circuit; wherein, when the second switch device K2 is implemented by a MOS device or a gallium nitride device, the test circuit 100 of this embodiment also includes: a corresponding second gate control module (not shown in the figure), which controls the on and off of the corresponding MOS device or gallium nitride device.
[0053] The first end of the low-voltage bias and measurement module 130 is connected to the drain end of the power device DUT to be tested through the third switching device K3, and the second end is connected to the source end of the power device DUT to be tested; it is used to apply a bias low voltage to the drain end of the power device DUT to be tested, measure the drain-source current of the power device DUT to be tested and feed it back to the excitation and measurement module 110.
[0054] Specifically, the low-voltage bias and measurement module 130 includes a low-voltage bias and measurement unit 131 and a feedback unit 132, and the feedback unit 132 is connected between the low-voltage bias and measurement unit 131 and the third switching device K3; the low-voltage bias and measurement unit 131 is used to apply a bias low voltage to the drain end of the power device DUT under test and measure the drain-source current of the power device DUT under test, and the feedback unit 132 is used to feed back the measured drain-source current to the excitation and measurement module 100.
[0055] As an example, the low voltage bias and measurement unit 131 is implemented by SMU, and the feedback unit 132 is implemented by feedback resistor; in this embodiment, the SMU used as the low voltage bias and measurement unit 131 mainly works in FV mode and MI mode, that is, FVMI mode. It should be noted that the bias low voltage is a forward bias voltage, which is a fixed voltage, usually a low voltage less than 10 volts.
[0056] As an example, the third switch device K3 is implemented by a relay, a MOS device or a gallium nitride device to perform fast switching of the switch, thereby performing fast switching of the test circuit; wherein, when the third switch device K3 is implemented by a MOS device or a gallium nitride device, the test circuit 100 of this embodiment also includes: a corresponding third gate control module (not shown in the figure), which controls the on and off of the corresponding MOS device or gallium nitride device.
[0057] The fourth switch device K4 is connected between the drain terminal and the source terminal of the power device under test DUT; when the fourth switch device K4 is turned on, the drain terminal and the source terminal of the power device under test DUT are short-circuited.
[0058] As an example, the fourth switch device K4 is implemented by a relay, a MOS device or a gallium nitride device to perform fast switching of the switch, thereby performing fast switching of the test circuit; wherein, when the fourth switch device K4 is implemented by a MOS device or a gallium nitride device, the test circuit 100 of this embodiment further includes: a corresponding fourth gate control module (not shown in the figure) to control the on and off of the corresponding MOS device or gallium nitride device. It should be noted that when at least two of the first switch device K1 to the fourth switch device K4 are implemented by a MOS device or a gallium nitride device, the gate control modules corresponding to the multiple switch devices can be controlled by the same gate control module to improve the control accuracy.
[0059] The leakage current protection module 140 is connected between the second switch device K2 and the high-voltage bias module 120 , and is used to protect the high-voltage bias module 120 from being damaged due to leakage current.
[0060] As an example, the leakage protection module 140 includes: an inductor L1, a load resistor R1 and a freewheeling diode D1; the inductor L1 and the load resistor R1 are connected in series and then connected in parallel with the freewheeling diode D1 between the second switch device K2 and the high-voltage bias module 120, wherein the positive end of the freewheeling diode D1 is connected to the second switch device K2, and the negative end is connected to the high-voltage bias module 120. When the second switch device K2 is turned off after being turned on for a period of time, the leakage current will be consumed by the load resistor R1 through the freewheeling diode D1, and therefore, the high-voltage bias module 120 will not be damaged.
[0061] In this embodiment, the power device DUT to be tested includes a gallium nitride device. Of course, the power device DUT to be tested may also include a silicon device, etc. This has no substantial impact on this embodiment. This embodiment takes the case where the power device DUT to be tested is a gallium nitride device as an example. In practical applications, the source end of the power device DUT to be tested is connected to the reference ground.
[0062] Accordingly, this embodiment further provides a method for testing the dynamic threshold voltage of a power device, comprising steps S1 to S3; the testing method is implemented based on the test circuit 100 as described above, that is, a dynamic threshold voltage test is performed on the power device DUT under test based on the test circuit 100 as described above. Wherein:
[0063] Step S1: before bias is applied, a threshold voltage test is performed on the power device under test (DUT).
[0064] As an example, a method for performing a threshold voltage test on a power device DUT to be tested includes: controlling the first switch device K1 to be turned on, short-circuiting the gate and drain terminals of the power device DUT to be tested, and applying a driving voltage to the gate terminal of the power device DUT to be tested through the excitation and measurement module 110, wherein the driving voltage increases step by step starting from a preset value; measuring the drain-source current of the power device DUT to be tested through the excitation and measurement module 110, and stopping the increase of the driving voltage when the drain-source current reaches a set current, so as to obtain the threshold voltage of the power device DUT to be tested based on the current driving voltage, such as using the current driving voltage as the threshold voltage of the power device DUT to be tested, and completing the threshold voltage test of the power device DUT to be tested before bias is applied; thereafter, controlling the first switch device K1 to be turned off.
[0065] As another example, a method for performing a threshold voltage test on a power device DUT to be tested includes: controlling the third switch device K3 to be turned on, applying a bias low voltage to the drain terminal of the power device DUT to be tested through the low-voltage bias and measurement module 130, and applying a driving voltage to the gate terminal of the power device DUT to be tested through the excitation and measurement module 110, wherein the driving voltage increases step by step starting from a preset value; measuring the drain-source current of the power device DUT to be tested through the low-voltage bias and measurement module 130 and feeding it back to the excitation and measurement module 110, the excitation and measurement module 110 stops increasing the driving voltage when the drain-source current reaches a set current, so as to obtain the threshold voltage of the power device DUT to be tested based on the current driving voltage, such as using the current driving voltage as the threshold voltage of the power device DUT to be tested, and completing the threshold voltage test of the power device DUT to be tested before the bias is applied; thereafter, controlling the third switch device K3 to be turned off.
[0066] Step S2: After the test is completed, a bias is applied to the power device under test DUT.
[0067] As an example, the method for applying bias to the power device under test DUT includes: controlling the second switch device K2 to be turned on, applying zero voltage to the gate terminal of the power device under test DUT through the excitation and measurement module 110, and applying bias high voltage to the drain terminal of the power device under test DUT through the high-voltage bias module 120, and controlling the second switch device K2 to be turned off after a first set time to complete the bias application, and the relevant voltage is as follows Figure 2 It should be noted that the first set time should be set according to actual needs and there is no restriction on this.
[0068] As another example, the method for applying bias to the power device DUT to be tested includes: controlling the fourth switch device K4 to be turned on, short-circuiting the drain terminal and the source terminal of the power device DUT to be tested, applying a bias voltage to the gate terminal of the power device DUT to be tested through the excitation and measurement module 110, and controlling the fourth switch device K4 to be turned off after a second set time to complete the application of the bias. The relevant voltage is as follows Figure 3 or Figure 4 It should be noted that the second set time should be set according to actual needs and there is no restriction on this.
[0069] Step S3: After bias is applied, threshold voltage test is performed on the power device DUT. When threshold voltage test is performed on the power device DUT, this step is consistent with step S1 and also includes two solutions. The relevant contents can be found in the above text and will not be described here.
[0070] As an example, before and after bias application, the same method is used to perform a threshold voltage test on the power device DUT under test, that is, step S1 and step S3 use the same method to perform a threshold voltage test on the power device DUT under test; for example, step S1 and step S3 both perform a threshold voltage test on the power device DUT under test by controlling the first switch device K1 to be turned on, or step S1 and step S3 both perform a threshold voltage test on the power device DUT under test by controlling the third switch device K3 to be turned on.
[0071] In summary, the present invention provides a test circuit and method for the dynamic threshold voltage of a power device, which completes the pulse test in a very short time by high-speed switch switching, realizes the threshold voltage test of the power device to be tested before and after the bias is applied, and thereby tests the transient change of the threshold voltage, i.e., the dynamic threshold voltage; the present invention includes two threshold voltage test methods and two bias application methods, which are conducive to exploring the drift of the dynamic threshold voltage of the power device to be tested under different test conditions. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.
[0072] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.
Claims
1. A test circuit for dynamic threshold voltage of a power device, characterized in that: The test circuit comprises: An excitation and measurement module, a high voltage bias module, a low voltage bias and measurement module, a first switch device, a second switch device, a third switch device and a fourth switch device; The first end of the excitation and measurement module is connected to the gate end of the power device to be measured and is connected to the drain end of the power device to be measured through the first switch device, and the second end is connected to the source end of the power device to be measured, and is used to apply a voltage to the gate end of the power device to be measured and measure the drain-source current of the power device to be measured to obtain the threshold voltage of the power device to be measured; The first end of the high-voltage bias module is connected to the drain end of the power device to be tested through the second switch device, and the second end is connected to the source end of the power device to be tested, so as to apply a bias high voltage to the drain end of the power device to be tested; The first end of the low voltage bias and measurement module is connected to the drain end of the power device to be measured through the third switch device, and the second end is connected to the source end of the power device to be measured, and is used to apply a bias low voltage to the drain end of the power device to be measured, measure the drain-source current of the power device to be measured, and feed it back to the excitation and measurement module; The fourth switch device is connected between the drain terminal and the source terminal of the power device to be tested.
2. The power device dynamic threshold voltage test circuit according to claim 1, characterized in that: The voltage applied by the excitation and measurement module to the gate terminal of the power device to be tested includes a zero voltage, a bias voltage and a step-by-step increasing driving voltage; when the excitation and measurement module applies a step-by-step increasing driving voltage to the gate terminal of the power device to be tested, the excitation and measurement module is also used to compare the drain-source current and the set current, and when the drain-source current reaches the set current, stop increasing the driving voltage, so as to obtain the threshold voltage of the power device to be tested based on the current driving voltage.
3. The power device dynamic threshold voltage test circuit according to claim 1, characterized in that: The low-voltage bias and measurement module includes a low-voltage bias and measurement unit and a feedback unit, wherein the feedback unit is connected between the low-voltage bias and measurement unit and the third switching device; the low-voltage bias and measurement unit is used to apply a bias low voltage to the drain end of the power device to be tested and measure the drain-source current of the power device to be tested, and the feedback unit is used to feed back the measured drain-source current to the excitation and measurement module.
4. The power device dynamic threshold voltage test circuit according to claim 1, characterized in that: The test circuit further includes: a leakage protection module connected between the second switch device and the high-voltage bias module.
5. The power device dynamic threshold voltage test circuit according to claim 4, characterized in that: The leakage protection module includes: an inductor, a load resistor and a freewheeling diode; the inductor and the load resistor are connected in series and then connected in parallel with the freewheeling diode between the second switch device and the high-voltage bias module, wherein the positive end of the freewheeling diode is connected to the second switch device, and the negative end is connected to the high-voltage bias module.
6. The power device dynamic threshold voltage test circuit according to any one of claims 1 to 5, characterized in that: The power device to be tested includes a gallium nitride device; the first switch device, the second switch device, the third switch device and the fourth switch device are implemented by relays, MOS devices or gallium nitride devices, wherein when the corresponding switch device is implemented by a MOS device or a gallium nitride device, the test circuit further includes: a corresponding gate control module to control the on and off of the corresponding MOS device or gallium nitride device.
7. A method for testing the dynamic threshold voltage of a power device, characterized in that: Based on the test circuit according to any one of claims 1 to 6, a dynamic threshold voltage test is performed on the power device to be tested, and the test method comprises: Before bias is applied, a threshold voltage test is performed on the power device to be tested; After the test is completed, applying a bias to the power device to be tested; After the bias is applied, a threshold voltage test is performed on the power device to be tested.
8. The method for testing the dynamic threshold voltage of a power device according to claim 7, characterized in that: The method for performing a threshold voltage test on the power device to be tested comprises: Controlling the first switch device to be turned on, short-circuiting the gate terminal and the drain terminal of the power device to be tested, and applying a driving voltage to the gate terminal of the power device to be tested through the excitation and measurement module, wherein the driving voltage is increased step by step from a preset value; measuring the drain-source current of the power device to be tested through the excitation and measurement module, and stopping the increase of the driving voltage when the drain-source current reaches a set current, so as to obtain the threshold voltage of the power device to be tested based on the current driving voltage; Alternatively, the third switching device is controlled to be turned on, a bias low voltage is applied to the drain terminal of the power device to be tested through the low-voltage bias and measurement module, and a driving voltage is applied to the gate terminal of the power device to be tested through the excitation and measurement module, wherein the driving voltage increases step by step starting from a preset value; the drain-source current of the power device to be tested is measured by the low-voltage bias and measurement module and fed back to the excitation and measurement module, and the excitation and measurement module stops the increase of the driving voltage when the drain-source current reaches a set current, so as to obtain the threshold voltage of the power device to be tested based on the current driving voltage.
9. The method for testing the dynamic threshold voltage of a power device according to claim 8, characterized in that: Before and after the bias is applied, the threshold voltage test of the power device to be tested is performed using the same method.
10. The method for testing the dynamic threshold voltage of a power device according to claim 7, characterized in that: The method of applying bias to the power device to be tested comprises: Controlling the second switch device to be turned on, applying a zero voltage to the gate terminal of the power device to be tested through the excitation and measurement module, and applying a bias high voltage to the drain terminal of the power device to be tested through the high-voltage bias module; Alternatively, the fourth switch device is controlled to be turned on, the drain terminal and the source terminal of the power device to be measured are short-circuited, and a bias voltage is applied to the gate terminal of the power device to be measured through the excitation and measurement module.