A test circuit and test method for dynamic resistance of gallium nitride power device

Abstract

The present application belongs to the field of integrated circuit testing, and specifically provides a test circuit and test method for the dynamic resistance of a gallium nitride power device. The test circuit includes a driving branch, a high-voltage switch branch, a current source branch, and a voltage measurement branch; wherein the current source branch includes a charge and discharge electron branch. The driving branch is connected to the gate of the gallium nitride power device under test; the high-voltage switch branch is connected in parallel to the drain and source of the gallium nitride power device under test; the current source branch is connected in parallel to the drain and source of the gallium nitride power device under test; and the voltage measurement branch is connected in parallel to the drain and source of the gallium nitride power device under test. Based on the technical solution provided by the present invention, the current establishment speed during the dynamic resistance test of the gallium nitride power device can be improved, which is more conducive to detecting problems with the gallium nitride power device.

Description

Technical Field

[0001] The present invention relates to the field of power electronics, and in particular to a test circuit and a test method for the dynamic resistance of a gallium nitride power device. Background Art

[0002] As a representative of third-generation semiconductor devices, gallium nitride (GaN) devices hold a key position in the power electronics field thanks to their wide bandgap, high thermal conductivity, high temperature resistance, radiation resistance, acid and alkali resistance, high strength, and high hardness. As GaN power devices become increasingly widely used, their measurement becomes increasingly important.

[0003] Dynamic testing of GaN power devices primarily refers to testing the device's dynamic resistance under dynamic operating conditions. During dynamic testing, high-voltage stress triggers a current collapse effect, manifesting as a dynamic change in the device's on-resistance during the switching process. The high-voltage stress during the off-state causes the device's on-resistance to change dynamically after it is turned on. From the off-state to the on-state, the drain voltage drops from hundreds of volts to hundreds of millivolts. Therefore, the switching speed from off to on must be as fast as possible, meaning the current buildup speed of the GaN device must be as fast as possible. However, current buildup times in existing test circuits for GaN devices are often tens of microseconds or even longer, which fails to meet the dynamic resistance testing requirements. Summary of the Invention

[0004] In view of the above problems in the prior art, the present invention provides a test circuit for the dynamic resistance of a GaN power device, which improves the current build-up speed when the GaN power device is turned on during the dynamic resistance test of the GaN power device.

[0005] To achieve the above-mentioned objectives, the present invention provides, in a first aspect, a test circuit for the dynamic resistance of a gallium nitride power device, comprising: a driving branch, a high-voltage switch branch, a current source branch, and a voltage measurement branch; wherein the current source branch comprises a charge and discharge electron branch; the driving branch is connected to the gate and source of the gallium nitride power device under test, and is used to drive the gate of the gallium nitride power device under test to be turned on or off; the high-voltage switch branch is connected in parallel to the drain and source of the gallium nitride power device under test, and is used to supply a voltage to the gallium nitride power device under test when the connection between the high-voltage switch branch and the gallium nitride power device under test is connected. A high voltage is provided between the drain and the source; the current source branch is connected in parallel to the drain and source of the GaN power device under test, and is used to charge the charge and discharge electron branch when the connection between the current source branch and the GaN power device under test is disconnected; and is also used to provide a preset current between the drain and the source of the GaN power device under test through the charge and discharge electron branch when the connection between the current source branch and the GaN power device under test is connected; the voltage measurement branch is connected in parallel to the drain and source of the GaN power device under test, and is used to measure the voltage between the drain and the source of the GaN power device under test.

[0006] As described above, in the GaN power device dynamic resistance test circuit provided by this application, a charge and discharge electron branch is provided within the current source branch. When the GaN power device under test is turned on, the charge and discharge electron branch powers the GaN power device under test, thereby significantly improving the current buildup speed of the GaN power device. Specifically, the test circuit provided by this application achieves a current buildup speed that is more than ten times faster than when directly powering the GaN power device with a current source.

[0007] As a possible implementation of the first aspect, the high-voltage switch branch includes: a high-voltage source, a first switch, and a first resistor connected in series in sequence; wherein a low end of the high-voltage source is connected to a source of the gallium nitride power device under test, and an end of the first resistor remote from the first switch is connected to a drain of the gallium nitride power device under test.

[0008] From the above, the high voltage source can provide a voltage not higher than 1000V, the first switch can be a MOS switch, and the first resistor is used to clamp the high voltage source current when switching from high voltage to low voltage.

[0009] As a possible implementation of the first aspect, the current source branch includes: a charging and discharging electronic branch and an isolating switch sub-branch; the charging and discharging electronic branch includes a loop-connected current source, an inductor, and a freewheeling circuit; the high end of the current source is connected to one end of the inductor, the low end of the current source is connected to one end of the freewheeling circuit, and the low end of the current source is connected to the source of the gallium nitride power device under test; one end of the isolating switch sub-branch is connected to the drain of the gallium nitride power device under test, and the other end of the isolating switch sub-branch is connected to the connection point between the inductor and the freewheeling circuit.

[0010] As described above, when the connection between the current source branch and the GaN power device under test is disconnected, the freewheeling circuit is charged by the current source; when the connection between the current source branch and the GaN power device under test is connected, the freewheeling circuit discharges to provide current to the GaN power device under test, thereby quickly establishing current between the source and drain of the GaN power device under test.

[0011] As a possible implementation of the first aspect, the freewheeling circuit includes: a circuit composed of diodes; or a circuit composed of resistors; or a circuit composed of a mixture of diodes and resistors.

[0012] As a possible implementation of the first aspect, the isolating switch sub-branch includes: an isolating switch sub-branch composed of diodes; or an isolating switch sub-branch composed of power devices; or an isolating switch sub-branch composed of relays; or an isolating switch sub-branch composed of diodes and relays.

[0013] As a possible implementation of the first aspect, the voltage measurement branch includes: a clamping circuit and a voltmeter connected in series; the clamping circuit is used to clamp the high voltage at the drain of the gallium nitride power device under test; wherein, an end of the clamping circuit remote from the voltmeter is connected to the drain of the gallium nitride power device under test, and an end of the voltmeter remote from the clamping circuit is connected to the source of the gallium nitride power device under test.

[0014] From the above, the voltage measurement branch is a high-precision voltage measurement branch, which is used to collect the voltage between the drain and source of the gallium nitride power device.

[0015] As a possible implementation of the first aspect, the driving branch, the high-voltage switch branch, and the voltage measurement branch are synchronously programmable branches.

[0016] A second aspect of the present application provides a method for testing the dynamic resistance of a gallium nitride power device, comprising: controlling the on / off switching of a driving branch and a high-voltage switch branch through a preset control sequence; wherein the driving branch and the high-voltage switch branch are not turned on at the same time; when the driving branch is turned on, controlling the current source branch to be turned on and providing a preset current between the drain and source of the gallium nitride power device under test through an inductor in the current source branch; measuring a measured value of the current provided by the inductor using a current source in the current source branch, and measuring a measured value of the voltage between the drain and source of the gallium nitride power device under test using a voltage measurement branch; and determining the dynamic resistance of the gallium nitride power device under test based on the measured current and voltage values.

[0017] As described above, using the test method provided in this aspect and based on the test circuit provided in the first aspect to test the dynamic resistance of the GaN power device is conducive to detecting faults in the GaN power device, thereby effectively ensuring the performance of the GaN power device on the market.

[0018] As a possible implementation of the second aspect, the preset control sequence includes: the preset control sequence includes: a dual-pulse control sequence or a multi-pulse control sequence; wherein the number of pulses in the multi-pulse control sequence is greater than 2.

[0019] As a possible implementation of the second aspect, the dual-pulse control timing includes: controlling the driving branch to drive the GaN power device under test to turn on, so that the connection between the current source branch and the GaN power device under test is conducted, and the inductor in the current source branch provides a preset current between the drain and source of the GaN power device under test, for a duration of T1; when the driving branch is turned off, disconnecting the current source branch from the GaN power device under test, causing the current source in the current source branch to charge the inductor, and controlling the high-voltage switch branch to provide a high voltage between the drain and source of the GaN power device under test, for a duration of T2; and when the high-voltage switch branch is turned off, controlling the driving branch to drive the GaN power device under test to turn on, so that the connection between the current source branch and the GaN power device under test is conducted, and causing the inductor in the current source branch to provide a preset current between the drain and source of the GaN power device under test, for a duration of T3.

[0020] As a possible implementation of the second aspect, the multi-pulse control sequence includes multiple repeated pulse control sequences; wherein one pulse control sequence includes: controlling the high-voltage switch branch to provide a high voltage between the drain and source of the gallium nitride power device under test, thereby disconnecting the current source branch from the gallium nitride power device under test and causing the current source in the current source branch to charge the inductor, for a duration of T2; and when the high-voltage switch branch is disconnected, controlling the drive branch to drive the gallium nitride power device under test to turn on, thereby connecting the current source branch to the gallium nitride power device under test and causing the inductor in the current source branch to provide current between the drain and source of the gallium nitride power device under test, for a duration of T3.

[0021] As a possible implementation of the second aspect, before applying the multi-pulse control sequence, the method further includes: controlling the drive branch to drive the gallium nitride power device under test to turn on, so that the connection between the current source branch and the gallium nitride power device under test is turned on and the inductor in the current source branch provides a preset current between the drain and the source of the gallium nitride power device under test, for a duration of T1.

[0022] As a possible implementation of the second aspect, the method further includes: obtaining a first dynamic resistance value of the gallium nitride power device under test within the T1 time period; obtaining a second dynamic resistance value of the gallium nitride power device under test within the T3 time period of the last pulse of the control sequence; and determining whether the gallium nitride power device under test is faulty based on the first dynamic resistance value and the second dynamic resistance value.

[0023] As shown above, a normal GaN power device has a low on-resistance in the low-voltage state, resulting in a high current flowing through the drain and source. When a high voltage is applied to the GaN power device for a period of time and then switched to a low voltage, the on-resistance of the GaN power device increases. Switching to a low voltage again reduces the on-resistance again. By comparing the difference in on-resistance between the two low-voltage states, it is possible to determine whether the GaN power device is functioning properly or faulty.

[0024] These and other aspects of the invention will be apparent from and elucidated with reference to the following description of the embodiment(s). BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A circuit diagram of a dynamic resistance test circuit for a gallium nitride power device provided by an embodiment of the present invention;

[0026] Figure 2a A circuit structure diagram of a freewheeling circuit provided in an embodiment of the present invention;

[0027] Figure 2bA circuit structure diagram of another freewheeling circuit provided in an embodiment of the present invention;

[0028] Figure 2c A circuit structure diagram of another freewheeling circuit provided in an embodiment of the present invention;

[0029] Figure 3a A circuit structure diagram of an isolating switch sub-branch provided in an embodiment of the present invention;

[0030] Figure 3b A circuit structure diagram of an isolating switch sub-branch provided in an embodiment of the present invention;

[0031] Figure 3c A circuit structure diagram of an isolating switch sub-branch provided in an embodiment of the present invention;

[0032] Figure 3d A circuit structure diagram of an isolating switch sub-branch provided in an embodiment of the present invention;

[0033] Figure 3e A circuit structure diagram of an isolating switch sub-branch provided in an embodiment of the present invention;

[0034] Figure 4 A circuit structure diagram of a clamping circuit provided by an embodiment of the present invention;

[0035] Figure 5 A flow chart of a method for testing the dynamic resistance of a gallium nitride power device provided by an embodiment of the present invention;

[0036] Figure 6 A timing diagram of the dual pulse control timing provided by an embodiment of the present invention;

[0037] Figure 7 This is a timing diagram of the multi-pulse control timing provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The words "first, second, third, etc." or module A, module B, module C and the like in the specification and claims are used only to distinguish similar objects and do not represent a specific ordering of the objects. It is understood that the specific order or sequence can be interchanged where permitted so that the embodiments of the invention described herein can be implemented in an order other than that illustrated or described herein.

[0039] In the following description, the numbers representing the steps, such as S110, S120, etc., do not necessarily mean that the steps must be executed in this manner. If permitted, the order of the steps can be interchanged or they can be executed simultaneously.

[0040] The term "comprising" as used in the specification and claims should not be construed as limiting to what is listed thereafter; it does not exclude other elements or steps. Thus, it should be interpreted as specifying the presence of the recited features, integers, steps, or components, but not excluding the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Thus, the expression "a device comprising means A and B" should not be limited to a device consisting solely of components A and B.

[0041] References in this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Therefore, appearances of the phrases "in one embodiment" or "in an embodiment" throughout this specification do not necessarily refer to the same embodiment, but may do so. Furthermore, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. In the event of any inconsistency, the meanings herein described or derived from the contents described herein shall prevail. In addition, the terms used herein are for the purpose of describing the embodiments of the present invention only and are not intended to limit the present invention.

[0043] Referring to the figures below, a test circuit for the dynamic resistance of a gallium nitride power device provided in an embodiment of the present application is described in detail.

[0044] like Figure 1 The figure shows the circuit structure of a dynamic resistance test circuit for a GaN power device according to an embodiment of the present invention. In this embodiment, the test circuit includes a driving branch 110, a high-voltage switch branch 120, a current source branch 130, and a voltage measurement branch 140. The driving branch 110 is connected to the gate G and source S of the GaN power device under test Q. The high-voltage switch branch 120 is connected in parallel to the drain D and source S of the GaN power device under test Q. The current source branch 130 is connected in parallel to the drain D and source S of the GaN power device under test Q. The voltage measurement branch 140 is connected in parallel to the drain D and source S of the GaN power device under test Q. Each branch is described in detail below.

[0045] The driver branch 110 can be a synchronously programmable high-speed driver. A synchronous control signal 1 (i.e., a control pulse Vgs) is applied to the high-speed driver to control its on / off state. When the driver is in the on state, it drives the gate of the GaN power device Q under test to conduct. When the driver is in the off state, the driver branch 110 is inoperative, and the gate of the GaN power device Q is also off.

[0046] The high-voltage switch branch 120 includes a high-voltage source HVI, a first switch K1, and a first resistor R1. The high-voltage source HVI, the first switch K1, and the first resistor R1 are connected in series. Figure 1 As shown, the high end of the high-voltage source HVI is connected to the first end of the first switch K1, the low end of the high-voltage source HVI is connected to the source S of the tested gallium nitride power device Q, the second end of the first switch K1 is connected to the first end of the first resistor R1, and the second end of the first resistor R1 is connected to the drain D of the tested gallium nitride power device Q. As can be seen from the above connection relationship, the first end of the first resistor R1 is the end connected to the first switch K1, and the second end of the first resistor R1 is the end away from the first switch K1.

[0047] In this embodiment, the voltage provided by the high voltage source HVI is generally not higher than 1000V.

[0048] In this embodiment, the first switch K1 may be a MOS switch. The high-voltage switch branch 120 is controlled to be on or off by applying a synchronous control signal 2 (i.e., a control pulse Vds) to the first switch K1. When the first switch K1 is on, the high-voltage switch branch 120 is connected to the GaN power device under test Q. At this time, a high voltage is provided between the drain D and source S of the GaN power device under test Q via the high-voltage switch branch 120.

[0049] In this embodiment, the resistance of the first resistor R1 may be 1000 ohms, and is used to achieve current clamping of the high voltage source HVI when switching from high voltage to low voltage.

[0050] The current source branch 130 includes a charge and discharge electron branch 131 and an isolation switch sub-branch 132 .

[0051] The charge and discharge electronic branch 131 includes a loop-connected current source FPVI, an inductor L, and a freewheeling circuit. Specifically, the high end of the current source FPVI is connected to the first end of the inductor L, the second end of the inductor L is connected to the first end of the freewheeling circuit, and the second end of the freewheeling circuit is connected to the low end of the current source FPVI. The low end of the current source FPVI is also connected to the source S of the gallium nitride power device Q under test. One end of the isolation switch sub-branch 132 is connected to the drain D of the gallium nitride power device Q under test, and the other end of the isolation switch sub-branch 132 is connected to the connection point between the inductor L and the freewheeling circuit, i.e., the second end of the inductor L (i.e., the first end of the freewheeling circuit).

[0052] In this embodiment, the current range provided by the current source FPVI is no greater than 10A.

[0053] As an optional implementation, the freewheeling circuit may be composed of diodes, and the number of the diodes may be one or more. Figure 2a The figure shows a freewheeling circuit composed of a plurality of diode strings (D1 to Dx).

[0054] As another optional implementation, the freewheeling circuit may be composed of resistors, and the number of the resistors may be one or more. Figure 2b The figure shows a freewheeling circuit composed of multiple resistors (R1 to Rx) connected in series.

[0055] As another optional implementation, the freewheeling circuit may be composed of a mixture of diodes and resistors, and the number of the diodes and resistors may be one or more. Figure 2c The figure shows a freewheeling circuit composed of a plurality of diodes (D1-Dx) and a plurality of resistors (R1-Rx) connected in series. In the freewheeling circuit, one diode is adjacent to one resistor.

[0056] It should be understood that Figure 2a-2c The freewheeling circuits shown are examples and do not limit the freewheeling circuit. In other embodiments, the freewheeling circuit may be composed of other components or have other connection relationships. For example, when the freewheeling circuit includes multiple diodes and multiple resistors, the connection relationship of the freewheeling circuit may be such that a resistor is connected after every two diodes, and two diodes are connected after the resistors, etc.

[0057] In this embodiment, as an optional implementation, the isolating switch sub-branch 132 may be composed of diodes, which are required to withstand high voltage and have fast switching speed. The number of diodes in the isolating switch sub-branch 132 may be one or more. Figure 3a Shown is an isolating switch sub-branch consisting of a single diode (D1).

[0058] As another optional implementation, the isolation switch sub-branch 132 may be composed of power devices, including but not limited to IGBT tubes or MOSFET tubes, etc. The number of power devices in the isolation switch sub-branch may be one or more. Figure 3b Shown is an isolating switch sub-branch consisting of a single IGBT tube (A1).

[0059] As another optional implementation, the isolating switch sub-branch 132 may be composed of relays, which may be high-voltage relays, wherein the number of the relays may be one or more. Figure 3c The diagram shows an isolating switch sub-branch consisting of a single relay (K1). In the isolating switch sub-branch, the relay may be a relay supporting a synchronous program control function.

[0060] As another optional implementation, the isolation switch sub-branch 132 may be composed of a combination of diodes and relays, and the number of diodes and relays may be one or more. Figure 3d The figure shows the isolating switch sub-branch consisting of a diode and a relay in series. Figure 3e Shown is an isolating switch sub-branch consisting of a diode and a relay connected in parallel.

[0061] It should be understood that Figure 3a-Figure 3e The isolating switch sub-branches shown are examples and do not limit the isolating switch sub-branches. In other embodiments, the isolating switch sub-branches may also be composed of other components or have other forms of connection relationships.

[0062] In this embodiment, when the current source branch 130 is disconnected from the GaN power device Q under test (i.e., the isolating switch sub-branch 132 is in the off state), the current source FPVI, the inductor L, and the freewheeling circuit form a closed loop. The current source FPVI charges the inductor L, and the current flows back to the low end of the current source FPVI through the freewheeling circuit. When the current source branch 130 is connected to the GaN power device Q under test (i.e., the isolating switch sub-branch 132 is in the on state), the inductor L quickly provides a preset current between the drain D and source S of the GaN power device Q under test, thereby improving the current build-up speed between the drain D and source S of the GaN power device Q under test and reducing the current build-up time.

[0063] The voltage measurement branch 140 includes a clamping circuit and a voltmeter QVM, which are connected in series. The clamping circuit is used to clamp the high voltage of the drain D of the GaN power device Q under test. For example, Figure 4As shown, the clamping circuit can be two diodes connected in reverse parallel. The voltmeter QVM is a high-precision voltmeter used to collect the voltage value between the drain D and the source S of the tested gallium nitride power device Q when it is turned on at low voltage.

[0064] The GaN power device dynamic resistance test circuit provided in this embodiment significantly shortens the current buildup time between the drain D and source S of the GaN power device under test by charging the inductor when the current source branch is disconnected from the device under test. When the current source branch is connected to the device under test, the inductor instantly discharges to provide current to the device under test. This significantly reduces the current buildup time between the drain D and source S of the device under test. Based on this embodiment, the test circuit can achieve a current buildup speed of less than 3 μs.

[0065] The following describes a method for testing the dynamic resistance of a GaN power device based on the test circuit for the dynamic resistance of the GaN power device in the above embodiment.

[0066] like Figure 5 The flowchart of the test method is shown. The test method includes steps S110-S140. Each step is described in detail below.

[0067] S110: Control the on / off state of the driving branch 110 and the high-voltage switch branch 120 through a preset control sequence. The driving branch 110 and the high-voltage switch branch 120 are not turned on at the same time, i.e., when the driving branch 110 is turned on, the high-voltage switch branch 120 is turned off; and when the high-voltage switch branch 120 is turned on, the driving branch 110 is turned off.

[0068] In this embodiment, the control sequence can be a dual-pulse control sequence or a multi-pulse control sequence. The dual-pulse control sequence is first introduced below:

[0069] like Figure 6 FIG. 1 shows a dual-pulse control timing sequence provided by this embodiment. Figure 6 In the figure, Vds represents the control sequence of the high-voltage switch branch 120, Vgs represents the control sequence of the driver branch 110, and Ids represents the current between the drain D and source S of the tested GaN power device Q. It should be understood that the isolation switch in the current source branch 130 can be a programmable circuit or a non-programmable circuit. If the isolation switch circuit in the current source branch 130 supports programmable functions, its control sequence is synchronized with the control sequence of the driver branch 110.

[0070] First, a high voltage (i.e., G_ON) is applied to the driver branch 110, causing the driver branch 110 to drive the GaN power device Q under test to turn on. At this point, the connection between the current source branch 130 and the GaN power device Q under test is turned on, i.e., the isolation switch circuit is closed. At this point, a preset current is provided between the drain D and source S of the GaN power device Q under test via the inductor L in the current source branch 130. This process lasts for T1, where Tr is the time it takes for the current to establish between the drain D and source S of the GaN power device Q under test, and Id indicates when the current has stabilized.

[0071] When the drive branch 110 is turned off (i.e., the drive pulse Vgs of the drive branch 110 is at a low level), the connection between the current source branch and the GaN power device Q under test is disconnected, that is, the isolation switch circuit is disconnected. At this time, the inductor L is charged through the current source FPVI in the current source branch 130, and the high-voltage switch branch 120 is controlled to provide a high voltage between the drain D and the source S of the GaN power device Q under test (i.e., the drive pulse Vds of the high-voltage switch branch 120 is at a high level). This process lasts for T2.

[0072] When the high-voltage switch branch 120 is turned off (i.e., the drive pulse Vds of the high-voltage switch branch 120 is at a low level), the drive branch 110 is controlled again to drive the GaN power device Q under test to turn on, so that the connection between the current source branch 130 and the GaN power device Q under test is connected, that is, the isolation switch circuit is closed. At this time, a preset current is provided between the drain D and the source S of the GaN power device Q under test through the inductor L in the current source branch 130. This process lasts for T3.

[0073] The process of testing the dynamic resistance of a GaN power device using this dual-pulse control sequence includes calculating the dynamic resistance of the GaN power device under test during time period T1. Then, calculating the dynamic resistance of the GaN power device under test during time period T3. The two calculated dynamic resistances are compared to determine whether the GaN power device under test is faulty. Alternatively, the ratio of the two dynamic resistances can be used to determine whether the device is faulty.

[0074] Next, we introduce the multi-pulse control timing:

[0075] like Figure 7 FIG. 1 shows a multi-pulse control timing sequence provided by this embodiment. Figure 7 Here, Vds represents the control sequence of the high-voltage switch branch 120, Vgs represents the control sequence of the driver branch 110, and Ids represents the current between the drain D and source S of the GaN power device Q under test. The following description uses one pulse control sequence from this multi-pulse control sequence. The other pulse control sequences are identical to the one used in this example and are therefore not further described.

[0076] The high-voltage switch branch 120 is controlled to provide a high voltage between the drain D and the source S of the GaN power device Q under test, so that the connection between the current source branch 130 and the GaN power device Q under test is cut off and the current source PFVI in the current source branch 130 charges the inductor L for a duration of T2.

[0077] When the high-voltage switch branch 120 is turned off, the driving branch 110 is controlled to drive the GaN power device Q under test to turn on, so that the connection between the current source branch 130 and the GaN power device Q under test is conducted and the inductor L in the current source branch 130 provides current between the drain D and the source S of the GaN power device Q under test, for a duration of T3.

[0078] T2 and T3 are a repetitive unit, that is, the multi-pulse control sequence includes multiple repetitive T2 and T3.

[0079] In this embodiment, before the first T2 of the multi-pulse control sequence, the following further comprises: T1: controlling the driving branch 110 to drive the GaN power device Q under test to conduct, thereby establishing a connection between the current source branch 130 and the GaN power device Q under test and causing the inductor L in the current source branch to provide a preset current between the drain D and source S of the GaN power device Q under test, for a duration of T1. The purpose of including T1 before T2 is to use the dynamic resistance calculated during the T1 period as a reference for comparison with the dynamic resistance calculated during the T3 period of the last repeated pulse of the multi-pulse control sequence, thereby determining whether the GaN device under test is faulty.

[0080] The process of testing the dynamic resistance of a GaN power device based on this multi-pulse control sequence includes calculating the dynamic resistance of the GaN power device under test during time period T1. Then, calculating the dynamic resistance of the GaN power device under test during time period T3 during the last repeated pulse. The two calculated dynamic resistances are compared to determine whether the GaN power device under test is faulty.

[0081] S120: When the driving branch is turned on, controlling the current source branch to be turned on and providing a preset current between the drain and the source of the gallium nitride power device under test through the inductor in the current source branch.

[0082] In this embodiment, the instantaneous discharge of the inductor can quickly establish a current between the drain and the source of the GaN power device under test.

[0083] S130: Using the current source in the current source branch to measure and obtain a measured value of the current provided by the inductor, and using the voltage measurement branch to measure and obtain a measured value of the voltage between the drain and the source of the measured gallium nitride power device.

[0084] In this embodiment, the voltmeter QVM in the voltage measurement branch can be used to obtain the actual measured value of the voltage between the drain and the source of the GaN power device under test.

[0085] S140: Determine a dynamic resistance value of the measured GaN power device according to the measured current value and the measured voltage value.

[0086] By comparing the resistance value before applying the high voltage with the resistance value after applying the high voltage, it can be determined whether the device under test is normal or faulty.

[0087] Another embodiment of the present application provides a method for testing the dynamic resistance of a gallium nitride power device, specifically comprising:

[0088] Test preparation phase: The driver branch 110 is controlled to turn off the gate G of the GaN power device Q under test. The high-voltage switch branch 120 is controlled to disconnect it from the GaN power device Q under test (i.e., the first switch K1 is controlled to be turned off). The current source branch 130 is controlled to disconnect it from the GaN power device Q under test (i.e., the isolation switch circuit is controlled to be turned off). The inductor L is charged via the current source FPVI. During this phase, the voltage measurement branch 140 is inoperative.

[0089] In the first test phase, the driver branch 110 is controlled to turn on the gate G of the GaN power device Q under test. The current source branch 130 is controlled to connect to the GaN power device Q under test (i.e., the isolation switch circuit is controlled to turn on), and a preset current is supplied between the drain D and source S of the GaN power device Q under test via the inductor L. At this point, the current source FPVI in the current source branch 130 measures the actual value of the preset current, and the voltage measurement branch 140 measures the actual value of the voltage between the drain D and source S of the GaN power device Q under test. During this phase, the high-voltage switch branch 110 does not need to be operated; it remains disconnected from the GaN power device Q under test, as in the test preparation phase.

[0090] In this test phase, the resistance value Ron1 of the tested gallium nitride power device Q is calculated based on the actual measured values ​​of current and voltage.

[0091] In the second measurement phase, the driver branch 110 is controlled to turn off the gate G of the GaN power device Q under test, the high-voltage switch branch 120 is controlled to connect to the GaN power device Q under test (i.e., the first switch K1 is controlled to turn on), the current source branch 130 is controlled to disconnect from the GaN power device Q under test (i.e., the isolation switch circuit is controlled to turn off), and the inductor L is charged via the current source FPVI. During this phase, the voltage measurement branch 140 is inoperative.

[0092] In the third measurement phase, the driving branch 110 is controlled to turn on the gate G of the GaN power device Q under test, the high-voltage switch branch 120 is controlled to disconnect the high-voltage switch branch 120 from the GaN power device Q under test (i.e., the first switch K1 is controlled to be turned off), the current source branch 130 is controlled to connect the current source branch 130 to the GaN power device Q under test (i.e., the isolation switch circuit is controlled to be turned on), and a preset current is provided between the drain D and the source S of the GaN power device Q under test via the inductor L. At this time, the actual value of the preset current is measured using the current source FPVI in the current source branch 130, and the actual value of the voltage between the drain D and the source S of the GaN power device Q under test is measured using the voltage measurement branch 140.

[0093] In this test phase, the resistance value Ron2 of the tested gallium nitride power device Q is calculated based on the actual measured values ​​of current and voltage.

[0094] Fault judgment stage: Compare the resistance value Ron1 in the first test stage and the resistance value Ron2 in the third test stage after high voltage is applied, so as to determine whether the tested GaN power device Q is a faulty device.

[0095] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in greater detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of protection of the present invention.

Claims

1. A test circuit for dynamic resistance of a gallium nitride power device, characterized in that: include: A driving branch, a high-voltage switch branch, a current source branch, and a voltage measurement branch; wherein the current source branch includes a charge and discharge electronic branch; The driving branch is connected to the gate and source of the GaN power device under test, and is used to drive the gate of the GaN power device under test to be turned on or off; The high-voltage switch branch is connected in parallel to the drain and source of the GaN power device under test, and is configured to provide a high voltage between the drain and source of the GaN power device under test when the connection between the high-voltage switch branch and the GaN power device under test is conducted; The current source branch is connected in parallel to the drain and source of the GaN power device under test, and is used to charge the charge-discharge electron branch when the connection between the current source branch and the GaN power device under test is disconnected; and is also used to provide a preset current between the drain and source of the GaN power device under test through the charge-discharge electron branch when the connection between the current source branch and the GaN power device under test is connected. When the high-voltage switch branch provides a high voltage between the drain and source of the GaN power device under test, the connection between the current source branch and the GaN power device under test is disconnected; when the drive branch drives the GaN power device under test to turn on, the connection between the current source branch and the GaN power device under test is connected. The voltage measurement branch is connected in parallel to the drain and source of the GaN power device under test, and is used to measure the voltage between the drain and source of the GaN power device under test when it is turned on; The current source branch comprises: Charge and discharge electronic branch and disconnector sub-branch; The charge and discharge electronic branch includes a current source, an inductor, and a freewheeling circuit connected in a loop; the high end of the current source is connected to one end of the inductor, the low end of the current source is connected to one end of the freewheeling circuit, and the low end of the current source is connected to the source of the gallium nitride power device under test; One end of the isolating switch sub-branch is connected to the drain of the gallium nitride power device under test, and the other end of the isolating switch sub-branch is connected to the connection point between the inductor and the freewheeling circuit; the isolating switch sub-branch is composed of a diode; The freewheeling circuit is a freewheeling circuit composed of a plurality of diodes connected in series, or the freewheeling circuit is a freewheeling circuit composed of resistors, or the freewheeling circuit is a freewheeling circuit composed of a mixture of diodes and resistors.

2. The circuit according to claim 1, wherein: The high-voltage switch branch comprises: A high voltage source, a first switch and a first resistor connected in series in sequence; The low end of the high voltage source is connected to the source of the gallium nitride power device under test, and the end of the first resistor away from the first switch is connected to the drain of the gallium nitride power device under test.

3. The circuit according to claim 2, characterized in that The first resistor is used to achieve current clamping of the high voltage source when switching from high voltage to low voltage.

4. The circuit according to claim 1, wherein: The isolating switch sub-branch comprises: A sub-branch consisting of power devices; or a sub-branch consisting of relays; or A sub-branch consisting of a diode and a relay.

5. The circuit according to claim 1, wherein: The voltage measurement branch comprises: A clamping circuit and a voltmeter connected in series; the clamping circuit is used to clamp the high voltage at the drain of the gallium nitride power device under test; The end of the clamping circuit away from the voltmeter is connected to the drain of the gallium nitride power device under test, and the end of the voltmeter away from the clamping circuit is connected to the source of the gallium nitride power device under test.

6. A method for testing the dynamic resistance of a gallium nitride power device according to any one of claims 1 to 5, characterized in that: include: The driving branch and the high-voltage switch branch are turned on or off by controlling a preset control timing; wherein the driving branch and the high-voltage switch branch are not turned on at the same time; When the driving branch is turned on, controlling the current source branch to be turned on and providing a preset current between the drain and the source of the gallium nitride power device under test through the inductor in the current source branch; Using the current source in the current source branch to measure and obtain a measured value of the current provided by the inductor, and using the voltage measurement branch to measure and obtain a measured value of the voltage between the drain and the source of the gallium nitride power device under test; The dynamic resistance value of the measured gallium nitride power device is determined according to the measured value of the current and the measured value of the voltage.

7. The method according to claim 6, characterized in that The preset control sequence includes: Double pulse control timing or multi-pulse control timing; Wherein, the number of pulses in the multi-pulse control sequence is greater than 2.

8. The method according to claim 7, characterized in that The dual pulse control timing includes: controlling the driving branch to drive the GaN power device under test to turn on, so that the connection between the current source branch and the GaN power device under test is conducted and the inductor in the current source branch provides a preset current between the drain and the source of the GaN power device under test, for a duration of T1; When the driving branch is turned off, the connection between the current source branch and the GaN power device under test is disconnected, the current source in the current source branch is caused to charge the inductor, and the high-voltage switch branch is controlled to provide a high voltage between the drain and the source of the GaN power device under test, for a duration of T2; When the high-voltage switch branch is turned off, the driving branch is controlled to drive the GaN power device under test to turn on, so that the connection between the current source branch and the GaN power device under test is conducted and the inductor in the current source branch provides a preset current between the drain and the source of the GaN power device under test, for a duration of T3.

9. The method according to claim 7, characterized in that The multi-pulse control sequence includes multiple repeated pulse control sequences; wherein a pulse control sequence includes: controlling the high-voltage switch branch to provide a high voltage between the drain and the source of the GaN power device under test, thereby disconnecting the current source branch from the GaN power device under test and causing the current source in the current source branch to charge the inductor, for a duration of T2; When the high-voltage switch branch is turned off, the driving branch is controlled to drive the GaN power device under test to turn on, so that the connection between the current source branch and the GaN power device under test is conducted and the inductor in the current source branch provides current between the drain and the source of the GaN power device under test, for a duration of T3.

10. The method according to claim 9, characterized in that Before applying the multi-pulse control timing, the method further includes: The driving branch is controlled to drive the GaN power device under test to turn on, so that the connection between the current source branch and the GaN power device under test is turned on and the inductor in the current source branch provides a preset current between the drain and the source of the GaN power device under test, for a duration of T1.

11. The method according to claim 8 or 10, characterized in that Also includes: Obtaining a first dynamic resistance value of the gallium nitride power device under test within the time period T1; Obtaining a second dynamic resistance value of the gallium nitride power device under test within the T3 time period of the last pulse of the control sequence; Determine whether the tested gallium nitride power device is faulty according to the first dynamic resistance value and the second dynamic resistance value.

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