Test circuit

Abstract

The embodiment of the utility model discloses a test circuit. The test circuit comprises a power supply module and an energy storage module. The first end of the charging module is electrically connected with the first end of the power supply module; the first end of the discharging module is electrically connected with the second end of the charging module, and the second end of the discharging module is electrically connected with the second end of the power supply module; the first end and the second end of the comparison module are electrically connected with the first end and the second end of the discharging module respectively, and the two output ends of the comparison module are electrically connected with the control end of the charging module and the control end of the discharging module respectively; the bus capacitor is connected in parallel with the energy storage module through a switch; and the controller is electrically connected with each module. The test circuit provided by the embodiment of the utility model can realize high-efficiency voltage regulation without wasting energy.

Description

Technical Field

[0001] The embodiments of the present utility model relate to semiconductor device testing technologies, and particularly to a testing circuit. Background Art

[0002] Semiconductor devices are electronic devices that utilize the special electrical properties of semiconductor materials to perform specific functions and are widely used in multiple fields of production and life. Before using semiconductor devices such as SiC-MOSFET (Silicon Carbide Metal-Oxide-Semiconductor Field-Effect Transistor), in order to verify whether their parameters and performance meet the requirements, a testing circuit is required to test the semiconductor devices for evaluating switching characteristics such as switching delay time, voltage and current rise and fall times, voltage and current change rates, voltage and current stresses, and switching losses, or other testing requirements. Currently, existing testing circuits usually adopt fixed voltage testing. In tests that require voltage changes, due to the power limitation of the high-voltage power supply, the bus capacitor that provides the test voltage cannot be quickly voltage-regulated, resulting in low testing efficiency of semiconductor devices. Summary of the Utility Model

[0003] The embodiments of the present utility model provide a testing circuit to achieve efficient voltage regulation without wasting energy.

[0004] In a first aspect, the embodiments of the present utility model provide a testing circuit, including:

[0005] A power supply module and an energy storage module;

[0006] A charging module, the first end of which is electrically connected to the first end of the power supply module;

[0007] A discharging module, the first end of which is electrically connected to the second end of the charging module, and the second end of which is electrically connected to the second end of the power supply module;

[0008] A comparison module, the first end and the second end of which are respectively electrically connected to the first end and the second end of the discharging module, and the two output ends of which are respectively electrically connected to the control end of the charging module and the control end of the discharging module;

[0009] A bus capacitor, which is connected in parallel with the energy storage module through a switch;

[0010] A controller, electrically connected to each module, is configured to receive a control instruction, determine the change requirement of the current test voltage according to the control instruction, and control the working states of the charging module, and / or the discharging module, and / or the comparison module, and / or the energy storage module according to the change requirement of the current test voltage, so as to adjust the voltage of the bus capacitor and test the device under test through the voltage of the bus capacitor.

[0011] Optionally, the energy storage module includes an energy storage inductor, a diode and a plurality of switches. The first end and the second end of the discharging module are respectively connected to the first end of the energy storage inductor through a first switch and a second switch, wherein the positive electrode of the diode is connected to the first end of the energy storage inductor; the first end and the second end of the discharging module are also respectively connected to the second end of the energy storage inductor through a third switch and a fourth switch.

[0012] Optionally, the comparison module includes a first comparison unit, a voltage dividing unit and a second comparison unit. The first end and the second end of the voltage dividing unit are respectively used as the first end and the second end of the comparison module. The negative input terminal of the first comparison unit and the positive input terminal of the second comparison unit are respectively electrically connected to the third end and the fourth end of the voltage dividing unit. The positive input terminal of the first comparison unit and the negative input terminal of the second comparison unit both serve as the control terminals of the comparison module.

[0013] Optionally, both the first comparison unit and the second comparison unit include comparators. The positive input terminal, the negative input terminal and the output terminal of the comparator in the first comparison unit are respectively used as the positive input terminal, the negative input terminal and the output terminal of the first comparison unit. The positive input terminal, the negative input terminal and the output terminal of the comparator in the second comparison unit are respectively used as the positive input terminal, the negative input terminal and the output terminal of the second comparison unit; the voltage dividing unit includes a plurality of serially connected voltage dividing resistors.

[0014] Optionally, the comparison module includes a voltage dividing unit, a collection unit and two driving units. The collection unit collects the voltage of the bus capacitor through the voltage dividing unit and sends it to the controller; one end of one driving unit is connected to the controller, and the other end is connected to the control terminal of the charging module. The other driving unit has one end connected to the controller and the other end connected to the control terminal of the discharging module; a comparison unit is provided in the controller.

[0015] Optionally, the charging module includes a first switching tube. The first pole, the second pole and the gate of the first switching tube are respectively used as the first end, the second end and the control terminal of the charging module.

[0016] Optionally, the discharging module includes a second switching tube. The first pole, the second pole and the gate of the second switching tube are respectively used as the first end, the second end and the control terminal of the discharging module.

[0017] Optionally, the switching tube is a unidirectional or bidirectional switch, and the switching tube includes a MOSFET or an IGBT.

[0018] Optionally, the power supply module includes a power supply and a capacitor, and the power supply is connected in parallel with the capacitor.

[0019] The test circuit provided by the embodiment of the present invention includes: a power supply module and an energy storage module; a charging module, the first end of the charging module is electrically connected to the first end of the power supply module; a discharging module, the first end of the discharging module is electrically connected to the second end of the charging module, and the second end of the discharging module is electrically connected to the second end of the power supply module; a comparison module, the first end and the second end of the comparison module are respectively electrically connected to the first end and the second end of the discharging module, and the two output ends of the comparison module are respectively electrically connected to the control end of the charging module and the control end of the discharging module; a bus capacitor, which is connected in parallel with the energy storage module through a switch; a controller, which is electrically connected to each module, and the controller is used to receive a control instruction, determine the change requirement of the current test voltage according to the control instruction, and control the working states of the charging module, and / or the discharging module, and / or the comparison module, and / or the energy storage module according to the change requirement of the current test voltage, so as to adjust the voltage of the bus capacitor and test the device to be tested through the voltage of the bus capacitor. The test circuit provided by the embodiment of the present invention controls the working states of each module through the controller. For example, when the current test voltage needs to be increased, the controller controls the energy storage module to charge the bus capacitor, then makes the charging module work by controlling the comparison module to output a high level, and controls the power supply module to charge the bus capacitor through the charging module, so as to quickly change the voltage value of the bus capacitor and make the voltage of the bus capacitor meet the change requirement of the current test voltage, thereby realizing the test of the device to be tested through the voltage of the bus capacitor, and realizing the efficient regulation of the voltage while not wasting energy. Description of the Drawings

[0020] Figure 1 is a structural block diagram of a test circuit provided by an embodiment of the present invention;

[0021] Figure 2 is a structural schematic diagram of a test circuit provided by an embodiment of the present invention;

[0022] Figure 3 is a structural schematic diagram of another test circuit provided by an embodiment of the present invention;

[0023] Figure 4 is a structural schematic diagram of still another test circuit provided by an embodiment of the present invention;

[0024] Figure 5 is a structural schematic diagram of still another test circuit provided by an embodiment of the present invention;

[0025] Figure 6 It is a schematic diagram of the energy storage inductor current and the bus capacitor voltage provided by the embodiment of the present utility model;

[0026] Figure 7 It is another schematic diagram of the energy storage inductor current and the bus capacitor voltage provided by the embodiment of the present utility model;

[0027] Figure 8 It is a schematic diagram of a charging timing provided by the embodiment of the present utility model;

[0028] Figure 9 It is another schematic diagram of a charging timing provided by the embodiment of the present utility model;

[0029] Figure 10 It is a schematic diagram of a discharging timing provided by the embodiment of the present utility model;

[0030] Figure 11 It is a flowchart of a double-pulse test method provided by the embodiment of the present utility model;

[0031] Figure 12 It is a schematic diagram of the bus capacitor current and the drive pulse provided by the embodiment of the present utility model;

[0032] Figure 13 It is a flowchart of a test voltage regulation method provided by the embodiment of the present utility model. Detailed implementation manners

[0033] The present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present utility model, rather than limiting the present utility model. Additionally, it should be noted that for the sake of description, only the parts related to the present utility model rather than all the structures are shown in the accompanying drawings.

[0034] Figure 1 It is a structural block diagram of a test circuit provided by the embodiment of the present utility model. Refer to Figure 1 , the test circuit includes: a power supply module 10, an energy storage module 20, a charging module 30, a discharging module 40, a comparison module 60, a bus capacitor Cbus, and a controller 70.

[0035] Among them, the first end of the charging module 30 is electrically connected to the first end of the power supply module 10; the first end of the discharging module 40 is electrically connected to the second end of the charging module 30, and the second end of the discharging module 40 is electrically connected to the second end of the power supply module 10; the first end and the second end of the comparison module 60 are respectively electrically connected to the first end and the second end of the discharging module 40, and the two output ends of the comparison module 60 are respectively electrically connected to the control end of the charging module 30 and the control end of the discharging module 40; the bus capacitor Cbus is connected in parallel with the energy storage module 20 through the switch K0; the controller 70 is electrically connected to each module. The controller 70 is configured to receive a control instruction, determine the change requirement of the current test voltage according to the control instruction, and control the working states of the charging module 30, and / or the discharging module 40, and / or the comparison module 60, and / or the energy storage module 20 according to the change requirement of the current test voltage, so as to adjust the voltage of the bus capacitor Cbus and test the device to be tested through the voltage of the bus capacitor Cbus.

[0036] Specifically, the controller 70 can control the working states of each module, including but not limited to: the controller 70 controls the input voltage of the comparison module 60 according to the change requirement of the current test voltage. The comparison module 60 outputs a high level or a low level according to the input voltage, so that the charging module 30 works or the discharging module 40 works; when the current test voltage needs to be increased, the controller 70 controls the energy storage module 20 to charge the bus capacitor Cbus, and then controls the comparison module 60 to output a high level to make the charging module 30 work, and controls the power supply module 10 to charge the bus capacitor Cbus through the charging module 30, so as to quickly change the voltage value of the bus capacitor Cbus and make the voltage of the bus capacitor Cbus meet the change requirement of the current test voltage, thereby realizing efficient voltage regulation when testing the device to be tested through the voltage of the bus capacitor Cbus without wasting energy. In this embodiment, the power supply module 10 may include at least one capacitor such as a parallel capacitor bank, and the energy of the energy storage module 20 can also be released to the power supply module 10.

[0037] As can be seen from the above, in the test circuit of this embodiment, the energy storage module 20 can temporarily store the energy discharged by the bus capacitor Cbus. The stored energy can charge the bus capacitor according to the actual situation, or be released to the capacitor bank of the power supply module for storage, reducing the energy loss in the whole process. At the same time, it can also realize efficient regulation of the test voltage.

[0038] The test circuit provided in this embodiment controls the working states of each module through a controller. For example, when the current test voltage needs to be increased, the controller controls the energy storage module to charge the bus capacitor, and then controls the comparison module to output a high level to make the charging module work, and controls the power supply module to charge the bus capacitor through the charging module, so as to quickly change the voltage value of the bus capacitor and make the voltage of the bus capacitor meet the change requirements of the current test voltage. Thus, when testing the device to be tested through the voltage of the bus capacitor, energy is not wasted while efficient voltage regulation is achieved.

[0039] Figure 2 It is a schematic structural diagram of a test circuit provided by an embodiment of the present invention. Figure 3 It is a schematic structural diagram of another test circuit provided by an embodiment of the present invention. Refer to Figure 2 and Figure 3 , optionally, the energy storage module 20 includes an energy storage inductor L2 and multiple switches. The first end and the second end of the discharge module 40 are respectively connected to the first end of the energy storage inductor L2 through a first switch and a second switch, and the first end and the second end of the discharge module 40 are also respectively connected to the second end of the energy storage inductor L2 through a third switch and a fourth switch. In the embodiment shown in Figure 3 , the first switch is diode D2, the second switch is switch K7, the third switch is switch K5, and the fourth switch is switch K6. In other implementation manners of the present application, the first switch can also be a relay switch, and the fourth switch can also be a diode switch. The positive pole of the diode switch is connected to the second end of the energy storage inductor L2. The present application is not limited thereto.

[0040] Among them, each switch is electrically connected to the controller 70, and the energy storage inductor L2 can store energy and charge the bus capacitor Cbus. Specifically, Figure 6 It is a schematic diagram of the energy storage inductor current and the bus capacitor voltage provided by an embodiment of the present invention, Figure 7 It is another schematic diagram of the energy storage inductor current and the bus capacitor voltage provided by an embodiment of the present invention. Refer to Figure 3 , Figure 6 and Figure 7 , when, according to the test requirements, the voltage of the bus capacitor Cbus needs to be decreased, first control the bus capacitor Cbus to charge the energy storage inductor L2. At this time, switch K8 remains off, switches K1 and K2 remain on, switches K5, K7, and K0 are on, and switch K6 is off. The bus capacitor Cbus charges the energy storage inductor L2. When the voltage of the bus capacitor Cbus drops to the specified value, switch K7 is turned off; switches K5, the energy storage inductor L2, and diode D2 form a loop to conduct freewheeling for the energy storage inductor L2.

[0041] In some alternative implementation manners of the present application, the power supply module 10 can also pre-charge the energy storage inductor L2 so that the energy stored in the energy storage inductor L2 can supplement the subsequent rapid charging of the bus capacitor Cbus.

[0042] For the test circuit of this embodiment, as Figure 3 shown, the specific control process of controlling the stored energy of the energy storage module to be transferred to the power supply module is as follows: K0 is disconnected, switch K6 is turned on, switches K5 and K7 are disconnected, K1 and K2 are turned on, the voltage of the energy storage inductor L2 changes suddenly, and a pressure difference is formed with the capacitors C1-Cm (C1... Cm are connected in parallel) of the power supply module. The energy stored in the energy storage inductor L2 can charge the power supply module 10, and the current I of the energy storage inductor L2 L2 flows into the capacitor of the power supply module 10 through the diode of the first switching tube SW1 to achieve charging. Among them, the on and off of each switch are all controlled by the controller 70. In Figure 5 the shown embodiment, in the specific control process of controlling the stored energy of the energy storage module to be transferred to the power supply module, K1 needs to be disconnected, and the others are the same as the above control process.

[0043] For the test circuit of this embodiment, controlling the energy storage module to charge the bus capacitor, that is, the energy transferred from the bus capacitor Cbus to the energy storage module 20 can return to the bus capacitor Cbus again. The specific control process is as follows: control switches K0 and K6 to be turned on, switch K5 to be disconnected, K1 and K2 to be turned on, the voltage of the energy storage inductor L2 changes suddenly, and a pressure difference is formed with the bus capacitor Cbus to achieve charging of the energy storage inductor L2 to the bus capacitor Cbus.

[0044] Referring to Figure 2 , optionally, the comparison module 60 includes a first comparison unit 61, a second comparison unit 62 and a voltage dividing unit 63. The first end and the second end of the voltage dividing unit 63 are respectively used as the first end and the second end of the comparison module 60. The negative input terminal of the first comparison unit 61 and the positive input terminal of the second comparison unit 62 are respectively electrically connected to the third end and the fourth end of the voltage dividing unit 63. The positive input terminal of the first comparison unit 61 and the negative input terminal of the second comparison unit 62 are both used as the control terminal of the comparison module 60.

[0045] Exemplarily, when the first comparison unit 61 outputs a high level, that is, when the control terminal of the charging module 30 is at a high level, the charging module 30 operates. When the second comparison unit 62 outputs a high level, the discharging module 40 operates. The level output by the first comparison unit 61 is opposite to the level output by the second comparison unit 62. Specifically, the controller 70 inputs different comparison voltages to the positive input terminal of the first comparison unit 61 and the negative input terminal of the second comparison unit 62 respectively. The voltage dividing unit 63 inputs the same voltage to the negative input terminal of the first comparison unit 61 and the positive input terminal of the second comparison unit 62. The first comparison unit 61 and the second comparison unit 62 control the level signals they output according to the voltages input to their respective two input terminals. For example, if the voltage input to the positive input terminal of the first comparison unit is higher than the voltage input to the negative input terminal, a high level is output; otherwise, a low level is output.

[0046] Reference Figure 3 , optionally, both the first comparison unit 61 and the second comparison unit 62 include comparators. The positive input terminal, negative input terminal, and output terminal of the comparator DA1 in the first comparison unit 61 serve as the positive input terminal, negative input terminal, and output terminal of the first comparison unit 61 respectively. The positive input terminal, negative input terminal, and output terminal of the comparator DA2 in the second comparison unit 62 serve as the positive input terminal, negative input terminal, and output terminal of the second comparison unit 62 respectively; the voltage dividing unit 63 includes a plurality of voltage dividing resistors R1 - Rn connected in series.

[0047] Among them, the comparator DA1 in the first comparison unit 61 can be a comparator with an isolation function. The power supply terminals of each comparator input a DC voltage VCC, and the voltage transmitted by the voltage dividing unit 63 to each comparator is the voltage V of the resistor Rn. Rn . The first comparison unit 61 and the second comparison unit 62 can respectively control the working states of the charging module and the discharging module. The first comparison unit 61 and the second comparison unit 62 control the level signals they output according to the voltages input to their respective two input terminals. For example, if the voltage input to the positive input terminal of the first comparison unit is higher than the voltage input to the negative input terminal, a high level is output; otherwise, a low level is output.

[0048] In another implementation manner of the present application, as Figure 4 shown, the comparison module 60 may further include a voltage dividing unit, a sampling unit, and two driving units. The sampling unit can be an AD sampling unit. The AD sampling unit samples the voltage across Rn, that is, after sampling the bus capacitor voltage and performing analog - to - digital conversion, it sends the result to the controller. A comparison unit is set in the controller, and set values N1 and N2 are preset. After the controller receives the digital quantity signal from the AD sampling unit, it respectively performs digital quantity comparison with the set values N1 and N2, and according to the comparison result, controls the charging module 30 to operate or controls the discharging module 40 to operate through the driving unit 1 or the driving unit 2.

[0049] In some embodiments of the present application, with reference to Figure 2 and Figure 3 , optionally, the charging module 30 includes a first switching transistor SW1 and a first relay switch K1. The first pole, second pole, and gate of the first switching transistor SW1 serve as the first end, second end, and control end of the charging module 30 respectively. The second pole and the gate of the first switching transistor SW1 are connected through the first relay switch K1. In this embodiment, the first switching transistor SW1 is a MOSFET, and its first pole is the drain of the MOSFET, and the second pole is the source of the MOSFET.

[0050] Exemplarily, when a high level is input to the gate of the first switching transistor SW1, that is, when the comparator DA1 in the first comparison unit 61 outputs a high level, the first switching transistor SW1 conducts, and the charging module 30 operates to charge the bus capacitor Cbus. At this time, the first relay switch K1 is disconnected and the comparator DA2 in the second comparison unit 62 outputs a low level, and the discharging module 40 does not operate. The capacitor in the power supply module 10 is charged through the power supply POW. The controller 70 outputs a set value N1 and a set value N2 (the set value N2 is kept higher than the set value N1). VRn < the set value N1, the comparator DA1 in the first comparison unit 61 outputs a high level, and the first switching transistor SW1 is controlled to conduct through the driving resistor RF1. The power supply module 10 charges the bus capacitor Cbus, and the voltage value of Cbus rises. After the test is completed, the voltage value of the bus capacitor Cbus drops, and the voltage of the resistor Rn in the voltage dividing unit 63 decreases. When V Rn < the set value N1, the charging process starts again. When the bus capacitor Cbus does not need to be charged, the controller 70 controls the first relay switch K1 to close, which can quickly short-circuit the gate and the source of the first switching transistor SW1, realize the turn-off of the charging circuit, and at the same time ensure that the capacitor in the power supply module will not affect the test when testing the device to be tested subsequently.

[0051] In some embodiments, the working processes of the charging module and the discharging module of the test circuit of the present application can be illustrated by the following timing diagrams: Figure 8 is a schematic diagram of a charging timing provided by an embodiment of the present invention, Figure 9 is another schematic diagram of a charging timing provided by an embodiment of the present invention. With reference to Figure 8 and Figure 9 , when the difference between the charging set value and the discharging set value (the difference between the above set values N1 and N2) is small, that is, when the voltage accuracy is high, the schematic diagram of the charging timing is as shown in Figure 8As shown, from t0 to t1: The comparator DA1 outputs a high level, the charging circuit is turned on, i.e., the charging module works, the comparator DA2 outputs a low level, the discharging circuit is turned off, i.e., the discharging module does not work, and the voltage of the bus capacitor Cbus rises; from t1 to t2: At the moment t1, the voltage of the bus capacitor Cbus rises to the set value N1, and the comparator DA1 is turned off; from t2 to t3: Since it takes a certain time for the first switch tube SW1 to turn off, the voltage of the bus capacitor Cbus will still continue to rise. When it exceeds the discharging set value, the comparator DA2 outputs a high level, the discharging circuit is turned on, so that the voltage rising speed rapidly decreases and turns to decrease; from t3 to t5: Since it takes a certain time for the second switch tube SW2 to turn off, the voltage of the bus capacitor Cbus will still continue to decrease. When it is lower than the charging set value, the comparator DA1 outputs a high level, the charging circuit is turned on, so that the voltage decreasing speed rapidly decreases and turns to increase. When the difference between the charging set value and the discharging set value is large, that is, the voltage accuracy requirement is not very high, the charging timing diagram is as Figure 9 shown, from t0 to t1: The comparator DA1 outputs a high level, the charging circuit is turned on, the comparator DA2 outputs a low level, the discharging circuit is turned off, and the voltage of the bus capacitor Cbus rises; from t1 to t2: The voltage of the bus capacitor Cbus continues to rise and then remains stable; from t2 to t3: During the test process, the voltage of the bus capacitor Cbus decreases; from t3 to t4: The test process ends, and the voltage of the bus capacitor Cbus remains stable; from t4 to t5: The comparator DA1 outputs a high level, the charging circuit is turned on, and the voltage of the bus capacitor Cbus rises.

[0052] Reference Figure 2 and Figure 3 , optionally, the discharging module 40 includes a second switch tube SW2 and a second relay switch K2. The first pole, second pole and gate of the second switch tube SW2 are respectively used as the first end, second end and control end of the discharging module 40. The second pole and gate of the second switch tube SW2 are connected through the second relay switch K2; the discharging module 40 further includes a discharging resistor RS2. The drain of the second switch tube SW2 is electrically connected to the source of the first switch tube SW1 through the discharging resistor RS2. In this embodiment, the second switch tube SW2 is a MOSFET, its first pole is the drain of the MOSFET, and its second pole is the source of the MOSFET.

[0053] Exemplarily, when a high level is input to the gate of the second switch tube SW2, that is, when the comparator DA2 in the second comparison unit 62 outputs a high level, the second switch tube SW2 is turned on, the discharging module 40 works, and the bus capacitor Cbus discharges through the discharging module 40. At this time, the second relay switch K2 is turned off and the comparator DA1 in the first comparison unit 61 outputs a low level, and the charging module 30 does not work. When the voltage value of the bus capacitor Cbus rises, the voltage drop of the resistor Rn in the voltage dividing unit 63 increases. When V RnWhen the comparator DA2 in the second comparison unit 62 outputs a high level at the set value N2, the second switching transistor SW2 is controlled to conduct through the driving resistor RF2, and the bus capacitor Cbus and the discharging resistor RS2 form a discharging loop, and the voltage value of the bus capacitor Cbus decreases. When the bus capacitor Cbus does not need to be discharged, the controller 70 controls the second relay switch K2 to close, which can quickly short-circuit the gate and source of the second switching transistor SW2 to turn off the discharging loop. When the device under test is being tested, both the first switching transistor SW1 and the second switching transistor SW2 are turned off to protect the voltage safety in the subsequent test process.

[0054] Further, the set values N1 and N2 in the embodiments of the present application are related to the voltage target value of the bus capacitor Cbus. For example, in one example, if the voltage V Cbus of the bus capacitor Cbus needs to be stabilized at 95V to 100V, the set value N1 = 95V * Rn / (R1 +... Rn), the set value N2 = 100V * Rn / (R1 +... Rn), and the voltage comparison value V Rn = V Cbus * Rn / (R1 +... Rn). When V Rn < the set value N1, that is, V Cbus < 95V, charging is performed. When V Rn > the set value N2, that is, V Cbus > 100V, discharging is performed. Figure 10 is a schematic diagram of a discharging timing provided by an embodiment of the present invention. When the difference between the charging set value and the discharging set value is large, that is, when the voltage accuracy requirement is not very high, the schematic diagram of the discharging timing is as Figure 10 shown. t0 - t1: The comparator DA2 outputs a high level, the discharging loop is turned on, the comparator DA1 outputs a low level, the charging loop is turned off, and the voltage of the bus capacitor Cbus decreases; t1 - t2: After the voltage of the bus capacitor Cbus continues to decrease, it remains stable; t2 - t3: During the test process, the voltage of the bus capacitor Cbus decreases; t3 - t4: After the test process ends, the voltage of the bus capacitor Cbus remains stable; t4 - t5: The comparator DA1 outputs a high level, the charging loop is turned on, and the voltage of the bus capacitor Cbus rises.

[0055] Optionally, in another implementation manner of the present application, referring to Figure 4, the charging module 30 includes a first switching transistor SW1, and the first pole, second pole, and gate of the first switching transistor SW1 serve as the first terminal, second terminal, and control terminal of the charging module 30 respectively. The discharging module 40 includes a second switching transistor SW2, and the first pole, second pole, and gate of the second switching transistor serve as the first terminal, second terminal, and control terminal of the discharging module respectively. In this implementation manner, instead of setting switches K1 and K2 on the hardware, after the controller compares the acquisition values of the acquisition unit with the set values N1 and N2, before operating the driving unit 1 or the driving unit 2, it first determines whether a charging or discharging operation is required at this time (for example, when the energy of the bus capacitor is first stored in the energy storage module, even if the driving unit 2 outputs a high level at this time, in order not to make the discharging module work, SW2 needs to be non-conductive at this time and no discharging is performed). If necessary, then control the driving unit 2 to output a high level to control SW2 to conduct and perform discharging.

[0056] It should be noted that the above examples have illustrated the specific states of each switch and the like during the process of the bus capacitor Cbus storing energy in the energy storage module, the energy storage module charging the bus capacitor Cbus, and the charging and discharging modules working. For the regulation of the sequence of each module in actual applications, refer to the method embodiments of this application.

[0057] Optionally, the switching transistor in the embodiment of the present application is a unidirectional or bidirectional switch, and the switching transistor may specifically include a MOSFET or an IGBT. In Figures 2 to 4 the schematic diagram, a schematic diagram of the switching transistor being a unidirectional MOSFET is given. In Figure 5 the schematic diagram shown, a schematic diagram of the switching transistor SW1 being a bidirectional MOSFET is given.

[0058] Specifically, as Figure 5 shown, when SW1 is a bidirectional switching transistor, it can be applicable to the application scenario where the voltage of the capacitor bank in the power supply module 10 is lower than the voltage of the bus capacitor. Once K0 is closed, the bidirectional switching transistor can prevent the voltage of the bus capacitor from flowing to the capacitor bank in the power supply module 10, thus not affecting the operation of the bus capacitor charging the energy storage module, etc.

[0059] It can be understood that the switching transistor of the present application may also include other forms of unidirectional or bidirectional switches, and this embodiment is not limited thereto.

[0060] Exemplarily, both the first switching transistor SW1 and the second switching transistor SW2 are SiC-MOSFETs. SiC-MOSFETs have the ability to operate with large currents and high voltages and can achieve fast switching operations. Additionally, the resistor RS1 connected to the drain of the first switching transistor SW1 can limit the charging current value, and the discharging resistor RS2 connected to the drain of the second switching transistor SW2 can limit the discharging current value. Moreover, the discharging resistor RS2 connected to the drain of the second switching transistor SW2 is a small-value power resistor, enabling rapid energy discharge of the bus capacitor Cbus.

[0061] Reference Figure 2 and Figure 3 , optionally, the test circuit further includes a test module 50. The test module 50 includes a test inductor L1, a diode D1, and at least two switches. The first end of the test inductor L1 is electrically connected to the positive electrode of the diode D1. The second end of the test inductor L1 is electrically connected to the first end of the discharging module 40 through a switch K3. The negative electrode of the diode D1 is electrically connected to the first end of the discharging module 40. The second end of the test inductor L1 is electrically connected to the second end of the discharging module 40 through another switch K4. The first end of the test inductor L1 is electrically connected to the second end of the discharging module 40 through the device under test DUT.

[0062] Among them, each switch is electrically connected to the controller. The test inductor L1 can store energy and charge the bus capacitor. Specifically, Figure 11 is a flowchart of a dual-pulse test method provided by an embodiment of the present invention, Figure 12 is a schematic diagram of the bus capacitor current and driving pulses provided by an embodiment of the present invention. Reference Figure 11 and Figure 12 , when performing a dual-pulse test on the device under test, the controller controls the working states of each module to adjust the bus capacitor voltage value. When the bus capacitor voltage value reaches the first target voltage, the test module is controlled to perform the first dual-pulse test on the device under test. Then, when the voltage value of the bus capacitor is adjusted to reach the second target voltage, the test module is controlled to perform the second dual-pulse test on the device under test, thereby achieving efficient voltage regulation for the dual-pulse test of the device under test. Moreover, for multiple dynamic parameter tests of the device under test, such as dual-pulse, short-circuit, and gate charge tests, the bus voltage value needs to be frequently changed. This circuit can efficiently change the bus voltage and save test time.

[0063] A switch K8 is provided between the bus capacitor Cbus and the test module 50. Specifically, the controller 70 can control the on / off of the switch K8 to control the on / off of the circuit between the test module 50, the bus capacitor Cbus, and other modules. Additionally, in this embodiment, the switches K1-K8 can all be switches of different relays, and the controller 70 can control the on / off of the switches K1-K8, thereby controlling the working states of each module in the test circuit.

[0064] Reference Figure 2 and Figure 3 Optionally, the power module 10 includes a power supply POW and capacitors C1-Cm, and the power supply POW is connected in parallel with the capacitors.

[0065] Wherein, m is a positive integer greater than or equal to 1, the control terminal of the power supply POW serves as the control terminal of the power module 10, and the power supply POW can charge the capacitors C1-Cm. The voltage values of the capacitors C1-Cm are greater than the rated voltage value of the bus capacitor Cbus. During the charging process, the capacitors C1-Cm can provide a charging current much larger than that of the voltage source, realizing rapid charging of the bus capacitor Cbus.

[0066] It should be noted that the specific magnitudes of the above preset values can be determined according to actual test requirements and are not limited herein.

[0067] Figure 13 is a flowchart of a test voltage regulation method provided by an embodiment of the present invention. The test voltage regulation method is executed by a controller as described in any embodiment of the present invention. The test voltage regulation method includes:

[0068] Step 110: Receive a control instruction.

[0069] Step 120: Determine the change requirement of the current test voltage according to the control instruction.

[0070] Step 130: Control the working states of the charging module, and / or the discharging module, and / or the comparison module, and / or the energy storage module in the test circuit according to the change requirement of the current test voltage, so as to adjust the voltage of the bus capacitor in the test circuit, and test the device under test through the voltage of the bus capacitor.

[0071] Specifically, if the current test voltage needs to be reduced, after controlling a part of the voltage of the bus capacitor to be transmitted to the energy storage module, control the discharging module to work. If the current test voltage needs to be increased, when the stored energy of the energy storage module is equal to the energy to be adjusted, control the energy storage module to charge the bus capacitor; and / or, when the stored energy of the energy storage module is lower than the energy to be adjusted and greater than zero, control the energy storage module to charge the bus capacitor and then control the power module to charge the bus capacitor through the charging module; and / or, when the stored energy of the energy storage module is higher than the energy to be adjusted, control all the stored energy of the energy storage module to be transmitted to the power module and then control the power module to charge the bus capacitor through the charging module; and / or, when the stored energy of the energy storage module is higher than the energy to be adjusted, control the energy storage module to transmit the stored energy corresponding to the energy to be adjusted to the bus capacitor; and / or, when the stored energy of the energy storage module is zero, control the power module to charge the bus capacitor through the charging module.

[0072] That is to say, for the test voltage regulation method according to the embodiments of the present application, when the bus capacitor needs to be charged, the energy stored in the energy storage module can be preferentially used to charge the bus capacitor. When the stored energy in the energy storage module is insufficient, it is supplemented by the charging module, so as to improve the test voltage regulation rate and further improve the test efficiency of semiconductor devices.

[0073] Exemplarily, if the current test voltage needs to be reduced from 1000V to 800V, that is, the voltage of the bus capacitor needs to be reduced from 1000V to 800V, the bus capacitor needs to output 200V voltage to meet the change requirement of the current test voltage:

[0074] S1. Control a part of the voltage of the bus capacitor, such as 150V, to be transmitted to the energy storage module; specifically, it can be controlled by controlling the working duration of the switch. The specific control process has been described in the above embodiments and will not be elaborated here;

[0075] S2. Control the discharge module to work, so that the bus capacitor discharges 50V through the discharge module, thereby reducing the voltage from 1000V to 800V. At this time, the values of the set values N1 and N2 are related to the target voltage 800V. The specific value-taking process and the discharge control process have been described in the above embodiments and will not be elaborated here.

[0076] Exemplarily, if the current test voltage needs to be increased from 800V to 1000V, that is, the voltage of the bus capacitor needs to be increased from 800V to 1000V, the bus capacitor needs to be charged by 200V;

[0077] S1. If the stored energy in the energy storage module is 200V at this time, control the energy storage module to charge the bus capacitor; specifically, it can be controlled by controlling the working duration of the switch. The specific control process has been described in the above embodiments and will not be elaborated here;

[0078] S2. If the stored energy in the energy storage module is lower than 200V and greater than zero at this time, after controlling the energy storage module to charge the bus capacitor, control the power supply module to charge the bus capacitor through the charging module; at this time, the values of the set values N1 and N2 are related to the target voltage 1000V. The specific value-taking process and the charging control process have been described in the above embodiments and will not be elaborated here.

[0079] S3. If the stored energy in the energy storage module is higher than 200V at this time, control all the stored energy in the energy storage module to be transmitted to the power supply module, and then control the power supply module to charge the bus capacitor through the charging module; or control the energy storage module to transmit the energy corresponding to 200V voltage to the bus capacitor.

[0080] S4. If the stored energy in the energy storage module is zero, control the power supply module to charge the bus capacitor by 200V through the charging module, so that the voltage of the bus capacitor rises from 800V to 1000V.

[0081] Through the above control processes of the energy storage module, the charging module, and the discharging module, the changing requirements of the current test voltage are met, thereby quickly adjusting the voltage of the bus capacitor in the test circuit, and testing the device to be tested through the voltage of the bus capacitor.

[0082] The test voltage regulation method provided in this embodiment and the test circuit provided in any embodiment of the present invention belong to the same inventive concept and have corresponding beneficial effects. For the technical details not elaborated in this embodiment, please refer to the test circuit provided in any embodiment of the present invention.

[0083] Note that the above is only the preferred embodiment of the present invention and the applied technical principle. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. Various obvious changes, re-adjustments, combinations, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the inventive concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A test circuit, characterized in that, Comprising: A power supply module and an energy storage module; A charging module, the first end of the charging module being electrically connected to the first end of the power supply module; A discharging module, the first end of the discharging module being electrically connected to the second end of the charging module, and the second end of the discharging module being electrically connected to the second end of the power supply module; A comparison module, the first end and the second end of the comparison module being respectively electrically connected to the first end and the second end of the discharging module, and the two output ends of the comparison module being respectively electrically connected to the control end of the charging module and the control end of the discharging module; A bus capacitor, being connected in parallel with the energy storage module through a switch; A controller, being electrically connected to each module, the controller being configured to receive a control instruction, determine the change requirement of the current test voltage according to the control instruction, and control the working states of the charging module, and / or the discharging module, and / or the comparison module, and / or the energy storage module according to the change requirement of the current test voltage, so as to adjust the voltage of the bus capacitor, and test the device to be tested through the voltage of the bus capacitor.

2. The test circuit according to claim 1, characterized in that The energy storage module includes an energy storage inductor and a plurality of switches, the first end and the second end of the discharging module being respectively connected to the first end of the energy storage inductor through a first switch and a second switch; the first end and the second end of the discharging module are also respectively connected to the second end of the energy storage inductor through a third switch and a fourth switch.

3. The test circuit according to claim 1, wherein The comparison module includes a first comparison unit, a voltage dividing unit and a second comparison unit, the first end and the second end of the voltage dividing unit being respectively used as the first end and the second end of the comparison module, the negative input end of the first comparison unit and the positive input end of the second comparison unit being respectively electrically connected to the third end and the fourth end of the voltage dividing unit, and the positive input end of the first comparison unit and the negative input end of the second comparison unit both being used as the control end of the comparison module.

4. The test circuit according to claim 3, characterized in that Both the first comparison unit and the second comparison unit include a comparator, the positive input end, the negative input end and the output end of the comparator in the first comparison unit being respectively used as the positive input end, the negative input end and the output end of the first comparison unit, and the positive input end, the negative input end and the output end of the comparator in the second comparison unit being respectively used as the positive input end, the negative input end and the output end of the second comparison unit; the voltage dividing unit includes a plurality of serially connected voltage dividing resistors.

5. The test circuit according to claim 1, characterized in that, The comparison module includes a voltage dividing unit, a collecting unit and two driving units, the collecting unit collects the voltage of the bus capacitor through the voltage dividing unit and sends it to the controller; one end of one driving unit is connected to the controller, and the other end is connected to the control end of the charging module, and one end of the other driving unit is connected to the controller, and the other end is connected to the control end of the discharging module; a comparison unit is arranged in the controller.

6. The test circuit according to claim 1, wherein The charging module includes a first switching tube, the first pole, the second pole and the gate of the first switching tube being respectively used as the first end, the second end and the control end of the charging module.

7. The test circuit according to claim 1, wherein The discharging module includes a second switching tube, the first pole, the second pole and the gate of the second switching tube being respectively used as the first end, the second end and the control end of the discharging module.

8. The test circuit according to claim 6 or 7, characterized in that, The switching tube is a unidirectional or bidirectional switch, and the switching tube includes a MOSFET or an IGBT.

9. The test circuit according to claim 1, wherein The power supply module includes a power supply and a capacitor, and the power supply is connected in parallel with the capacitor.

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