Detection circuit, detection method, and power semiconductor switching device

Abstract

A detection circuit, a detection method, and a power semiconductor switching device. The power semiconductor switching device comprises a main switching device, and the main switching device comprises a first path terminal, a second path terminal, and a first switch control terminal; the detection circuit comprises an inductive switching device, and the inductive switching device and the main switching device are disposed on a same substrate; the inductive switching device comprises a third path terminal, a fourth path terminal, and a second switch control terminal, wherein the third path terminal is used for being electrically connected to a current source, and the current source is used for supplying a current of a preset current value to the inductive switching device; the first path terminal, the second path terminal, the third path terminal, and the fourth path terminal are further used for being electrically connected to a voltage measurement circuit; and the voltage measurement circuit is used for measuring the voltage between the first path terminal and the second path terminal, and is further used for measuring the voltage between the third path terminal and the fourth path terminal.

Description

Detection circuits and methods, power semiconductor switching devices Technical Field

[0001] This disclosure relates to the semiconductor field, and more specifically to a detection circuit and detection method, and a power semiconductor switching device. Background Technology

[0002] Power semiconductor switching devices, also known as power electronic switching devices, are used for power processing, handling high voltage and high current. They are the core of power electronic devices for energy conversion and circuit control, primarily used for voltage control, DC-AC conversion, and frequency regulation. Power semiconductor switching devices have wide applications in computers, communications, consumer electronics, new energy, automobiles, and industrial manufacturing. The junction temperature and current detection of power semiconductor switching devices are key factors determining the performance and reliability of power electronic device systems. Among related technologies, current detection circuits for power semiconductor switching devices are complex and costly. Summary of the Invention

[0003] This disclosure is made to address at least one of the aforementioned problems. According to a first aspect of this disclosure, a detection circuit for a power semiconductor switching device is provided. The power semiconductor switching device includes a main switching device, which includes a first path terminal, a second path terminal, and a first switch control terminal. The detection circuit includes a sensing switching device disposed on the same substrate as the main switching device. The sensing switching device includes a third path terminal, a fourth path terminal, and a second switch control terminal. The third path terminal is electrically connected to a current source, which supplies a current of a preset current value to the sensing switching device. The first path terminal, the second path terminal, the third path terminal, and the fourth path terminal are also electrically connected to a voltage measurement circuit. The voltage measurement circuit measures the voltage between the first path terminal and the second path terminal, and also measures the voltage between the third path terminal and the fourth path terminal.

[0004] In one embodiment of this disclosure, the main switching device further includes at least one first transistor; the first electrode of each first transistor is electrically connected to the first path terminal, the second electrode of each first transistor is electrically connected to the second path terminal, and the control electrode of each first transistor is electrically connected to the first switch control terminal.

[0005] In one embodiment of this disclosure, the inductive switching device further includes at least one second transistor; the first electrode of each second transistor is electrically connected to the third path terminal, the second electrode of each second transistor is electrically connected to the fourth path terminal, and the control electrode of each second transistor is electrically connected to the second switch control terminal.

[0006] In one embodiment of this disclosure, the minimum spacing between the second transistor and the first transistor is less than a preset spacing.

[0007] In one embodiment of this disclosure, a transistor array is disposed on the substrate; some of the transistors in the transistor array are the first transistors, and some of the transistors are the second transistors.

[0008] In one embodiment of this disclosure, the first electrode of the first transistor is the drain, the second electrode of the first transistor is the source, and the control electrode of the first transistor is the gate; the first electrode of the second transistor is the drain, the second electrode of the second transistor is the source, and the control electrode of the second transistor is the gate.

[0009] In one embodiment of this disclosure, the number of the inductive switching devices is at least two; each of the inductive switching devices is located at a different position of the power semiconductor switching device.

[0010] In one embodiment of this disclosure, the third path terminals of at least two of the inductive switching devices are interconnected, and the fourth path terminals of at least two of the inductive switching devices are interconnected.

[0011] In one embodiment of this disclosure, the number of current sources is one, and the third path terminals of at least two of the inductive switching devices are connected to the same current source.

[0012] In one embodiment of this disclosure, the second switch control terminals of at least two of the inductive switching devices are interconnected; or, the second switch control terminals of at least two of the inductive switching devices are separated from each other.

[0013] In one embodiment of this disclosure, the third path terminals of at least two of the inductive switching devices are separated from each other, and the fourth path terminals of at least two of the inductive switching devices are interconnected.

[0014] In one embodiment of this disclosure, the number of current sources is at least two; the at least two current sources correspond one-to-one with the at least two inductive switching devices, and the third path terminal of each inductive switching device is connected to the corresponding current source.

[0015] In one embodiment of this disclosure, the second switch control terminals of at least two of the inductive switching devices are separated from each other.

[0016] In one embodiment of this disclosure, the first path terminal and the third path terminal are separated from each other, the first switch control terminal and the second switch control terminal are interconnected, and the second path terminal and the fourth path terminal are interconnected; or, the first path terminal and the third path terminal are separated from each other, the first switch control terminal and the second switch control terminal are separated from each other, and the second path terminal and the fourth path terminal are interconnected; or, the first path terminal and the third path terminal are separated from each other, the first switch control terminal and the second switch control terminal are separated from each other, and the second path terminal and the fourth path terminal are separated from each other; or, the first path terminal and the third path terminal are interconnected, the first switch control terminal and the second switch control terminal are separated from each other, and the second path terminal and the fourth path terminal are interconnected; or, the first path terminal and the third path terminal are interconnected, the first switch control terminal and the second switch control terminal are separated from each other, and the second path terminal and the fourth path terminal are separated from each other.

[0017] In one embodiment of this disclosure, the current source is a constant current source, or the current source is a current source operating in an on / off state.

[0018] In one embodiment of this disclosure, the detection circuit further includes: the current source and the voltage measurement circuit; wherein, the current source is electrically connected to the third path terminal and is used to supply a current of a preset current value to the inductive switching device; the voltage measurement circuit is electrically connected to the first path terminal, the second path terminal, the third path terminal and the fourth path terminal, and is used to measure the voltage between the first path terminal and the second path terminal, and also to measure the voltage between the third path terminal and the fourth path terminal.

[0019] According to a second aspect of this disclosure, a method for detecting the current of a power semiconductor switching device is also provided. The detection method is based on a detection circuit for any of the power semiconductor switching devices described above. The detection method includes: acquiring the inductance between an inductive switching device and a main switching device; controlling the inductive switching device to conduct, supplying a current of a preset current value to the inductive switching device, and measuring the voltage between a third path terminal and a fourth path terminal; and controlling the main switching device to conduct, measuring the voltage between a first path terminal and a second path terminal; and determining the current flowing through the main switching device based on the inductance, the preset current value, the voltage between the third path terminal and the fourth path terminal, and the voltage between the first path terminal and the second path terminal.

[0020] In one embodiment of this disclosure, obtaining the inductance rate between the inductive switching device and the main switching device includes: obtaining a first number of transistors in the main switching device that meet preset conditions, and a second number of transistors in the inductive switching device that meet the preset conditions; wherein, the preset conditions include: the junction temperatures of the main switching device and the inductive switching device are the same, and when the main switching device and the inductive switching device are turned on, the voltage between the first switch control terminal and the second path terminal is equal to the voltage between the second switch control terminal and the fourth path terminal; the quotient of the first number divided by the second number is taken as the inductance rate between the inductive switching device and the main switching device.

[0021] In one embodiment of this disclosure, determining the through current of the main switching device based on the inductance, the preset current value, the voltage between the third and fourth path terminals, and the voltage between the first and second path terminals includes: calculating the voltage between the first and second path terminals, dividing it by the voltage between the third and fourth path terminals to obtain a quotient; multiplying the quotient, the inductance, and the preset current value as the detection current detected by the inductive switching device; and determining the through current of the main switching device based on the detection current.

[0022] In one embodiment of this disclosure, the number of the sensing switch devices is one; determining the through current of the main switch device based on the detected current includes: using the detected current as the through current of the main switch device.

[0023] In one embodiment of this disclosure, the number of inductive switching devices is at least two, and each inductive switching device is located at a different position of the main switching device; the step of determining the through current of the main switching device based on the detected current includes: taking the average value of the detected currents obtained by the at least two inductive switching devices as the through current of the main switching device.

[0024] In one embodiment of this disclosure, the detection method further includes: simultaneously, when the inductive switching device is turned on and a current of the preset current value is supplied to the inductive switching device, maintaining the voltage between the second switch control terminal and the fourth path terminal at a preset voltage value; determining the detected junction temperature obtained by the inductive switching device based on a first voltage-junction temperature change relationship and the voltage between the third path terminal and the fourth path terminal; wherein, the first voltage-junction temperature change relationship is obtained through pre-testing; and determining the junction temperature of the main switching device based on the detected junction temperature.

[0025] In one embodiment of this disclosure, the first voltage-junction temperature change relationship is obtained through pre-testing, including: controlling the inductive switching device to conduct, while simultaneously supplying the inductive switching device with the current of the preset current value, maintaining the voltage between the second switch control terminal and the fourth path terminal at the preset voltage value; adjusting the junction temperature of the power semiconductor switching device, and measuring the voltage between the third path terminal and the fourth path terminal at different junction temperatures to obtain the first voltage-junction temperature change relationship.

[0026] In one embodiment of this disclosure, the number of the sensing switch devices is one; determining the junction temperature of the main switch device based on the detected junction temperature includes: using the detected junction temperature as the junction temperature of the main switch device.

[0027] In one embodiment of this disclosure, the number of inductive switching devices is at least two, and each inductive switching device is located at a different position of the power semiconductor switching device; determining the junction temperature of the main switching device based on the detected junction temperature includes: taking the average value of the detected junction temperatures obtained by at least two inductive switching devices as the junction temperature of the main switching device.

[0028] In one embodiment of this disclosure, the number of inductive switching devices is at least two, and each inductive switching device is located at a different position of the power semiconductor switching device. Obtaining the inductance between the inductive switching devices and the main switching device includes: obtaining a first number of transistors in the main switching device that satisfy a preset condition, and a second number of transistors in each inductive switching device that satisfy the preset condition; wherein the preset condition includes: the junction temperature of the main switching device and each inductive switching device is the same, and when the main switching device and each inductive switching device are turned on, the voltage between the first switch control terminal and the second path terminal is equal to the voltage between the second switch control terminal and the fourth path terminal; calculating the sum of the second numbers of at least two inductive switching devices to obtain a third number; and dividing the first number by the third number as the inductance between the at least two inductive switching devices and the main switching device.

[0029] In one embodiment of this disclosure, controlling the inductive switching device to conduct, supplying a current of a preset current value to the inductive switching device, and measuring the voltage between the third path terminal and the fourth path terminal include: controlling at least two of the inductive switching devices to conduct, supplying a total current to the at least two inductive switching devices equal to the preset current value, and measuring the total voltage between the third path terminal and the fourth path terminal of the at least two inductive switching devices.

[0030] In one embodiment of this disclosure, determining the through current of the main switching device based on the inductance, the preset current value, the voltage between the third and fourth path terminals, and the voltage between the first and second path terminals includes: calculating the voltage between the first and second path terminals, dividing it by the total voltage to obtain a quotient; and using the product of the quotient, the inductance, and the preset current value as the through current of the main switching device.

[0031] In one embodiment of this disclosure, the detection method further includes: while at least two of the inductive switching devices are turned on and the total current flowing into the at least two inductive switching devices is the preset current value, maintaining the voltage between the second switch control terminal and the fourth path terminal at a preset voltage value; determining the detection junction temperature detected by the at least two inductive switching devices based on the second voltage-junction temperature change relationship and the total voltage between the third path terminal and the fourth path terminal of the at least two inductive switching devices; wherein the second voltage-junction temperature change relationship is obtained through pre-testing; and using the detection junction temperature detected by the at least two inductive switching devices as the junction temperature of the main switching device.

[0032] In one embodiment of this disclosure, the second voltage-junction temperature change relationship is obtained through pre-testing, including: controlling at least two of the inductive switching devices to be turned on, while the current supplied to the at least two inductive switching devices is the preset current value, and maintaining the voltage between the second switch control terminal and the fourth path terminal at the preset voltage value; adjusting the junction temperature of the power semiconductor switching device, and measuring the total voltage between the third path terminal and the fourth path terminal at different junction temperatures to obtain the second voltage-junction temperature change relationship.

[0033] In one embodiment of this disclosure, controlling the main switch device to turn on specifically involves controlling the main switch device to turn on through the first switch control terminal and the second path terminal; controlling the inductive switch device to turn on specifically involves controlling the inductive switch device to turn on through the second switch control terminal and the fourth path terminal.

[0034] According to a third aspect of this disclosure, a power semiconductor switching device is also provided, the power semiconductor switching device comprising: a main switching device, the main switching device comprising: a first path terminal, a second path terminal and a first switching control terminal; the power semiconductor switching device further comprising a detection circuit of any of the power semiconductor switching devices described above.

[0035] In one embodiment of this disclosure, the power semiconductor switching device is: a SiC-based N-channel depletion-type MOSFET device, a SiC-based P-channel depletion-type MOSFET device, a SiC-based N-channel enhancement-type MOSFET device, a SiC-based P-channel enhancement-type MOSFET device, a SiC-based N-channel depletion-type IGBT device, a SiC-based P-channel depletion-type IGBT device, a SiC-based N-channel enhancement-type IGBT device, a SiC-based P-channel enhancement-type IGBT device, a Si-based N-channel depletion-type MOSFET device, a Si-based P-channel depletion-type MOSFET device, a Si-based N-channel enhancement-type MOSFET device, a Si-based P-channel enhancement-type MOSFET device, a Si-based N-channel depletion-type IGBT device, a Si-based P-channel depletion-type IGBT device, a Si-based N-channel enhancement-type IGBT device, a Si-based P-channel enhancement-type IGBT device, a depletion-type GaN device, and an enhancement-type GaN device.

[0036] According to the detection circuit and method, and power semiconductor switching device provided in this disclosure, an inductive switching device is disposed on a substrate on which a main switching device is disposed. The inductive switching device includes a third path terminal, a fourth path terminal, and a second switch control terminal. During current detection, a preset current value is passed through the inductive switching device via the third path terminal, and the voltage between the first and second path terminals, as well as the voltage between the third and fourth path terminals, are measured. Combined with the inductance between the inductive switching device and the main switching device, the current flowing through the main switching device can be determined. Compared to related technologies, current detection can be completed simply by using an inductive switching device, thereby simplifying the circuit structure and reducing costs. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 is a schematic diagram of an on-chip integrated diode temperature detector shown in the related technology.

[0039] Figure 2 shows a circuit diagram of a sense FET as illustrated in the related technology.

[0040] Figure 3 shows a current-sensing IGBT circuit diagram based on related technologies.

[0041] Figure 4 illustrates a current sensing method based on a Sense FET using an operational amplifier virtual ground.

[0042] Figure 5 is a schematic diagram of a detection circuit for a power semiconductor switching device according to an embodiment of this disclosure.

[0043] Figure 6 is a schematic diagram of current and junction temperature detection based on the detection circuit shown in Figure 5.

[0044] Figure 7 is a schematic diagram of a detection circuit for a power semiconductor switching device according to an embodiment of the present disclosure.

[0045] Figure 8 is a schematic diagram of current and junction temperature detection based on the detection circuit shown in Figure 7.

[0046] Figure 9 is a schematic diagram of a detection circuit for a power semiconductor switching device according to an embodiment of the present disclosure.

[0047] Figure 10 is a schematic diagram of current and junction temperature detection based on the detection circuit shown in Figure 9.

[0048] Figure 11 is a flowchart illustrating a current detection method for a power semiconductor switching device according to an embodiment of this disclosure.

[0049] Figure 12 is a flowchart illustrating junction temperature detection of a power semiconductor switching device according to another embodiment of this disclosure.

[0050] Figure 13 is a flowchart illustrating junction temperature detection of a power semiconductor switching device according to another embodiment of this disclosure.

[0051] Figure 14 is a schematic diagram of the circuit connection of a plurality of inductive switching devices according to an embodiment of the present disclosure.

[0052] Figure 15 is a schematic diagram of the circuit connection of a plurality of inductive switching devices according to an embodiment of the present disclosure.

[0053] Figure 16 is a schematic diagram of the circuit connection of a plurality of inductive switching devices according to an embodiment of the present disclosure.

[0054] Figure 17 is a schematic diagram of the circuit connection of a plurality of inductive switching devices according to an embodiment of the present disclosure.

[0055] Figure 18 is a schematic diagram of a detection circuit for a power semiconductor switching device according to an embodiment of the present disclosure.

[0056] Figure 19 is a schematic diagram of current and junction temperature detection based on the detection circuit shown in Figure 18.

[0057] Figure 20 is a schematic diagram of a detection circuit for a power semiconductor switching device according to an embodiment of the present disclosure.

[0058] Figure 21 is a schematic diagram of current and junction temperature detection based on the detection circuit shown in Figure 20. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this disclosure more apparent, exemplary embodiments according to this disclosure will be described in detail below with reference to the accompanying drawings. The described embodiments are merely some embodiments of this disclosure, and not all embodiments of this disclosure. It should be understood that this disclosure is not limited to the exemplary embodiments described herein. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort should fall within the protection scope of this disclosure.

[0060] Numerous specific details are set forth in the following description in order to provide a more thorough understanding of this disclosure. However, those skilled in the art will recognize that this disclosure may be practiced without one or more of these details.

[0061] It should be understood that this disclosure can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0062] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprise” and / or “comprising,” when used in this specification, confirm the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0063] In related technologies, current measurement of power semiconductor switching devices mainly includes two methods: direct measurement and indirect measurement. Among them, (1) the direct measurement method is based on Ohm's law. The current passes through a current sensing resistor with a known resistance and low temperature drift, and the current value is accurately calculated by measuring the voltage across the current sensing resistor. This method is simple and accurate. However, the current sensing resistor introduces additional power loss. In addition, considering the current detection accuracy under small current conditions, the resistance value of the current sensing resistor cannot be too small, and for large current conditions, such a current sensing resistor will generate serious heat. (2) The indirect measurement method is based on the principle that a magnetic field is generated around a current-carrying conductor. The current sensor can detect the magnetic field to know the magnitude of the current, thereby realizing indirect measurement. Indirect measurement does not require connection to the circuit, so there is no additional loss to the circuit, especially for the measurement of large currents; however, the current sensor for indirect measurement is large in size and expensive.

[0064] In related technologies, there are two main methods for measuring the junction temperature of power semiconductor switching devices: direct measurement and indirect measurement. Among them, (1) the direct measurement method is shown in Figure 1. The power semiconductor switching device integrates a structure based on multiple polysilicon diodes connected in parallel. The near-linear relationship between the forward voltage drop Vf of the diode and the junction temperature is used to monitor the chip junction temperature. The integrated temperature sensor (the On-Chip Temperature Sensor in Figure 1 represents the integrated temperature sensor) has high temperature measurement accuracy, which helps to accurately estimate the chip current design margin, reduce the heat sink volume, and improve the power density. However, this method is only effective for devices containing this integrated temperature sensor. (2) The indirect measurement method involves installing an NTC thermistor (Negative Temperature Coefficient thermistor) near the power semiconductor switching device to achieve tight thermal coupling. NTC thermistors are simple to use, but they are only suitable for characterizing the junction temperature of power semiconductor switching devices under stable operating conditions. Under transient phenomena (such as the rapid rise in junction temperature of power semiconductor switching devices caused by a transient large current), the NTC thermistor cannot reflect the junction temperature change of the device in time, resulting in the failure of temperature protection.

[0065] Figures 2 and 3 illustrate a current sensing circuit provided in related technologies. For current sensing in power semiconductor switching devices, the technology of a current-sensing field-effect transistor (FET), also often called a Sense FET (or mirror FET, where FET stands for Field Effect Transistor), has been proposed, as shown in Figure 2. For IGBT devices, it is called a current-sensing IGBT (or mirror IGBT), as shown in Figure 3. Compared to the direct measurement method of detecting current through resistance, the Sense FET provides lossless detection. Compared to the indirect measurement method of detecting current through a current sensor, the Sense FET circuit is simpler, lower in cost, and smaller in size.

[0066] The following section uses a Sense FET for current sensing as an example to illustrate this technology in detail. As shown in Figure 2, a MOSFET integrating a Sense FET contains thousands of transistor cells, each with an identical structure, including a main FET and a Sense FET. The Sense FET is constructed as a small part of the device. The Sense FET and the main FET share a common drain and gate, but each has a separate source electrode.

[0067] The Sense FET conducts only a small portion of the current applied to its common drain. This small portion of the current is inversely proportional to the inductance N, which is a current rate determined by the ratio of the number of transistor cells Nm in the main FET to the number of transistor cells Ns in the Sense FET. The inductance N = Nm / Ns, and is obtained under the condition that the sources of the Sense FET and the main FET are at the same potential. When the inductance is known, the total current I flowing through the device can be calculated from the measured source current IS of the Sense FET: I = (N+1)*IS.

[0068] As shown in Figure 4, in the use of Sense FETs, to provide more accurate current measurement, especially when higher sensing voltages are required, a virtual ground sensing of an operational amplifier is typically used. The non-inverting input of the operational amplifier is connected to ground (the source of the main FET), and its inverting input is connected to the source of the Sense FET. Therefore, the source of the Sense FET is virtually grounded, and its potential is the same as that of the source of the main FET, thus ensuring that the current through the Sense FET is 1 / N of that through the main FET.

[0069] However, the drawbacks of the related technologies are analyzed as follows:

[0070] (1) The virtual ground sensing circuit based on Sense FET is constructed using operational amplifiers and resistor networks, and requires a second inverting operational amplifier to generate a positive output. Therefore, the peripheral circuit is complex and increases the BOM cost (Bill of Material cost, which is the sum of all direct and indirect costs required in the manufacturing process).

[0071] (2) Sense FET technology only provides current detection. If junction temperature measurement of power semiconductor switching devices is required, a dedicated junction temperature measurement circuit for power semiconductor switching devices is also needed.

[0072] To address some of the problems in the related art, the present disclosure is presented as shown below.

[0073] To fully understand this disclosure, a detailed structure will be presented in the following description to illustrate the technical solutions proposed herein. Optional embodiments of this disclosure are described in detail below; however, in addition to these detailed descriptions, this disclosure may have other implementations.

[0074] The following detailed description of some embodiments of this disclosure is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0075] First, let me introduce the application scenario of the detection circuit of the power semiconductor switching device illustrated in this disclosure. The detection circuit of the power semiconductor switching device is used for current detection of the power semiconductor switching device.

[0076] Referring to Figures 5, 7, and 9, this disclosure provides a detection circuit for a power semiconductor switching device. The power semiconductor switching device includes a main switching device, which comprises a first path terminal, a second path terminal, and a first switch control terminal. The detection circuit includes a sensing switching device disposed on the same substrate as the main switching device. The sensing switching device includes a third path terminal, a fourth path terminal, and a second switch control terminal. The third path terminal is electrically connected to a current source, which supplies a preset current value to the sensing switching device. The first, second, third, and fourth path terminals are also electrically connected to a voltage measurement circuit (not shown in the figures). The voltage measurement circuit measures the voltage between the first and second path terminals, and also measures the voltage between the third and fourth path terminals.

[0077] In the above scheme, an inductive switching device is set on the substrate on which the main switching device is set. The inductive switching device includes a third path terminal, a fourth path terminal, and a second switch control terminal. During current detection, a preset current value is passed to the inductive switching device through the third path terminal, and the voltage between the first and second path terminals, as well as the voltage between the third and fourth path terminals, are measured. Combined with the inductance between the inductive switching device and the main switching device, the current flowing through the main switching device can be determined. Compared with related technologies, current detection can be completed by setting an inductive switching device, thereby simplifying the circuit structure and reducing costs. The following is a detailed description of the above structures with reference to the accompanying drawings.

[0078] The substrate for the power semiconductor switching device can be made of any type of substrate material. For example, the substrate material can be, but is not limited to, silicon and silicon carbide. That is, the substrate can be a silicon substrate or a silicon carbide substrate.

[0079] A main switching device is formed on the substrate. Referring to Figures 5, 7, and 9, the main switching device includes a first pass terminal, a second pass terminal, and a first switch control terminal. That is, the main switching device is a three-terminal switching device, with the first pass terminal and the second pass terminal being the two pass terminals, and the control terminal being the first switch control terminal. The main switching device may include one transistor unit. The main switching device may also include multiple transistor units to increase its current-carrying capacity. For example, the second pass terminal and the first switch control terminal can jointly control the on and off states of the main switching device.

[0080] For example, referring to Figures 5, 7, and 9, the main switching device further includes at least one first transistor. The first electrode of each first transistor is electrically connected to a first path terminal, the second electrode of each first transistor is electrically connected to a second path terminal, and the control electrode of each first transistor is electrically connected to a first switch control terminal.

[0081] Referring, as exemplarily to Figures 5, 7, and 9, the main switching device may include one first transistor. Alternatively, the main switching device may include at least two first transistors. When the main switching device includes at least two first transistors, the at least two first transistors are connected in parallel, thereby increasing the current-carrying capacity of the main switching device. Exemplarily, the type of the first transistor may be, but is not limited to, MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), IGBT (Insulated Gate Bipolar Transistor), etc. Exemplarily, the first transistor may be a depletion-mode transistor or an enhancement-mode transistor. Exemplarily, the first transistor may be an N-channel transistor or a P-channel transistor. Exemplarily, the first transistor may be a transistor based on SiC (Silicon Carbide), Si (Silicon), or GaN (Gallium Nitride). Exemplarily, the first transistor can be: a SiC-based N-channel depletion-type MOSFET, a SiC-based P-channel depletion-type MOSFET, a SiC-based N-channel enhancement-type MOSFET, a SiC-based P-channel enhancement-type MOSFET, a SiC-based N-channel depletion-type IGBT, a SiC-based P-channel depletion-type IGBT, a SiC-based N-channel enhancement-type IGBT, a SiC-based P-channel enhancement-type IGBT, a Si-based N-channel depletion-type MOSFET, a Si-based P-channel depletion-type MOSFET, a Si-based N-channel enhancement-type MOSFET, a Si-based P-channel enhancement-type MOSFET, a Si-based N-channel depletion-type IGBT, a Si-based P-channel depletion-type IGBT, a Si-based N-channel enhancement-type IGBT, a Si-based P-channel enhancement-type IGBT, a depletion-type GaN device, or an enhancement-type GaN device. Exemplarily, the first transistor includes a first electrode, a second electrode, and a control electrode. Exemplarily, the first electrode of the first transistor can be the drain, the second electrode of the first transistor can be the source, and the control electrode of the first transistor can be the gate. It should be noted that the types of the first electrode, second electrode, and control electrode of the first transistor are specifically related to the type of the first transistor.

[0082] For example, a transistor array is disposed on a substrate, and some of the transistors in the transistor array can be first transistors. In application, most of the transistors in the transistor array can be first transistors, and multiple first transistors can be connected in parallel through metal traces to increase the current carrying capacity of the main switching device.

[0083] For example, referring to Figures 5, 7 and 9, the detection circuit includes: an inductive switching device, wherein the inductive switching device and the main switching device are disposed on the same substrate, thereby enabling the inductive switching device and the main switching device to have a stable inductance, and also enabling the junction temperatures of the inductive switching device and the main switching device to be the same or similar, so as to facilitate the measurement of the temperature of the main switching device using the inductive switching device.

[0084] Referring to Figures 5, 7, and 9, the inductive switching device includes a third terminal, a fourth terminal, and a second switch control terminal. That is, the inductive switching device is also a three-terminal switching device, with the third and fourth terminals being the two primary terminals, and the second switch control terminal being the control terminal. The inductive switching device may include one transistor unit. It may also include multiple transistor units to increase its current-carrying capacity. For example, the fourth terminal and the second switch control terminal can jointly control the switching on and off of the inductive switching device.

[0085] Referring to Figures 6, 8, and 10, the third path terminal is used to electrically connect a current source, which is used to supply a preset current value to the inductive switching device. For example, the preset current value can be IS. The first, second, third, and fourth path terminals are also used to electrically connect a voltage measurement circuit. The voltage measurement circuit is used to measure the voltage between the first and second path terminals, and also to measure the voltage between the third and fourth path terminals. Through the current source and the voltage measurement circuit, the through current or junction temperature of the main switching device can be measured. Specific measurement methods are described in the detection method section below.

[0086] When determining the number of sensing switches on the substrate, the number can be one or at least two. For example, when there are at least two sensing switches, each sensing switch is located at a different position on the power semiconductor switch, thereby improving the measurement accuracy of current and junction temperature at different positions on the main switch. In specific applications, for high-current applications, the area of ​​the power semiconductor switch becomes very large. Due to the different distributed resistance and contact resistance of the metal interconnects connecting the transistor units in the power semiconductor switch, and due to manufacturing variations, the electrical characteristics of each transistor unit are not absolutely consistent, resulting in non-uniform current at different positions on the power semiconductor switch. Furthermore, the non-uniformity of the current also depends on the different local temperatures of different units within the power semiconductor switch. If the sensing switch is placed in one location, such as the main center of the power semiconductor switch, the accuracy of current detection will be affected. Therefore, this embodiment proposes placing multiple sensing switches to solve this problem; specifically, at least two sensing switches are located at different positions on the main switch, thereby improving the measurement accuracy of current and junction temperature at different positions on the main switch.

[0087] For example, when there are at least two inductive switching devices, the connection between the third and fourth path terminals of different inductive switching devices can be achieved in various ways, as illustrated below. Referring to Figures 14 to 17, the number of inductive switching devices is m, where m is any positive integer greater than 1.

[0088] For example, referring to Figures 14-16, the third path terminals of at least two inductive switching devices can be interconnected, and the fourth path terminals of at least two inductive switching devices can be interconnected. Specifically, the third path terminals of all inductive switching devices can be interconnected, and the fourth path terminals of all inductive switching devices can be interconnected. In this case, the number of current sources can be one; specifically, the third path terminals of at least two inductive switching devices are connected to the same current source. Alternatively, the number of current sources can be multiple, and each current source is electrically connected to the third path terminals of all inductive switching devices.

[0089] At this point, there are no restrictions on the connection method of the second switch control terminals of at least two inductive switching devices; any connection method can be used. For example, referring to FIG14, the second switch control terminals of at least two inductive switching devices are interconnected, meaning that the second switch control terminals of all inductive switching devices are interconnected. In some embodiments, referring to FIGS. 15 and 16, the second switch control terminals of at least two inductive switching devices are separated from each other, meaning that the second switch control terminals of all inductive switching devices are separated from each other.

[0090] For example, referring to Figure 17, the third path terminals of at least two inductive switching devices are separated from each other, and the fourth path terminals of at least two inductive switching devices are interconnected. Specifically, the third path terminals of different inductive switching devices can be separated from each other without interconnection, while the fourth path terminals of all inductive switching devices are interconnected. In this case, the number of current sources can be at least two, with each current source corresponding to one of the at least two inductive switching devices. The third path terminal of each inductive switching device is connected to the corresponding current source, so that different current sources can input known equal or unequal current values ​​to the third path terminals of the corresponding inductive switching devices. In some embodiments, the number of current sources can also be one, and this current source is electrically connected to the third path terminals of all inductive switching devices.

[0091] There are no restrictions on the interconnection method of the second switch control terminals of at least two inductive switching devices; any connection method can be used. For example, the second switch control terminals of at least two inductive switching devices are interconnected, meaning that the second switch control terminals of all inductive switching devices are interconnected. In some embodiments, referring to FIG17, the second switch control terminals of at least two inductive switching devices are separated from each other, meaning that the second switch control terminals of all inductive switching devices are separated from each other.

[0092] For example, referring to Figures 5, 7 and 9, the inductive switching device further includes at least one second transistor; the first electrode of each second transistor is electrically connected to a third path terminal, the second electrode of each second transistor is electrically connected to a fourth path terminal, and the control electrode of each second transistor is electrically connected to a second switch control terminal.

[0093] Referring, as exemplarily to Figures 5, 7, and 9, the inductive switching device may include one second transistor. Alternatively, the inductive switching device may include at least two second transistors. When the inductive switching device includes at least two second transistors, the at least two second transistors are connected in parallel, thereby increasing the current-carrying capacity of the inductive switching device. Exemplarily, the type of the second transistor may be, but is not limited to, MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), IGBT (Insulated Gate Bipolar Transistor), etc. Exemplarily, the second transistor may be a depletion-mode transistor or an enhancement-mode transistor. Exemplarily, the second transistor may be an N-channel transistor or a P-channel transistor. Exemplarily, the second transistor may be a transistor based on SiC (Silicon Carbide), Si (Silicon), or GaN (Gallium Nitride). Exemplarily, the second transistor can be: a SiC-based N-channel depletion-type MOSFET, a SiC-based P-channel depletion-type MOSFET, a SiC-based N-channel enhancement-type MOSFET, a SiC-based P-channel enhancement-type MOSFET, a SiC-based N-channel depletion-type IGBT, a SiC-based P-channel depletion-type IGBT, a SiC-based N-channel enhancement-type IGBT, a SiC-based P-channel enhancement-type IGBT, a Si-based N-channel depletion-type MOSFET, a Si-based P-channel depletion-type MOSFET, a Si-based N-channel enhancement-type MOSFET, a Si-based P-channel enhancement-type MOSFET, a Si-based N-channel depletion-type IGBT, a Si-based P-channel depletion-type IGBT, a Si-based N-channel enhancement-type IGBT, a Si-based P-channel enhancement-type IGBT, a depletion-type GaN device, or an enhancement-type GaN device. Exemplarily, the second transistor includes a first electrode, a second electrode, and a control electrode. Exemplarily, the first electrode of the second transistor can be the drain, the second electrode of the second transistor can be the source, and the control electrode of the second transistor can be the gate. It should be noted that the types of the first electrode, the second electrode, and the control electrode of the second transistor are specifically related to the type of the second transistor.

[0094] For example, a transistor array is disposed on a substrate, and some of the transistors in the transistor array can be second transistors. In application, a few transistors in the transistor array can be second transistors. When multiple second transistors are included in each inductive switching device, the multiple second transistors can be connected in parallel through metal traces to increase the current carrying capacity of the inductive switching device.

[0095] For example, referring to Figures 5, 7, and 9, the minimum spacing between the second transistor and the first transistor can be less than a preset spacing, so that the junction temperature measured by the inductive switching device is basically the same as the junction temperature of the first transistor of the main switching device near the inductive switching device, thereby improving the measurement accuracy of the junction temperature. For example, some of the second transistors in the inductive switching device can be arranged adjacent to some of the first transistors, that is, the preset spacing is the spacing between two transistor units in the transistor array, thereby improving the measurement accuracy of the junction temperature. When the inductive switching device includes multiple second transistors, some or all of the second transistors can be arranged adjacent to some of the first transistors in the main switching device, thereby improving the measurement accuracy of the current and junction temperature of the inductive switching device.

[0096] For example, referring to Figure 5, the first path terminal and the third path terminal can be separated from each other, the first switch control terminal and the second switch control terminal can be interconnected, and the second path terminal and the fourth path terminal can be interconnected.

[0097] For example, referring to FIG7, the first path terminal and the third path terminal can also be separated from each other, the first switch control terminal and the second switch control terminal can be separated from each other, and the second path terminal and the fourth path terminal can be interconnected.

[0098] For example, referring to FIG9, the first path terminal and the third path terminal can also be separated from each other, the first switch control terminal and the second switch control terminal can be separated from each other, and the second path terminal and the fourth path terminal can be separated from each other.

[0099] Referring, as exemplarily to Figures 5-10, the detection circuit may further include a current source and a voltage measurement circuit. The current source is electrically connected to the third path terminal and is used to supply a preset current value to the sensing switching device. Exemplarily, the current source can be an on / off current source, meaning it can switch between on and off states to minimize detection power consumption. In other embodiments, the current source may also be a constant current source. The voltage measurement circuit is electrically connected to the first path terminal, the second path terminal, the third path terminal, and the fourth path terminal. The voltage measurement circuit is used to measure the voltage between the first and second path terminals, and also to measure the voltage between the third and fourth path terminals. The voltage measurement circuit can be configured in any way that can measure voltage values.

[0100] In the various embodiments shown above, an inductive switching device is disposed on the substrate on which the main switching device is disposed. The inductive switching device includes a third path terminal, a fourth path terminal, and a second switch control terminal. During current detection, a preset current value is supplied to the inductive switching device through the third path terminal, and the voltage between the first and second path terminals, as well as the voltage between the third and fourth path terminals, are measured. Combined with the inductance between the inductive switching device and the main switching device, the current flowing through the main switching device can be determined. Compared with related technologies, current detection can be completed simply by disposing of an inductive switching device, thereby simplifying the circuit structure and reducing costs.

[0101] In view of the two shortcomings of the Sense FET technology in the related technologies, the detection circuit of the power semiconductor switching device provided in some embodiments of this disclosure has two objectives. (1) It proposes a lossless detection circuit for the current of the power semiconductor switching device. The circuit is simple, low-cost, and small in size. In terms of performance, it can achieve the same or even higher current detection accuracy as the virtual ground sensing circuit based on Sense FET. At the same time, it saves one operational amplifier in the peripheral circuit, and the circuit design is simple and low-cost. (2) The lossless current detection circuit can also detect the junction temperature of the power semiconductor switching device, and realize the junction temperature and current detection of the power semiconductor switching device at the same time. This greatly simplifies the design of the junction temperature and current detection circuit, and provides lossless current detection, high accuracy and high bandwidth detection.

[0102] In addition, this disclosure also provides a method for detecting a power semiconductor switching device. Referring to Figures 5 to 11, the detection method is based on the detection circuit of any of the above-mentioned power semiconductor switching devices, and the detection method includes steps S111 to S113.

[0103] Step S111: Obtain the inductance between the inductive switching device and the main switching device.

[0104] Step S112: Control the inductive switch device to conduct, apply a current of a preset value to the inductive switch device, and measure the voltage between the third and fourth path terminals; and control the main switch device to conduct, and measure the voltage between the first and second path terminals.

[0105] Step S113: Determine the current flowing through the main switching device based on the inductance, the preset current value, the voltage between the third and fourth path terminals, and the voltage between the first and second path terminals.

[0106] In the above scheme, an inductive switching device is set on the substrate on which the main switching device is set. The inductive switching device includes a third path terminal, a fourth path terminal, and a second switch control terminal. During current detection, a preset current value is passed to the inductive switching device through the third path terminal, and the voltage between the first and second path terminals, as well as the voltage between the third and fourth path terminals, are measured. Combined with the inductance between the inductive switching device and the main switching device, the current flowing through the main switching device can be determined. Compared with related technologies, current detection can be completed simply by setting an inductive switching device, thereby simplifying the circuit structure and reducing costs. The following is a detailed description of each step with reference to the accompanying drawings.

[0107] First, referring to Figure 11, the inductance between the inductive switching device and the main switching device is obtained. Various methods can be used to obtain the inductance between the inductive switching device and the main switching device.

[0108] For example, obtaining the inductance rate between the inductive switching device and the main switching device may include: first, obtaining a first number of transistors in the main switching device that meet preset conditions, and a second number of transistors in the inductive switching device that meet preset conditions; wherein, the preset conditions include: the junction temperatures of the main switching device and the inductive switching device are the same, and when the main switching device and the inductive switching device are turned on, the voltage between the first switch control terminal and the second path terminal is equal to the voltage between the second switch control terminal and the fourth path terminal; then, the quotient of the first number divided by the second number is taken as the inductance rate between the inductive switching device and the main switching device.

[0109] For example, the first number of transistors satisfying the preset conditions in the main switching device can be Nm, and the second number of transistors satisfying the preset conditions in the inductive switching device can be Ns. Then, the inductance N between the inductive switching device and the main switching device is Nm / Ns. When the first electrode of the transistors in the inductive switching device and the main switching device is the drain, the second electrode is the source, and the control electrode is the gate, it can be seen from the above that the inductance N between the inductive switching device and the main switching device is obtained under the conditions that the gate-source voltages of the inductive switching device and the main switching device are at the same potential when the inductive switching device and the main switching device are turned on, and the junction temperature of the inductive switching device and the main switching device is the same.

[0110] It should be noted that the number of inductive switching devices can be one or more. The method described above for obtaining the inductance rate between the inductive switching device and the main switching device is applicable to obtaining the inductance rate between a single inductive switching device and the main switching device. That is, when there are multiple inductive switching devices, the method described above can be used to sequentially obtain the inductance rate between each inductive switching device and the main switching device.

[0111] For example, referring to Figure 17, the first number of transistors in the main switching device that meet the preset conditions is Nm, and the second number of transistors in the i-th inductive switching device that meet the preset conditions is Nsi (i = 1, 2, ..., m, where m is the number of inductive switching devices). Then, the inductance between the i-th inductive switching device and the main switching device is Ni = Nm / Nsi.

[0112] When there are at least two inductive switching devices, other methods can be used to obtain the inductance between the inductive switching devices and the main switching device.

[0113] For example, when there are at least two inductive switching devices, each located at a different position of the power semiconductor switching device, obtaining the inductance between the inductive switching devices and the main switching device may include: firstly, obtaining a first number of transistors in the main switching device that meet preset conditions, and a second number of transistors in each inductive switching device that meet preset conditions; wherein, the preset conditions include: the junction temperature of the main switching device and each inductive switching device is the same, and when the main switching device and each inductive switching device are turned on, the voltage between the first switch control terminal and the second path terminal is equal to the voltage between the second switch control terminal and the fourth path terminal. This step is the same as the corresponding step described above, requiring the second number of each of the at least two inductive switching devices to be obtained sequentially. The following steps differ from the aforementioned steps. Specifically, the sum of the second numbers of the at least two inductive switching devices is calculated to obtain a third number, i.e., the second numbers of all inductive switching devices are accumulated to obtain the third number. Then, the quotient of the first number divided by the third number is taken as the inductance between the at least two inductive switching devices and the main switching device. The inductance obtained in this way is the inductance between at least two inductive switching devices as a whole and the main switching device, rather than the inductance between a single inductive switching device and the main switching device.

[0114] For example, referring to Figures 14 to 16, the first number of transistors in the main switching device that meet the preset conditions can be Nm. The number of transistors in the i-th inductive switching device that meet the preset conditions is Nsi (i = 1, 2, ..., m, where m is the number of inductive switching devices), then the inductance between the m inductive switching devices and the main switching device is N = Nm / Ns, where...

[0115] It should be noted that the different methods of obtaining the inductance shown above correspond to different methods of calculating the current, which will be explained in detail below.

[0116] Next, referring to Figure 11, control the inductive switch device to conduct, apply a current of a preset value to the inductive switch device, and measure the voltage between the third and fourth path terminals; and control the main switch device to conduct, and measure the voltage between the first and second path terminals.

[0117] It should be noted that the control of the inductive switching device and the control of the main switching device can be performed separately or simultaneously; that is, there is no restriction on the order in which the control of the inductive switching device and the main switching device are turned on.

[0118] For example, multiple methods can be used to control the main switching device to turn on. Specifically, controlling the main switching device to turn on can be achieved by jointly controlling the main switching device to turn on via the first switch control terminal and the second path terminal. Similarly, multiple methods can be used to control the inductive switching device to turn on. Specifically, controlling the inductive switching device to turn on can be achieved by jointly controlling the inductive switching device to turn on via the second switch control terminal and the fourth path terminal.

[0119] When a preset current value is applied to the inductive switching device, the preset current value can be applied to the inductive switching device through a current source connected to the third path terminal in the detection circuit described above. For example, the voltage between the first and second path terminals, and the voltage between the third and fourth path terminals, can be measured using the voltage measurement circuit shown in the detection circuit described above.

[0120] When there is only one inductive switch device, the method of passing a preset current value to the inductive switch device is simply to pass a preset current value to the single inductive switch device.

[0121] When there are at least two inductive switching devices, there are various ways to apply a preset current value to the inductive switching devices and to measure the voltage between the third and fourth path terminals. Several methods are illustrated below.

[0122] For example, referring to Figures 14 and 15, the current supplied to the inductive switching device with a preset current value can be: the total current supplied to at least two inductive switching devices is equal to the preset current value. That is, at this time, only the total current supplied to all inductive switching devices is equal to the preset current value, without considering the specific current supplied to a single inductive switching device. Correspondingly, referring to Figures 14 and 15, the voltage measurement between the third and fourth path terminals can specifically be: measuring the total voltage between the third and fourth path terminals of at least two inductive switching devices. This method is applicable in scenarios where the third path terminals of at least two inductive switching devices are interconnected, and the fourth path terminals of at least two inductive switching devices are interconnected. It is particularly applicable when the second switch control terminals of at least two inductive switching devices are also interconnected. Using this method, at least two inductive switching devices can be controlled to conduct simultaneously. In some embodiments, if the second switch control terminals of at least two inductive switching devices are separated, the logic for simultaneous triggering of control can also be used to control at least two inductive switching devices to conduct simultaneously. In other words, as long as at least two inductive switching devices can be controlled to conduct simultaneously, the method described above, in which the total current supplied to at least two inductive switching devices is equal to a preset current value, can be used. For example, the following method can be adopted.

[0123] For example, referring to Figures 14 and 15, when there are at least two inductive switching devices, each inductive switching device is located at a different position of the power semiconductor switching device, controlling the inductive switching devices to conduct, passing a current of a preset current value to the inductive switching devices, and measuring the voltage between the third and fourth path terminals may include: controlling at least two inductive switching devices to conduct, the total current passing through the at least two inductive switching devices being a preset current value, and measuring the total voltage between the third and fourth path terminals of the at least two inductive switching devices.

[0124] For example, the current supplied to the inductive switching device with a preset current value can also be: the current supplied to a single inductive switching device with a preset current value. In this case, referring to Figures 16 and 17, the voltage between the third and fourth path terminals of the inductive switching device is measured, specifically: the voltage between the third and fourth path terminals of a single inductive switching device is measured, rather than the total voltage between the third and fourth path terminals of all inductive switching devices.

[0125] Whether a preset current value is supplied to a single inductive switching device in turn, or to a single inductive switching device simultaneously, depends on the connection method of at least two inductive switching devices and the current source.

[0126] For example, referring to Figure 16, a preset current value can be sequentially supplied to individual inductive switching devices. This method is applicable to scenarios where at least two inductive switching devices have their third path terminals interconnected, at least two inductive switching devices have their fourth path terminals interconnected, and the second switch control terminals of at least two inductive switching devices are separated from each other. In this scenario, only one current source can be used to interconnect with the third path terminals of all inductive switching devices. The individual inductive switching devices can be sequentially controlled to conduct by the second switch control terminals of different inductive switching devices, thereby allowing the single current source to sequentially supply a preset current value to the individual inductive switching devices. For example, in the above scenario, controlling the current supplying the preset current value to the inductive switching devices and measuring the voltage can be done in the following manner.

[0127] For example, referring to FIG16, controlling the inductive switch device to conduct, passing a current of a preset current value to the inductive switch device, and measuring the voltage between the third path terminal and the fourth path terminal may include: sequentially controlling each of at least two inductive switch devices to conduct, passing a current of a preset current value to the conducted inductive switch device, and measuring the voltage between the third path terminal and the fourth path terminal of the conducted inductive switch device.

[0128] For example, referring to Figure 17, a preset current value can be simultaneously supplied to a single inductive switching device. This method is applicable to the following scenario: the third path terminals of at least two inductive switching devices are separated from each other, the fourth path terminals of at least two inductive switching devices are interconnected, the number of current sources can be at least two, and the at least two current sources correspond one-to-one with the at least two inductive switching devices. The third path terminal of each inductive switching device is connected to the corresponding current source. In this scenario, the current values ​​output by different current sources can be equal or unequal. For example, the current values ​​output by at least two current sources are both equal preset current values. For example, the current values ​​output by at least two current sources are sequentially: a first preset current value Is1, a second preset current value Is2, a third preset current value Is3, etc. These preset current values ​​are known in advance, and these preset current values ​​can be partially or completely unequal.

[0129] Next, the current flowing through the main switching device is determined based on the inductance, the preset current value, the voltage between the third and fourth path terminals, and the voltage between the first and second path terminals. As mentioned earlier, different methods of obtaining the inductance, inputting the preset current value, and measuring the voltage of the inductive switching device will lead to different methods of determining the current flowing through the main switching device. This will be explained in detail below.

[0130] First category of calculation methods:

[0131] The first category of calculation methods is based on the following: The inductance rate between the inductive switching device and the main switching device is obtained by dividing the first quantity by the second quantity, which is taken as the inductance rate between the inductive switching device and the main switching device. In other words, it involves obtaining the inductance rate between a single inductive switching device and the main switching device. In this first category of calculation methods, the current flowing through the main switching device can be determined based on the inductance rate, the preset current value, the voltage between the third and fourth path terminals, and the voltage between the first and second path terminals, as follows:

[0132] First, calculate the voltage between the first and second path terminals, and divide it by the voltage between the third and fourth path terminals to obtain the quotient.

[0133] Then, the product of the quotient, inductance and preset current value obtained above is used as the detection current detected by the inductive switching device.

[0134] Then, the current through the main switching device is determined based on the detected current.

[0135] The above method applies to both cases where there is one inductive switching device and cases where there are at least two inductive switching devices, and where the detection current can be detected through each inductive switching device. The only difference lies in the method of determining the current through the main switching device based on the detection current when the number of inductive switching devices differs. Details are as follows.

[0136] For example, when there is only one inductive switching device, the above-mentioned determination of the current through the main switching device based on the detected current may include: using the detected current as the current through the main switching device. That is, when there is only one inductive switching device, the detected current measured by that single inductive switch is directly used as the current through the main switching device.

[0137] For example, when there are at least two sensing switching devices, each located at a different position of the main switching device, determining the current flowing through the main switching device based on the detected current may include: taking the average of the detected currents obtained through at least two sensing switching devices as the current flowing through the main switching device. That is, after a detected current is obtained through each sensing switching device, the average value obtained by averaging the detected currents obtained through all sensing switching devices can be used as the current flowing through the main switching device.

[0138] For example, referring to Figures 6, 8 and 10, the voltage between the third and fourth path terminals can be V1, and the voltage between the first and second path terminals can be V2. Then, the quotient obtained by dividing the voltage between the first and second path terminals by the voltage between the third and fourth path terminals is equal to V2 / V1.

[0139] For example, the preset current value can be IS. For example, the main switching device can be a MOSFET, then the current I through the main switching device is... FET The formula is as follows: I FET = (V2 / V1)*N*IS

[0140] Where N represents the inductance between a single inductive switching device and the main switching device, V1 represents the voltage between the third and fourth path terminals of a single inductive switching device, and V2 represents the voltage between the first and second path terminals.

[0141] In addition, based on the first category of calculation methods (the aforementioned acquisition of the inductance between a single inductive switching device and the main switching device), referring to Figure 12, the detection method may further include: S121, controlling the inductive switching device to conduct, while simultaneously supplying a current of a preset current value to the inductive switching device, and maintaining the voltage between the second switch control terminal and the fourth path terminal at a preset voltage value; S122, determining the junction temperature detected by the inductive switching device based on the first voltage-junction temperature change relationship and the voltage between the third path terminal and the fourth path terminal, wherein the first voltage-junction temperature change relationship is obtained through pre-testing; S123, determining the junction temperature of the main switching device based on the detected junction temperature obtained by the inductive switching device.

[0142] For example, during junction temperature measurement, the inductive switch is turned on, and a current of a preset value is supplied to the inductive switch while the voltage between the second switch control terminal and the fourth path terminal is maintained at a preset voltage value.

[0143] The first voltage-junction temperature relationship is obtained through pre-testing. Specifically, the test method can be as follows: Control the inductive switching device to conduct, simultaneously applying a preset current value to the inductive switching device while maintaining the voltage between the second switch control terminal and the fourth path terminal at a preset voltage value. Then, adjust the junction temperature of the power semiconductor switching device and measure the voltage between the third and fourth path terminals of the inductive switching device at different junction temperatures to obtain the first voltage-junction temperature relationship. Specifically, the junction temperature of the power semiconductor switching device can be adjusted to a temperature T1, and the voltage V1 between the third and fourth path terminals of the inductive switching device at that temperature can be measured; then the junction temperature of the power semiconductor switching device can be adjusted to another temperature T2, and the voltage V2 between the third and fourth path terminals of the inductive switching device at that temperature can be measured. This process is repeated to obtain the first voltage-junction temperature relationship. The first voltage-junction temperature relationship can be displayed using methods such as, but not limited to, tables or function curves.

[0144] Referring to Figure 12, the junction temperature of the main switching device is also determined based on the junction temperature detected by the inductive switching device. That is, after obtaining the detected junction temperature from the inductive switching device, it is not directly used as the junction temperature of the main switching device. Instead, the processing of the detected junction temperature is determined based on the number of inductive switching devices to obtain the junction temperature of the main switching device. For example, the determination of the junction temperature of the main switching device based on the detected junction temperature is specifically related to the number of inductive switching devices.

[0145] For example, referring to Figures 6, 8, and 10, the number of inductive switching devices can be one. In this case, determining the junction temperature of the main switching device based on the detected junction temperature obtained by the inductive switching device can include: using the detected junction temperature obtained by the inductive switching device as the junction temperature of the main switching device.

[0146] For example, the number of sensing switching devices can be at least two, with each sensing switching device located at a different position on the power semiconductor switching device. In this case, determining the junction temperature of the main switching device based on the detected junction temperature obtained by the sensing switching devices can include using the average of the detected junction temperatures obtained by the at least two sensing switching devices as the junction temperature of the main switching device. In specific applications, for high-current applications, the area of ​​the power semiconductor switching device becomes very large, and different local temperatures exist in different units within the power semiconductor switching device. If the sensing switching devices are placed in one location, such as the main center of the power semiconductor switching device, the accuracy of junction temperature detection will be affected. Therefore, this embodiment proposes to place multiple sensing switching devices to solve this problem. Specifically, at least two sensing switching devices are located at different positions on the power semiconductor switching device, and the measurement accuracy of the junction temperature at different positions of the main switching device is improved by using the average of the junction temperatures obtained by the at least two sensing switching devices as the junction temperature of the main switching device.

[0147] The following describes the current detection and junction temperature detection methods when a main switching device and an inductive switching device are used as examples, with the main switching device containing a first transistor and the inductive switching device containing a second transistor. The first and third path terminals are separated from each other, while the second and fourth path terminals are interconnected or separated from each other, and the first and second switch control terminals are interconnected or separated from each other.

[0148] Example 1

[0149] For example, referring to Figures 5 and 6, the first and third path terminals are separated, the first and second switch control terminals are interconnected, and the second and fourth path terminals are interconnected. For distinction, this can be defined as a first type of power semiconductor switching device. The current detection method for this first type of power semiconductor switching device is as follows:

[0150] Referring to Figure 6, when the main switch and the inductive switch are turned on, a current of known value IS is allowed to flow through the inductive switch, and the voltage V1 between the third and fourth terminals of the corresponding inductive switch is measured. Simultaneously, the voltage V2 between the first and second terminals of the main switch is measured. Then, the current I flowing through the main switch is... FET It can be calculated using the following formula: I FET = (V2 / V1)*N*IS

[0151] Here, N represents the inductance between the inductive switching device and the main switching device. This inductance depends on the ratio of the number of transistor units Nm in the main switching device that meet the preset conditions to the number of transistor units Ns in the inductive switching device that meet the preset conditions. The inductance is N = Nm / Ns.

[0152] Furthermore, when the voltage between the fourth path terminal and the second switch control terminal of the first type of power semiconductor switching device is fixed at a preset voltage value, and the inductive switching device carries a current with a known current value of the preset current value IS, the magnitude of the voltage V1 between the third and fourth path terminals of the inductive switching device is determined solely by the junction temperature of the inductive switching device. The voltage-junction temperature relationship between the voltage V1 between the third and fourth path terminals of the inductive switching device and the junction temperature of the inductive switching device (exemplarily, a functional relationship) can be obtained through offline testing. Therefore, by measuring the voltage V1 between the third and fourth path terminals of the inductive switching device, the junction temperature of the inductive switching device can be derived from the measured value of V1. The junction temperature of the inductive switching device also represents the junction temperature of the adjacent main switching device.

[0153] Example 2

[0154] For example, referring to Figures 7 and 8, the first and third path terminals are separated from each other, the first and second switch control terminals are separated from each other, and the second and fourth path terminals are interconnected. For distinction, this can be defined as a second type of power semiconductor switching device. The current detection method for this second type of power semiconductor switching device is as follows:

[0155] Referring to Figure 8, the switching control terminals of the main switching device and the inductive switching device are separate. When the inductive switching device is turned on and a current of known value IS flows through it, the voltage V1 between the third and fourth path terminals of the corresponding inductive switching device is measured. When the main switching device is turned on, the voltage V2 between the first and second path terminals of the main switching device is measured. Then, the current I flowing through the main switching device... FET It can be calculated using the following formula: I FET = (V2 / V1)*N*IS

[0156] Furthermore, when the voltage between the fourth path terminal and the second switch control terminal of the second type of power semiconductor switching device is fixed at a preset voltage value, and the inductive switching device carries a current with a known current value of the preset current value IS, the magnitude of the voltage V1 between the third and fourth path terminals of the inductive switching device is determined solely by the junction temperature of the inductive switching device. The voltage-junction temperature relationship between the voltage V1 between the third and fourth path terminals of the inductive switching device and the junction temperature of the inductive switching device (exemplarily, a functional relationship) can be obtained through offline testing. Therefore, by measuring the voltage V1 between the third and fourth path terminals of the inductive switching device, the junction temperature of the inductive switching device can be derived from the measured value of V1. The junction temperature of the inductive switching device also represents the junction temperature of the adjacent main switching device.

[0157] Example 3

[0158] For example, referring to Figures 9 and 10, the first and third path terminals are separated from each other, the first and second switch control terminals are separated from each other, and the second and fourth path terminals are separated from each other. For distinction, this can be defined as a third type of power semiconductor switching device. The current detection method for this third type of power semiconductor switching device is as follows:

[0159] Referring to Figure 10, the switching control terminals of the main switching device and the inductive switching device are separated, and the second path terminal of the main switching device and the fourth path terminal of the inductive switching device are also separated. When the inductive switching device is turned on, and a current of known value IS flows through it, the voltage V1 between the third and fourth path terminals of the corresponding inductive switching device is measured. When the main switching device is turned on, the voltage V2 between the first and second path terminals of the main switching device is measured. The current I flowing through the main switching device is then... FET It can be calculated using the following formula: I FET = (V2 / V1)*N*IS

[0160] Furthermore, when the voltage between the fourth path terminal and the second switch control terminal of the third-class power semiconductor switching device is fixed at a preset voltage value, and the inductive switching device carries a current with a known current value of the preset current value IS, the magnitude of the voltage V1 between the third and fourth path terminals of the inductive switching device is determined solely by the junction temperature of the inductive switching device. The voltage-junction temperature relationship between the voltage V1 between the third and fourth path terminals of the inductive switching device and the junction temperature of the inductive switching device (exemplarily, a functional relationship) can be obtained through offline testing. Therefore, by measuring the voltage V1 between the third and fourth path terminals of the inductive switching device, the junction temperature of the inductive switching device can be derived from the measured value of V1. The junction temperature of the inductive switching device also represents the junction temperature of the adjacent main switching device.

[0161] The following section, using Figures 16 and 17 as examples, details the measurement methods for the through current and junction temperature of the main switching device.

[0162] For example, referring to Figures 16 and 17, the first number of transistors in the main switching device that meet the preset conditions is Nm, and the second number of transistors in the i-th inductive switching device that meet the preset conditions is Nsi (i = 1, 2, ..., m, where m is the number of inductive switching devices). Then, the inductance between the i-th inductive switching device and the main switching device is Ni = Nm / Nsi.

[0163] Referring to Figures 16 and 17, if the i-th inductive switch is turned on, then I si The preset current value flowing through the i-th inductive switching device is I at this time. si This is the preset current value for the i-th element. At this time, the voltage between the third and fourth paths of the i-th inductive switching device can be V1i. When the main switching device is turned on, the voltage V2 between the first and second paths is measured, and then the on-state current I of the main switching device is determined. FET It can be calculated using the following formula:

[0164] Here, I FETi =(V2 / V1i)*Ni*I si This refers to the current flowing through the main switching device detected by the i-th sensing switching device. Ultimately, the on-state current I of the main switching device... FET That is, I FETi The average value of (i = 1, 2, ..., m).

[0165] For example, referring to Figures 16 and 17, when the second switch control terminal of the i-th inductive switch device is controlled, causing the i-th inductive switch device to be turned on, then I... si I is the preset current value flowing through the i-th inductive switching device.si This is the preset current value for the i-th element. At this time, the voltage between the third and fourth paths of the i-th inductive switching device can be V1i. First, the junction temperature Tj of the power semiconductor switching devices (main switching device + m inductive switching devices) is changed offline. The voltage across the i-th inductive switching device at different Tj values ​​is recorded, based on the preset current value. si The corresponding V1i value yields the first voltage-junction temperature relationship for the i-th inductive switching device.

[0166] Referring to Figures 16 and 17, during the use of power semiconductor switching devices, controlling the second switch control terminal of the i-th inductive switching device to turn on the i-th inductive switching device, then I... si I is the preset current value flowing through the i-th inductive switching device. si The current is the preset value of the i-th inductive switch. By measuring the voltage V1i between the third and fourth terminals of the i-th inductive switch, and using the measured value of V1i and the first voltage-junction temperature change relationship of the i-th inductive switch, the junction temperature detected by the i-th inductive switch can be calculated. The junction temperature detected by the i-th inductive switch also represents the junction temperature of the adjacent main switch portion. When the area of ​​the main switch is large, the junction temperature of the main switch is inconsistent, exhibiting a certain temperature gradient distribution. Thus, by placing m inductive switches as shown in Figures 16 and 17, the detected junction temperature of the i-th inductive switch can represent the junction temperature of the main switch portion immediately adjacent to the i-th inductive switch. In practical applications, the average temperature of the detected junction temperatures of the m inductive switches can also be used to approximate the junction temperature of the main switch.

[0167] The second category of calculation methods:

[0168] The second category of calculation methods differs from the first category in that the inductance rate between the inductive switching devices and the main switching device is obtained by dividing the first quantity by the third quantity, using this quotient as the inductance rate between at least two inductive switching devices and the main switching device. In other words, it uses the inductance rate between at least two inductive switching devices as a whole and the main switching device. It can be seen that the second category of calculation methods is only applicable when the number of inductive switching devices is at least two, and the total current through all inductive switching devices is known, but the current through each individual inductive switching device is not detected. For example, referring to Figures 14 and 15, a detailed description follows.

[0169] When a preset current value is applied to at least two inductive switching devices and the voltage of the inductive switching devices is measured, specifically: the total current applied to at least two inductive switching devices is the preset current value, and the total voltage between the third and fourth path terminals of at least two inductive switching devices is measured.

[0170] In the second category of calculation methods, the current flowing through the main switching device can be determined based on the inductance, preset current value, voltage between the third and fourth path terminals, and voltage between the first and second path terminals, as follows:

[0171] First, calculate the voltage between the first and second path terminals, divide it by the total voltage, and obtain the quotient.

[0172] Then, the product of the quotient, inductance, and preset current value is used as the through current of the main switching device.

[0173] In the second category of calculation methods, since the inductance between at least two inductive switching devices and the main switching device is obtained, and the current supplied to the inductive switching device is the total current supplied to at least two inductive switching devices, which is equal to the preset current value, and the voltage of the inductive switching device is the total voltage between the third and fourth path terminals of all inductive switching devices, it is only necessary to calculate the entire inductive switching device as a whole to directly obtain the current through the main switching device, without calculating the detection current of a single inductive switching device.

[0174] For example, referring to Figures 14 and 15, when the second switch control terminal of m inductive switching devices is controlled, causing all m inductive switching devices to be simultaneously turned on, then the preset current value is... I si Let Is be the current flowing through the i-th inductive switching device, a preset current value. At this point, the total voltage between the third and fourth path terminals of the m inductive switching devices can be V1. When the main switching device is turned on, the voltage V2 between the first and second path terminals is measured, and the current I flowing through the main switching device is then determined. FET It can be calculated using the following formula: I FET = (V2 / V1)*N*Is

[0175] Furthermore, based on the fundamentals of the second category of calculation methods (the aforementioned acquisition of the inductance between at least two inductive switching devices as a whole and the main switching device, the total current flowing into the at least two inductive switching devices being a preset current value, and the measurement of the total voltage between the third and fourth path terminals of the at least two inductive switching devices), referring to Figure 13, the detection method may further include: S131, while at least two inductive switching devices are turned on and the total current flowing into the at least two inductive switching devices is a preset current value, the voltage between the second switch control terminal and the fourth path terminal is maintained at a preset voltage value; S132, based on the second voltage-junction temperature change relationship and the total voltage between the third and fourth path terminals of the at least two inductive switching devices, the detection junction temperature detected by the at least two inductive switching devices is determined, wherein the second voltage-junction temperature change relationship is obtained through prior testing; S133, the detection junction temperature detected by the at least two inductive switching devices is used as the junction temperature of the main switching device.

[0176] For example, during junction temperature measurement, the inductive switching device is turned on, and the total current supplied to at least two inductive switching devices is a preset current value, while the voltage between the second switch control terminal and the fourth path terminal is maintained at a preset voltage value.

[0177] The second voltage-junction temperature relationship, obtained through prior testing, may include: controlling at least two inductive switching devices to conduct, while simultaneously maintaining the voltage between the second switch control terminal and the fourth path terminal at a preset current value. Then, the junction temperature of the power semiconductor switching device is adjusted, and the total voltage between the third and fourth path terminals of the inductive switching device is measured at different junction temperatures to obtain the second voltage-junction temperature relationship. Specifically, the junction temperature of the power semiconductor switching device can be adjusted to a temperature T1, and the total voltage V1 between the third and fourth path terminals of the inductive switching device at that temperature can be measured; then the junction temperature of the power semiconductor switching device can be adjusted to another temperature T2, and the total voltage V2 between the third and fourth path terminals of the inductive switching device at that temperature can be measured. This process is repeated to obtain the second voltage-junction temperature relationship. The second voltage-junction temperature relationship can be displayed using methods such as, but not limited to, tables or function curves.

[0178] For example, referring to Figures 14 and 15, the second switch control terminals of m inductive switching devices are controlled so that all m inductive switching devices are simultaneously turned on. I siLet Is be the current flowing through the i-th inductive switching device, which is a preset current value. At this time, the total voltage between the third and fourth path terminals of the m inductive switching devices can be V1. First, the junction temperature Tj of the power semiconductor switching device (main switching device + m inductive switching devices) is changed offline, and the V1 value corresponding to Is under different Tj is recorded to obtain the second voltage-junction temperature change relationship of the m inductive switching devices.

[0179] Referring to Figures 14 and 15, during the use of power semiconductor switching devices, the second switch control terminals of m inductive switching devices are controlled so that all m inductive switching devices are simultaneously turned on. Then... I si Let Is be the current flowing through the i-th inductive switching device, a preset current value. Then, by measuring the voltage V1 between the third and fourth paths of the m inductive switching devices, the junction temperature of the m inductive switching devices can be calculated from the measured value of V1. This junction temperature is typically the average junction temperature detected by all m inductive switching devices. The average junction temperature detected by the m inductive switching devices also represents the junction temperature of the adjacent main switching device.

[0180] In the various embodiments shown above, an inductive switching device is disposed on the substrate on which the main switching device is disposed. The inductive switching device includes a third path terminal, a fourth path terminal, and a second switch control terminal. During current detection, a preset current value is supplied to the inductive switching device through the third path terminal, and the voltage between the first and second path terminals, as well as the voltage between the third and fourth path terminals, are measured. Combined with the inductance between the inductive switching device and the main switching device, the current flowing through the main switching device can be determined. Compared with related technologies, current detection can be completed simply by disposing of an inductive switching device, thereby simplifying the circuit structure and reducing costs.

[0181] In view of the two shortcomings of the Sense FET technology in the related technologies, the power semiconductor switching device detection method provided in some embodiments of this disclosure has two objectives. (1) It proposes a lossless detection method for the current of power semiconductor switching devices, which has a simple circuit, low cost, and small size; in terms of performance, it can achieve the same or even higher current detection accuracy as the virtual ground sensing circuit based on Sense FET, while saving one operational amplifier in the peripheral circuit, making the circuit design simple and low cost. (2) This lossless current detection method can also detect the junction temperature of the power semiconductor switching device, and realize the junction temperature and current detection of the power semiconductor switching device at the same time, which greatly simplifies the design of the junction temperature and current detection circuit, and has low cost, lossless current detection, high accuracy and high bandwidth detection.

[0182] Example 4

[0183] As shown in Figure 18, the power semiconductor switching device has a first path terminal of the main switching device interconnected with the third path terminal of one or more inductive switching devices, a first switch control terminal of the main switching device and a second switch control terminal of one or more inductive switching devices separated from each other, and a second path terminal of the main switching device interconnected with the fourth path terminal of one or more inductive switching devices.

[0184] As shown in Figure 19, the first path switch control terminal of the main switch device and the second path switch control terminal of the inductive switch device in the power semiconductor switching device provided in Example 4 are separated. When the inductive switch device is turned on and a known current Is flows through it, the voltage V1 between the third and fourth path terminals of the inductive switch device is measured. When the main device is turned on, the voltage V2 between the first and second path terminals of the main switch device is measured. The current IFET through the main device can then be calculated using the following formula: IFET=IS*N*V2 / V1

[0185] Example 5

[0186] As shown in Figure 20, the power semiconductor switching device has a first path terminal of the main switching device interconnected with the third path terminal of one or more inductive switching devices, a first switch control terminal of the main switching device and a second switch control terminal of one or more inductive switching devices separated from each other, and a second path terminal of the main switching device and a fourth path terminal of one or more inductive switching devices separated from each other.

[0187] As shown in Figure 21, the first path switch control terminal of the main switch device and the second path switch control terminal of the inductive switch device in the power semiconductor switching device provided in Example 5 are separated. When the inductive switch device is turned on and a known current Is flows through it, the voltage V1 between the third and fourth path terminals of the inductive switch device is measured. When the main device is turned on, the voltage V2 between the first and second path terminals of the main switch device is measured. The current IFET through the main device can then be calculated using the following formula: IFET=IS*N*V2 / V1

[0188] Furthermore, this disclosure also provides a power semiconductor switching device. Referring to Figures 5 to 10, the power semiconductor switching device includes a main switching device, which includes a first path terminal, a second path terminal, and a first switching control terminal. The power semiconductor switching device also includes a detection circuit of any of the above-mentioned power semiconductor switching devices.

[0189] Exemplary, the power semiconductor switching device can be any type of semiconductor switching device. For example, the power semiconductor switching device can be, but is not limited to, MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) devices, IGBT (Insulated Gate Bipolar Transistor) devices, etc. Exemplary, the power semiconductor switching device can be a depletion-mode switching device or an enhancement-mode switching device. Exemplary, the power semiconductor switching device can be an N-channel switching device or a P-channel switching device. Exemplary, the power semiconductor switching device can be a device based on Si, SiC, or GaN. For example, the power semiconductor switching device can be: a SiC-based N-channel depletion-type MOSFET device, a SiC-based P-channel depletion-type MOSFET device, a SiC-based N-channel enhancement-type MOSFET device, a SiC-based P-channel enhancement-type MOSFET device, a SiC-based N-channel depletion-type IGBT device, a SiC-based P-channel depletion-type IGBT device, a SiC-based N-channel enhancement-type IGBT device, a SiC-based P-channel enhancement-type IGBT device, a Si-based N-channel depletion-type MOSFET device, a Si-based P-channel depletion-type MOSFET device, a Si-based P-channel enhancement-type MOSFET device, a Si-based N-channel depletion-type IGBT device, a Si-based P-channel depletion-type IGBT device, a Si-based N-channel enhancement-type IGBT device, a Si-based P-channel enhancement-type IGBT device, a depletion-type GaN device, or an enhancement-type GaN device.

[0190] This disclosure has been described through the above embodiments; however, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit this disclosure to the described embodiments. Furthermore, those skilled in the art will understand that this disclosure is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of this disclosure, all of which fall within the scope of protection claimed by this disclosure. The scope of protection of this disclosure is defined by the appended claims and their equivalents.

Claims

1. A detection circuit for a power semiconductor switching device, the power semiconductor switching device comprising a main switching device, the main switching device comprising a first path terminal, a second path terminal, and a first switching control terminal; characterized in that, The detection circuit includes: An inductive switching device is disposed on the same substrate as the main switching device; the inductive switching device includes a third path terminal, a fourth path terminal, and a second switch control terminal. The third path terminal is used to electrically connect to a current source, and the current source is used to supply a current of a preset current value to the inductive switching device. The first path terminal and the second path terminal are electrically connected to a first voltage measuring circuit, which is used to measure the voltage between the first path terminal and the second path terminal. The third and fourth access terminals are electrically connected to a second voltage measurement circuit, which is used to measure the voltage between the third and fourth access terminals.

2. The detection circuit as described in claim 1, characterized in that, The main switching device further includes at least one first transistor; For each of the at least one first transistor, the first electrode of the first transistor is electrically connected to the first path terminal, the second electrode of the first transistor is electrically connected to the second path terminal, and the control electrode of the first transistor is electrically connected to the first switch control terminal.

3. The detection circuit as described in claim 2, characterized in that, The inductive switching device further includes at least one second transistor; For each of the at least one second transistor, the first electrode of the second transistor is electrically connected to the third path terminal, the second electrode of the second transistor is electrically connected to the fourth path terminal, and the control electrode of the second transistor is electrically connected to the second switch control terminal.

4. The detection circuit as described in claim 1, characterized in that, The minimum distance between the main switching device and the inductive switching device is less than a preset distance.

5. The detection circuit as described in claim 3, characterized in that, A transistor array is disposed on the substrate; Some of the transistors in the transistor array are the first transistors, and some of the transistors are the second transistors.

6. The detection circuit as described in claim 3, characterized in that, The first electrode of the first transistor is the drain, the second electrode of the first transistor is the source, and the control electrode of the first transistor is the gate. The first electrode of the second transistor is the drain, the second electrode of the second transistor is the source, and the control electrode of the second transistor is the gate.

7. The detection circuit as described in any one of claims 1 to 6, characterized in that, The number of the inductive switching devices is at least two; Each of the aforementioned inductive switching devices is located at a different position within the power semiconductor switching device.

8. The detection circuit as described in claim 7, characterized in that, The third path terminals of the at least two inductive switching devices are interconnected. The fourth path terminals of the at least two inductive switching devices are interconnected.

9. The detection circuit as described in claim 8, characterized in that, The third path terminal of the at least two inductive switching devices is connected to the same current source.

10. The detection circuit as described in claim 8, characterized in that, The second switch control terminals of the at least two inductive switching devices are interconnected; or, The second switch control terminals of the at least two inductive switching devices are separated from each other.

11. The detection circuit as described in claim 7, characterized in that, The third path terminals of the at least two inductive switching devices are separated from each other. The fourth path terminals of the at least two inductive switching devices are interconnected.

12. The detection circuit as described in claim 11, characterized in that, The number of current sources is at least two; each of the at least two current sources corresponds to one of the at least two inductive switching devices, and the third path terminal of each inductive switching device is connected to the corresponding current source.

13. The detection circuit as described in claim 11, characterized in that, The second switch control terminals of the at least two inductive switching devices are separated from each other.

14. The detection circuit as described in claim 1, characterized in that, The first path terminal and the third path terminal are separated from each other, the first switch control terminal and the second switch control terminal are interconnected, and the second path terminal and the fourth path terminal are interconnected. or, The first path terminal and the third path terminal are separated from each other, the first switch control terminal and the second switch control terminal are separated from each other, and the second path terminal and the fourth path terminal are interconnected; or, The first and third path terminals are separated from each other, the first and second switch control terminals are separated from each other, and the second and fourth path terminals are separated from each other; or The first path terminal and the third path terminal are interconnected; the first switch control terminal and the second switch control terminal are separate from each other; and the second path terminal and the fourth path terminal are interconnected; or The first path terminal and the third path terminal are interconnected, the first switch control terminal and the second switch control terminal are separated from each other, and the second path terminal and the fourth path terminal are separated from each other.

15. The detection circuit as described in claim 1, characterized in that, The current source is a constant current source, or the current source switches between an on state and an off state.

16. The detection circuit as described in claim 1, characterized in that, Also includes: The current source is electrically connected to the third path terminal and is used to supply the preset current value to the inductive switching device. The first voltage measurement circuit is electrically connected to the first path terminal and the second path terminal, and is used to measure the voltage between the first path terminal and the second path terminal. The second voltage measurement circuit is electrically connected to the third and fourth path terminals and is used to measure the voltage between the third and fourth path terminals.

17. A method for detecting power semiconductor switching devices, characterized in that, The detection method is based on the detection circuit of the power semiconductor switching device according to any one of claims 1 to 16, and the detection method includes: Obtain the inductance between the inductive switching device and the main switching device; The system controls the inductive switch to be turned on, applies a current of a preset value to the inductive switch, and measures the voltage between the third and fourth path terminals; and controls the main switch to be turned on, and measures the voltage between the first and second path terminals. The current through the main switching device is determined based on the inductance, the preset current value, the voltage between the third and fourth path terminals, and the voltage between the first and second path terminals.

18. The detection method as described in claim 17, characterized in that, The step of obtaining the inductance between the inductive switching device and the main switching device includes: Obtain a first number of transistors in the main switching device that meet preset conditions, and a second number of transistors in the inductive switching device that meet the preset conditions; wherein, the preset conditions include: the junction temperature of the main switching device and the inductive switching device is the same, and when the main switching device and the inductive switching device are turned on, the voltage between the first switch control terminal and the second path terminal is equal to the voltage between the second switch control terminal and the fourth path terminal; The quotient of the first quantity divided by the second quantity is taken as the inductance rate between the inductive switching device and the main switching device.

19. The detection method as described in claim 18, characterized in that, Determining the current flowing through the main switching device based on the inductance, the preset current value, the voltage between the third and fourth path terminals, and the voltage between the first and second path terminals includes: Calculate the voltage between the first and second access terminals and divide it by the quotient of the voltage between the third and fourth access terminals; The product of the quotient, the inductance, and the preset current value is used as the detection current obtained by the inductive switching device. The current flowing through the main switching device is determined based on the detected current.

20. The detection method as described in claim 19, characterized in that, The number of the inductive switch device is one; Determining the through current of the main switching device based on the detected current includes: using the detected current as the through current of the main switching device.

21. The detection method as described in claim 19, characterized in that, The number of the inductive switching devices is at least two, and each of the inductive switching devices is located at a different position of the main switching device; Determining the through current of the main switching device based on the detected current includes: taking the average value of the detected currents obtained by the at least two inductive switching devices as the through current of the main switching device.

22. The detection method according to any one of claims 18 to 21, characterized in that, Also includes: When the inductive switch is turned on, and a current of the preset current value is supplied to the inductive switch, the voltage between the second switch control terminal and the fourth path terminal is maintained at the preset voltage value. The detected junction temperature of the inductive switching device is determined based on the first voltage-junction temperature change relationship and the voltage between the third and fourth path terminals; wherein, the first voltage-junction temperature change relationship indicates the relationship between the voltage between the third and fourth path terminals and the junction temperature of the power semiconductor switching device. The junction temperature of the main switching device is determined based on the detected junction temperature.

23. The detection method as described in claim 22, characterized in that, The first voltage-junction temperature relationship was obtained through prior testing, including: The inductive switch device is turned on, and a current of the preset current value is supplied to the inductive switch device. At the same time, the voltage between the second switch control terminal and the fourth path terminal is maintained at the preset voltage value. Adjust the junction temperature of the power semiconductor switching device and measure the voltage between the third and fourth path terminals at different junction temperatures to obtain the first voltage-junction temperature change relationship.

24. The detection method as described in claim 22, characterized in that, The number of the inductive switch device is one; Determining the junction temperature of the main switching device based on the detected junction temperature includes: using the detected junction temperature as the junction temperature of the main switching device.

25. The detection method as described in claim 22, characterized in that, The number of the inductive switching devices is at least two, and each of the inductive switching devices is located at a different position of the power semiconductor switching device; Determining the junction temperature of the main switching device based on the detected junction temperature includes: taking the average value of the detected junction temperatures obtained by the at least two sensing switching devices as the junction temperature of the main switching device.

26. The detection method as described in claim 17, characterized in that, The number of the inductive switching devices is at least two, and each of the inductive switching devices is located at a different position of the power semiconductor switching device; The step of obtaining the inductance between the inductive switching device and the main switching device includes: Obtain a first number of transistors in the main switching device that meet preset conditions, and a second number of transistors in each of the sensing switching devices that meet the preset conditions; wherein, the preset conditions include: the junction temperature of the main switching device and each of the sensing switching devices is the same, and when the main switching device and each of the sensing switching devices are turned on, the voltage between the first switch control terminal and the second path terminal is equal to the voltage between the second switch control terminal and the fourth path terminal; The third quantity is obtained by summing the second quantities of each of the at least two inductive switching devices; The quotient of the first quantity divided by the third quantity is taken as the inductance between the at least two inductive switching devices and the main switching device.

27. The detection method as described in claim 26, characterized in that, Applying a preset current value to the inductive switching device and measuring the voltage between the third and fourth path terminals includes: Control the at least two inductive switching devices to be turned on, the total current supplied to the at least two inductive switching devices is the preset current value, and measure the total voltage between the third path terminal and the fourth path terminal of the at least two inductive switching devices.

28. The detection method as described in claim 27, characterized in that, Determining the current flowing through the main switching device based on the inductance, the preset current value, the voltage between the third and fourth path terminals, and the voltage between the first and second path terminals includes: Calculate the voltage between the first path terminal and the second path terminal, and divide the quotient by the total voltage; The product of the quotient, the inductance, and the preset current value is used as the through current of the main switching device.

29. The detection method according to any one of claims 27 to 28, characterized in that, Also includes: While at least two inductive switching devices are turned on and the total current supplied to the at least two inductive switching devices is the preset current value, the voltage between the second switch control terminal and the fourth path terminal is maintained at the preset voltage value. The detection junction temperature detected by the at least two sensing switching devices is determined based on the second voltage-junction temperature change relationship and the total voltage between the third and fourth path terminals of the at least two sensing switching devices; wherein, the second voltage-junction temperature change relationship indicates the relationship between the total voltage between the third and fourth path terminals and the junction temperature of the power semiconductor switching device; The junction temperature detected by the at least two inductive switching devices is taken as the junction temperature of the main switching device.

30. The detection method as described in claim 29, characterized in that, The second voltage-junction temperature relationship was obtained through prior testing, including: Controlling the at least two inductive switching devices to be turned on, while the current supplied to the at least two inductive switching devices is the preset current value, the voltage between the second switch control terminal and the fourth path terminal is maintained at the preset voltage value; Adjust the junction temperature of the power semiconductor switching device and measure the total voltage between the third and fourth path terminals at different junction temperatures to obtain the second voltage-junction temperature change relationship.

31. The detection method as described in claim 17, characterized in that, The control of the main switch device to turn on is specifically achieved by controlling the main switch device to turn on through the first switch control terminal and the second path terminal; The control of the inductive switch device to conduct is specifically achieved by controlling the inductive switch device to conduct through the second switch control terminal and the fourth path terminal.

32. A power semiconductor switching device, characterized in that, include: A main switching device, the main switching device comprising: a first path terminal, a second path terminal, and a first switch control terminal; The detection circuit of the power semiconductor switching device as described in any one of claims 1 to 16.

33. The power semiconductor switching device as described in claim 32, characterized in that, The power semiconductor switching devices are: SiC-based N-channel depletion-type MOSFET devices, SiC-based P-channel depletion-type MOSFET devices, SiC-based N-channel enhancement-type MOSFET devices, SiC-based P-channel enhancement-type MOSFET devices, SiC-based N-channel depletion-type IGBT devices, SiC-based P-channel depletion-type IGBT devices, SiC-based N-channel enhancement-type IGBT devices, SiC-based P-channel enhancement-type IGBT devices, Si-based N-channel depletion-type MOSFET devices, Si-based P-channel depletion-type MOSFET devices, Si-based P-channel enhancement-type MOSFET devices, Si-based N-channel depletion-type IGBT devices, Si-based P-channel depletion-type IGBT devices, Si-based N-channel enhancement-type IGBT devices, Si-based P-channel enhancement-type IGBT devices, depletion-type GaN devices, or enhancement-type GaN devices.

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