A driver protection function test circuit and test method

Abstract

The application provides a kind of driver protection function test circuit and test method, the test circuit includes: short-circuit protection function test circuit, gate under-voltage protection function test circuit and high-voltage active clamping protection test circuit, wherein, short-circuit protection function test circuit is tested by double-path voltage division between the collector / drain and emitter / source of the driver to be tested, power emitter / source and emitter / source to apply voltage to carry out short-circuit protection function test;Gate under-voltage protection function test circuit is tested by series voltage division to adjust the power supply voltage of the driver to be tested to carry out gate under-voltage protection function test;High-voltage active clamping protection test circuit carries out active clamping protection test by detecting high-voltage DC power output current. By implementing the application, the protection function test of the driver is realized, and the function retest of the driver under the condition of no structural damage before final shipment is solved.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and more specifically to a test circuit and test method for driver protection function. Background Technology

[0002] High-power fully voltage-controlled devices mainly include insulated-gate bipolar transistors (IGBTs), power transistors (GTRs), and power field-effect transistors (MOSFETs). Currently, SiC-MOSFETs and IGBTs are the most widely used in electric vehicles, industrial frequency converters, wind and solar power generation, and DC grids. In practical applications, the driver plays a crucial role in switching control and safety assurance, making driver reliability paramount. Drivers require individual functional testing during mass production to ensure proper functioning. Current driver inspection and testing primarily involve soldering checks, circuit checks, and basic functional tests before conformal coating. However, after conformal coating, only visual inspection is performed during the factory or assembly stage. To improve the testing process and mitigate the risk of driver damage during conformal coating, a final functional test is needed before assembly, especially for the driver's protection functions. This ensures the reliability of the driver's protection after shipment. Therefore, a test circuit and method that can quickly test the driver's protection functions without damaging the conformal coating is needed to fill the gap in the final testing stage of driver production, providing safety assurance for the mass production and engineering applications of drivers. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the driver testing process in the prior art, which is imperfect and lacks the final protection function test process before installation, thereby providing a driver protection function test circuit and test method.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] In a first aspect, embodiments of the present invention provide a driver protection function test circuit, comprising: a short-circuit protection function test circuit, a gate undervoltage protection function test circuit, and a high-voltage active clamping protection test circuit, wherein...

[0006] The short-circuit protection function test circuit applies voltages between the collector / drain and emitter / source, and between the power emitter / source and emitter / source of the driver under test through dual-channel voltage division to perform short-circuit protection function testing;

[0007] The gate undervoltage protection function test circuit adjusts the power supply voltage of the driver under test in a series voltage divider manner to perform the gate undervoltage protection function test.

[0008] The high-voltage active clamping protection test circuit performs active clamping protection testing by detecting the output current of the high-voltage DC power supply.

[0009] Optionally, the short-circuit protection function test circuit includes: a first controllable switch, a second controllable switch, a third controllable switch, a fourth controllable switch, a first resistor, a second resistor, a third resistor, and a fourth resistor, wherein...

[0010] The first terminal of the first controllable switch is connected to the positive terminal of an external power supply. The control terminal of the first controllable switch is connected to an external control signal. The second terminal of the first controllable switch is connected to one end of the first resistor. The other end of the first resistor is connected to one end of the third resistor and the collector / drain of the driver under test. The other end of the third resistor is connected to the emitter / source of the driver under test and the negative terminal of the external power supply.

[0011] The first terminal of the second controllable switch is connected to the positive terminal of the external power supply. The control terminal of the second controllable switch is connected to an external control signal. The second terminal of the second controllable switch is connected to one end of the second resistor. The other end of the second resistor is connected to one end of the fourth resistor and the power emitter / power source of the driver under test. The other end of the fourth resistor is connected to the emitter / source of the driver under test and the negative terminal of the external power supply.

[0012] The third controllable switch is connected in parallel with the third resistor, and the control terminal of the third controllable switch is connected to an external control signal;

[0013] The fourth controllable switch is connected in parallel with the fourth resistor, and the control terminal of the fourth controllable switch is connected to an external control signal;

[0014] The control terminal of the driver under test is connected to an external control signal, and the power supply terminal of the driver under test is connected to an external power source.

[0015] Optionally, the driver protection function test circuit further includes: a controller, the first terminal of which is connected to the control terminal of the first controllable switch, the second terminal of which is connected to the control terminal of the second controllable switch, the third terminal of which is connected to the control terminal of the third controllable switch, the fourth terminal of which is connected to the control terminal of the fourth controllable switch, and the fifth terminal of which is connected to the control terminal of the driver under test.

[0016] Optionally, the driver protection function test circuit further includes: a multi-channel adjustable DC power supply.

[0017] The positive terminal of the first power output terminal of the multi-channel adjustable DC power supply is connected to the first terminal of the first controllable switch and the first terminal of the second controllable switch, respectively. The negative terminal of the first power output terminal of the multi-channel adjustable DC power supply is connected to the other end of the third resistor, the other end of the fourth resistor, and the emitter / source of the driver under test, respectively.

[0018] The second power output terminal of the multi-channel adjustable DC power supply is connected to the power output terminal of the driver under test.

[0019] The third power output terminal of the multi-channel adjustable DC power supply is connected to the power supply terminal of the controller.

[0020] Optionally, the gate undervoltage protection function test circuit includes a series voltage divider circuit, one end of which is connected to the second power output terminal of the multi-channel adjustable DC power supply, and the other end of which is connected to the power supply terminal of the driver under test.

[0021] Optionally, the series voltage divider circuit includes: a fifth resistor and a sixth resistor, wherein,

[0022] One end of the fifth resistor is connected to the positive terminal of the second power output terminal of the multi-channel adjustable DC power supply, and the other end of the fifth resistor is connected to one end of the sixth resistor and the positive terminal of the power supply terminal of the driver under test, respectively. The other end of the sixth resistor is connected to the negative terminal of the power supply terminal of the driver under test and the negative terminal of the second power output terminal of the multi-channel adjustable DC power supply, respectively.

[0023] Optionally, the high-voltage active clamping protection test circuit includes: a high-voltage DC power supply, a disconnecting switch, a current-limiting resistor, a current detection module, and a signal delay control module, wherein...

[0024] The positive output terminal of the high-voltage DC power supply is connected to the first terminal of the disconnecting switch, the second terminal of the disconnecting switch is connected to one end of the current-limiting resistor, the other end of the current-limiting resistor is connected to the first terminal of the current detection module, the second terminal of the current detection module is connected to the collector / drain of the driver under test, the third terminal of the current detection module is connected to one end of the signal delay control module, the other end of the signal delay control module is connected to the control terminal of the disconnecting switch, and the negative output terminal of the high-voltage DC power supply is connected to the emitter / source of the driver under test.

[0025] Optionally, the short-circuit protection function test circuit further includes: a first diode and a second diode, wherein,

[0026] The anode of the first diode is connected to the second terminal of the first controllable switch, and the cathode of the first diode is connected to one end of the first resistor;

[0027] The anode of the second diode is connected to the second terminal of the second controllable switch, and the cathode of the second diode is connected to one end of the second resistor.

[0028] Optionally, the driver protection function test circuit further includes: an oscilloscope, the oscilloscope being used to monitor the voltage across the third resistor, the voltage across the fourth resistor, and the gate voltage of the driver under test.

[0029] Secondly, embodiments of the present invention provide a driver protection function testing method, based on the driver protection function testing circuit of the first aspect of the present invention, the driver protection function testing method comprising:

[0030] Short-circuit protection function is tested by applying voltages between the collector / drain and emitter / source, and between the power emitter / source and emitter / source, using a dual-channel voltage divider.

[0031] The gate undervoltage protection function was tested by adjusting the power supply voltage of the driver under test using a series voltage divider method.

[0032] Active clamping protection is tested by detecting the output current of the high-voltage DC power supply.

[0033] Optionally, the short-circuit protection function test performed by applying a voltage between the collector / drain and emitter / source of the driver under test through a dual-path voltage divider includes:

[0034] The test driver is controlled to be normally open, and the second controllable switch is controlled to close, thus exiting the current slope protection function test.

[0035] Start the multi-channel adjustable DC power supply, control the first controllable switch to be in the normally open state, and gradually adjust the first power output of the multi-channel adjustable DC power supply from low to high;

[0036] Monitor the voltage across the third resistor. When the voltage across the third resistor reaches the desaturation short-circuit protection threshold voltage designed inside the driver under test, control the driver under test to change from normally open to normally closed.

[0037] The gate voltage of the driver under test is monitored using an oscilloscope, and the saturation short-circuit protection function is tested and determined based on the gate voltage of the driver under test.

[0038] Optionally, the short-circuit protection function test performed by applying a voltage between the power emitter / source and emitter / source of the driver under test through a dual-channel voltage divider includes:

[0039] The driver under test is controlled to be normally open, and the first controllable switch is controlled to close, thus exiting the saturation short circuit protection function test.

[0040] Start the multi-channel adjustable DC power supply, control the second controllable switch to be in the normally open state, and gradually adjust the first power output of the multi-channel adjustable DC power supply from low to high;

[0041] Monitor the voltage across the fourth resistor. When the voltage across the fourth resistor reaches the current slope short-circuit protection threshold voltage designed inside the driver under test, control the driver under test to change from normally open to normally closed.

[0042] The gate voltage of the driver under test is monitored using an oscilloscope, and the current slope protection function is tested and determined based on the gate voltage of the driver under test.

[0043] Optionally, the gate undervoltage protection function test performed by adjusting the supply voltage of the driver under test through a series voltage divider includes:

[0044] Start the multi-channel adjustable DC power supply, and control the first power output terminal of the multi-channel adjustable DC power supply to have no output, while the third power output terminal of the multi-channel adjustable DC power supply outputs normally.

[0045] Adjust the second power supply output of the multi-channel adjustable DC power supply until the voltage across the sixth resistor reaches the normal operating voltage value of the driver under test.

[0046] Gradually reduce the output of the second power supply of the multi-channel adjustable DC power supply, and monitor the gate voltage of the driver under test;

[0047] When the gate voltage of the driver under test drops to the gate undervoltage protection threshold, the gate of the driver under test is turned off.

[0048] Optionally, active clamping protection testing is performed by detecting the output current of the high-voltage DC power supply, including:

[0049] Close the isolating switch and adjust the output voltage of the high-voltage DC power supply;

[0050] When the current detection module detects that the current has reached the set current protection threshold, it outputs a control signal, which controls the delay control module to trigger the disconnect switch to open after a preset delay.

[0051] The technical solution of this invention has the following advantages:

[0052] 1. This invention provides a driver protection function test circuit, comprising: a short-circuit protection function test circuit, a gate undervoltage protection function test circuit, and a high-voltage active clamping protection test circuit. The short-circuit protection function test circuit applies voltages between the collector / drain and emitter / source of the driver under test, and between the power emitter / source and emitter / source, using a dual-path voltage divider to perform short-circuit protection function testing. The gate undervoltage protection function test circuit adjusts the supply voltage of the driver under test using a series voltage divider to perform gate undervoltage protection function testing. The high-voltage active clamping protection test circuit detects the output current of the high-voltage DC power supply to perform active clamping protection testing. Overcurrent or circuit protection function testing is performed by applying voltages between the collector / drain and emitter / source of the driver, and between the power emitter / source and emitter / source, using a dual-path voltage divider circuit. Gate undervoltage protection function testing is performed by adjusting the supply voltage using a series voltage divider. Active clamping protection function testing is performed by detecting the output current of the high-voltage DC power supply. It enables multiple protection function tests of the drive, solves the problem of functional retesting of the drive under conditions of no structural damage before final delivery, forms a complete chain of production, testing and assembly, and ensures that the drive functions normally.

[0053] 2. This invention provides a method for testing the protection function of a driver, comprising: applying voltages between the collector / drain and emitter / source, and between the power emitter / source and emitter / source of the driver under test via a dual-channel voltage divider to perform a short-circuit protection function test; adjusting the supply voltage of the driver under test via a series voltage divider to perform a gate undervoltage protection function test; and detecting the output current of the high-voltage DC power supply to perform an active clamping protection test. Its simple test circuit and convenient operation process can meet the testing requirements of existing protection types of drivers, achieving final functional verification of the driver before factory shipment or installation, and ensuring product performance. Attached Figure Description

[0054] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0055] Figure 1 This is a schematic diagram of the test circuit for the short-circuit and undervoltage protection function of the driver in an embodiment of the present invention;

[0056] Figure 2 This is a schematic diagram of the test circuit for the high-voltage active clamping protection function of the driver in an embodiment of the present invention;

[0057] Figure 3A flowchart illustrating a specific example of the driver protection function testing method in an embodiment of the present invention;

[0058] Figure 4 This is a flowchart of the test procedure for the short-circuit and undervoltage protection function of the driver in an embodiment of the present invention;

[0059] Figure 5 This is a flowchart of the test procedure for the high-voltage active clamping protection function of the driver in an embodiment of the present invention. Detailed Implementation

[0060] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0062] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0063] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0064] Example 1

[0065] This invention provides a driver protection function test circuit, including: a short-circuit protection function test circuit, a gate undervoltage protection function test circuit, and a high-voltage active clamping protection test circuit. The short-circuit protection function test circuit applies voltages between the collector / drain and emitter / source terminals, and between the power emitter / source terminals and emitter / source terminals of the driver under test using a dual-channel voltage divider to perform short-circuit protection function testing. The gate undervoltage protection function test circuit adjusts the supply voltage of the driver under test using a series voltage divider to perform gate undervoltage protection function testing. The high-voltage active clamping protection test circuit performs active clamping protection testing by detecting the output current of the high-voltage DC power supply.

[0066] In one specific embodiment, such as Figure 1 As shown, the short-circuit protection function test circuit includes: a first controllable switch S1, a second controllable switch S2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first diode D1, and a second diode D2.

[0067] The short-circuit protection function test circuit is divided into two types: desaturation protection and current slope protection. The desaturation short-circuit protection function test circuit applies a voltage between the collector / drain and emitter / source of the driver under test using a dual-channel voltage divider. The current slope protection function test circuit applies a voltage between the power emitter / source and emitter / source of the driver under test using a dual-channel voltage divider. Specifically, the first controllable switch S1, the first diode D1, the first resistor R1, and the third resistor R3 constitute the desaturation short-circuit protection function test circuit; the second controllable switch S2, the second diode D2, the second resistor R2, and the fourth resistor R4 constitute the current slope short-circuit protection function test circuit.

[0068] like Figure 1 As shown, the specific connection relationship of the desaturation short-circuit protection function test circuit is as follows: The first terminal of the first controllable switch S1 is connected to the positive terminal of the external power supply; the control terminal of the first controllable switch S1 is connected to an external control signal; the second terminal of the first controllable switch S1 is connected to the anode of the first diode D1; the cathode of the first diode D1 is connected to one end of the first resistor R1; the other end of the first resistor R1 is connected to one end of the third resistor R3 and the collector / drain (C / D) of the driver under test; the other end of the third resistor R3 is connected to the emitter / source (E / S) of the driver under test and the negative terminal of the external power supply. The control terminal of the driver under test is connected to an external control signal, and the power supply terminal of the driver under test is connected to the external power supply.

[0069] like Figure 1As shown, the specific connection relationship of the current slope short-circuit protection function test circuit is as follows: the first terminal of the second controllable switch S2 is connected to the positive terminal of the external power supply, the control terminal of the second controllable switch S2 is connected to the external control signal, the second terminal of the second controllable switch S2 is connected to the anode of the second diode D2, the cathode of the second diode D2 is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the fourth resistor R4 and the power emitter / power source (Ep / Sp) of the driver under test, and the other end of the fourth resistor R4 is connected to the emitter / source (E / S) of the driver under test and the negative terminal of the external power supply.

[0070] The short-circuit protection function test circuit also includes: a third controllable switch K1 and a fourth controllable switch K2. The third controllable switch K1 is connected in parallel with the third resistor R3, and its control terminal is connected to an external control signal. The fourth controllable switch K2 is connected in parallel with the fourth resistor R4, and its control terminal is also connected to an external control signal. When the third controllable switch K1 is closed, the third resistor R3 is short-circuited, and the desaturation short-circuit protection function is disabled. When the fourth controllable switch K2 is closed, the fourth resistor R4 is short-circuited, and the current slope protection function is disabled.

[0071] Furthermore, the driver protection function test circuit also includes: a controller and a multi-channel adjustable DC power supply. Specifically, the first terminal of the controller is connected to the control terminal of the first controllable switch S1, the second terminal of the controller is connected to the control terminal of the second controllable switch S2, the third terminal of the controller is connected to the control terminal of the third controllable switch K1, the fourth terminal of the controller is connected to the control terminal of the fourth controllable switch K2, and the fifth terminal of the controller is connected to the control terminal of the driver under test.

[0072] The positive terminal V1+ of the first power output terminal V1 of the multi-channel adjustable DC power supply is connected to the first terminal of the first controllable switch S1 and the first terminal of the second controllable switch S2, respectively. The negative terminal V1- of the first power output terminal V1 of the multi-channel adjustable DC power supply is connected to the other end of the third resistor R3, the other end of the fourth resistor R4, and the emitter / source (E / S) terminal of the driver under test, respectively. The second power output terminal V2 of the multi-channel adjustable DC power supply is connected to the power supply terminal of the driver under test. The third power output terminal V3 of the multi-channel adjustable DC power supply is connected to the power supply terminal of the controller.

[0073] In this embodiment of the invention, the first controllable switch S1 and the second controllable switch S2 are MOS switching transistors, which is only an example and not a limitation. The first diode D1 and the second diode D2 are light-emitting diodes. Figure 1 In this example, the driver under test is only shown using a power field-effect transistor (MOSFET). However, other high-power fully voltage-controlled devices can be replaced with the power field-effect transistor (MOSFET), and no specific restrictions are imposed here.

[0074] The multi-channel adjustable DC power supply output V1 is used as the power supply circuit. V1+, as the positive terminal of the power supply voltage for the short-circuit protection function test circuit, is connected to the drain terminals of MOS switches S1 and S2 respectively. The source terminals of S1 and S2 are connected to the anodes of LEDs D1 and D2 respectively. The cathodes of the LEDs are connected to two series voltage divider resistors R1 / R3 and R2 / R4 respectively. In the series voltage divider circuit R1 / R3, the other end of R1 is connected to the collector / drain (C / D) of the driver under test, and the short-circuit switch K1 is connected in parallel with R3. In the series voltage divider circuit R2 / R4, the other end of R2 is connected to the power emitter / power source (Ep / Sp) of the driver under test, and the short-circuit switch K2 is connected in parallel with R4, and finally connected to V1- of the multi-channel adjustable DC power supply and the emitter / source (E / S) of the driver under test. MOS switches S1 and S2, shorting switches K1 and K2, and the control signal interface of the driver under test are connected to the controller, which controls their switching on and off. The controller is powered by a multi-channel adjustable DC power supply V3. The voltages across R3 and R4 and the gate voltage of the driver under test are monitored by an oscilloscope.

[0075] During the desaturation short-circuit protection function test, the controller closes the short-circuit switch K2, the driver under test (DUT) is in a normally open state, the current slope protection function is disabled, and the multi-channel adjustable DC power supply is activated to ensure that the output voltages of channels V2 and V3 are normal, guaranteeing the normal operation of the DUT and the controller. The controller provides a normally open signal to the gate of the MOS switch S1, gradually adjusting the output voltage V1 from low to high. The D1 indicator light illuminates, indicating that the desaturation short-circuit protection function test has been initiated. When the voltage across R3 reaches the desaturation short-circuit protection threshold voltage designed internally by the DUT, the driver generates a power device shutdown command, and the DUT changes from a normally open state to a normally off state. The gate voltage of the DUT monitored by the oscilloscope will rapidly change from a positive voltage to a negative voltage and maintain this position. At this point, the desaturation short-circuit protection function test is deemed normal.

[0076] During the current slope short-circuit protection function test, the controller closes the short-circuit switch K1, the driver under test (DUT) is in a normally open state, the desaturation short-circuit protection function is disabled, and the multi-channel adjustable DC power supply is activated to ensure that the output voltages of channels V2 and V3 are normal, guaranteeing the normal operation of the DUT and the controller. The controller provides a normally open signal to the gate of the MOS switch S2, gradually adjusting the output voltage V1 from low to high. The D2 indicator light illuminates, indicating that the current slope short-circuit protection function test has been initiated. When the voltage across R4 reaches the current slope short-circuit protection threshold voltage designed internally by the driver, the DUT generates a power device shutdown command, and the driver changes from a normally open state to a normally off state. The gate voltage of the DUT monitored by the oscilloscope will rapidly change from a positive voltage to a negative voltage and maintain this position. At this point, the current slope short-circuit protection function test is considered normal.

[0077] By controlling the opening and closing of short-circuit switches K1 and K2 and MOS switches S1 and S2, the two protection modes can be effectively switched. Then, the output voltage of the multi-channel adjustable DC power supply V1 is adjusted to change the voltage across R3 or R4 and compared with the protection threshold voltage to realize the short-circuit protection function test of the driver under test.

[0078] Preferably, such as Figure 1 As shown, the gate undervoltage protection function test circuit includes a series voltage divider circuit. One end of the series voltage divider circuit is connected to the second power output terminal V2 of the multi-channel adjustable DC power supply, and the other end of the series voltage divider circuit is connected to the power supply terminal of the driver under test.

[0079] In one specific embodiment, the series voltage divider circuit includes a fifth resistor R5 and a sixth resistor R6. One end of the fifth resistor R5 is connected to the positive terminal V2+ of the second power output terminal V2 of the multi-channel adjustable DC power supply. The other end of the fifth resistor R5 is connected to one end of the sixth resistor R6 and the positive terminal Vd+ of the power supply of the driver under test. The other end of the sixth resistor R6 is connected to the negative terminal Vd- of the power supply of the driver under test and the negative terminal V2- of the second power output terminal V2 of the multi-channel adjustable DC power supply.

[0080] In this embodiment of the invention, in the gate undervoltage protection function test circuit, the multi-channel adjustable DC power supply output V2 is connected in series with R5 and R6. The driver under test Vd+ is connected to the common terminal of R5 and R6, and Vd- is connected to the other end of R6 and connected to V2-, serving as the power supply circuit for the driver under test. The output voltage of V2 is adjusted so that the driver under test gradually decreases from the normal operating voltage until the driver under test can no longer work normally, the gate voltage drops, and it is turned off.

[0081] Furthermore, during the gate undervoltage protection function test, the multi-channel adjustable DC power supply V1 had no output, while the output voltage of V3 was normal, and the controller was functioning correctly, with short-circuit switches K1 and K2 closed. The output of V2 was then activated, and its output voltage was adjusted until the voltage across R6 reached the normal operating voltage of the driver under test. Then, the V2 voltage was gradually reduced, causing the supply voltage Vd of the driver under test (i.e., the voltage across R6) to gradually decrease as well. Consequently, the gate voltage of the driver under test also gradually decreased. When it dropped to the gate undervoltage protection threshold, the gate of the driver under test was turned off, and the voltage rapidly decreased from a positive value to a negative value. At this point, the gate undervoltage protection function test was determined to be normal.

[0082] Optionally, such as Figure 2 As shown, the high-voltage active clamping protection test circuit includes: a high-voltage DC power supply, an isolating switch K, a current-limiting resistor R, a current detection module, and a signal delay control module. The positive terminal V+ of the high-voltage DC power supply is connected to the first terminal of the isolating switch K; the second terminal of the isolating switch K is connected to one end of the current-limiting resistor R; the other end of the current-limiting resistor R is connected to the first terminal of the current detection module; the second terminal of the current detection module is connected to the collector / drain of the driver under test; the third terminal of the current detection module is connected to one end of the signal delay control module; the other end of the signal delay control module is connected to the control terminal of the isolating switch K; and the negative terminal V- of the high-voltage DC power supply is connected to the emitter / source of the driver under test.

[0083] In one specific embodiment, during the high-voltage active clamping protection function test, the isolating switch K is closed, and the interface of the driver under test is connected as described above. A current protection threshold (i.e., the minimum leakage current value for active clamping action) is set, and the output voltage of the high-voltage DC power supply is adjusted. When the current reaches the set protection threshold, the current detection module outputs a control signal. After a predetermined delay by the signal delay control module, the isolating switch K is triggered to open. Leakage current is monitored through the current detection module. When the current exceeds the current protection threshold, it is considered that the D / S terminal of the driver under test has experienced overvoltage breakdown, forming a clamp. Finally, after the set delay, the isolating switch K is controlled to trip, disconnecting the high-voltage DC power supply.

[0084] Example 2

[0085] This invention provides a driver protection function testing method. Based on the aforementioned driver protection function testing circuit, the driver protection function testing method is as follows: Figure 3 As shown, it includes the following steps:

[0086] S1: Short-circuit protection function test is performed by applying voltages between the collector / drain and emitter / source, and between the power emitter / source and emitter / source of the driver under test through dual-channel voltage division.

[0087] In one specific embodiment, the short-circuit protection function test circuit is divided into two types: desaturation protection and current slope protection. Specifically, the desaturation short-circuit protection function test is performed by applying a voltage between the collector / drain and emitter / source of the driver under test through a dual-channel voltage divider, and includes the following steps:

[0088] S101: Controls the driver under test to be in the normally open state, controls the second controllable switch S2 to close, and exits the current slope protection function test.

[0089] S102: Start the multi-channel adjustable DC power supply, control the first controllable switch S1 to be in the normally open state, and gradually adjust the first power supply output of the multi-channel adjustable DC power supply from low to high.

[0090] S103: Monitors the voltage across the third resistor R3. When the voltage across the third resistor R3 reaches the desaturation short-circuit protection threshold voltage designed inside the driver under test, it controls the driver under test to change from the normally open state to the normally closed state.

[0091] S104: Use an oscilloscope to monitor the gate voltage of the driver under test, and determine the saturation short-circuit protection function based on the gate voltage of the driver under test.

[0092] In this embodiment of the invention, the first controllable switch S1 and the second controllable switch S2 are MOS switching transistors, which are used as examples only and are not limited thereto. A first diode D1 is set to indicate the change of the V1 power supply voltage in the desaturation short-circuit protection function test circuit. The V1 power supply is the first power supply, the V2 power supply is the second power supply, and the V3 power supply is the third power supply.

[0093] During the desaturation short-circuit protection function test, the controller closes the short-circuit switch K2, the driver under test (DUT) is in a normally open state, the current slope protection function is disabled, and the multi-channel adjustable DC power supply is activated to ensure that the output voltages of channels V2 and V3 are normal, guaranteeing the normal operation of the DUT and the controller. The controller provides a normally open signal to the gate of the MOS switch S1, gradually adjusting the first power supply V1 from low to high. The D1 indicator light illuminates, indicating that the desaturation short-circuit protection function test has been activated. When the voltage across R3 reaches the desaturation short-circuit protection threshold voltage designed internally by the DUT, the driver generates a power device shutdown command, and the DUT changes from a normally open state to a normally off state. The gate voltage of the DUT monitored by the oscilloscope will rapidly change from a positive voltage to a negative voltage and maintain this position. At this point, the desaturation short-circuit protection function test is considered normal.

[0094] Furthermore, the current slope protection function is tested by applying a voltage between the power emitter / source and emitter / source terminals of the driver under test through a dual-channel voltage divider. The specific steps include the following:

[0095] S111: Controls the driver under test to be in the normally open state, controls the first controllable switch S1 to close, and exits the saturation short circuit protection function test.

[0096] S112: Start the multi-channel adjustable DC power supply, control the second controllable switch S2 to be in the normally open state, and gradually adjust the first power supply output of the multi-channel adjustable DC power supply from low to high.

[0097] S113: Monitor the voltage across the fourth resistor R4. When the voltage across the fourth resistor R4 reaches the current slope short-circuit protection threshold voltage designed inside the driver under test, control the driver under test to change from normally open to normally closed.

[0098] S114: Use an oscilloscope to monitor the gate voltage of the driver under test, and perform a current slope protection function test based on the gate voltage of the driver under test.

[0099] In this embodiment of the invention, a second diode D2 is used to indicate the change in the supply voltage of the V1 path in the current slope short-circuit protection function test circuit. During the current slope short-circuit protection function test, the controller controls the short-circuit switch K1 to close, the driver under test is in a normally open state, the desaturation short-circuit protection function is in an inactive state, and the multi-channel adjustable DC power supply is started, so that the output voltages of the V2 and V3 paths are normal, ensuring the normal operation of the driver under test and the controller. The controller provides a normally open signal to the gate of the MOS switch S2, gradually adjusting the output first power supply V1 from low to high. The D2 indicator light illuminates, indicating that the current slope short-circuit protection function test has been started. When the voltage across R4 reaches the current slope short-circuit protection threshold voltage designed inside the driver, the driver under test generates a power device shutdown command, and the driver will change from a normally open state to a normally off state. The gate voltage of the driver under test monitored by the oscilloscope will rapidly change from a positive voltage to a negative voltage and maintain this state. At this time, the current slope short-circuit protection function test is determined to be normal.

[0100] S2: The gate undervoltage protection function is tested by adjusting the power supply voltage of the driver under test through series voltage division.

[0101] In one specific embodiment, S2 includes the following steps:

[0102] S20: Start the multi-channel adjustable DC power supply, control the first power output terminal of the multi-channel adjustable DC power supply to have no output, and control the third power output terminal of the multi-channel adjustable DC power supply to output normally.

[0103] S21: Adjust the second power supply output of the multi-channel adjustable DC power supply until the voltage across the sixth resistor reaches the normal operating voltage value of the driver under test.

[0104] S22: Gradually reduce the second power supply output of the multi-channel adjustable DC power supply to monitor the gate voltage of the driver under test.

[0105] S23: When the gate voltage of the driver under test drops to the gate undervoltage protection threshold, the gate of the driver under test is turned off.

[0106] In this embodiment of the invention, during the gate undervoltage protection function test, the multi-channel adjustable DC power supply V1 has no output, the output voltage of V3 is normal, and the controller is working normally, with short-circuit switches K1 and K2 closed. The output of V2 is activated, and the output voltage of V2 is adjusted until the voltage across R6 reaches the normal operating voltage value of the driver under test. Then, the voltage of V2 is gradually reduced, causing the supply voltage Vd of the driver under test (i.e., the voltage across R6) to gradually decrease as well. The gate voltage of the driver under test will also gradually decrease. When it drops to the gate undervoltage protection threshold, the gate of the driver under test is turned off, and the voltage rapidly drops from a positive value to a negative value. At this point, the gate undervoltage protection function test is determined to be normal.

[0107] S3: Active clamping protection test by detecting the output current of the high-voltage DC power supply.

[0108] In one specific embodiment, S3 includes the following steps:

[0109] S31: Close the isolating switch to adjust the output voltage of the high-voltage DC power supply.

[0110] S32: When the current detection module detects that the current has reached the set current protection threshold, it outputs a control signal to control the delay control module to trigger the disconnect switch to open after a preset delay.

[0111] In this embodiment of the invention, during the high-voltage active clamping protection function test, the isolating switch K is closed, and the interface of the driver under test is connected as described above. A current protection threshold (i.e., the minimum leakage current value for active clamping action) is set, and the output voltage of the high-voltage DC power supply is adjusted. When the current reaches the set protection threshold, it is considered that the D / S terminal of the driver under test has experienced overvoltage breakdown, forming a clamp. The current detection module outputs a control signal, and only after the signal delay control module performs the specified delay, the isolating switch K is triggered to open.

[0112] like Figure 4 The diagram shows a flowchart of the driver short-circuit and undervoltage protection function test in a specific embodiment of this application. After the test begins, the multi-channel adjustable DC power supply is first started, and the output voltages of channels V2 and V3 are adjusted to ensure the controller and driver operate normally, while keeping the driver in a normally open state (gate output is positive voltage). The controller controls K2 to close, S1 to be normally open, and S2 to be normally closed. The output voltage of channel V1 of the multi-channel adjustable DC power supply is slowly adjusted, starting from 0V and gradually increasing. When the D1 light illuminates, it indicates that the desaturation short-circuit protection function test mode has been entered. The voltage V1 is continued to be increased until the voltage across R3 U... R3When the drain-source voltage exceeds the desaturation short-circuit protection voltage threshold, the driver issues a device shutdown command. The oscilloscope monitors the gate voltage rapidly dropping to a negative value, ending the desaturation short-circuit protection function test. Next, the V1 output voltage is adjusted to 0V, the driver is powered on and reset, the controller disconnects K2 and closes K1, S1 is normally closed, and S2 is normally open. The output voltage of the multi-channel adjustable DC power supply V1 is then slowly adjusted, gradually increasing from 0V. When the D2 indicator lights up, it indicates that the current slope short-circuit protection function test mode has been entered. The voltage V1 is continued to be increased until the voltage across R4 U... R4 When the voltage between the power source and auxiliary source exceeds the current slope short-circuit protection voltage threshold, the driver issues a device shutdown command. The oscilloscope monitors the gate voltage rapidly dropping to a negative value, ending the current slope short-circuit protection function test. Finally, the V1 output voltage is adjusted back to 0V, the driver is powered on and reset, the controller closes K1 and K2, and S1 and S2 are normally closed. The output voltage of the multi-channel adjustable DC power supply V2 is adjusted, gradually decreasing from the rated operating voltage, with the gate voltage also decreasing accordingly, until the voltage across R6, U... GS When the gate-source voltage (i.e., the gate voltage) is less than the gate undervoltage protection voltage threshold, the driver issues a device shutdown command, and the oscilloscope monitors the gate voltage rapidly dropping to a negative value, thus ending the gate undervoltage protection function test.

[0113] like Figure 5 The diagram shows a flowchart of the high-voltage active clamping protection function test for the driver in a specific embodiment of this application. During the test, the isolating switch K is first closed, and a current protection threshold is set in the current detection module. Then, the high-voltage DC power supply is started, and the output voltage V is gradually increased from 0V. When this voltage reaches the clamping action voltage value, the current I will exceed the judgment threshold. The current detection module issues a tripping command to the isolating switch K. After a delay time t required for voltage confirmation and holding time, the isolating switch K is triggered to trip, completing the high-voltage active clamping protection function test and ending the test.

[0114] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A driver protection function test circuit, characterized in that, include: Short-circuit protection function test circuit, gate undervoltage protection function test circuit, and high-voltage active clamping protection test circuit, among which, The short-circuit protection function test circuit applies voltages between the collector / drain and emitter / source, and between the power emitter / source and emitter / source of the driver under test through dual-channel voltage division to perform short-circuit protection function testing; The gate undervoltage protection function test circuit adjusts the power supply voltage of the driver under test in a series voltage divider manner to perform the gate undervoltage protection function test. The high-voltage active clamping protection test circuit performs active clamping protection testing by detecting the output current of the high-voltage DC power supply. The short-circuit protection function test circuit includes: a first controllable switch, a second controllable switch, a third controllable switch, a fourth controllable switch, a first resistor, a second resistor, a third resistor, and a fourth resistor, wherein... The first terminal of the first controllable switch is connected to the positive terminal of an external power supply. The control terminal of the first controllable switch is connected to an external control signal. The second terminal of the first controllable switch is connected to one end of the first resistor. The other end of the first resistor is connected to one end of the third resistor and the collector / drain of the driver under test. The other end of the third resistor is connected to the emitter / source of the driver under test and the negative terminal of the external power supply. The first terminal of the second controllable switch is connected to the positive terminal of the external power supply. The control terminal of the second controllable switch is connected to an external control signal. The second terminal of the second controllable switch is connected to one end of the second resistor. The other end of the second resistor is connected to one end of the fourth resistor and the power emitter / power source of the driver under test. The other end of the fourth resistor is connected to the emitter / source of the driver under test and the negative terminal of the external power supply. The third controllable switch is connected in parallel with the third resistor, and the control terminal of the third controllable switch is connected to an external control signal; The fourth controllable switch is connected in parallel with the fourth resistor, and the control terminal of the fourth controllable switch is connected to an external control signal; The control terminal of the driver under test is connected to an external control signal, and the power supply terminal of the driver under test is connected to an external power supply. The driver protection function test circuit further includes: a controller, the first terminal of which is connected to the control terminal of the first controllable switch, the second terminal of which is connected to the control terminal of the second controllable switch, the third terminal of which is connected to the control terminal of the third controllable switch, the fourth terminal of which is connected to the control terminal of the fourth controllable switch, and the fifth terminal of which is connected to the control terminal of the driver under test. The short-circuit protection function test circuit further includes: a first diode and a second diode, wherein, The anode of the first diode is connected to the second terminal of the first controllable switch, and the cathode of the first diode is connected to one end of the first resistor; The anode of the second diode is connected to the second terminal of the second controllable switch, and the cathode of the second diode is connected to one end of the second resistor.

2. The driver protection function test circuit according to claim 1, characterized in that, The driver protection function test circuit also includes: a multi-channel adjustable DC power supply. The positive terminal of the first power output terminal of the multi-channel adjustable DC power supply is connected to the first terminal of the first controllable switch and the first terminal of the second controllable switch, respectively. The negative terminal of the first power output terminal of the multi-channel adjustable DC power supply is connected to the other end of the third resistor, the other end of the fourth resistor, and the emitter / source of the driver under test, respectively. The second power output terminal of the multi-channel adjustable DC power supply is connected to the power output terminal of the driver under test. The third power output terminal of the multi-channel adjustable DC power supply is connected to the power supply terminal of the controller.

3. The driver protection function test circuit according to claim 2, characterized in that, The gate undervoltage protection function test circuit includes a series voltage divider circuit. One end of the series voltage divider circuit is connected to the second power output terminal of the multi-channel adjustable DC power supply, and the other end of the series voltage divider circuit is connected to the power supply terminal of the driver under test.

4. The driver protection function test circuit according to claim 3, characterized in that, The series voltage divider circuit includes: a fifth resistor and a sixth resistor, wherein, One end of the fifth resistor is connected to the positive terminal of the second power output terminal of the multi-channel adjustable DC power supply, and the other end of the fifth resistor is connected to one end of the sixth resistor and the positive terminal of the power supply terminal of the driver under test, respectively. The other end of the sixth resistor is connected to the negative terminal of the power supply terminal of the driver under test and the negative terminal of the second power output terminal of the multi-channel adjustable DC power supply, respectively.

5. The driver protection function test circuit according to claim 1, characterized in that, The high-voltage active clamping protection test circuit includes: a high-voltage DC power supply, an isolating switch, a current-limiting resistor, a current detection module, and a signal delay control module, wherein... The positive output terminal of the high-voltage DC power supply is connected to the first terminal of the disconnecting switch, the second terminal of the disconnecting switch is connected to one end of the current-limiting resistor, the other end of the current-limiting resistor is connected to the first terminal of the current detection module, the second terminal of the current detection module is connected to the collector / drain of the driver under test, the third terminal of the current detection module is connected to one end of the signal delay control module, the other end of the signal delay control module is connected to the control terminal of the disconnecting switch, and the negative output terminal of the high-voltage DC power supply is connected to the emitter / source of the driver under test.

6. The driver protection function test circuit according to claim 1, characterized in that, Also includes: An oscilloscope for monitoring the voltage across the third resistor, the voltage across the fourth resistor, and the gate voltage of the driver under test.

7. A method for testing the protection function of a driver, characterized in that, Based on the driver protection function test circuit according to any one of claims 1-6, the driver protection function test method includes: Short-circuit protection function is tested by applying voltages between the collector / drain and emitter / source, and between the power emitter / source and emitter / source, using a dual-channel voltage divider. The gate undervoltage protection function was tested by adjusting the power supply voltage of the driver under test using a series voltage divider method. Active clamping protection is tested by detecting the output current of the high-voltage DC power supply.

8. The driver protection function test method according to claim 7, characterized in that, The short-circuit protection function test, which applies a voltage between the collector / drain and emitter / source of the driver under test through a dual-path voltage divider, includes: The test driver is controlled to be normally open, and the second controllable switch is controlled to close, thus exiting the current slope protection function test. Start the multi-channel adjustable DC power supply, control the first controllable switch to be in the normally open state, and gradually adjust the first power output of the multi-channel adjustable DC power supply from low to high; Monitor the voltage across the third resistor. When the voltage across the third resistor reaches the desaturation short-circuit protection threshold voltage designed inside the driver under test, control the driver under test to change from normally open to normally closed. The gate voltage of the driver under test is monitored using an oscilloscope, and the saturation short-circuit protection function is tested and determined based on the gate voltage of the driver under test.

9. The driver protection function test method according to claim 8, characterized in that, The short-circuit protection function test, which applies a voltage between the power emitter / source and emitter / source terminals of the driver under test via a dual-channel voltage divider, includes: The driver under test is controlled to be normally open, and the first controllable switch is controlled to close, thus exiting the saturation short circuit protection function test. Start the multi-channel adjustable DC power supply, control the second controllable switch to be in the normally open state, and gradually adjust the first power output of the multi-channel adjustable DC power supply from low to high; Monitor the voltage across the fourth resistor. When the voltage across the fourth resistor reaches the current slope short-circuit protection threshold voltage designed inside the driver under test, control the driver under test to change from normally open to normally closed. The gate voltage of the driver under test is monitored using an oscilloscope, and the current slope protection function is tested and determined based on the gate voltage of the driver under test.

10. The driver protection function test method according to claim 7, characterized in that, The gate undervoltage protection function test, which involves adjusting the power supply voltage of the driver under test using a series voltage divider method, includes: Start the multi-channel adjustable DC power supply, and control the first power output terminal of the multi-channel adjustable DC power supply to have no output, while the third power output terminal of the multi-channel adjustable DC power supply outputs normally. Adjust the second power supply output of the multi-channel adjustable DC power supply until the voltage across the sixth resistor reaches the normal operating voltage value of the driver under test. Gradually reduce the output of the second power supply of the multi-channel adjustable DC power supply, and monitor the gate voltage of the driver under test; When the gate voltage of the driver under test drops to the gate undervoltage protection threshold, the gate of the driver under test is turned off.

11. The driver protection function test method according to claim 7, characterized in that, Active clamping protection testing is performed by detecting the output current of a high-voltage DC power supply, including: Close the isolating switch and adjust the output voltage of the high-voltage DC power supply; When the current detection module detects that the current has reached the set current protection threshold, it outputs a control signal, which controls the delay control module to trigger the disconnect switch to open after a preset delay.

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