A method for measuring dynamic driving voltage of power switch tube

Abstract

The present invention provides a method for measuring the dynamic drive voltage of a power switch tube, comprising obtaining a measured drive voltage, a parasitic resistance voltage of a switch tube gate, and a package parasitic inductance voltage between measurement points; and subtracting the parasitic resistance voltage of the switch tube gate and the package parasitic inductance voltage between measurement points from the measured drive voltage to obtain a desired actual drive voltage on the switch tube chip. The ability to obtain the actual drive voltage on the switch tube chip ensures the correctness of the test results, improves measurement accuracy, and provides correct data for dynamic process analysis of the device, which includes a switching process and crosstalk, thereby guiding device research and development and circuit applications.

Description

Technical Field

[0001] The invention relates to a method for measuring the dynamic driving voltage of a power switch tube. Background Art

[0002] The main dynamic processes of Si MOSFET, SiC MOSFET, IGBT and GaN HEMT include switching and crosstalk. The dynamic drive voltage measurement results during these dynamic processes provide guidance for device development and circuit applications.

[0003] The traditional non-Kelvin package of semiconductor switching devices has three pins. Taking MOSFET as an example, there are three pins: drain (D), source (S), and gate (G). Its equivalent circuit is as follows: Figure 1 As shown. The drive circuit is connected to the G pin and the S pin, and the power circuit is connected to the D pin and the S pin. With the development of technology, the switching speed of the device is getting faster and faster, and the above problems are becoming more and more serious. Various manufacturers have introduced Kelvin packaging. Taking MOSFET as an example, there are four pins: drain (D), source (PS), gate (G), and Kelvin source (KS). Its equivalent circuit is as follows Figure 2 As shown in Figure 1, the drive circuit is connected to the G and KS pins, and the main circuit is connected to the D and PS pins. This prevents the drive circuit and the main power commutation circuit from sharing a common line, achieving decoupling of the two circuits.

[0004] Currently, when measuring the dynamic drive voltage of power semiconductor switching devices, the method used is to directly connect the voltage probe to the pins of the device for measurement. For IGBTs, the connection is to the gate and emitter pins; for Si MOSFETs, SiC MOSFETs, and GaN HEMTs, the connection is to the gate and drain pins.

[0005] The disadvantage of existing methods is that the voltage probe can only be connected to the pins of the device and cannot directly contact the switching tube chip. Therefore, the parasitic parameters of the device package and the chip are included between the test points. The package parasitic inductance between the measurement points includes the parasitic inductance of the package pins and frame, and the parasitic inductance of the package bonding wires; the chip parasitic parameter is the chip gate parasitic resistance. Therefore, when performing dynamic drive voltage testing, the voltage drop on these parasitic parameters is also measured and included in the drive voltage. This makes the measurement result the sum of the actual drive voltage on the chip and the voltage on the parasitic parameters included between the voltage probe measurement points. This causes the measurement result to differ from the actual drive voltage on the chip, greatly affecting the correctness and accuracy of the measurement result, and thus has a negative impact on device analysis and application circuit design.

[0006] The driving voltage waveform obtained by existing testing methods differs significantly from the actual driving voltage on the chip, leading to contradictions with theoretical analysis during switching process analysis. This can also easily mislead device R&D and circuit applications, resulting in wasted resources and project delays. Furthermore, existing testing methods can cause the crosstalk driving voltage waveform to differ significantly from the actual driving voltage waveform on the chip, leading to contradictions with theoretical analysis during crosstalk process analysis. This can also easily mislead device R&D and circuit applications, resulting in wasted resources, project delays, or reduced circuit reliability. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for measuring the dynamic driving voltage of a power switch tube, which can obtain the actual driving voltage on the switch tube chip, ensure the correctness of the test results, improve the measurement accuracy, and provide correct data for the analysis of the dynamic process of the device (including the switching process and crosstalk), thereby guiding device research and development and circuit applications.

[0008] The present invention is implemented as follows: a method for measuring the dynamic drive voltage of a power switch tube, specifically comprising the following steps:

[0009] Step 1: Obtain the measured driving voltage, the parasitic resistance voltage of the switching tube gate, and the parasitic inductance voltage of the package between the measurement points;

[0010] Step 2: Subtract the parasitic resistance voltage of the switch tube gate and the parasitic inductance voltage of the package between the measurement points from the measured driving voltage to obtain the actual driving voltage on the required switch tube chip.

[0011] Furthermore, the measured driving voltage is obtained by measuring with an oscilloscope and a voltage probe, and the voltage probe measurement point is on the device package pin.

[0012] Furthermore, the parasitic resistance voltage of the switching tube gate is the driving current I G and the parasitic resistance of the switching tube gate R G(int) The product of multiplication; where I G Measured using a current probe, Rogowski coil, current waveform analyzer, or sampling resistor; R G(int) Measured using a curve tracer or impedance analyzer.

[0013] Further,

[0014] For non-Kelvin packaged devices, the package parasitic inductance voltage between the measurement points is L S(pkg-M) and dI DS The product of / dt and L G(pkg-M) and dI G / dt multiplied by the sum of the products, where dI DS / dt is I DS Time rate of change, dI G / dt is I G The time rate of change, where I G and I DS Measured using a current probe, Rogowski coil, current waveform analyzer, or sampling resistor; L S(pkg-M) is the source / emitter package parasitic inductance between the measurement points, L G(pkg-M) Gate package parasitic inductance between measurement points, L S(pkg-M) and L G(pkg-M) It can be measured using an impedance analyzer or simulated using electromagnetic simulation software;

[0015] For Kelvin packaged devices, the parasitic inductance voltage between the measurement points is L G(pkg-M) and dI G The product of / dt and L KS(pkg-M) and dI G / dt multiplied by the sum of the products, where dI G / dt is I G The time rate of change, where I G Measured using a current probe, Rogowski coil, current waveform analyzer, or sampling resistor; L G(pkg-M) is the parasitic inductance of the gate package between measurement points, L KS(pkg-M) is the parasitic inductance of the driver source / emitter package between the measurement points, L G(pkg-M) and L KS(pkg-M) Obtained using impedance analyzer measurement or electromagnetic simulation software simulation.

[0016] The present invention has the following advantages:

[0017] The present invention can obtain a more accurate driving voltage waveform during the device switching process, providing accurate data for device switching process analysis, thereby drawing accurate conclusions. This provides powerful data for device R&D and circuit application, avoids device waste, and facilitates project progress control.

[0018] A more accurate device crosstalk driving voltage waveform can be obtained, which can provide correct data for device crosstalk characteristic analysis and crosstalk suppression in circuit application, thereby enabling correct conclusions to be drawn. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Figure 1 It is the equivalent circuit diagram of non-Kelvin package in the prior art.

[0021] Figure 2 It is the equivalent circuit diagram of Kelvin package in the prior art.

[0022] Figure 3 This is a flow chart of a method for measuring the dynamic drive voltage of a power switch tube according to the present invention.

[0023] Figure 4 Schematic diagram of the equivalent circuit for measuring gate voltage in a non-Kelvin package according to the present invention.

[0024] Figure 5 This is a schematic diagram of the equivalent circuit for measuring the gate voltage of the Kelvin package of the present invention. DETAILED DESCRIPTION

[0025] like Figure 3 As shown, the present invention provides a method for measuring the dynamic driving voltage of a power switch tube, which specifically includes the following steps:

[0026] Step 1: Obtain the measured driving voltage, the parasitic resistance voltage of the switching tube gate, and the parasitic inductance voltage of the package between the measurement points. The measured driving voltage is measured by an oscilloscope and a voltage probe. The voltage probe measurement point is on the device package pin. is the driving current I G and the parasitic resistance of the switching tube gate R G(int) The product of multiplication; where I G Measured using a current probe, Rogowski coil, current waveform analyzer, or sampling resistor; R G(int) Measured using a curvetracer or impedance analyzer;

[0027] Step 2: Subtract the parasitic resistance voltage of the switch tube gate and the parasitic inductance voltage of the package between the measurement points from the measured driving voltage to obtain the actual driving voltage on the required switch tube chip.

[0028] For non-Kelvin packaged devices, the package parasitic inductance voltage between the measurement points is L S(pkg-M) and dI DS The product of / dt and L G(pkg-M) and dI G / dt multiplied by the sum of the products, where dI DS / dt is I DS Time rate of change, dI G / dt is I G The time rate of change, where I G and I DS Measured using a current probe, Rogowski coil, current waveform analyzer, or sampling resistor; L S(pkg-M) is the source / emitter package parasitic inductance between the measurement points, L G(pkg-M)Gate package parasitic inductance between measurement points, L S(pkg-M) and L G(pkg-M) It can be measured using an impedance analyzer or simulated using electromagnetic simulation software;

[0029] For Kelvin packaged devices, the parasitic inductance voltage between the measurement points is L G(pkg-M) and dI G The product of / dt and L KS(pkg-M) and dI G / dt multiplied by the sum of the products, where dI G / dt is I G The time rate of change, where I G Measured using a current probe, Rogowski coil, current waveform analyzer, or sampling resistor; L G(pkg-M) is the parasitic inductance of the gate package between measurement points, L KS(pkg-M) is the parasitic inductance of the driver source / emitter package between the measurement points, L G(pkg-M) and L KS(pkg-M) Obtained using impedance analyzer measurement or electromagnetic simulation software simulation.

[0030] The package parasitic inductance voltage between the measurement points includes the gate package parasitic inductance voltage between the measurement points, the source / emitter package parasitic inductance voltage between the measurement points, and the driving source / emitter package parasitic inductance voltage between the measurement points.

[0031] The power switch tubes include but are not limited to SiMOSFET, SiCMOFET, IGBT and GaN HEMT.

[0032] Example 1

[0033] 1. For non-Kelvin package devices, the equivalent circuit is as follows Figure 4 As shown, where R G(int) is the internal gate resistance of the device under test; L G(pkg-M) and L S(pkg-M) The gate and source / emitter package parasitic inductances between the measurement points are L G(pkg-O) and L S(pkg-O) I is the parasitic inductance of the gate and source / emitter package outside the measurement point; G is the driving current, the positive direction is shown by the arrow; I DS is the current flowing through the device under test, the positive direction is shown by the arrow; V GS The actual driving voltage on the device under test chip, the positive direction is as marked; V GS(M) To measure the driving voltage, the positive direction is marked as V GS(M) Measured using a voltage probe and an oscilloscope;

[0034] By IG and R G(int) Multiply them together to get G It can be measured using any of the following methods: current probe, Rogowski coil, current waveform analyzer, or sampling resistor; R G(int) It can be measured using a curve tracer or impedance analyzer; By L G(pkg-M) and dI G / dt multiplied to obtain, where dI G / dt is I G The time rate of change, I G It can be measured using any of the following methods: current probe, Rogowski coil, current waveform analyzer, or sampling resistor; L G(pkg-M) It can be measured using an impedance analyzer and simulated using electromagnetic simulation software; By L S(pkg-M) and dI DS / dt is multiplied to obtain. DS / dt is I DS The time rate of change, I DS It can be measured using any of the following methods: current probe, Rogowski coil, current waveform analyzer, or sampling resistor; L S(pkg-M) It can be obtained by measuring with an impedance analyzer or simulating with electromagnetic simulation software.

[0035] Then V GS(M) and V GS The relationship is:

[0036]

[0037] From V GS(M) Subtract I from G In R G(int) Pressure drop dI G / dt in L G(pkg-M) Pressure drop on dI DS / dt in L S(pkg-M) Pressure drop on You can get V GS .

[0038] 2. For non-Kelvin package devices, the equivalent circuit is as follows Figure 5 As shown, where R G(int) is the internal gate resistance of the device under test; L S(pkg) L is the parasitic inductance of the source or collector package of the device under test; G(pkg-M) and L KS(pkg-M) The parasitic inductances of the gate and driver source / driver emitter package between the measurement points are L G(pkg-O) and L KS(pkg-O)They are the parasitic inductance of the gate and driver source / driver emitter packages outside the measurement point, I G is the driving current, the positive direction is shown by the arrow; I DS is the current flowing through the device under test, the positive direction is shown by the arrow; V GS The actual driving voltage on the device under test chip, the positive direction is as marked; V GS(M) To measure the driving voltage, the positive direction is marked as V GS(M) Measured using a voltage probe and an oscilloscope; By I G and R G(int) Multiply them together to get G It can be measured using a current probe, Rogowski coil, current waveform analyzer, or sampling resistor; R G(int) It can be measured using a curve tracer or impedance analyzer; By L G(pkg-M) and dI G / dt is obtained by multiplying. Where dI G / dt is I G The time rate of change, I G It can be measured using any of the following methods: current probe, Rogowski coil, current waveform analyzer, or sampling resistor; L G(pkg-M) It can be measured using an impedance analyzer and simulated using electromagnetic simulation software; By L KS(pkg-M) and dI G / dt is obtained by multiplying. Where dI G / dt is I G The time rate of change, I G It can be measured using any of the following methods: current probe, Rogowski coil, current waveform analyzer, or sampling resistor; L KS(pkg-M) It can be obtained by measuring with an impedance analyzer or simulating with electromagnetic simulation software.

[0039] Then V GS(M) and V GS The relationship is:

[0040]

[0041] From V GS(M) Subtract I from G In R G(int) Pressure drop dI G / dt in L G(pkg-M) Pressure drop on dI G / dt in L KS(pkg-M) Pressure drop on You can get V GS .

[0042] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for measuring the dynamic driving voltage of a power switch tube, characterized in that: The specific steps include: Step 1: Obtain the measured driving voltage, the parasitic resistance voltage of the switching tube gate, and the parasitic inductance voltage of the package between the measurement points; Step 2: Subtract the parasitic resistance voltage of the switch tube gate and the parasitic inductance voltage of the package between the measurement points from the measured driving voltage to obtain the actual driving voltage on the required switch tube chip; For non-Kelvin packaged devices, the package parasitic inductance voltage between the measurement points is L S(pkg-M) and dI DS The product of / dt and L G(pkg-M) and dI G / dt multiplied by the sum of the products, where dI DS / dt is I DS Time rate of change, dI G / dt is I G The time rate of change of G and I DS Measured using a current probe, Rogowski coil, current waveform analyzer, or sampling resistor; L S(pkg-M) is the source / emitter package parasitic inductance between the measurement points, L G(pkg-M) Gate package parasitic inductance between measurement points, L S(pkg-M) and L G(pkg-M) It can be measured using an impedance analyzer or simulated using electromagnetic simulation software.

2. The method for measuring the dynamic driving voltage of a power switch tube according to claim 1, wherein: The measured driving voltage is obtained by measuring with an oscilloscope and a voltage probe, with the voltage probe measuring point being on the device package pin.

3. The method for measuring the dynamic driving voltage of a power switch tube according to claim 1, wherein: The parasitic resistance voltage of the switching tube gate is the driving current I G and the parasitic resistance of the switching tube gate R G(int) The product of multiplication; where I G Measured using a current probe, Rogowski coil, current waveform analyzer, or sampling resistor; R G(int) Measured using a curvetracer or impedance analyzer.

4. The method for measuring the dynamic driving voltage of a power switch tube according to claim 1, wherein: For Kelvin packaged devices, the parasitic inductance voltage between the measurement points is L G(pkg-M) and dI G The product of / dt and L KS(pkg-M) and dI G / dt multiplied by the sum of the products, where dI G / dt is I G The time rate of change, where I G Measured using a current probe, Rogowski coil, current waveform analyzer, or sampling resistor; L G(pkg-M) is the parasitic inductance of the gate package between measurement points, L KS(pkg-M) is the parasitic inductance of the driver source / emitter package between the measurement points, L G(pkg-M) and L KS(pkg-M) Obtained using impedance analyzer measurement or electromagnetic simulation software simulation.

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