Test system that can increase the testing speed of static parameters

Abstract

A test system capable of increasing the test speed of static parameters, characterized in that the test system comprises a pulse constant current source, a bias source unit, a voltage measurement unit, and a switching matrix, wherein, The pulse constant current source, the bias source unit, and the voltage measurement unit are each adaptively connected to a component unit to be tested via the switching matrix; the component unit to be tested comprises at least one bridge circuit, the bridge circuit comprises two adaptively connected components to be tested, each component to be tested comprises a power switching component and a freewheeling diode that serves for freewheeling when the power switching component is blocked; The switching matrix selects the pulse constant current source, the bias source unit, and the voltage measurement unit, and connects them adaptively to the component unit under test in order to test the bridge circuit or component under test, wherein, the pulse constant current source is used to provide an excitation current to the bridge circuit or component under test; the bias source unit provides a drive bias to drive the corresponding power switching element into the conducting state or the blocking state; The voltage measurement unit is used to perform a voltage measurement on the component under test in order to determine the static parameters of the component unit under test based on the measured test voltage.

Description

Technical area

[0001] The present utility model relates to a test system, in particular a test system that can increase the test speed of static parameters. Background technology

[0002] The static properties of power semiconductor devices are important characteristics and must be tested before delivery. Using IGBT devices (Insulated Gate Bipolar Transistors) as an example (also applicable to power devices such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), diodes, BJTs (Bipolar Junction Transistors), SCRs (Silicon-Controlled Rectifiers), IGCTs (Integrated Gate-Commutated Thyristors), and HEMTs (High Electron Mobility Transistors)), their static parameters include VGE(th), V(BR)CES, ICES, VCEsat, VF, IGES, etc., where VGE(th) is the gate-emitter threshold voltage of the IGBT device, V(BR)CES is the collector-emitter reverse voltage of the IGBT device, ICES is the collector-emitter leakage current of the IGBT device, VCEsat is the saturation voltage drop of the IGBT device, VF is the forward voltage drop of the freewheeling diode adaptively connected to the IGBT device, and IGES is the gate-emitter leakage current of the IGBT device.

[0003] In the mass production of power semiconductor devices, static testing is performed on the production line using static test equipment. Test efficiency is a critical performance characteristic of the static test equipment and directly determines production efficiency and costs. Among the test points for the static properties of power semiconductor devices, the saturation voltage drop (VCesat) and the forward voltage drop of the freewheeling diode (VF) are two relatively time-consuming test points, in particular: Inside the static test apparatus, various test circuits are switched by mechanical switches (which enable the on / off switching of circuits through mechanical movement; relays are a type of mechanical switch) to perform the tests of the different test points. The two test points, saturation voltage drop VCEsat and forward voltage drop of the freewheeling diode VF, require the use of high currents (several amperes to tens of thousands of amperes) to excite the power semiconductor device. Their test circuits necessitate the use of high-voltage, high-current mechanical switches (which can withstand high voltages when open and carry high currents when closed).Such mechanical high-voltage, high-current switches have moving parts with large volume and mass, which leads to long actuation times, so that the two test points saturation voltage drop VCEsat and forward voltage drop of the freewheeling diode VF often become the efficiency bottleneck in static testing.

[0004] According to the test standards, various static test points must be tested with different circuits. This means that before a specific test is performed, the component under test must first be connected to the corresponding test circuit, for which mechanical switches are typically used to toggle the test circuits. The time spent testing each static parameter generally consists of two parts: the circuit switching time and the test time.

[0005] To improve the testing efficiency of the static test equipment, the conventional method is to continuously shorten the circuit switching time and the test time, in particular the switching time for the saturation voltage drop VCEsat and the forward voltage drop of the freewheeling diode VF during the static test process. This essentially compresses the actuation time of the mechanical high-voltage, high-current switches. However, the physical characteristics of high-voltage, high-current switches are that the distance between the moving contact and the fixed contact is large (to ensure sufficient dielectric strength) and the mass of the moving contact is large (to ensure sufficient current-carrying capacity).A large distance between the moving contact and the fixed contact means a large displacement distance during switch actuation (which requires more actuation time), and a large mass of the moving contact means a low acceleration of the movement of the moving contact during switch actuation (which requires more actuation time).

[0006] Currently, the actuation time of mechanical high-voltage, high-current switches can be reduced almost exclusively by increasing the actuation force of the moving contact. However, excessive actuation force leads to a violent impact between the moving and fixed contacts during switch actuation, which generates very loud noise and reduces the service life of the mechanical switch (the impact causes wear, deformation, or even breakage of the moving and fixed contacts). Therefore, simply increasing the actuation force of the moving contact is not an effective means of improving the testing efficiency of static parameters. How to effectively improve the testing efficiency of static parameters of power semiconductor devices remains a pressing technical problem that needs to be solved. Content of the invention

[0007] The purpose of the present utility model is to overcome the shortcomings of the prior art and to provide a test system that can increase the test speed of static parameters, effectively increase the test speed of static parameters of semiconductor devices and extend the lifetime of the switching matrix.

[0008] According to the technical solution provided by the present utility model, a test system that can increase the test speed of static parameters, wherein the test system comprises a pulse constant current source, a bias source unit, a voltage measurement unit and a switching matrix, wherein, The pulse constant current source, the bias source unit, and the voltage measurement unit are each adaptively connected to a component unit to be tested via the switching matrix; the component unit to be tested comprises at least one bridge circuit, the bridge circuit comprises two adaptively connected components to be tested, each component to be tested comprises a power switching component and a freewheeling diode that serves for freewheeling when the power switching component is blocked; The switching matrix selects the pulse constant current source, the bias source unit, and the voltage measurement unit, and connects them adaptively to the component unit under test in order to test the bridge circuit or component under test, wherein, the pulse constant current source is used to provide an excitation current to the bridge circuit or component under test; The bias source unit provides a drive bias to... to drive the corresponding power switching element into the conductive state; The voltage measurement unit is used to perform a voltage measurement on the component under test in order to determine the static parameters of the component unit under test based on the measured test voltage. For any power switching element, an adaptively connected first auxiliary connection and a first main connection are provided at the first connection terminal of the power switching element, wherein the first main connection and the first auxiliary connection are both electrically connected to the first connection terminal; an adaptively connected second auxiliary connection and a second main connection are provided at the second connection terminal of the semiconductor device, wherein the second main connection and the second auxiliary connection are both electrically connected to the second connection terminal; For a component to be tested, within the component to be tested, the cathode terminal of the freewheeling diode is electrically connected to the first connection terminal of the power switching element, and the anode terminal of the freewheeling diode is electrically connected to the second connection terminal of the power switching element; Within the bridge circuit, a component under test forms an upper bridge arm unit, another component under test forms a lower bridge arm unit, and the second main connection terminal within the upper bridge arm unit is electrically connected to the first main connection terminal within the lower bridge arm unit; when testing a component under test, the component under test is adaptively connected to the pulse constant current source via the first main connection terminal and the second main connection terminal, and the excitation current flows into the component under test via the first main connection terminal or the second main connection terminal. the switching matrix comprises a constant current source switching unit that is adaptively connected to the pulse constant current source, wherein, the constant current source switching unit comprises a first constant current excitation branch and a second constant current excitation branch, wherein the first constant current excitation branch and the second constant current excitation branch are adaptively connected to the pulse constant current source; the first constant current excitation branch comprises several first constant current excitation branch switches; the second constant current excitation branch comprises several second constant current excitation branch switches; the number of first constant current excitation branch switches and the number of second constant current excitation branch switches is not less than the number of power switching components in the component unit under test; When testing the bridge circuit or a component under test, a corresponding first constant current excitation branch switch in the first constant current excitation branch is configured to be in the closed state, and a corresponding second constant current excitation branch switch in the second constant current excitation branch is configured to be in the closed state, so that the pulse constant current source is adaptively connected to the bridge circuit or component under test; For any component to be tested, the direction of the excitation current fed into the power switching element is opposite to the direction of the excitation current fed into the freewheeling diode. the pulse constant current source comprises a current source and a current direction reversal circuit that is adaptively connected to the current source, wherein, The current direction reversing circuit comprises a first direction reversing branch and a second direction reversing branch, which are connected in parallel to the current source; the first direction switching branch comprises an NMOS transistor Q1 and an NMOS transistor Q3, wherein the drain terminal of the NMOS transistor Q1 is connected to the positive terminal of the current source, and the source terminal of the NMOS transistor Q1 is adaptively connected to the drain terminal of the NMOS transistor Q3 and to the first constant current excitation branch; the second direction-switching branch comprises an NMOS transistor Q2 and an NMOS transistor Q4, wherein the drain terminal of the NMOS transistor Q2 is connected to the positive terminal of the current source, and the source terminal of the NMOS transistor Q2 is adaptively connected to the drain terminal of the NMOS transistor Q4 and to the second constant current excitation branch; the source terminal of NMOS transistor Q3 and the source terminal of NMOS transistor Q4 are both connected to the negative terminal of the power source; when configured so that NMOS transistor Q1 and NMOS transistor Q4 are simultaneously in the conducting state and NMOS transistor Q2 and NMOS transistor Q3 are simultaneously in the blocking state, the pulse current source provides an excitation current in a first current direction; When configured so that NMOS transistor Q2 and NMOS transistor Q3 are simultaneously in the conducting state and NMOS transistor Q1 and NMOS transistor Q4 are simultaneously in the blocking state, the pulse current source provides an excitation current in a second current direction. for any first constant current excitation branch switch, the first terminal of the first constant current excitation branch switch is connected to the source terminal of the NMOS transistor Q1 and the drain terminal of the NMOS transistor Q3, and the second terminal of the first constant current excitation branch switch is electrically connected to a corresponding first main connection terminal of a power switching device; For any second constant current excitation branch switch, the first terminal of the second constant current excitation branch switch is connected to the source terminal of the NMOS transistor Q2 and the drain terminal of the NMOS transistor Q4, and the second terminal of the second constant current excitation branch switch is electrically connected to a corresponding second main connection terminal of a power switching device. the pulse constant current source further comprises a reversing control circuit, wherein the reversing control circuit comprises at least four reversing control modules to configure the NMOS transistor Q1, the NMOS transistor Q2, the NMOS transistor Q3 and the NMOS transistor Q4 to each be adaptively connected to a reversing control module; Any reversing control module comprises, in series, an optocoupler isolator, a driver amplifier, a signal conditioning circuit, and a driver interconnect circuit, wherein, The driver interconnect circuit comprises a first driver interconnect NMOS transistor and a second driver interconnect NMOS transistor, wherein the gate terminal of the first driver interconnect NMOS transistor and the gate terminal of the second driver interconnect NMOS transistor are both connected to the signal conditioning circuit; the drain terminal of the first driver interconnect NMOS transistor is connected to the isolation voltage output by an isolated power supply, the source terminal of the first driver interconnect NMOS transistor is connected to the drain terminal of the second driver interconnect NMOS transistor and to the gate terminal of an NMOS transistor in the current direction reversing circuit; the source terminal of the second driver interconnect NMOS transistor is connected to the source terminal of the connected NMOS transistor in the current direction reversing circuit. the bias source unit comprises two bias sources, and the switching matrix comprises two groups of bias switching units, wherein the bias sources and the bias switching units interact in a one-to-one connection; for any bias switching unit, the bias switching unit comprises a first bias branch and a second bias branch, wherein, the first biasing branch comprises several first biasing branch switches; the second bias branch comprises several second bias branch switches; the number of first bias branch switches and the number of second bias branch switches is not less than the number of bridge circuits in the component unit under test; For a power switching element, the control terminal of the power switching element is connected to the positive pole of the corresponding bias source via a first bias branch switch, and the second auxiliary connection terminal of the power switching element is connected to the negative pole of the corresponding bias source via a second bias branch switch. The voltage measurement unit comprises two groups of voltage measurement components, wherein, Each group of voltage measurement components corresponds to a component under test, in order to measure the voltage between the first main connection terminal and the second auxiliary connection terminal, the voltage between the first auxiliary connection terminal and the second auxiliary connection terminal, and the voltage between the second main connection terminal and the second auxiliary connection terminal using the voltage measurement components. Each group of voltage measurement components comprises three voltmeters, and the switching matrix comprises one voltmeter switching unit corresponding to each group of voltage measurement components, wherein, the voltmeter switching unit includes voltmeter leads, each connected to the three voltmeters; For any voltmeter line, the voltmeter line comprises a first voltmeter branch and a second voltmeter branch, and the voltmeter is adaptively connected to the power switching element via the first voltmeter branch and the second voltmeter branch to perform a voltage measurement. The first constant-current excitation branch switch and the second constant-current excitation branch switch are both mechanical high-voltage, high-current switches. Advantages of the present utility model: The switching matrix allows the selection of the pulse constant-current source, the bias source unit, and the voltage measurement unit, which are adaptively connected to the component under test to test the bridge circuit or component. Multiple VCEsat and VF parameters can be measured in parallel in a single test, increasing test efficiency. This contributes to extending the service life of the test equipment and the mean time between failures, reducing the wear and tear on the switches in the switching matrix, and lowering equipment maintenance costs. Figures Fig. Figure 1 is a circuit principle diagram of an embodiment of the present utility model for testing static parameters of a component unit under test. Fig. Figure 2 is a schematic diagram of an embodiment of the present utility model for testing the VCEsat parameter of a power switching element of an upper bridge arm unit. Fig. Figure 3 is a schematic diagram of an embodiment of the present utility model for testing the VF parameter of a freewheeling diode of an upper bridge arm unit. Fig. Figure 4 is a schematic diagram of an embodiment of the present utility model for simultaneously testing the VCEsat parameters of two power switching devices of a bridge circuit. Fig. Figure 5 is a schematic diagram of an embodiment of the present utility model for sequentially testing VCEsat parameters and VF parameters of a bridge circuit during the same test procedure. Fig. Figure 6 is a circuit principle diagram of an embodiment of a pulse constant current source of the present utility model. Specific embodiments

[0009] The present utility model is described in more detail below in conjunction with the attached drawings and examples of embodiments.

[0010] To effectively increase the testing speed of static parameters of semiconductor devices and to extend the service life of the switching matrix, the present utility model provides a test system for increasing the testing speed of static parameters, in particular the test system comprises a pulse constant current source, a bias source unit, a voltage measurement unit and a switching matrix, wherein, The pulse constant current source, the bias source unit, and the voltage measurement unit are each adaptively connected to a component unit to be tested via the switching matrix; the component unit to be tested comprises at least one bridge circuit, the bridge circuit comprises two adaptively connected components to be tested, each component to be tested comprises a power switching component and a freewheeling diode that serves for freewheeling when the power switching component is blocked; The switching matrix selects the pulse constant current source, the bias source unit, and the voltage measurement unit, and connects them adaptively to the component unit under test in order to test the bridge circuit or component under test, wherein, the pulse constant current source is used to provide an excitation current to the bridge circuit or component under test; the bias source unit provides a drive bias to drive the corresponding power switching element into the conducting state or the blocking state; The voltage measurement unit is used to perform a voltage measurement on the component under test in order to determine the static parameters of the component unit under test based on the measured test voltage.

[0011] It should be noted that the static parameter test performed by the test system of this utility model is the aforementioned static parameter test for power semiconductors; the situation regarding the static parameters can be seen in the description above. When testing static parameters, a component unit to be tested should be provided, which constitutes the test object of the test system of this utility model. In particular, the component unit to be tested should comprise at least one bridge circuit, the number of which can be selected as required, and each bridge circuit should comprise two components to be tested; that is, two components to be tested can form a bridge circuit by connecting them together. The formation of a bridge circuit is explained below by way of example.

[0012] In the specific implementation, the two components under test preferably use the same form factor. Each component under test should include a power switching element and a freewheeling diode. The power switching element can be of the aforementioned type of power semiconductor device, such as the IGBT or MOSFET mentioned above. For each component under test, freewheeling via the freewheeling diode is possible when the power switching element is off. The nature and purpose of the freewheeling via the freewheeling diode are state of the art. It is understood that when testing static parameters, the corresponding static parameters of the power switching element and the freewheeling diode within the component under test are primarily tested and determined.

[0013] To meet the requirements of static testing, the test system of this utility model should comprise a pulsed constant current source, a bias source unit, a voltage measurement unit, and a switching matrix. The pulsed constant current source, the bias source unit, and the voltage measurement unit are each adaptively connected to the component under test via the switching matrix. The switching matrix allows control of the connection state of the pulsed constant current source, the bias source unit, and the voltage measurement unit with the component under test. By controlling the connection state with the component under test, static parameter testing can be performed under various test requirements, thus enabling rapid testing of static parameters.Therefore, the method of controlling the connection state is specifically tailored to the requirements of testing static parameters under various test conditions. The connection state control process will be described in detail later.

[0014] When testing static parameters, the static parameter test can be performed on the entire bridge circuit or on a component within the bridge circuit under test. In this case, the bridge circuit or the component within the bridge circuit under test constitutes the test object, and the test object's configuration can be selected as needed. Specifically, the pulse constant current source can provide the excitation current required for testing static parameters; that is, the pulse constant current source can supply an excitation current to the bridge circuit or the component under test during the static test.

[0015] It should be understood that when testing the static parameters of a power switching device, the device should be configured in the appropriate operating state. For example, if the static parameter being tested is the VCEsat parameter, the device should be configured in the conducting state. If the static parameter being tested is the V(BR)CES and ICES parameters, the device should be configured in the blocking state. Specifically, the bias source unit can provide a drive bias to force the device into either the conducting or blocking state. The drive state of the device depends on the requirements of the static parameter test.For example, when the VCEsat parameter test is performed on a bridge circuit, the bias source unit should drive both power switching devices within the same bridge circuit into the conducting state. When the VCEsat parameter test is performed on a single device under test, only the power switching device can be driven into the conducting state during the static parameter test. The drive state of the power switching device by the drive bias can depend on the type of power switching device. The situation in which the power switching device is driven into the conducting or blocking state by the drive bias is state of the art and is not discussed further here.

[0016] The following description uses the VCEsat parameter test, performed on the power switching device, as an example to explain the type and process of the static parameter test performed by the present utility model; i.e., in the following description, the static parameter test specifically refers to the VCEsat parameter test, which can serve as a reference here.

[0017] In the specific implementation, when testing the static parameters of a power switching device, the device should first be configured to conduct. Then, the pulse constant current source is applied to supply the excitation current. When the excitation current flows through the conducting bridge circuit or the component under test, a voltage drop occurs. At this point, the voltage measurement unit can be used to measure the voltage across the component under test. The static parameters of the device under test can then be determined from the measured test voltage. The method for determining static parameters from the test voltage is explained below with an example.

[0018] It should be noted that when testing static parameters, the conditions for freewheeling operation are not met. Therefore, when testing the static parameters of a freewheeling diode, the corresponding power switching device should be configured in the off state. When the excitation current is applied, it can flow completely through the freewheeling diode to perform the static parameter test. The method used to test the static parameters of the freewheeling diode can be state-of-the-art. As described in Fig. As shown in Figure 1, when testing static parameters of the freewheeling diode DUT-U, the excitation current should flow from the anode terminal of the freewheeling diode DUT-U to the cathode terminal of the freewheeling diode DUT-U, or, as shown in Figure 1, Fig. 4. The test of static parameters can be performed simultaneously on the freewheeling diode DUT-U and the freewheeling diode DUT-L within the bridge circuit.

[0019] It should be clear that when testing the static parameters of a freewheeling diode, the VF parameter of the freewheeling diode is primarily determined. Furthermore, when testing the static parameters of a freewheeling diode, the direction of the excitation current flowing through the freewheeling diode is opposite to the direction of the excitation current flowing through the power switching device.

[0020] In one embodiment of the present utility model, for any power switching element, an adaptively connected first auxiliary connection and a first main connection are provided at the first connection terminal of the power switching element, wherein the first main connection and the first auxiliary connection are both electrically connected to the first connection terminal; an adaptively connected second auxiliary connection and a second main connection are provided at the second connection terminal of the semiconductor device, wherein the second main connection and the second auxiliary connection are both electrically connected to the second connection terminal; For a component to be tested, within the component to be tested, the cathode terminal of the freewheeling diode is electrically connected to the first connection terminal of the power switching element, and the anode terminal of the freewheeling diode is electrically connected to the second connection terminal of the power switching element; Within the bridge circuit, a component under test forms an upper bridge arm unit, another component under test forms a lower bridge arm unit, and the second main connection terminal within the upper bridge arm unit is electrically connected to the first main connection terminal within the lower bridge arm unit; when testing a component under test, the component under test is adaptively connected to the pulse constant current source via the first main connection terminal and the second main connection terminal, and the excitation current flows into the component under test via the first main connection terminal or the second main connection terminal.

[0021] It should be noted that the power switching device is the aforementioned power semiconductor device (excluding diode devices). The power switching device is a three-terminal device, where the three terminals are the first connection terminal, the second connection terminal, and the control terminal. The types of the three terminals depend on the type of power switching device. For example, if the power switching device is an IGBT device, the control terminal is the gate terminal of the IGBT device, the first connection terminal is the collector terminal of the IGBT device, and the second connection terminal is the emitter terminal of the IGBT device.If the power switching device is a MOSFET, the control terminal is the gate terminal of the MOSFET, the first connection terminal is the drain terminal, and the second connection terminal is the source terminal. If the power switching device is of a different type, the positions of the control terminal, first connection terminal, and second connection terminal can be determined according to the type of power switching device, which will not be explained in detail here.

[0022] It should be noted that in the component under test of this utility model, the power switching element and the freewheeling diode may be housed within a single, integrated power module. In this integrated power module, the first connection terminal of the power switching element generally features a first auxiliary connection terminal and a first main connection terminal. The first main connection terminal is typically used for connecting high-current circuits and is also larger. The first auxiliary connection terminal is typically used for connecting small-signal circuits and is also smaller. In the following description, main terminal and auxiliary terminal have the same meaning and can be used for reference.Similarly, a second auxiliary connection and a second main connection are provided at the second connection terminal of the power switching element.

[0023] In Fig. 1 to Fig. Figure 4 shows an embodiment in which the test system of the present utility model tests a component unit to be tested. The figures illustrate the case where the power switching component is an IGBT component. Fig. 1 to Fig. 4. G1 and G2 are two power switching devices, DUT-U and DUT-L are two freewheeling diodes, where the power switching device G1 and the freewheeling diode DUT-U can form one component under test, and the power switching device G2 and the freewheeling diode DUT-L can form one component under test, and the two components under test are adaptively connected to form a bridge circuit. That is to say, in Fig. 1 to Fig. Figure 4 shows an embodiment in which the component unit under test comprises a bridge circuit. If the component unit under test comprises two bridge circuits, the two bridge circuits are independent of each other and connected via the switching matrix to the aforementioned pulse constant current source, bias source unit, and voltage measurement unit. The difference lies in the shape of the switching matrix, which is described in detail below.

[0024] In Fig. 1 to Fig. 4. P1 is the first main connection of the power switching element G1, C1 is the first auxiliary connection of the power switching element G1, E1 is the second auxiliary connection of the power switching element G1, U is the shape formed by connecting the second main connection of the power switching element G1 with the first main connection of the power switching element G2, C2 is the first auxiliary connection of the power switching element G2, E2 is the second auxiliary connection of the power switching element G2, and N1 is the second main connection of the power switching element G2. Therefore, the shape of the bridge circuit can be described as follows: Fig. 1 to Fig. 4. It should be noted that Fig. 1 to Fig. Figure 4 only schematically shows the correspondence between main terminals and auxiliary terminals. The relationship between main terminals and auxiliary terminals can be found in the description above.

[0025] From the above description of the power switching element type, it is evident that when testing a component under test, the power switching element is adaptively connected to the pulse constant current source within the component via the first and second main connection terminals, and the excitation current flows into the component under test via either the first or the second main connection terminal. The excitation current configuration for testing static parameters on the bridge circuit can be determined similarly.

[0026] In one embodiment of the present utility model, the switching matrix comprises a constant current source switching unit which is adaptively connected to the pulse constant current source, wherein, the constant current source switching unit comprises a first constant current excitation branch and a second constant current excitation branch, wherein the first constant current excitation branch and the second constant current excitation branch are adaptively connected to the pulse constant current source; the first constant current excitation branch comprises several first constant current excitation branch switches; the second constant current excitation branch comprises several second constant current excitation branch switches; the number of first constant current excitation branch switches and the number of second constant current excitation branch switches is not less than the number of power switching components in the component unit under test; When testing the bridge circuit or a component under test, a corresponding first constant current excitation branch switch in the first constant current excitation branch is configured to be in the closed state, and a corresponding second constant current excitation branch switch in the second constant current excitation branch is configured to be in the closed state, so that the pulse constant current source is adaptively connected to the bridge circuit or component under test; For any component to be tested, the direction of the excitation current fed into the power switching element is opposite to the direction of the excitation current fed into the freewheeling diode.

[0027] The above description indicates that the test object for testing static parameters can vary. If the test object is different, the pulse constant current source should be able to supply an excitation current to the corresponding test object. In the specific implementation, if the test object is different, the excitation current supply can be adjusted via the constant current source switching unit in the switching matrix. To control the excitation current supply, the constant current source switching unit should include a first constant current excitation branch and a second constant current excitation branch, with the first constant current excitation branch comprising several first constant current excitation branch switches and the second constant current excitation branch comprising several second constant current excitation branch switches.In general, the number of first constant-current excitation branch switches and the number of second constant-current excitation branch switches are not less than the number of power switching devices in the component unit under test. As in . Fig. 1 to Fig. 4. If the component unit under test comprises two power switching devices, the number of first constant current excitation branch switches and the number of second constant current excitation branch switches should be at least 2. Other situations are described in this document and are not listed individually.

[0028] In Fig. 1 to Fig. 4. Switches K1a and K1b are two first constant-current excitation branch switches in the first constant-current excitation branch, and switches K1c and K1d are two second constant-current excitation branch switches in the second constant-current excitation branch. It should be understood that the first and second constant-current excitation branches should also include appropriate connecting lines to allow for adaptive connection to the pulse constant-current source. It should be noted that both the first and second constant-current excitation branch switches are mechanical high-voltage, high-current switches, due to the large excitation current value. Fig. 1 to Fig. 4. The first terminal of switch K1a and the first terminal of switch K1b are connected to the pulse constant current source, the second terminal of switch K1a is connected to the first main connection terminal of the power switching element G1, the second terminal of switch K1b is connected to the first main connection terminal of the power switching element G2, the first terminal of switch K1c and the first terminal of switch K1d are connected to the pulse constant current source, the second terminal of switch K1c is connected to the second main connection terminal of the power switching element G1, and the second terminal of switch K1d is connected to the second main connection terminal of the power switching element G2.

[0029] Fig. Figure 2 shows an embodiment of the test of static parameters on the power switching device G1. At this point, the power switching device G1 is in the conducting state. It should be configured so that switch K1a and switch K1c are in the closed state. The pulse constant current source injects an excitation current into the power switching device G1, with the excitation current direction running from the first connection terminal of the power switching device G1 to the second connection terminal of the power switching device G1.

[0030] Fig. Figure 3 shows an embodiment of the test of static parameters on the freewheeling diode DUT-U. At this point, switches K1a and K1c are still configured to be in the closed state, but the excitation current flows from the second terminal of the power switching device G1 to the first terminal of the power switching device G1. The difference is that the power switching device G1 should be in the off state at this point, and the excitation current flows through the freewheeling diode DUT-U.

[0031] Fig. Figure 4 shows an embodiment of the static parameter test on the bridge circuit. At this point, both the power switching element G1 and the power switching element G2 are in the conducting state. Switches K1a and K1d should be configured to be in the closed state. During the static parameter test, the excitation current flows from the first terminal of power switching element G1, through the second terminal of power switching element G1, through the first main terminal of power switching element G2, through the second main terminal of power switching element G2, and back to the pulse constant current source, thus forming a closed circuit.

[0032] If the test of static parameters on the freewheeling diode DUT-U and the freewheeling diode DUT-L needs to be performed within the bridge circuit, the above can be used. Fig. 4, Fig. Reference is made to section 3 and the corresponding descriptions above, which will not be elaborated upon here. Furthermore, if the test of static parameters must be performed simultaneously on two bridge circuits, the switching matrix can be adapted with reference to the situation in section 3. Fig. 4 can be configured, specifically so that the testing of static parameters on the two bridge circuits can be implemented.

[0033] In one embodiment of the present utility model, the pulse constant current source comprises a current source and a current direction reversal circuit which is adaptively connected to the current source, wherein, The current direction reversing circuit comprises a first direction reversing branch and a second direction reversing branch, which are connected in parallel to the current source; the first direction switching branch comprises an NMOS transistor Q1 and an NMOS transistor Q3, wherein the drain terminal of the NMOS transistor Q1 is connected to the positive terminal of the current source, and the source terminal of the NMOS transistor Q1 is adaptively connected to the drain terminal of the NMOS transistor Q3 and to the first constant current excitation branch; the second direction-switching branch comprises an NMOS transistor Q2 and an NMOS transistor Q4, wherein the drain terminal of the NMOS transistor Q2 is connected to the positive terminal of the current source, and the source terminal of the NMOS transistor Q2 is adaptively connected to the drain terminal of the NMOS transistor Q4 and to the second constant current excitation branch; the source terminal of NMOS transistor Q3 and the source terminal of NMOS transistor Q4 are both connected to the negative terminal of the power source; when configured so that NMOS transistor Q1 and NMOS transistor Q4 are simultaneously in the conducting state and NMOS transistor Q2 and NMOS transistor Q3 are simultaneously in the blocking state, the pulse current source provides an excitation current in a first current direction; When configured so that NMOS transistor Q2 and NMOS transistor Q3 are simultaneously in the conducting state and NMOS transistor Q1 and NMOS transistor Q4 are simultaneously in the blocking state, the pulse current source provides an excitation current in a second current direction.

[0034] In Fig. 1 to Fig. 4 and Fig. Figure 6 shows an embodiment of a pulse constant current source. The figures show that the pulse constant current source can comprise a current source and a current direction reversal circuit. The current source can take a conventional, standard form. Fig. 1 to Fig. 4 as well Fig. In 6, I1 is the current source, and an excitation current can be provided via the current source. Therefore, the current source can take a form that can provide the required excitation current. A current reversal circuit can be used to implement a current polarity reversal, such as the realization of the two different current directions in Fig. 2 and Fig. 3, to meet the requirements of the static parameter test. In the specific implementation, the output of excitation currents in different current directions is achieved by configuring the corresponding conducting states of the NMOS transistors Q1, NMOS transistor Q2, NMOS transistor Q3, and NMOS transistor Q4.

[0035] If the pulse constant current source takes the above form, then: for any first constant current excitation branch switch, the first terminal of the first constant current excitation branch switch is connected to the source terminal of the NMOS transistor Q1 and the drain terminal of the NMOS transistor Q3, and the second terminal of the first constant current excitation branch switch is electrically connected to a corresponding first main connection terminal of a power switching device; For any second constant current excitation branch switch, the first terminal of the second constant current excitation branch switch is connected to the source terminal of the NMOS transistor Q2 and the drain terminal of the NMOS transistor Q4, and the second terminal of the second constant current excitation branch switch is electrically connected to a corresponding second connection main terminal of a power switching device.

[0036] In Fig. 1 to Fig. 4. The first terminal of switch K1a and the first terminal of switch K1b are connected to the source terminal of NMOS transistor Q1 and the drain terminal of NMOS transistor Q3, and the first terminal of switch K1c and the first terminal of switch K1d are connected to the source terminal of NMOS transistor Q2 and the drain terminal of NMOS transistor Q3.

[0037] In one embodiment of the present utility model, the pulse constant current source further comprises a polarity reversal control circuit, wherein, The reversing control circuit comprises at least four reversing control modules to configure the NMOS transistor Q1, the NMOS transistor Q2, the NMOS transistor Q3, and the NMOS transistor Q4 to each be adaptively connected to a reversing control module; Any reversing control module comprises, in series, an optocoupler isolator, a driver amplifier, a signal conditioning circuit, and a driver interconnect circuit, wherein, The driver interconnect circuit comprises a first driver interconnect NMOS transistor and a second driver interconnect NMOS transistor, wherein the gate terminal of the first driver interconnect NMOS transistor and the gate terminal of the second driver interconnect NMOS transistor are both connected to the signal conditioning circuit; the drain terminal of the first driver interconnect NMOS transistor is connected to the isolation voltage output by an isolated power supply, the source terminal of the first driver interconnect NMOS transistor is connected to the drain terminal of the second driver interconnect NMOS transistor and to the gate terminal of an NMOS transistor in the current direction reversing circuit; the source terminal of the second driver interconnect NMOS transistor is connected to the source terminal of the connected NMOS transistor in the current direction reversing circuit.

[0038] The above description shows that the current reversal circuit can reverse the polarity of the current output by the power source. If the current reversal circuit takes the form shown above, it is necessary to drive and control the corresponding conducting states of the NMOS transistors Q1 and Q4 in the current reversal circuit via the polarity reversal control circuit. Fig. Figure 6 shows an embodiment of a polarity reversal control circuit. In the figure, the polarity reversal control circuit comprises four polarity reversal control modules, each corresponding to the NMOS transistor Q1 to NMOS transistor Q4, i.e., one polarity reversal control module can control one corresponding NMOS transistor. Fig. Figure 6 represents the structure in each dashed frame as a polarity reversal control module.

[0039] Out of Fig. Figure 6 shows that each polarity reversal control module can comprise an optocoupler isolator, a driver amplifier, a signal conditioning circuit, and a driver interconnect circuit connected in series. The example of the polarity reversal control module connected to the NMOS transistor Q4 in Fig. 6 corresponds to, is explained: In Fig. 6. OG4 is the optocoupler isolator, OA4 is the driver amplifier, and OD4 is the signal conditioning circuit. The driver interconnect circuit comprises the NMOS transistor M40 and the NMOS transistor M41, with NMOS transistor M40 forming the first driver interconnect NMOS transistor and NMOS transistor M41 forming the second driver interconnect NMOS transistor. The optocoupler isolator OG4 can isolate the input signal. The driver amplifier OA4 can amplify the signal output by the optocoupler isolator OG4. The signal conditioning circuit OD4 is used to condition the signal output by the driver amplifier OA4, for example, by filtering and other signal conditioning. The form of the signal conditioning circuit OD4 can be selected according to requirements.

[0040] Out of Fig. Figure 6 shows that each polarity reversal control module can be powered by a DC-DC isolated power supply. The DC-DC isolated power supply can output a supply voltage of 15 V. Fig. 6. "Isolated Power Supply" refers to the DC-DC isolated power supply. In this specific implementation, the drive states of all reversing drive modules are configured by the forward signal, the backward signal, and the GND signal. Specifically, when the forward signal is high relative to the GND signal and the backward signal is low relative to the GND signal, NMOS transistors Q1 and Q3 can be driven to conduct, and the current output by the pulse constant current source is the excitation current in the first current direction. Conversely, when the forward signal is low relative to the GND signal and the backward signal is high relative to the GND signal, NMOS transistors Q2 and Q4 can be driven to conduct, and the pulse constant current source outputs the excitation current in the second current direction.

[0041] Of course, the polarity reversal control circuit can also take other forms. The control method used by the polarity reversal control circuit can be selected as needed, as long as it can implement the polarity reversal control of the ground current direction switching circuit, which will not be explained in detail here.

[0042] In one embodiment of the present utility model, the bias source unit comprises two bias sources, and the switching matrix comprises two groups of bias switching units, wherein the bias sources and the bias switching units interact in a one-to-one connection; for any given preload switching unit, the preload switching unit comprises a first preload branch and a second preload branch, wherein, the first biasing branch comprises several first biasing branch switches; the second bias branch comprises several second bias branch switches; the number of first bias branch switches and the number of second bias branch switches is not less than the number of bridge circuits in the component unit under test; For a power switching element, the control terminal of the power switching element is connected to the positive pole of the corresponding bias source via a first bias branch switch, and the second auxiliary connection terminal of the power switching element is connected to the negative pole of the corresponding bias source via a second bias branch switch.

[0043] In Fig. 1 to Fig. Figure 4 shows an embodiment in which the bias source unit comprises two bias sources. In the figures, VS1 and VS2 are two voltage sources, with voltage source VS1 providing a drive bias to the power switching device G1 and voltage source VS2 providing a drive bias to the power switching device G2. It is important to note that the drive bias provided by voltage source VS1 must primarily be able to control the power switching device G1 in a conducting or blocking state. Similarly, the drive bias provided by voltage source VS2 should be able to control the power switching device G2 in a conducting or blocking state. Therefore, the waveform used by voltage sources VS1 and VS2 and the output voltage should be dimensioned to achieve the conducting or blocking control of the power switching device.

[0044] Similar to the pulse constant current source mentioned above, each bias source should interact with a bias switching unit in a suitable connection to configure the bias supply state via the bias switching unit. The bias switching unit comprises a first bias branch and a second bias branch, the first bias branch comprising multiple first bias branch switches; the second bias branch comprising multiple second bias branch switches. Specifically, the number of first bias branch switches and the number of second bias branch switches are not less than the number of bridge circuits in the component unit under test. For example, if the component unit under test includes a bridge circuit, the number of first bias branch switches in each bias switching unit should be 1.If it comprises 2 bridge units, the number of first bias branch switches in each bias switching unit should be 2.

[0045] In Fig. 1 to Fig. 4. K2a is a first bias branch switch, K2b a second bias branch switch. Switches K2a and K2b correspond to the voltage source VS1. The first terminal of switch K2a is connected to the positive terminal of voltage source VS1, the second terminal of switch K2a is connected to the control terminal of the power switching device G1, and the second auxiliary connection terminal of the power switching device G1 is connected via switch K2b to the negative terminal of voltage source VS1. Therefore, when both switches K2a and K2b are closed, voltage source VS1 can control the power switching device G1 to either conduct or block it.Similarly, K2c is a first bias branch switch, K2d is a second bias branch switch, switches K2c and K2d correspond to the voltage source VS2, the voltage source VS2 is connected to the power switching element G2 via switches K2c and K2d, and the situation of the interaction and the conducting or blocking control of the power switching element G2 can be seen from the above description of the interaction of the power switching element G1 and the voltage source VS1, which is not elaborated further here.

[0046] If multiple bridge circuits are present, voltage source VS1 or voltage source VS2 can be used to implement the conducting or blocking control of power switching devices in different bridge circuits. At this point, the bias switching unit in the switching matrix must be configured to fulfill the required control purpose, which will not be explained in detail here.

[0047] In one embodiment of the present utility model, the voltage measuring unit comprises two groups of voltage measuring components, wherein, Each group of voltage measurement components corresponds to a component under test, in order to measure the voltage between the first main connection terminal and the second main connection terminal, the voltage between the first auxiliary connection terminal and the second main connection terminal, and the voltage between the second auxiliary connection terminal and the second main connection terminal using the voltage measurement components.

[0048] The above description indicates that the static parameters of the power switching device can be determined by voltage measurement during testing. Therefore, the voltage measurement unit for a bridge circuit should comprise two groups of voltage measurement components, with one group being used to perform the required voltage measurement on the component under test.

[0049] In one embodiment of the present utility model, each group of voltage measuring components comprises three voltmeters, and the switching matrix comprises a voltmeter switching unit corresponding to each group of voltage measuring components, wherein, the voltmeter switching unit includes voltmeter leads, each connected to the three voltmeters; For any voltmeter line, the voltmeter line comprises a first voltmeter branch and a second voltmeter branch, and the voltmeter is adaptively connected to the power switching element via the first voltmeter branch and the second voltmeter branch to perform a voltage measurement.

[0050] In Fig. 1 to Fig. Figure 4 shows an embodiment in which two groups of voltage measuring components are present, and each group of voltage measuring components comprises three voltmeters. In the figures, voltmeters V11 to V13 belong to the same voltage measuring component, and voltmeters V14 to V16 belong to the same voltage measuring component. It should be noted that in Fig. 1 to Fig. Four components that are not in working order are shown in gray, while components in working order are shown with normal lines. As in Fig. The two leads corresponding to voltmeters V14 and V16 are gray, indicating they are not in operation. Further details can be found in this description.

[0051] In Fig. 2. For voltmeter V11, the first voltmeter branch includes switch K3a and switch K3b. One terminal of voltmeter V11 is connected via switch K3a to the first main connection of the power switching element G1, and the other terminal of voltmeter V11 is connected via switch K3b to the second main connection of the power switching element G1. This means that voltmeter V11 can measure the voltage between the first and second main connections of the power switching element G1. The situation where voltmeters V12 and V16 are adaptively connected to the power switching element via voltmeter leads can be described as follows: Fig. 2 to Fig. 4 and this description.

[0052] In Fig. 2. Voltmeters V11 and V13 can measure the voltages corresponding to the power switching element G1. In particular, after the voltage measurement, the voltage drop between the first main connection terminal, the first auxiliary connection terminal, and the second auxiliary connection terminal of the power switching element G1 in the conducting state and the second main connection terminal can be measured (designated as VU1, VU2, VU3). At this time, the following holds: VCEsat(UCm-UEm)=VU1, VCEsat(UCa-UEa)=VU2-VU3, VCEsat(UCm-UEa)=VU1-VU3, VCEsat(UCa-UEm)=VU2, where, In the above symbol U, the upper half-bridge arm in the bridge circuit is represented. As in Fig. 1. The power switching element G1 is located in the upper half-bridge arm of the bridge circuit, DUT-U represents the freewheeling diode corresponding to the power switching element, and L represents the lower half-bridge arm of the bridge circuit. The situation of L can be deduced from this description of U and is not repeated in detail. C represents the collector of the power switching device, E the emitter of the power switching device, m the main terminal corresponding to the power switching device, and a the auxiliary terminal corresponding to the power switching device; therefore, UCm represents the measurement position at the collector main terminal corresponding to the power switching device G1, UEm the measurement position at the emitter main terminal corresponding to the power switching device G1, and UEa the measurement position at the emitter auxiliary terminal corresponding to the power switching device. Other situations can be found in this description and are not explained individually. It is evident from this that a single test can simultaneously determine VCEsat parameters for various combinations of main and auxiliary terminals. Other situations involving voltage measurement and determination of static parameters can be found in this description.

[0053] It should be noted that in the switching matrix, apart from the first constant current excitation branch switch and the second constant current excitation branch switch, which are both mechanical high-voltage high-current switches, all other switches are mechanical high-voltage low-current switches.

[0054] The above description shows that the test system of the present utility model can combine the corresponding tests for the VCEsat parameters and VF parameters into a single test. Fig. Figure 5 shows a time diagram of a combined check of VCEsat parameters and VF parameters, with the specific process proceeding as follows: Time t0: Setting the bias voltage for the power switching element to make the power switching element under test conductive. Time t1: NMOS transistors Q1 / NMOS transistor Q3 become conductive (in Fig. 5 (the conduction of NMOS transistors Q1 / NMOS transistor Q3 is represented by a high level), the blocking of NMOS transistors Q2 / NMOS transistor Q4 (in Fig. 5 (the blocking of the NMOS transistors Q2 / NMOS transistor Q4 is represented by a low level). Period t2~t3: At time t2, the current source begins to output current. The current gradually increases over time and reaches the target current value at time t3, where it remains constant; this is the excitation current. During this period, the voltage VCE of the power switching device under test will exhibit a transient voltage waveform response, but this voltage change process need not be considered. Period t3~t4: During this period, the excitation current of the power switching device under test is constant, and the voltage response quickly transitions to a steady state. The voltage waveform is recorded, and the average value of the waveform in the stable section is taken as the VCESat parameter of the power switching device. Time t4: NMOS transistors Q2 / NMOS transistor Q4 are made conductive, NMOS transistors Q1 / NMOS transistor Q3 are made inactive. At this time, the excitation current reverses polarity, changing its direction from forward (injection via the collector, outflow via the emitter, flowing through the power switching element) to reverse (injection via the emitter, outflow via the collector, flowing through the freewheeling diode). Time t5: Blocking the power switching component under test to ensure that the entire excitation current flows into the freewheeling diode. Period t5~t6: During this period, the excitation current of the freewheeling diode under test is constant, and the voltage response quickly transitions to a steady state. The voltage waveform is recorded, and the average value of the waveform in the stable section is taken, with its absolute value being used as the VF parameter of the freewheeling diode. Period t6~t7: The power source begins to reduce the output current, which gradually decreases over time and drops to 0 at time t7. During this period, the voltage VCE of the power switching element in the component under test will exhibit a transient voltage waveform response, but this voltage change process does not need to be considered. Time t8: NMOS transistors Q2 / NMOS transistor Q4 are switched off, end of test.

[0055] It should be noted that in other cases, when testing static parameters of a test object, the configuration of the interaction of the pulse constant current source, the bias source with the test object, and the manner in which the voltage measurement is carried out can be taken from this description and will not be explained further.

[0056] Furthermore, the test system described above only shows examples of testing VCEsat parameters on the power switching device and VF parameters on the freewheeling diode. If other static parameter tests are required, appropriate test components can be added to the test system according to the test requirements of the respective static parameters, and the corresponding tests can be performed accordingly. The method and process for testing other static parameters are not explained individually here.

Claims

[1] Test system that can increase the test speed of static parameters, characterized by that the test system comprises a pulse constant current source, a bias source unit, a voltage measurement unit, and a switching matrix, wherein, The pulse constant current source, the bias source unit, and the voltage measurement unit are each adaptively connected to a component unit to be tested via the switching matrix; the component unit to be tested comprises at least one bridge circuit, the bridge circuit comprises two adaptively connected components to be tested, each component to be tested comprises a power switching element and a freewheeling diode that serves for freewheeling when the power switching element is blocked; The switching matrix selects the pulse constant current source, the bias source unit, and the voltage measurement unit, and connects them adaptively to the component unit under test in order to test the bridge circuit or component under test, wherein, the pulse constant current source is used to provide an excitation current to the bridge circuit or component under test; the bias source unit provides a drive bias to drive the corresponding power switching element into the conducting state or the blocking state; The voltage measurement unit is used to perform a voltage measurement on the component under test in order to determine the static parameters of the component unit under test based on the measured test voltage. [2] Test system according to claim 1, which can increase the test speed of static parameters, characterized by, that: for any power switching element, an adaptively connected first auxiliary connection and a first main connection are provided at the first connection terminal of the power switching element, wherein the first main connection and the first auxiliary connection are both electrically connected to the first connection terminal; an adaptively connected second auxiliary connection and a second main connection are provided at the second connection terminal of the semiconductor device, wherein the second main connection and the second auxiliary connection are both electrically connected to the second connection terminal; For a component to be tested, within the component to be tested, the cathode terminal of the freewheeling diode is electrically connected to the first connection terminal of the power switching element, and the anode terminal of the freewheeling diode is electrically connected to the second connection terminal of the power switching element; Within the bridge circuit, a component under test forms an upper bridge arm unit, another component under test forms a lower bridge arm unit, and the second main connection terminal within the upper bridge arm unit is electrically connected to the first main connection terminal within the lower bridge arm unit; when testing a component under test, the component under test is adaptively connected to the pulse constant current source via the first main connection terminal and the second main connection terminal, and the excitation current flows into the component under test via the first main connection terminal or the second main connection terminal. [3] Test system according to claim 2, which can increase the test speed of static parameters, characterized by, that: the switching matrix comprises a constant current source switching unit which is adaptively connected to the pulse constant current source, wherein the constant current source switching unit comprises a first constant current excitation branch and a second constant current excitation branch, wherein the first constant current excitation branch and the second constant current excitation branch are adaptively connected to the pulse constant current source; the first constant current excitation branch comprises several first constant current excitation branch switches; the second constant current excitation branch comprises several second constant current excitation branch switches; the number of first constant current excitation branch switches and the number of second constant current excitation branch switches is not less than the number of power switching components in the component unit under test; When testing the bridge circuit or a component under test, a corresponding first constant current excitation branch switch in the first constant current excitation branch is configured to be in the closed state, and a corresponding second constant current excitation branch switch in the second constant current excitation branch is configured to be in the closed state, so that the pulse constant current source is adaptively connected to the bridge circuit or component under test; For any component to be tested, the direction of the excitation current fed into the power switching element is opposite to the direction of the excitation current fed into the freewheeling diode. [4] Test system according to claim 3, which can increase the test speed of static parameters, characterized by, that: the pulse constant current source comprises a current source and a current direction reversal circuit adaptively connected to the current source, wherein, The current direction reversing circuit comprises a first direction reversing branch and a second direction reversing branch connected in parallel to the current source; the first direction reversing branch comprises an NMOS transistor Q1 and an NMOS transistor Q3, wherein the drain terminal of the NMOS transistor Q1 is connected to the positive terminal of the current source, and the source terminal of the NMOS transistor Q1 is adaptively connected to the drain terminal of the NMOS transistor Q3 and to the first constant current excitation branch; the second direction-switching branch comprises an NMOS transistor Q2 and an NMOS transistor Q4, wherein the drain terminal of the NMOS transistor Q2 is connected to the positive terminal of the current source, and the source terminal of the NMOS transistor Q2 is adaptively connected to the drain terminal of the NMOS transistor Q4 and to the second constant current excitation branch; the source terminal of NMOS transistor Q3 and the source terminal of NMOS transistor Q4 are both connected to the negative terminal of the power source; When configured so that NMOS transistor Q1 and NMOS transistor Q4 are simultaneously in the conducting state and NMOS transistor Q2 and NMOS transistor Q3 are simultaneously in the blocking state, the pulse current source provides an excitation current in a first current direction; When configured so that NMOS transistor Q2 and NMOS transistor Q3 are simultaneously in the conducting state and NMOS transistor Q1 and NMOS transistor Q4 are simultaneously in the blocking state, the pulse current source provides an excitation current in a second current direction. [5] Test system according to claim 4, which can increase the test speed of static parameters, characterized by , that: for any first constant current excitation branch switch, the first terminal of the first constant current excitation branch switch is connected to the source terminal of the NMOS transistor Q1 and the drain terminal of the NMOS transistor Q3, and the second terminal of the first constant current excitation branch switch is electrically connected to a corresponding first main connection terminal of a power switching device; For any second constant current excitation branch switch, the first terminal of the second constant current excitation branch switch is connected to the source terminal of the NMOS transistor Q2 and the drain terminal of the NMOS transistor Q4, and the second terminal of the second constant current excitation branch switch is electrically connected to a corresponding second main connection terminal of a power switching device. [6] Test system according to claim 4, which can increase the test speed of static parameters, characterized by , that: the pulse constant current source further comprises a polarity reversal control circuit, wherein, The reversing control circuit comprises at least four reversing control modules to configure the NMOS transistor Q1, the NMOS transistor Q2, the NMOS transistor Q3, and the NMOS transistor Q4 to each be adaptively connected to a reversing control module; Any reversing control module comprises, in series, an optocoupler isolator, a driver amplifier, a signal conditioning circuit, and a driver interconnect circuit, wherein, The driver interconnect circuit comprises a first driver interconnect NMOS transistor and a second driver interconnect NMOS transistor, wherein the gate terminal of the first driver interconnect NMOS transistor and the gate terminal of the second driver interconnect NMOS transistor are both connected to the signal conditioning circuit; the drain terminal of the first driver interconnect NMOS transistor is connected to the isolation voltage output by an isolated power supply, the source terminal of the first driver interconnect NMOS transistor is connected to the drain terminal of the second driver interconnect NMOS transistor and to the gate terminal of an NMOS transistor in the current direction reversing circuit; the source terminal of the second driver interconnect NMOS transistor is connected to the source terminal of the connected NMOS transistor in the current direction reversing circuit. [7] Test system according to any one of claims 2 to 6, which can increase the test speed of static parameters, characterized by , that: the bias source unit comprises two bias sources, and the switching matrix comprises two groups of bias switching units, the bias sources and bias switching units interacting in a one-to-one connection; for any given preload switching unit, the preload switching unit comprises a first preload branch and a second preload branch, wherein, the first biasing branch comprises several first biasing branch switches; the second bias branch comprises several second bias branch switches; the number of first bias branch switches and the number of second bias branch switches is not less than the number of bridge circuits in the component unit under test; For a power switching element, the control terminal of the power switching element is connected to the positive pole of the corresponding bias source via a first bias branch switch, and the second auxiliary connection terminal of the power switching element is connected to the negative pole of the corresponding bias source via a second bias branch switch. [8] Test system according to any one of claims 2 to 6, which can increase the test speed of static parameters, characterized by , that: the voltage measuring unit comprises two groups of voltage measuring components, wherein, Each group of voltage measurement components corresponds to a component under test, in order to measure the voltage between the first main connection terminal and the second main connection terminal, the voltage between the first auxiliary connection terminal and the second main connection terminal, and the voltage between the second auxiliary connection terminal and the second main connection terminal using the voltage measurement components. [9] Test system according to claim 8, which can increase the test speed of static parameters, characterized by , that: each group of voltage measuring components comprises three voltmeters, and the switching matrix comprises one voltmeter switching unit corresponding to each group of voltage measuring components, wherein, the voltmeter switching unit includes voltmeter leads, each connected to the three voltmeters; For any voltmeter line, the voltmeter line comprises a first voltmeter branch and a second voltmeter branch, and the voltmeter is adaptively connected to the power switching element via the first voltmeter branch and the second voltmeter branch to perform a voltage measurement. [10] Test system according to claim 3, which can increase the test speed of static parameters, characterized by , that: the first constant current excitation branch switch and the second constant current excitation branch switch are both mechanical high-voltage high-current switches.

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