Test circuit, test device and test method for gallium nitride switch tube for communication power supply
By designing a combination of half-bridge circuit, inductor energy storage circuit and clamping circuit, high-precision electrical parameter measurement of gallium nitride switching transistors during reverse conduction was achieved, solving the problem of insufficient measurement accuracy in existing technologies and improving the accuracy and stability of the measurement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHONGTIAN BROADBAND TECH
- Filing Date
- 2026-06-16
- Publication Date
- 2026-07-24
AI Technical Summary
Existing technologies make it difficult to achieve high-precision measurement of the electrical parameters of gallium nitride switches during reverse conduction, which affects their stability and safety.
A test circuit including a half-bridge circuit, an inductor energy storage circuit, and a clamping circuit was designed. By controlling the on/off state of the switching transistor, the clamping circuit limits and stabilizes the voltage of the gallium nitride switching transistor, and a mirror current source is combined to achieve accurate current detection, thereby reducing parasitic capacitance and improving measurement accuracy.
This method enables high-precision measurement of electrical parameters of gallium nitride (GaN) switches during reverse conduction, reducing measurement errors, improving frequency response, and ensuring measurement accuracy and stability.
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Figure CN122449313A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor technology, and in particular to a test circuit, test equipment and test method for a gallium nitride switch for communication power supply. Background Technology
[0002] Gallium nitride (GaN) devices, as representative products of third-generation semiconductors, possess superior properties such as high frequency, high efficiency, high power, high voltage resistance, high temperature resistance, and strong radiation resistance. They are key core materials and electronic components supporting the independent innovation and transformation and upgrading of industries such as next-generation mobile communications, new energy vehicles, and high-speed rail. In particular, to ensure uninterrupted power supply and stable voltage for communication network equipment such as base stations, equipment rooms, switches, routers, and servers, it is especially important to study and understand the operating characteristics of gallium nitride switches in communication power supply systems.
[0003] Clearly, as gallium nitride (GaN) power devices become increasingly widely used, their measurement becomes increasingly important. Therefore, the ability to measure the electrical parameters of GaN devices during reverse conduction is crucial for their stability and safety. Summary of the Invention
[0004] In view of the above, it is necessary to provide a test circuit, test equipment and test method for gallium nitride (GaN) switching transistors used in communication power supplies, so as to measure the electrical parameters of GaN switching transistors when they are reverse-biased.
[0005] This application provides a test circuit for a gallium nitride (GaN) switch for communication power supplies, comprising a half-bridge circuit, an inductor energy storage circuit, and a clamping circuit. The half-bridge circuit is used to connect to a first DC power supply and includes a reference switch and a GaN switch connected in series. A first terminal of the reference switch is connected to the positive terminal of the first DC power supply, and a second terminal of the reference switch is connected to the first terminal of the GaN switch. The second terminal of the GaN switch is connected to the negative terminal of the first DC power supply. The inductor energy storage circuit includes at least an inductor. A first terminal of the inductor energy storage circuit is connected to the second terminal of the reference switch, and the second terminal of the inductor energy storage circuit is connected to the second terminal of the GaN switch through a load. The inductor energy storage circuit forms a reverse conduction loop for the GaN switch. The first terminal of the clamping circuit is connected to the first terminal of the gallium nitride (GaN) switching transistor, and the second terminal of the clamping circuit is connected to the second terminal of the GaN switching transistor. The clamping circuit is used to clamp the voltage of the GaN switching transistor when it is reverse-biased. The clamping circuit includes a first clamping branch and a mirror current source. The first clamping branch includes a first diode, a second diode, a Zener diode, and a resistor. The anode of the first diode is connected to the cathode of the Zener diode, and the anode of the Zener diode is connected to the anode of the second diode through the resistor. The cathode of the first diode serves as the first terminal of the first clamping branch, the anode of the first diode serves as the third terminal of the first clamping branch, the cathode of the second diode serves as the second terminal of the first clamping branch, and the anode of the second diode serves as the fourth terminal of the first clamping branch. The first and second terminals of the first clamping branch are respectively used to connect to the first and second terminals of the GaN switching transistor, and the third and fourth terminals of the first clamping branch are respectively used to connect to the reference input terminal and the mirror output terminal of the mirror current source.
[0006] A second aspect of this application provides a test method applied to the test circuit described above. The test method includes: controlling a reference switch to be turned on and controlling a gallium nitride (GaN) switch to be turned off; controlling the reference switch to be turned off; controlling the GaN switch to be turned on, and sampling a first reverse conduction voltage at the third terminal of the first clamping branch, a second reverse conduction voltage at the fourth terminal of the first clamping branch, and a reverse conduction current at the first terminal of the GaN switch.
[0007] A third aspect of this application provides a test apparatus for testing gallium nitride (GaN) switching transistors. The test apparatus includes the test circuit described above.
[0008] In the test circuit provided in this application, the reference switch is first turned on and the gallium nitride (GaN) switch is turned off, forming a loop with the first DC power supply, the reference switch, the inductor energy storage circuit, and the load. This allows the first DC power supply to charge the inductor energy storage circuit through the reference switch. Subsequently, the reference switch in the test circuit is turned off, causing the inductor energy storage circuit to also disconnect. However, at the instant the inductor energy storage circuit disconnects, the voltage across it changes abruptly. Then, the GaN switch is turned on again, forming a loop with the inductor energy storage circuit, the load, and the GaN switch. The GaN switch is reverse-biased. At this point, a clamping circuit can be used to limit and stabilize the voltage between the first and second terminals of the GaN switch, and the reverse conduction current flowing through the GaN switch and the reverse conduction voltage between the first and second terminals can be detected, thereby measuring the reverse conduction characteristics of the GaN switch. Furthermore, by setting up a first clamping branch, this application can achieve clamping using a Zener diode and a resistor, while simultaneously utilizing the first and second diodes to bear the total withstand voltage. This reduces the junction capacitance of the first and second diodes, thereby lowering the overall parasitic capacitance of the first clamping branch, improving its frequency response, and achieving high-precision measurement. Clearly, the test circuit provided by this application, based on a simple circuit structure, can quickly and accurately measure the electrical parameters of a gallium nitride switch when it is directionally on. Attached Figure Description
[0009] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0010] Figure 1 A circuit block diagram of the test circuit provided in the first embodiment of this application.
[0011] Figure 2 A circuit block diagram of the test circuit provided in the second embodiment of this application.
[0012] Figure 3 This is a partial circuit diagram of the test circuit in one embodiment of this application.
[0013] Figure 4 This is a partial circuit diagram of the test circuit in another embodiment of this application.
[0014] Figure 5A This is a partial equivalent circuit diagram of the test circuit at time T1 in one embodiment of this application. Figure 5B This is a schematic diagram of the electrical parameter curves of each node of the test circuit at time T1 in one embodiment of this application.
[0015] Figure 6A This is a partial equivalent circuit diagram of the test circuit at time T2 in one embodiment of this application. Figure 6BThis is a schematic diagram of the electrical parameter curves of each node of the test circuit at time T2 in one embodiment of this application.
[0016] Figure 7A This is a partial equivalent circuit diagram of the test circuit at time T3 in one embodiment of this application. Figure 7B This is a schematic diagram of the electrical parameter curves of each node of the test circuit at time T3 in one embodiment of this application.
[0017] Figure 8A This is a partial equivalent circuit diagram of the test circuit at time T4 in one embodiment of this application. Figure 8B This is a schematic diagram of the electrical parameter curves of each node of the test circuit at time T4 in one embodiment of this application.
[0018] Figure 9 A circuit block diagram of the test circuit provided in the third embodiment of this application.
[0019] Figure 10 This is a flowchart illustrating a testing method provided in one embodiment of this application.
[0020] Figure 11 This is a block diagram of a test device provided in one embodiment of this application. Detailed Implementation
[0021] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.
[0022] In the description of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists alone, A and B exist simultaneously, and B exists alone.
[0023] In the description of this application, the words "first," "second," etc., are used only to distinguish different objects and do not limit the quantity or order of execution, nor do they imply that they must be different. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.
[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
[0025] Some embodiments will now be described with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0026] Gallium nitride (GaN) devices, as representative products of third-generation semiconductors, possess superior properties such as high frequency, high efficiency, high power, high voltage resistance, high temperature resistance, and strong radiation resistance. They are key core materials and electronic components supporting the independent innovation and transformation and upgrading of industries such as next-generation mobile communications, new energy vehicles, and high-speed rail. In particular, to ensure uninterrupted power supply and stable voltage for communication network equipment such as base stations, equipment rooms, switches, routers, and servers, it is especially important to study and understand the operating characteristics of gallium nitride switches in communication power supply systems.
[0027] Clearly, as gallium nitride (GaN) power devices become increasingly widely used, their measurement becomes increasingly important. Therefore, the ability to measure the electrical parameters of GaN devices during reverse conduction is crucial for their stability and safety.
[0028] Based on this, this application provides a test circuit and test method for gallium nitride (GaN) switching transistors used in communication power supplies, so as to achieve high-precision measurement of the characteristic changes of GaN switching transistors during reverse conduction.
[0029] First, please refer to Figure 1 , Figure 1 This is a functional block diagram of a test circuit 10 provided in an embodiment of this application. The test circuit 10 includes a half-bridge circuit 11, an inductor energy storage circuit 12, and a clamping circuit 13. The half-bridge circuit 11 is used to connect to a first DC power supply 14. The half-bridge circuit 11 includes a reference switch 111 and a gallium nitride switch 112 connected in series.
[0030] In this design, the first terminal of the reference switch 111 is connected to the positive terminal of the first DC power supply 14, the second terminal of the reference switch 111 is connected to the first terminal of the gallium nitride switch 112, and the second terminal of the gallium nitride switch 112 is connected to the negative terminal of the first DC power supply 14. Understandably, by controlling the voltages at the controlled terminals of the reference switch 111 and the gallium nitride switch 112 respectively, the on / off control of the reference switch 111 and the gallium nitride switch 112 can be achieved. In some embodiments, the reference switch 111 is also a gallium nitride switch, which is beneficial for further improving measurement accuracy.
[0031] The inductor energy storage circuit 12 includes at least an inductor. A first terminal of the inductor energy storage circuit 12 is connected to the second terminal of the reference switch 111, and the second terminal of the inductor energy storage circuit 12 is connected to the second terminal of the gallium nitride switch 112 via a load 15. Understandably, the inductor voltage reverses at the moment of disconnection; therefore, this characteristic of the inductor can be used to form a reverse conduction loop for the gallium nitride switch 112.
[0032] The first terminal of the clamping circuit 13 is connected to the first terminal of the gallium nitride switch 112, and the second terminal of the clamping circuit 13 is connected to the second terminal of the gallium nitride switch 112. The clamping circuit 13 is used to clamp the voltage of the gallium nitride switch 112 when it is reverse-biased.
[0033] In the test circuit 10, the reference switch 111 is first turned on while the gallium nitride switch 112 is turned off, forming a circuit between the first DC power supply 14, the reference switch 111, the inductor energy storage circuit 12, and the load 15. This allows the first DC power supply 14 to charge the inductor energy storage circuit 12 through the reference switch 111. Subsequently, the reference switch 111 in the test circuit 10 is turned off, causing the inductor energy storage circuit 12 to also disconnect. However, at the instant the inductor energy storage circuit 12 disconnects, the voltage across it changes abruptly. Subsequently, the gallium nitride switch 112 is turned on, so that the inductor energy storage circuit 12, the load 15 and the gallium nitride switch 112 form a loop, and the gallium nitride switch 112 is reverse-biased. At this time, the clamping circuit 13 can be used to limit and regulate the voltage between the first and second terminals of the gallium nitride switch 112, and detect the reverse conduction current flowing through the gallium nitride switch 112 and the reverse conduction voltage between the first and second terminals of the gallium nitride switch 112, thereby realizing the measurement of the reverse conduction characteristics of the gallium nitride switch 112.
[0034] Please continue reading. Figure 2 In some embodiments, the clamping circuit 13 includes a clamping unit 131 and a mirror current source 132. The first and second terminals of the clamping unit 131 are connected to the first and second terminals of the gallium nitride switch 112, respectively. The third terminal of the clamping unit 131 is connected to the reference input terminal Iref of the mirror current source 132, and the fourth terminal of the clamping unit 131 is connected to the mirror output terminal IMir of the mirror current source 132. Understandably, the current at the mirror output terminal IMir of the mirror current source 132 is equal to the current at the reference input terminal Iref. Thus, by utilizing the clamping voltage limitation of the clamping unit 131 and the symmetrical micro-current conduction of the mirror current source 132, precise voltage tracking can be achieved.
[0035] Please continue reading. Figure 3In some embodiments, switch Q1 is a reference switch 111, and switch Q2 is a gallium nitride switch 112. The first terminals of both switches Q1 and Q2 are drains, and the second terminals of both switches Q1 and Q2 are sources. Understandably, by controlling the voltages at the controlled terminals (i.e., the gate voltages) of switches Q1 and Q2, respectively, the on / off control of switches Q1 and Q2, i.e., the reference switch 111 and the gallium nitride switch 112, can be achieved.
[0036] The inductor energy storage circuit 12 includes an inductor L. One end of the inductor L is connected between the second terminal of the switching transistor Q1 and the first terminal of the switching transistor Q2, and the other end of the inductor L is used to connect the load 15.
[0037] The clamping unit 131 includes a first clamping branch 1311. The first clamping branch 1311 includes a first diode D1, a second diode D2, a Zener diode ZD1, and a resistor R1. The anode of the first diode D1 is connected to the cathode of the Zener diode ZD1, and the anode of the Zener diode ZD1 is connected to the anode of the second diode D2 through the resistor R1. Specifically, the cathode of the first diode D1 serves as the first terminal of the first clamping branch 1311, the anode of the first diode D1 serves as the third terminal of the first clamping branch 1311, the cathode of the second diode D2 serves as the second terminal of the first clamping branch 1311, and the anode of the second diode D2 serves as the fourth terminal of the first clamping branch 1311. The first and second terminals of the first clamping branch 1311 are respectively connected to the first and second terminals of the switching transistor Q2, and the third and fourth terminals of the first clamping branch 1311 are respectively connected to the reference input terminal Iref and the mirror output terminal Imir of the current mirror source 132. In this way, by setting up the first clamping branch 1311, this application can achieve clamping using the Zener diode ZD1 and resistor R1, while using the first diode D1 and the second diode D2 to bear the total withstand voltage. This can reduce the junction capacitance of the first diode D1 and the second diode D2, thereby reducing the overall parasitic capacitance of the first clamping branch 1311, improving the frequency response of the first clamping branch 1311, and achieving high-precision measurement.
[0038] In some embodiments, the clamping unit 131 further includes at least one second clamping branch. The second clamping branch has the same circuit topology as the first clamping branch 1311, that is, each second clamping branch also includes a first diode, a second diode, a Zener diode, and a resistor. However, the specific parameters of each electronic device in the second clamping branch can be set according to actual needs and do not necessarily have to be the same as the specific parameters of the corresponding electronic device in the first clamping branch 1311. Furthermore, the first and second terminals of the first clamping branch 1311 are connected to the first and second terminals of the gallium nitride switch through at least one second clamping branch. Thus, the test circuit 10 provided in this application can further reduce the overall junction capacitance, improve the frequency response, and achieve high-precision measurement by setting multiple clamping branches to jointly bear the reverse voltage.
[0039] In some embodiments, when the clamping unit 131 includes a first clamping branch 1311 and a second clamping branch, the first end of the first clamping branch 1311 is connected to the third end of the second clamping branch, the second end of the first clamping branch 1311 is connected to the fourth end of the second clamping branch, and the first end and the second end of the second clamping branch are respectively connected to the first end and the second end of the gallium nitride switch.
[0040] In other embodiments, when the clamping unit 131 includes a first clamping branch 1311 and at least two second clamping branches, the at least two second clamping branches are sequentially connected to form a clamping link, which connects the two ends of the gallium nitride switch to the first clamping branch. Specifically, the third and fourth ends of each second clamping branch are respectively connected to the first and second ends of the next second clamping branch; and the first and second ends of the second clamping branch at one end of the clamping link serve as the first and second ends of the clamping link, respectively, and are connected to the first and second ends of the gallium nitride switch; the third and fourth ends of the second clamping branch at the other end of the clamping link serve as the third and fourth ends of the clamping link, respectively, and are connected to the first and second ends of the first clamping branch.
[0041] Please continue reading. Figure 4 ,by Figure 4Taking the clamping circuit 13 shown as an example, the clamping unit 131 includes a first clamping branch 1311 and at least two second clamping branches connected in sequence, such as second clamping branches 1312, ... and second clamping branches 131m. Here, m is a positive odd number greater than or equal to 3, and at least two second clamping branches are connected in sequence to form a clamping link. The third and fourth ends of each second clamping branch in the clamping link are respectively connected to the first and second ends of the next second clamping branch, and the second clamping branch 131m is located at one end of the clamping link. The first end of the second clamping branch 131m (i.e., the cathode of diode Dm) serves as the first end of the clamping link to connect to the first end of the switching transistor Q2, and the second end of the second clamping branch 131m (i.e., the cathode of diode D2m) serves as the second end of the clamping link to connect to the second end of the switching transistor Q2. The second clamping branch 1312 is located at the other end of the clamping link. The third end of the second clamping branch 1312 (i.e., the anode of diode D3) serves as the third end of the clamping link to connect to the first end of the first clamping branch 1311. The fourth end of the second clamping branch 1312 (i.e., the anode of diode D4) serves as the fourth end of the clamping link to connect to the second end of the first clamping branch 1311.
[0042] In the clamping circuit 13 provided in any of the above embodiments, the clamping voltage of the Zener diode ZD1 connected in series with the resistor R1 does not exceed a preset voltage threshold, and the preset voltage threshold is at least on the same order of magnitude as the voltage output by the first DC power supply 14, so as to reduce the reverse recovery time of the diode and improve the measurement accuracy. For example, in some embodiments, when the DC output voltage of the first DC power supply 14 is 36V, the clamping voltage of the Zener diode ZD1 connected in series with the resistor R1 does not exceed 3.6V.
[0043] In some embodiments, the load 15 can withstand a large current of 50A (Amperes), and the current mirror 132 supplies a current of no more than 1mA (milliamperes), which is only 0.2% of the 50A. Therefore, the measurement effect of the mirror current source 132 can be almost ignored.
[0044] Understandably, the junction capacitance in a diode can result in poor reverse recovery, and the embodiments of this application employ a similar... Figure 3 and Figure 4 The clamping circuit 13 shown reduces the diode junction capacitance by using multiple diodes connected in parallel, thereby reducing the diode reverse recovery time, improving the frequency response, and thus improving measurement accuracy.
[0045] In some embodiments, the first diode and the second diode (e.g., the first diode D1 and the second diode D2 in the first clamping branch 1311) in each clamping branch (i.e., the first clamping branch and the second clamping branch) are integrated, packaged dual diodes. This helps to reduce the parasitic parameters of the diodes, further reduce the reverse recovery time of the diodes, and improve the differential voltage measurement accuracy under the same temperature conditions, thus improving the stability of the sampling data. Taking a single diode as an example, its junction capacitance can be less than 5pF (picofarad), while when two independent diodes are packaged and connected in series, the capacitance value can be much less than 5pF.
[0046] Please continue reading. Figures 5A to 8B The following is combined with Figures 5A to 8B To explain Figure 3 The working principle of the test circuit 10 shown.
[0047] Please see Figure 5A At time T1, switch Q2 is turned off and switch Q1 is turned on. At this time, the first DC power supply 14 charges the inductor L in the inductor energy storage circuit 12. Although the mirror current source 132 outputs current to the clamping unit 131, because the mirror current source 132 outputs a micro-current, the anode potential of diode Dm is lower than the cathode potential (reference). Figure 5B V in BA (At this time, the voltage level is low). Therefore, all diodes and Zener diodes in the clamping unit 131 are reverse-biased and cut off, and the voltage between the first and second terminals of the switching transistor Q2 is clamped to the Zener value of the Zener diode ZD1, for example, 2.16V.
[0048] Please see Figure 6A At time T2, both switches Q2 and Q1 are turned off. However, at the instant Q1 turns off, the voltage across inductor L in the inductor energy storage circuit 12 changes abruptly. At this moment, the potential across inductor L is opposite to that at time T1. That is, the potential of inductor L connected to switch Q2 is lower than the potential of inductor L connected to load 15. Therefore, the gate voltage V of switch Q2 relative to point A is... GA When the current is positive, current flows in reverse between the source and drain of switching transistor Q2, and the potential at point A is lower than that of GND. Therefore, at time T2, diode Dm in clamping unit 131 conducts (see reference). Figure 6B V in BA This causes the mirror current source 132 to charge the junction capacitance of diode Dm, and simultaneously to forward charge the Zener diode ZDm. At this point, the Zener diode ZDm transitions from the reverse cutoff state to the forward conduction state (please refer to...). Figure 6B V in BC ).
[0049] Please see Figure 7AAt time T3, switching transistors Q1 and Q2 are turned off, and diode Dm is forward-biased (please refer to...). Figure 7B V in BA As the current mirror 132 continuously charges the junction capacitance of the Zener diode ZDm, ZDm begins to conduct in the forward direction and eventually clamps the voltage across the switching transistor Q2 near the turn-on voltage, for example, around 0.6V (please refer to...). Figure 7B V in C ).
[0050] Please see Figure 8A At time T4, switch Q2 is turned on, switch Q1 remains off, and diodes Dm and ZDm are forward-biased. At this time, the reverse conduction voltage of switch Q2 can be measured. ,Right now Figure 8B V in DE And the reverse conduction current of switch Q2 was measured. ,Right now Figure 8B I in X (U4:S), and the reverse conduction impedance of switch Q2 can be calculated based on the reverse conduction voltage and reverse conduction current using the following formula (1): in, Indicates the reverse conduction impedance; Indicates reverse conduction voltage; This indicates the reverse conduction current.
[0051] Thus, in the embodiments of this application Figure 3 or Figure 4 The test circuit 10 shown can employ a step-down circuit architecture and utilize gallium nitride devices as switches. By using the reverse isolation of diodes, the clamping and limiting voltage of Zener diodes, and the symmetrical micro-current conduction of mirror current sources, accurate voltage tracking is achieved, range accuracy is improved, and measurement errors are reduced. Moreover, due to the circuit design of multiple parallel diodes in the clamping unit 131, the diode junction capacitance can be reduced, the reverse recovery time of the diodes can be reduced, and the accuracy of the on-state voltage and current extraction can be improved, while also improving the frequency response. Thus, high-precision measurement of the electrical parameters of the gallium nitride switch 112 when it is reverse-conducting can be achieved.
[0052] Understandably, the times T1, T2, T3, and T4 mentioned above are used to indicate the order of time, not to indicate specific points in time.
[0053] Please continue reading. Figure 9In some embodiments, the test circuit 10 further includes a voltage detection unit 161 and a current detection unit 162. The voltage detection unit 161 is connected to the third terminal of the clamping unit 131 (i.e., the third terminal of the first clamping branch 1311). Figure 9 Point E in the diagram) and the fourth end (i.e., the fourth end of the first clamping branch 1311). Figure 9 Point D in the diagram). Voltage detection unit 161 is used to sample the first reverse conduction voltage V at the third terminal of the first clamping branch 1311 when the gallium nitride switch 112 is reverse conducted. E and the second reverse conduction voltage V at the fourth terminal of the first clamping branch 1311 D Understandably, the voltage detection unit 161 may include a voltage detection circuit or a voltage sensor. This application does not limit the specific circuit structure of the voltage detection unit 161, as long as the voltage detection unit 161 can realize the voltage detection function.
[0054] The current detection unit 162 is electrically connected to the first terminal of the gallium nitride switch 112 and is used to sample the reverse conduction current Ic flowing through the first terminal of the gallium nitride switch 112 when it is reverse-conducting. Understandably, the current detection unit 162 may include a current detection circuit or a current sensor. This application does not limit the specific circuit structure of the current detection unit 162, as long as the current detection unit 162 can perform the current detection function.
[0055] In some embodiments, the offset voltage of the current detection unit 162 is <5mV and the offset voltage of the voltage detection unit 161 is 0.5mV. This can further reduce measurement errors and achieve high-precision measurement.
[0056] In some embodiments, the test circuit 10 further includes a controller 17 and a drive unit 19. The controller 17 is electrically connected to the voltage detection unit 161 and the current detection unit 162 to acquire the first reverse conduction voltage V. E Second reverse conduction voltage V D and reverse conduction current Ic. The controller 17 is also electrically connected to the drive unit 19, so that the drive unit 19 can be electrically connected to the controlled terminals of the reference switch 111 and the gallium nitride switch 112, thereby realizing the on / off control of the reference switch 111 and the gallium nitride switch 112.
[0057] In some embodiments, the test circuit 10 further includes a power supply unit 18 for supplying power to the controller 17, voltage detection unit 161, current detection unit 162, drive unit 19, and mirror current source 132. This application does not limit the specific circuit structure of the power supply unit 18.
[0058] Furthermore, in some embodiments, the reverse conduction impedance of the gallium nitride switch 112, i.e., the reverse conduction impedance of the switch Q2 when it is reverse conducting, can also be calculated based on the following formula (2): ; in, It is the reverse conduction impedance; This is the second reverse conduction voltage; It is the sum of the forward conduction voltage drops of all the second diodes in the clamping circuit 13 (that is, all the second diodes in the clamping unit 131); This is the first reverse conduction voltage; It is the sum of the forward conduction voltage drops of all the first diodes in the clamping circuit 13 (that is, all the first diodes in the clamping unit 131); For reverse conduction current; This is the reference current for the mirror current source 132.
[0059] In other words, ;in, The forward voltage drop of diode D2 is... This is the forward voltage drop of diode D4. This is the forward voltage drop of diode D2m.
[0060] ;in, This is the forward voltage drop of diode D1. This is the forward voltage drop of diode D3. Let be the forward voltage drop of diode Dm.
[0061] In this way, the reverse conduction impedance calculated according to formula (2) can further improve the measurement accuracy of the reverse conduction impedance when the gallium nitride switch Q2 is reverse conducting.
[0062] In summary, by using the test circuit 10 provided in the above embodiment to measure the reverse conduction voltage of the gallium nitride device, the voltage extraction accuracy can be controlled within 0.18%, and the current accuracy within 0.2%. According to the error propagation formula, the relative error of the reverse conduction impedance is: The extraction accuracy is approximately 99.73% (1-0.269%), which is obviously a high level of extraction accuracy.
[0063] Please see Figure 10 , Figure 10 This is a flowchart illustrating the steps of a testing method according to an embodiment of this application. The testing method can be executed by controller 17. The testing method includes the following steps: S101: Controls the reference switch to turn on and the gallium nitride switch to turn off.
[0064] S102: Control reference switch transistor is off.
[0065] S103: Control the gallium nitride switch to turn on, and sample the first reverse conduction voltage at the third terminal of the first clamping branch, the second reverse conduction voltage at the fourth terminal of the first clamping branch, and the reverse conduction current at the first terminal of the gallium nitride switch.
[0066] In some embodiments, the testing method further includes the following step S104: Calculate the reverse conduction impedance of the gallium nitride switch based on the first reverse conduction voltage, the second reverse conduction voltage, and the reverse conduction current.
[0067] Understandably, in step S104, the reverse conduction impedance of the gallium nitride switch can be calculated based on the above formula (2), which will not be elaborated here.
[0068] Thus, by performing the above test method in the test circuit 10, high-precision electrical parameters of the gallium nitride switch Q2 when it is reverse-biased can be obtained.
[0069] Please continue reading. Figure 11 One embodiment of this application also provides a test device 100 for testing gallium nitride switching transistors. The test device 100 includes a test circuit 10 and a controller 17 as provided in any of the above embodiments.
[0070] Those skilled in the art will understand that, without conflict, the technical features of this embodiment and implementation scheme can be combined arbitrarily.
[0071] This application is not limited to the specific embodiments described above. Those skilled in the art will readily understand that many alternative solutions exist for the test fixture without departing from the principles and scope of this application. The scope of protection of this application is determined by the claims.
Claims
1. A test circuit for a gallium nitride (GaN) switching transistor used in communication power supplies, characterized in that, include: A half-bridge circuit is used to connect to a first DC power supply. The half-bridge circuit includes a reference switch and a gallium nitride switch connected in series. The first terminal of the reference switch is used to connect to the positive terminal of the first DC power supply, the second terminal of the reference switch is connected to the first terminal of the gallium nitride switch, and the second terminal of the gallium nitride switch is used to connect to the negative terminal of the first DC power supply. An inductor energy storage circuit, comprising at least an inductor, wherein a first terminal of the inductor energy storage circuit is connected to a second terminal of a reference switch, and the second terminal of the inductor energy storage circuit is connected to a second terminal of a gallium nitride switch via a load, and the inductor energy storage circuit is used to form a reverse conduction loop for the gallium nitride switch; A clamping circuit, wherein a first terminal of the clamping circuit is connected to a first terminal of the gallium nitride switch, and a second terminal of the clamping circuit is connected to a second terminal of the gallium nitride switch, and the clamping circuit is used to clamp the voltage of the gallium nitride switch when it is reverse-biased; The clamping circuit includes a first clamping branch and a mirror current source. The first clamping branch includes a first diode, a second diode, a Zener diode, and a resistor. The anode of the first diode is connected to the cathode of the Zener diode, and the anode of the Zener diode is connected to the anode of the second diode through the resistor. The cathode of the first diode serves as the first terminal of the first clamping branch, the anode of the first diode serves as the third terminal of the first clamping branch, the cathode of the second diode serves as the second terminal of the first clamping branch, and the anode of the second diode serves as the fourth terminal of the first clamping branch. The first and second terminals of the first clamping branch are respectively used to connect to the first and second terminals of the gallium nitride switch, and the third and fourth terminals of the first clamping branch are respectively used to connect to the reference input terminal and the mirror output terminal of the mirror current source.
2. The test circuit according to claim 1, characterized in that, The clamping circuit further includes at least one second clamping branch, which has the same circuit topology as the first clamping branch, and the first and second ends of the first clamping branch are connected to the first and second ends of the gallium nitride switch through at least one second clamping branch.
3. The test circuit according to claim 2, characterized in that, When the clamping circuit includes a second clamping branch, the first end of the first clamping branch is connected to the third end of the second clamping branch, the second end of the first clamping branch is connected to the fourth end of the second clamping branch, and the first and second ends of the second clamping branch are respectively connected to the first and second ends of the gallium nitride switching transistor.
4. The test circuit according to claim 2, characterized in that, When the clamping circuit includes at least two second clamping branches, the at least two second clamping branches are sequentially connected to form a clamping link, connecting the two ends of the gallium nitride switch to the first clamping branch, wherein, The third and fourth ends of each second clamping branch are respectively connected to the first and second ends of the next second clamping branch; and the first and second ends of the second clamping branch at one end of the clamping link serve as the first and second ends of the clamping link, respectively, to be connected to the first and second ends of the gallium nitride switch. The third and fourth ends of the second clamping branch at the other end of the clamping link serve as the third and fourth ends of the clamping link, respectively, and are connected to the first and second ends of the first clamping branch.
5. The test circuit according to any one of claims 1 to 4, characterized in that, The first diode and the second diode are an integrated, encapsulated dual diode.
6. The test circuit according to claim 1, characterized in that, The test circuit further includes a voltage detection unit, which is connected to the third and fourth terminals of the first clamping branch. The voltage detection unit is used to sample the first reverse conduction voltage at the third terminal of the first clamping branch and the second reverse conduction voltage at the fourth terminal of the first clamping branch when the gallium nitride switch is reverse conducted.
7. The test circuit according to claim 6, characterized in that, The test circuit also includes a current detection unit, which is electrically connected to the first terminal of the gallium nitride switch and is used to sample the reverse conduction current flowing through the first terminal of the gallium nitride switch when the gallium nitride switch is reverse conducted.
8. The test circuit according to claim 7, characterized in that, The reverse conduction impedance of the gallium nitride switch when it is reverse conducting is calculated using the following formula: ； in, The reverse conduction impedance; This is the second reverse conduction voltage; This is the sum of the forward voltage drops of all the second diodes in the clamping circuit; This is the first reverse conduction voltage; This is the sum of the forward voltage drops of all the first diodes in the clamping circuit; The reverse conduction current; The reference current of the mirror current source is given.
9. A testing apparatus for testing gallium nitride switching transistors, characterized in that, The test equipment includes the test circuit as described in any one of claims 1 to 8.
10. A test method applied to a test circuit as described in any one of claims 1 to 8, characterized in that: The testing method includes: Control the reference switch to be turned on, and control the gallium nitride switch to be turned off; The reference switch is turned off. The gallium nitride switch is controlled to turn on, and the first reverse conduction voltage of the third terminal of the first clamping branch, the second reverse conduction voltage of the fourth terminal of the first clamping branch, and the reverse conduction current of the first terminal of the gallium nitride switch are sampled.