Cascode power device and current detection method thereof

Abstract

The embodiment of the invention provides a cascode power device and a current detection method thereof, the cascode power device comprises a low-voltage switch device, a depletion type switch device and a current measurement resistor, the grid electrode of the depletion type switch device is electrically connected with the source electrode of the low-voltage switch device, and the source electrode of the depletion type switch device is electrically connected with the drain electrode of the low-voltage switch device; the current measuring resistor is electrically connected between the source electrode of the depletion type switching device and the drain electrode of the low-voltage switching device, and the voltage drop of the current measuring resistor is smaller than the threshold voltage of the depletion type switching device; the first end and the second end of the current measuring resistor are configured to be electrically connected with the current detection circuit so that the current detection circuit can measure the voltage difference value of the two ends of the current measuring resistor, the current value flowing through the current measuring resistor is calculated according to the voltage difference value and the resistance value of the current measuring resistor, and the working current value of the cascode power device is obtained. According to the embodiment of the invention, the working state of the cascode power device is not affected, the detection cost of the device is reduced, and the high current detection precision is maintained.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor technology, and particularly relates to a common-source common-gate power device and a current detection method thereof. BACKGROUND

[0002] The common-source common-gate (Cascode) power device is a structure widely used in the field of power electronics, which is usually composed of a low-voltage switching device and a high-voltage depletion-mode switching device in cascade. This structure combines the easy-to-drive property of the low-voltage device and the high-voltage property of the high-voltage depletion-mode switching device, forming an enhanced equivalent switch with excellent performance, which is suitable for high-frequency and high-efficiency power conversion systems.

[0003] In the working process of the power device, real-time current detection is crucial for system safety. Overcurrent, short circuit or other abnormal conditions may cause device damage or even system failure, so fast and accurate current detection technology is needed to trigger protection mechanisms (such as turning off the device or reducing power output). However, the existing current detection schemes have many limitations in practical application: On-resistance (Rdson) detection: using the on-resistance characteristics of the power device itself, the current is estimated by measuring the drain-source voltage (Vds). However, Rdson is easily affected by temperature, stress and aging, resulting in decreased detection accuracy, which requires complex temperature compensation or dynamic calibration.

[0004] Current mirror technology: the main current is copied by the sensing FET and measured in a low-power path, but the temperature dependence of device characteristics can cause current ratio mismatch, and the discrete design can introduce parasitic parameters, limiting high-frequency application performance.

[0005] Non-contact detection: such as Hall sensors or magnetoresistive sensors, although they do not need to directly contact the current path, but the cost is high, and they are sensitive to environmental temperature and magnetic field interference, making it difficult to meet the requirements of high integration.

[0006] In view of the above problems, there is an urgent need for a current detection scheme that can balance high precision, low loss, temperature stability and integration. Especially in the common-source common-gate structure, how to realize efficient and reliable current detection without affecting the working state of the device has become the key direction of technical improvement. SUMMARY

[0007] The embodiment of the present application provides a common-source common-gate power device and a current detection method thereof, which can maintain high current detection accuracy while not affecting the working state of the common-source common-gate power device and reducing the detection cost of the device.

[0008] In a first aspect, embodiments of the present application provide a cascode power device, comprising a low-voltage switch device, a depletion-mode switch device, and a current-sensing resistor, a gate of the depletion-mode switch device is electrically connected to a source of the low-voltage switch device, a source of the depletion-mode switch device is electrically connected to a drain of the low-voltage switch device; the current-sensing resistor is electrically connected between the source of the depletion-mode switch device and the drain of the low-voltage switch device, a voltage drop of the current-sensing resistor is less than a threshold voltage of the depletion-mode switch device. The first end of the current-sensing resistor and the second end of the current-sensing resistor are configured to be electrically connected to a current detection circuit, so that the current detection circuit measures a voltage difference between the first end and the second end of the current-sensing resistor, and calculates a current value flowing through the current-sensing resistor according to the voltage difference between the first end and the second end of the current-sensing resistor and a resistance value of the current-sensing resistor, to obtain a working current value of the cascode power device.

[0009] According to some embodiments of the present application, optionally, an absolute value of a temperature drift coefficient of the material of the current-sensing resistor is less than 200 ppm / ℃.

[0010] According to some embodiments of the present application, optionally, the material of the current-sensing resistor comprises titanium nitride or tantalum nitride.

[0011] According to some embodiments of the present application, optionally, the current-sensing resistor and the depletion-mode switch device are integrated on the same chip, and a distance between the current-sensing resistor and the depletion-mode switch device is greater than 200 μm in a horizontal distance inside the chip.

[0012] According to some embodiments of the present application, optionally, the current-sensing resistor is disposed in a metal interconnection layer of the depletion-mode switch device, and is electrically connected to the source of the depletion-mode switch device through a wire and / or a via.

[0013] According to some embodiments of the present application, optionally, the source of the depletion-mode switch device is led out as a first connection terminal, the drain of the low-voltage switch device is led out as a second connection terminal; the current-sensing resistor is a discrete device, a first end of the current-sensing resistor is electrically connected to the first connection terminal, and a second end of the current-sensing resistor is electrically connected to the second connection terminal.

[0014] According to some embodiments of the present application, optionally, the resistance value of the current-sensing resistor ranges from 0.1 mΩ to 200 mΩ.

[0015] According to some embodiments of the present application, optionally, the depletion mode switching device adopts a multi-finger gate structure, the depletion mode switching device at least includes a first depletion mode switching device and a second depletion mode switching device in parallel, the gate of the first depletion mode switching device and the gate of the second depletion mode switching device are electrically connected to the source of the low-voltage switching device, the source of the first depletion mode switching device and the source of the second depletion mode switching device are electrically connected to the drain of the low-voltage switching device; the first depletion mode switching device is located in the main current path of the common-source common-gate power device, and the second depletion mode switching device is located in the first detection path of the common-source common-gate power device; the current detection resistor is located in the first detection path and is electrically connected between the source of the second depletion mode switching device and the drain of the low-voltage switching device.

[0016] According to some embodiments of the present application, optionally, the source-drain resistance value of the second depletion mode switching device is more than 100 times of the source-drain resistance value of the first depletion mode switching device.

[0017] According to some embodiments of the present application, optionally, the depletion mode switching device further includes a third depletion mode switching device, the third depletion mode switching device is in parallel with the first depletion mode switching device and the second depletion mode switching device; the common-source common-gate power device further includes: a temperature-sensitive resistor, the temperature-sensitive resistor and the third depletion mode switching device are located in the second detection path of the common-source common-gate power device, and the temperature-sensitive resistor is electrically connected between the source of the third depletion mode switching device and the drain of the low-voltage switching device; the first end of the temperature-sensitive resistor and the second end of the temperature-sensitive resistor are configured to be electrically connected to the current detection circuit, so that the current detection circuit measures the voltage difference between the two ends of the temperature-sensitive resistor; according to the mapping relationship between the temperature of the temperature-sensitive resistor and the voltage difference, and the voltage difference between the two ends of the temperature-sensitive resistor, the current temperature is calculated; based on the current temperature, the resistance value of the current detection resistor is corrected; and according to the voltage difference between the two ends of the current detection resistor and the corrected resistance value of the current detection resistor, the current value flowing through the current detection resistor is calculated, and the working current value of the common-source common-gate power device is obtained.

[0018] According to some embodiments of the present application, optionally, the current detection circuit further includes: a temperature-sensitive resistor, the temperature-sensitive resistor is located in the first detection path and is electrically connected between the source of the second depletion mode switching device and the drain of the low-voltage switching device, the temperature-sensitive resistor is in series or parallel with the current detection resistor; The first end of the temperature-sensitive resistor and the second end of the temperature-sensitive resistor are configured to be electrically connected with the current detection circuit to enable the current detection circuit to measure a voltage difference across the temperature-sensitive resistor; a current temperature is calculated according to a mapping relationship between a temperature of the temperature-sensitive resistor and the voltage difference and the voltage difference across the temperature-sensitive resistor; a resistance value of the current measurement resistor is corrected based on the current temperature; and a current value flowing through the current measurement resistor is calculated according to the voltage difference across the current measurement resistor and the corrected resistance value of the current measurement resistor, to obtain the working current value of the cascode power device.

[0019] According to some embodiments of the present application, optionally, the temperature-sensitive resistor, the current measurement resistor and the depletion-mode switching device are integrated on the same chip, and the distance between the temperature-sensitive resistor and the depletion-mode switching device is less than the distance between the current measurement resistor and the depletion-mode switching device on a horizontal distance within the chip.

[0020] According to some embodiments of the present application, optionally, the low-voltage switching device comprises a silicon-based N-type field effect transistor, and the depletion-mode switching device comprises a depletion-mode gallium nitride field effect transistor or a depletion-mode junction field effect transistor.

[0021] In a second aspect, the embodiments of the present application provide a current detection method of a cascode power device, the cascode power device comprising a low-voltage switching device, a depletion-mode switching device and a current measurement resistor, a gate of the depletion-mode switching device being electrically connected with a source of the low-voltage switching device, a source of the depletion-mode switching device being electrically connected with a drain of the low-voltage switching device; the current measurement resistor being electrically connected between the source of the depletion-mode switching device and the drain of the low-voltage switching device, a voltage drop of the current measurement resistor being less than a threshold voltage of the depletion-mode switching device; the current detection method comprising: measuring a voltage difference across the current measurement resistor; and calculating a current value flowing through the current measurement resistor according to the voltage difference across the current measurement resistor and a resistance value of the current measurement resistor, to obtain a working current value of the cascode power device.

[0022] According to some embodiments of the present application, the depletion mode switching device adopts a multi-finger gate structure, the depletion mode switching device includes a first depletion mode switching device, a second depletion mode switching device and a third depletion mode switching device in parallel, the gate of the first depletion mode switching device, the gate of the second depletion mode switching device and the gate of the third depletion mode switching device are electrically connected to the source of the low-voltage switching device, and the source of the first depletion mode switching device, the source of the second depletion mode switching device and the source of the third depletion mode switching device are electrically connected to the drain of the low-voltage switching device; the first depletion mode switching device is located in the main current path of the cascode power device, the second depletion mode switching device and the current sensing resistor are located in the first detection path of the cascode power device, and the current sensing resistor is electrically connected between the source of the second depletion mode switching device and the drain of the low-voltage switching device; the third depletion mode switching device and the temperature-sensitive resistor are located in the second detection path of the cascode power device, and the temperature-sensitive resistor is electrically connected between the source of the third depletion mode switching device and the drain of the low-voltage switching device. The current detection method further includes: measuring a voltage difference across the temperature-sensitive resistor; calculating a current temperature according to a mapping relationship between the temperature of the temperature-sensitive resistor and the voltage difference and the voltage difference across the temperature-sensitive resistor; correcting a resistance value of the current sensing resistor based on the current temperature; and calculating a current value flowing through the current sensing resistor according to the voltage difference across the current sensing resistor and the resistance value of the current sensing resistor to obtain a working current value of the cascode power device, including: calculating the current value flowing through the current sensing resistor according to the voltage difference across the current sensing resistor and the corrected resistance value of the current sensing resistor to obtain the working current value of the cascode power device.

[0023] The cascode power device and the current detection method thereof provided by the embodiments of the present application have the following advantages: a current sensing resistor is connected in series between the source of the depletion mode switching device of the cascode power device and the drain of the low-voltage switching device, and the working current of the cascode power device can be accurately calculated directly through the voltage output of the current sensing resistor, without the need for an additional dynamic calibration circuit, thereby reducing the complexity of the peripheral circuit and saving the detection cost. Meanwhile, this circuit structure / way is compatible with the existing driving logic, and the driving logic of the cascode power device does not need to be changed. In addition, the voltage drop generated by the current sensing resistor is smaller than the threshold voltage of the depletion mode switching device, so the power loss of the current sensing resistor is negligible, and the working state of the device is slightly affected, which does not significantly change the current distribution or switching characteristics of the cascode power device, and can ensure that the device can normally turn on and off. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. For those skilled in the art, without creative labor, other drawings can also be obtained according to these drawings.

[0025] Figure 1 A circuit schematic diagram of a common-source common-gate power device provided by an embodiment of the present application; Figure 2 A circuit connection schematic diagram of a common-source common-gate power device and a current detection circuit provided by an embodiment of the present application; Figure 3 A partial top view schematic diagram of a current sensing resistor and a depletion-mode switching device provided by an embodiment of the present application; Figure 4 A cross-sectional schematic diagram of a current sensing resistor and a depletion-mode switching device provided by an embodiment of the present application; Figure 5 Another circuit schematic diagram of a common-source common-gate power device provided by an embodiment of the present application; Figure 6 A circuit schematic diagram of a common-source common-gate power device and a current detection circuit provided by an embodiment of the present application; Figure 7 Still another circuit schematic diagram of a common-source common-gate power device provided by an embodiment of the present application; Figure 8 Still another circuit schematic diagram of a common-source common-gate power device provided by an embodiment of the present application; Figure 9 Still another circuit schematic diagram of a common-source common-gate power device provided by an embodiment of the present application; Figure 10 A flow schematic diagram of a current detection method of a common-source common-gate power device provided by an embodiment of the present application; Figure 11 Another flow schematic diagram of a current detection method of a common-source common-gate power device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0026] The features and exemplary embodiments of various aspects of the present application will be described in detail below with reference to the drawings. The following detailed description is merely intended to explain the present application, and is not intended to limit the present application. The present application can be implemented without some of the specific details, which are well known to those skilled in the art. The following description of the embodiments is merely intended to provide a better understanding of the present application by showing examples of the present application.

[0027] It should be noted that, in the specification, relational terms such as first and second, and the like, are used solely to distinguish one from another entity or action, without necessarily requiring or implying any actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0028] It should be understood that the term "and / or" as used herein merely describes associated objects, and can exist in three forms: A and / or B, A or B, and A and B. In addition, the character " / " is generally used to represent an "or" relationship between the front and rear associated objects.

[0029] In the embodiments of the present application, the term "electrically connected" can refer to direct electrical connection between two components, or can refer to electrical connection between two components via one or more other components.

[0030] Various modifications and changes can be made to the present application in matters of construction and details without departing from the spirit and scope of the present application, which will be apparent to one skilled in the art. Accordingly, the present application is intended to cover all modifications and changes as falling within the scope of the corresponding claims (technical solutions claimed to be protected), and their equivalents. It should be noted that the embodiments provided by the present application can be combined with each other without contradiction, if possible.

[0031] Figure 1 A circuit schematic diagram of a common-source common-gate power device provided by the embodiments of the present application is shown in FIG. 1. As shown in FIG. 1, the common-source common-gate power device 10 provided by the embodiments of the present application can include a low-voltage switch device Q1, a depletion-mode switch device Q2, and a current measuring resistor Rs. Figure 1

[0032] ​The gate G2 of the depletion-mode switching device Q2 can be electrically connected with the source S1 of the low-voltage switching device Q1, and the source S2 of the depletion-mode switching device Q2 can be electrically connected with the drain D1 of the low-voltage switching device Q1. The gate G1 of the low-voltage switching device Q1 can be used as the gate G of the cascode power device 10, the source S1 of the low-voltage switching device Q1 can be used as the source S of the cascode power device 10, and the drain D2 of the depletion-mode switching device Q2 can be used as the drain D of the cascode power device 10. The low-voltage switching device Q1 and the depletion-mode switching device Q2 are connected in cascade to form the enhancement-mode cascode power device 10.

[0033] The current measurement resistor Rs can be electrically connected to the middle node of the cascode structure, that is, between the source S2 of the depletion-mode switching device Q2 and the drain D1 of the low-voltage switching device Q1. The voltage drop of the current measurement resistor Rs can be less than the threshold voltage |Vth| of the depletion-mode switching device Q2. For example, taking the depletion-mode switching device Q2 as a depletion-mode gallium nitride field effect transistor (d-mode GaN HEMT) as an example, the threshold voltage |Vth| of the d-mode GaN HEMT is usually greater than 5V, and the voltage drop generated on the current measurement resistor Rs can be much smaller than the order of |Vth|. Therefore, the power loss of the current measurement resistor Rs is negligible, and has little effect on the working state of the device, and will not significantly change the current distribution or switching characteristics of the cascode power device, so as to ensure that the device can normally turn on and off, and will not seriously affect the switching state of the device like the enhancement-mode gallium nitride field effect transistor (e-mode GaN HEMT).

[0034] Figure 2 A circuit connection schematic diagram of the cascode power device and the current detection circuit provided by the embodiment of the present application is shown in the figure. The current detection circuit 20 is electrically connected with the first end a1 of the current measurement resistor Rs and the second end a2 of the current measurement resistor Rs, so as to measure the voltage difference between the two ends of the current measurement resistor Rs, and calculate the current value flowing through the current measurement resistor Rs according to the voltage difference between the two ends of the current measurement resistor Rs and the resistance value of the current measurement resistor Rs, thereby obtaining the working current value of the cascode power device 10. Figure 1 and Figure 2 As shown in the figure, the first end a1 of the current measurement resistor Rs and the second end a2 of the current measurement resistor Rs are configured to be electrically connected with the current detection circuit 20, so that the current detection circuit 20 measures the voltage difference between the two ends of the current measurement resistor Rs, and calculates the current value flowing through the current measurement resistor Rs according to the voltage difference between the two ends of the current measurement resistor Rs and the resistance value of the current measurement resistor Rs, thereby obtaining the working current value of the cascode power device 10.

[0035] For example, the calculation expression of the current value of the current measurement resistor Rs is as follows: (1) wherein, I represents the current value of the current measurement resistor Rs, which can be used as the working current value of the cascode power device 10; V1 represents the voltage value of the first end of the current measurement resistor Rs; V2 represents the voltage value of the second end of the current measurement resistor Rs; represents a resistance value of the current sensing resistor Rs.

[0036] The common-source common-gate power device provided by the embodiments of the present application has a current sensing resistor connected in series between the source of the depletion-mode switch device and the drain of the low-voltage switch device of the common-source common-gate power device. The working current of the common-source common-gate power device can be accurately calculated directly through the voltage output of the current sensing resistor, without the need for an additional dynamic calibration circuit, thereby reducing the complexity of the peripheral circuit and saving the detection cost. At the same time, this circuit structure / way can be compatible with the existing driving logic, without the need for changing the driving logic of the common-source common-gate power device. In addition, the voltage drop generated by the current sensing resistor is less than the threshold voltage of the depletion-mode switch device, so the power loss of the current sensing resistor is negligible, and the working state of the device is slightly affected, which does not significantly change the current distribution or switching characteristics of the common-source common-gate power device, and can ensure that the device can normally turn on and off.

[0037] The common-source common-gate power device 10 will be described in detail below in combination with some specific embodiments.

[0038] The performance of the current sensing resistor Rs directly affects the current detection accuracy of the common-source common-gate power device 10. According to some embodiments of the present application, the absolute value of the temperature coefficient of resistance (TCR) of the material of the current sensing resistor Rs is less than 200 ppm / °C. The absolute value of the TCR < 200 ppm / °C means that the resistance value changes by no more than 0.02% when the temperature increases by 1 °C. Compared with ordinary metals (such as copper TCR ≈ 3900 ppm / °C) or alloy resistors (such as constantan TCR ≈ ± 50 ppm / °C), the temperature drift of the material of the current sensing resistor Rs is lower, which can significantly reduce the detection error caused by temperature. Therefore, the resistance value of the current sensing resistor Rs with low TCR material is less affected by temperature and aging (TCR absolute value < 200 ppm / °C), and the accuracy can be ensured without complex compensation, which helps to reduce the complexity of the peripheral circuit and the detection cost.

[0039] In some specific embodiments, the material for the current-measuring resistance Rs may optionally include titanium nitride (TiN) or tantalum nitride (TaN). The absolute value of the TCR of titanium nitride can be between 20 and 200 ppm / °C, and the TCR of titanium nitride can be optimized through process optimization. For example, during PVD deposition of titanium nitride, its crystallinity can be improved by appropriately increasing the deposition temperature, thereby stabilizing electron transport. And / or, the density of the material can be enhanced by changing the RF power during deposition or stabilizing the deposition rate. And / or, its nitrogen content can be adjusted by adjusting the atmosphere ratio, etc. These processes all contribute to reducing the TCR of titanium nitride. The absolute value of the TCR of tantalum nitride can be between 50 and 150 ppm / °C, and tantalum nitride has stable properties, strong corrosion resistance, and is suitable for high-temperature environments.

[0040] Furthermore, titanium nitride or tantalum nitride can be directly integrated into the chip of depletion-type switching devices through standard deposition (such as PVD, CVD), photolithography and etching processes, without the need for external discrete components. This can reduce the impact of parasitic parameters of discrete components (such as parasitic inductance) on depletion-type switching devices and improve their high-frequency response speed.

[0041] Figure 3 This is a partial top view schematic diagram of the current-measuring resistor and depletion-type switching device provided in an embodiment of this application. Figure 3 As shown, according to some embodiments of this application, optionally, the current-sensing resistor Rs and the depletion-type switching device Q2 are integrated on the same chip 30, and the distance between the current-sensing resistor Rs and the depletion-type switching device Q2 is greater than 200 μm in the horizontal spacing inside the chip 30.

[0042] Integrating the current-sensing resistor Rs with the depletion-mode switching device Q2 reduces parasitic parameters (such as parasitic inductance) of discrete components and their traces, thereby improving the high-frequency response speed of the device. Moreover, by directly fabricating the current-sensing resistor Rs through semiconductor processes (such as deposition, photolithography, and etching), the packaging and assembly costs of external discrete resistors can be eliminated.

[0043] In addition, the depletion-type switching device Q2 generates a lot of heat when it is working (the hot spot temperature may reach more than 100 ℃). By optimizing the layout and designing the distance between the current sensing resistor Rs and the depletion-type switching device Q2 to >200 μm, the influence of heat conduction on the resistance value of the current sensing resistor Rs can be effectively reduced, and its resistance value can be effectively prevented from drifting due to temperature rise, thereby further improving the accuracy of current detection.

[0044] like Figure 3 As shown, in some embodiments, the current-sensing resistor Rs can be set in the edge region of the chip 30, which facilitates PCB layout and connection of the current-sensing resistor Rs to peripheral circuits (such as current detection circuits), and is suitable for various package forms.

[0045] like Figure 3 As shown, in some embodiments, in the horizontal direction X of chip 30, the gate G2 of the depletion-type switching device Q2 can be located on the side of the source S2 of the depletion-type switching device Q2 away from the drain D2 of the depletion-type switching device Q2, that is, the source S2 of the depletion-type switching device Q2 is located between the gate G2 and the drain D2. In this way, the gate G2 of the depletion-type switching device Q2 is far away from the drain D2, which has a high voltage when it is turned on, which can improve the voltage isolation capability of the depletion-type switching device Q2. It should be noted that the size, relative position and spacing of the gate G2, source S2 and drain D2 of the depletion-type switching device Q2 can be flexibly adjusted. For example, the gate G2 of the depletion-type switching device Q2 can also be located between the source S2 and the drain D2. This application does not limit this.

[0046] Figure 4 This is a cross-sectional schematic diagram of a current-measuring resistor and a depletion-type switching device provided in an embodiment of this application. Figure 4 As shown, according to some embodiments of this application, optionally, chip 30 may include a substrate 01, a channel layer 02, a barrier layer 03, a gate metal layer Mg, a source metal layer Ms, a metal interconnect layer ML, and an insulating layer between any two metal layers. The interface between the channel layer 02 and the barrier layer 03 forms a two-dimensional electron gas (2DEG), providing a highly conductive channel. For simplicity, Figure 4 Only a portion of the film layers of chip 30 is shown; the other portion is not shown. In one embodiment, the gate G2 of the depletion-type switching device Q2 can be located in the gate metal layer Mg, and the source S2 and drain D2 of the depletion-type switching device Q2 can be located in the source metal layer Ms.

[0047] Along the direction perpendicular to substrate 01 (i.e., the chip thickness direction) Z, the metal interconnect layer ML can be located on the side of the source metal layer Ms away from substrate 01, and an interlayer insulating layer (ILD) exists between the metal interconnect layer ML and the source metal layer Ms. The current-sensing resistor Rs can be disposed in the metal interconnect layer ML and electrically connected to the source S2 of the depletion-type switching device Q2 via a connection L1 and / or a via g1. It should be noted that... Figure 4 Only one metal interconnect layer ML is shown, namely the first metal interconnect layer ML1. In other embodiments, the chip 30 may include multiple metal interconnect layers ML, such as the first metal interconnect layer ML1, the second metal interconnect layer ML2, etc. Figure 4 (not shown) and the third metal interconnect layer ML3 ( Figure 4 (Not shown), etc. The current-sensing resistor Rs can be located in any metal interconnect layer ML, such as the first metal interconnect layer ML1, the second metal interconnect layer ML2, or the third metal interconnect layer ML3, and this application does not limit it.

[0048] That is, when the current measurement resistor Rs is integrated on the same chip as the depletion-mode switching device Q2, after the gate, source and drain of the depletion-mode switching device Q2 are formed, a deposition and patterning step of the current measurement resistor material is inserted in the subsequent first metal interconnection layer ML1, second metal interconnection layer ML2 or third metal interconnection layer ML3 manufacturing process, and the current measurement resistor is electrically connected to the source of the depletion-mode switching device Q2 to measure the current in the current path.

[0049] One advantage of placing the current measurement resistor Rs on one of the metal interconnection layers ML is that the surface of the insulating layer (such as the interlayer insulating layer ILD) is generally planarized before the metal interconnection layer ML is placed, and the planar surface is easier to manufacture the current measurement resistor (resistor strip).

[0050] Figure 5 Another circuit schematic diagram of the cascode power device provided by the embodiments of the present application is provided. As shown in Figure 5 According to some embodiments of the present application, the source S2 of the depletion-mode switching device Q2 is optionally led out as a first connection terminal LD1, and the drain D1 of the low-voltage switching device Q1 is optionally led out as a second connection terminal LD2. The current measurement resistor Rs can be a discrete device, with a first end electrically connected to the first connection terminal LD1 and a second end electrically connected to the second connection terminal LD2.

[0051] In this way, the current measurement resistor Rs is connected to the circuit by packaging as a discrete device, which is advantageous for simplifying the manufacturing process. Moreover, the distance between the current measurement resistor Rs and the depletion-mode switching device Q2 can be more flexible, such as a distance greater than 200 μm, so as to effectively reduce the influence of heat conduction on the resistance value of the current measurement resistor Rs, effectively prevent the resistance value from drifting due to temperature rise, and further improve the accuracy of current detection.

[0052] According to some embodiments of the present application, the resistance value of the current measurement resistor Rs can range from 0.1 mΩ to 200 mΩ.

[0053] In this way, the power loss of the current measurement resistor Rs can be minimized while ensuring that the voltage across the current measurement resistor Rs can be reliably detected. In addition, the voltage drop (such as millivolts) generated by the current measurement resistor Rs can be much smaller than the threshold voltage |Vth| of the depletion-mode switching device (such as greater than 5V), so the power loss of the current measurement resistor can be negligible, and the device operating state is hardly affected, which does not significantly change the current distribution or switching characteristics of the cascode power device, and ensures that the device can normally turn on and off.

[0054] As mentioned above, the current detection circuit 20 can be used to measure the voltage difference across the current-measuring resistor Rs, and obtain the operating current value of the common-source cascode power device 10 based on the voltage difference across the current-measuring resistor Rs and the resistance value of the current-measuring resistor Rs. The circuit structure of the current detection circuit 20 can be flexibly adjusted according to actual conditions, and this application does not limit it in this regard.

[0055] Figure 6 This is a circuit diagram of a common-source cascode power device and current detection circuit provided in an embodiment of this application. Figure 6 As shown, for example, in some embodiments, the current detection circuit 20 may include a first voltage acquisition module 210 and a current calculation module 220. The first voltage acquisition module 210 may be electrically connected to the first terminal a1 and the second terminal a2 of the current measuring resistor Rs, respectively, for measuring the voltage difference across the current measuring resistor Rs, i.e., V2-V1.

[0056] The current calculation module 220 can be electrically connected to the first voltage acquisition module 210. It is used to calculate the current flowing through the current measuring resistor Rs based on the voltage difference across the current measuring resistor Rs and the resistance value of the current measuring resistor Rs, thereby obtaining the operating current value of the common source cascode power device 10. The current calculation expression is described above and will not be repeated here.

[0057] In some specific embodiments, the first voltage acquisition module 210 may optionally include a first differential amplifier. The first input terminal of the first differential amplifier may be electrically connected to the first terminal a1 of the current-measuring resistor Rs, and the second input terminal of the first differential amplifier may be electrically connected to the second terminal a2 of the current-measuring resistor Rs. The first differential amplifier may be used to measure the voltage difference across the current-measuring resistor.

[0058] like Figure 6 As shown, the current calculation module 220 may include an analog-to-digital converter (ADC) unit 221 and a processor 222. The ADC unit 221 is electrically connected between the output of the first differential amplifier and the input of the processor 222. The ADC unit 221 can be used to convert the voltage difference across the current-measuring resistor Rs from an analog signal to a digital signal. The processor 222 can be used to calculate the current flowing through the current-measuring resistor Rs based on the voltage difference across the current-measuring resistor Rs converted to a digital signal and the resistance value of the current-measuring resistor Rs, thereby obtaining the operating current value of the cascode power device 10.

[0059] Figure 7 This is another circuit diagram of a common-source, common-gate power device provided in an embodiment of this application. For example... Figure 7As shown, according to some embodiments of the present application, the depletion mode switching device Q2 can optionally adopt a multi-finger structure. The depletion mode switching device Q2 can include at least a first depletion mode switching device Q21 and a second depletion mode switching device Q22 in parallel.

[0060] The gate G21 of the first depletion mode switching device Q21 and the gate G22 of the second depletion mode switching device Q22 can both be electrically connected to the source S1 of the low voltage switching device Q1, and the source S21 of the first depletion mode switching device Q21 and the source S22 of the second depletion mode switching device Q22 can both be electrically connected to the drain D1 of the low voltage switching device Q1.

[0061] The first depletion mode switching device Q21 can be located in the main current path TZ of the cascode power device 10, and the second depletion mode switching device Q22 can be located in the first detection path TJ1 of the cascode power device 10. Thus, for example, when the depletion mode switching device Q2 is a d-mode GaN HEMT, the first depletion mode switching device Q21 can also be referred to as a Power HEMT, and the second depletion mode switching device Q22 can also be referred to as a Sense HEMT. The gate G21 of the first depletion mode switching device Q21 and the gate G22 of the second depletion mode switching device Q22 share the same control signal, and this arrangement can ensure that the current in the second depletion mode switching device Q22 accurately reflects the current in the first depletion mode switching device Q21.

[0062] The current sensing resistor Rs can be located in the first detection path TJ1 and electrically connected between the source S22 of the second depletion mode switching device Q22 and the drain D1 of the low voltage switching device Q1.

[0063] In some specific embodiments, the on-resistance (i.e. the source-drain resistance value) of the second depletion mode switching device Q22 can optionally be more than 100 times the on-resistance (i.e. the source-drain resistance value) of the first depletion mode switching device Q21. In this way, the main current can pass through the low-resistance path TZ of the first depletion mode switching device Q21, and only a small proportion of the current is shunted to the first detection path TJ1, thereby reducing the loss of the main path.

[0064] For example, assuming the on-resistance of the second depletion-mode switching device Q22 is 100 times that of the first depletion-mode switching device Q21, the first detection path current is only 1% of the total current. Assuming the total current is 100 A, the first detection path only shunts 1 A, and the power loss is only 0.1 W when the shunt resistor Rs=100 mΩ. In this way, compared to directly connecting the shunt resistor Rs in series with the main path, the power loss of the shunt resistor Rs can be further reduced. In addition, the multi-finger gate structure can disperse the heat source, which helps to avoid local overheating. The first detection path can be away from the hot spot of the main path (such as a distance > 200 μm), thereby reducing the temperature drift of the shunt resistor Rs.

[0065] When the shunt resistor Rs is located in the first detection path TJ1, the current (I_sense) of the first detection path and the main current (I_main) are in a fixed ratio (such as 1:100). Therefore, by measuring the voltage drop on the shunt resistor Rs, the main current, i.e., the working current value of the cascode power device, can be accurately inferred. The calculation expression of the main current is as follows: (2) wherein, R21 represents the on-resistance of the first depletion-mode switching device Q21, R22 represents the on-resistance of the second depletion-mode switching device Q22.

[0066] Figure 8 Another circuit schematic diagram of the cascode power device provided by the embodiments of the present application is provided. As shown in Figure 8 According to some embodiments of the present application, the depletion-mode switching device Q2 can also optionally include a third depletion-mode switching device Q23. The third depletion-mode switching device Q23 is in parallel with the first depletion-mode switching device Q21 and the second depletion-mode switching device Q22. The first depletion-mode switching device Q21, the second depletion-mode switching device Q22, and the third depletion-mode switching device Q23 together form a multi-finger gate structure.

[0067] Correspondingly, the cascode power device 10 can also include a temperature-sensitive resistor Rt, and the temperature-sensitive resistor Rt and the third depletion-mode switching device Q23 can be located in the second detection path TJ2 of the cascode power device 10. Specifically, the temperature-sensitive resistor Rt can be electrically connected between the source S23 of the third depletion-mode switching device Q23 and the drain D1 of the low-voltage switching device Q1.

[0068] The first end b1 of the temperature-sensitive resistor Rt and the second end b2 of the temperature-sensitive resistor Rt can be configured to be connected to a current detection circuit (such as a current mirror circuit) and a voltage detection circuit (such as a voltage mirror circuit) respectively. Figure 8(Not shown) An electrical connection is made to allow the current detection circuit to measure the voltage difference across the thermistor Rt. Based on the mapping relationship between the temperature of the thermistor and the voltage difference, and the voltage difference across the thermistor, the current temperature T is calculated. The expression for calculating the current temperature T is: T = f(V3 - V1). Where V1 represents the voltage at the first terminal b1 of the thermistor Rt, V3 represents the voltage at the second terminal b2 of the thermistor Rt, and f represents a predetermined conversion coefficient.

[0069] The current detection circuit can also be used to correct the resistance value of the current sensing resistor Rs based on the current temperature; and to calculate the current value flowing through the current sensing resistor Rs based on the voltage difference across the current sensing resistor Rs and the corrected resistance value of the current sensing resistor Rs, thereby obtaining the operating current value of the temperature-compensated common-source cascode power device.

[0070] In this way, by adjusting the resistance value of the current measuring resistor in real time through temperature compensation, the influence of temperature drift can be reduced, and the accuracy of current detection can be further improved.

[0071] Figure 9 This is another circuit diagram of a common-source, common-gate power device provided in an embodiment of this application. For example... Figure 9 As shown, with Figure 8 Unlike the illustrated embodiment, according to other embodiments of this application, optionally, the temperature-sensitive resistor Rt can also be located in the first detection path TJ1 and electrically connected between the source S22 of the second depletion-type switching device Q22 and the drain D1 of the low-voltage switching device Q1. The temperature-sensitive resistor Rt can be connected in series or in parallel with the current-measuring resistor Rs. Figure 9 The example is illustrated by connecting a temperature-sensitive resistor Rt and a current-measuring resistor Rs in series.

[0072] and Figure 8 Similarly, in the illustrated embodiment, the first terminal b1 and the second terminal b2 of the thermistor Rt can be configured to interact with the current detection circuit ( Figure 9 An electrical connection (not shown) is established to allow the current detection circuit to measure the voltage difference across the thermistor. Based on the mapping relationship between the thermistor's temperature and the voltage difference, and the voltage difference across the thermistor, the current is calculated. Based on the current temperature, the resistance value of the current-sensing resistor is corrected. Finally, based on the voltage difference across the current-sensing resistor and the corrected resistance value, the current flowing through the current-sensing resistor is calculated, yielding the operating current value of the cascode power device. Thus, by adjusting the resistance value of the current-sensing resistor in real time through temperature compensation, the influence of temperature drift can be reduced, further improving the accuracy of current detection.

[0073] According to some embodiments of the present application, optionally, the temperature-sensitive resistor Rt and the current-sensing resistor Rs can be integrated on the same chip as the depletion-mode switching device Q2. The distance between the temperature-sensitive resistor Rt and the depletion-mode switching device Q2 can be less than the distance between the current-sensing resistor Rs and the depletion-mode switching device Q2 on the horizontal pitch inside the chip. For example, the distance between the temperature-sensitive resistor Rt and the depletion-mode switching device Q2 can be less than 200 μm, and the distance between the current-sensing resistor Rs and the depletion-mode switching device Q2 can be greater than 200 μm. In this way, the temperature-sensitive resistor Rt is close to the heat source, and the current-sensing resistor Rs is away from the heat source, which can improve the accuracy of temperature sampling while reducing the temperature drift of the current-sensing resistor Rs, thereby facilitating the improvement of the accuracy of current detection.

[0074] In addition, the integration of the temperature-sensitive resistor Rt, the current-sensing resistor Rs, and the depletion-mode switching device Q2 can reduce the parasitic parameters (such as parasitic inductance or parasitic capacitance) of discrete components and their wiring, and improve the high-frequency response speed of the device. Moreover, the temperature-sensitive resistor Rt and the current-sensing resistor Rs can be directly manufactured by semiconductor processes (such as photolithography and deposition), which can save the packaging and assembly costs of external discrete resistors.

[0075] Of course, in other embodiments, the temperature-sensitive resistor Rt can also be a discrete component (or a discrete device) connected between the source S22 of the second depletion-mode switching device Q22 and the drain D1 of the low-voltage switching device Q1, or connected between the source S23 of the third depletion-mode switching device Q23 and the drain D1 of the low-voltage switching device Q1, which is not limited in the present application.

[0076] According to some embodiments of the present application, optionally, the device types of the low-voltage switching device Q1 and the depletion-mode switching device Q2 can be flexibly selected according to actual conditions, which is not limited in the present application. For example, in some examples, the low-voltage switching device Q1 includes but is not limited to a silicon-based N-type field effect transistor (Si N-MOSFET). The silicon-based N-type field effect transistor has the advantages of high input impedance, low conduction loss, and fast switching. The depletion-mode switching device Q2 includes but is not limited to a depletion-mode gallium nitride field effect transistor (d-mode GaN HEMT) and a depletion-mode junction field effect transistor (d-mode JFET).

[0077] Based on the common-source common-gate power device 10 provided in the above embodiments, correspondingly, the present application also provides a current detection method of a common-source common-gate power device. The current detection method can be used for current detection of the common-source common-gate power device 10 provided in the above embodiments.

[0078] As Figure 1As shown, the cascode power device 10 can include a low-voltage switch device Q1, a depletion-mode switch device Q2, and a current-sensing resistor Rs. The gate G2 of the depletion-mode switch device Q2 can be electrically connected to the source S1 of the low-voltage switch device Q1, and the source S2 of the depletion-mode switch device Q2 can be electrically connected to the drain D1 of the low-voltage switch device Q1.

[0079] The current-sensing resistor Rs can be electrically connected to the middle node of the cascode structure, i.e., between the source S2 of the depletion-mode switch device Q2 and the drain D1 of the low-voltage switch device Q1. In this case, the voltage drop of the current-sensing resistor Rs can be less than the threshold voltage |Vth| of the depletion-mode switch device Q2.

[0080] Figure 10 A flowchart of a current detection method of a cascode power device provided by an embodiment of the present application is shown in FIG. 1. As shown, the current detection method can include the following steps: Figure 10 S101: measuring the voltage difference across the current-sensing resistor; S102: calculating the current value flowing through the current-sensing resistor according to the voltage difference across the current-sensing resistor and the resistance value of the current-sensing resistor, to obtain the working current value of the cascode power device.

[0081] The specific processes of S101 and S102 have been described in detail above, and will not be described here again.

[0082] The current detection method of the cascode power device provided by the embodiment of the present application can connect a current-sensing resistor in series between the source of the depletion-mode switch device and the drain of the low-voltage switch device of the cascode power device, and directly calculate the working current of the cascode power device through the voltage output of the current-sensing resistor, without the need for an additional dynamic calibration circuit, thereby reducing the complexity of the peripheral circuit and saving the detection cost. At the same time, this circuit structure / way can be compatible with the existing driving logic, without the need for changing the driving logic of the cascode power device. In addition, the voltage drop generated by the current-sensing resistor is less than the threshold voltage of the depletion-mode switch device, so the power loss of the current-sensing resistor can be ignored, and the working state of the device is slightly affected, which will not significantly change the current distribution or switching characteristics of the cascode power device, and can ensure that the device can normally turn on and off.

[0083] As shown in FIG. 2, according to some embodiments of the present application, the depletion-mode switch device Q2 can optionally adopt a multi-finger structure. The depletion-mode switch device Q2 can include a first depletion-mode switch device Q21, a second depletion-mode switch device Q22, and a third depletion-mode switch device Q23 connected in parallel. Figure 8

[0084] ​​The gates of the first depletion-type switching device Q21, the second depletion-type switching device Q22, and the third depletion-type switching device Q23 can all be electrically connected to the source of the low-voltage switching device Q1. The sources of the first depletion-type switching device Q21, the second depletion-type switching device Q22, and the third depletion-type switching device Q23 can all be electrically connected to the drain of the low-voltage switching device Q1.

[0085] The first depletion-type switching device Q21 can be located in the main current path TZ of the cascode power device 10. The second depletion-type switching device Q22 and the current-sensing resistor Rs can be located in the first detection path TJ1 of the cascode power device 10, and the current-sensing resistor Rs is electrically connected between the source of the second depletion-type switching device Q22 and the drain of the low-voltage switching device Q1. The third depletion-type switching device Q23 and the thermistor Rt can be located in the second detection path TJ2 of the cascode power device 10, and the thermistor Rt is electrically connected between the source of the third depletion-type switching device Q23 and the drain of the low-voltage switching device Q1.

[0086] like Figure 9 As shown, according to some other embodiments of this application, optionally, the temperature-sensitive resistor Rt may also be located in the first detection path TJ1 and electrically connected between the source S22 of the second depletion-type switching device Q22 and the drain D1 of the low-voltage switching device Q1. The temperature-sensitive resistor Rt may be connected in series or in parallel with the current-measuring resistor Rs.

[0087] Combination Figure 8 or Figure 9 The illustrated embodiment, correspondingly, as Figure 11 As shown, the current detection method may also include the following steps: S201: Measures the voltage difference across the thermistor; S202: Calculate the current temperature based on the mapping relationship between the temperature and voltage difference of the thermistor and the voltage difference across the thermistor; S203: Correct the resistance value of the current measuring resistor based on the current temperature.

[0088] Accordingly, S102: Based on the voltage difference across the current-measuring resistor and the resistance value of the current-measuring resistor, calculate the current flowing through the current-measuring resistor to obtain the operating current value of the common-source cascode power device. This may include the following steps: Based on the voltage difference across the current-measuring resistor and the corrected resistance value of the current-measuring resistor, the current flowing through the current-measuring resistor is calculated, and the operating current value of the common-source cascode power device is obtained.

[0089] The specific process of the above steps has been described in detail above and will not be repeated here.

[0090] Thus, by adjusting the resistance value of the current detection resistor in real time through temperature compensation, the temperature drift can be reduced, and the current detection accuracy can be further improved.

[0091] It should be understood that the specific structure and cross-sectional structure of the circuit provided by the drawings of the embodiments of the present application are only some examples and are not intended to limit the present application. In addition, the above-mentioned various embodiments provided by the present application can be combined with each other without contradiction.

[0092] It should be clear that each embodiment in the present specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other, and each embodiment mainly describes the difference from other embodiments. According to the above-described embodiments of the present application, these embodiments do not describe all the details and do not limit the present application to the specific embodiments described. Obviously, according to the above description, many modifications and changes can be made. The present specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well utilize the present application and make modifications and uses on the basis of the present application. The present application is limited by the claims and their entire scope and equivalents.

[0093] Those skilled in the art should understand that the above embodiments are exemplary but not limiting. Different technical features appearing in different embodiments can be combined to achieve beneficial effects. Those skilled in the art should understand and implement other changed embodiments of the disclosed embodiments based on the drawings, the specification and the claims. In the claims, the term "comprising" does not exclude other structures; the number of "one" does not exclude multiple; the terms "first", "second" are used to mark the name and not to represent any specific order. Any reference signs in the claims should not be understood as limiting the scope of protection. The fact that certain technical features appear in different dependent claims does not mean that these technical features cannot be combined to achieve beneficial effects.

Claims

1. A cascode power device, characterized by The common-source common-gate power device comprises a low-voltage switch device, a depletion-mode switch device, and a current-measuring resistor, the gate of the depletion-mode switch device is electrically connected with the source of the low-voltage switch device, and the source of the depletion-mode switch device is electrically connected with the drain of the low-voltage switch device; the current-measuring resistor is electrically connected between the source of the depletion-mode switch device and the drain of the low-voltage switch device, and the voltage drop of the current-measuring resistor is less than the threshold voltage of the depletion-mode switch device. The first end of the current-measuring resistor and the second end of the current-measuring resistor are configured to be electrically connected with a current detection circuit, so that the current detection circuit measures the voltage difference across the current-measuring resistor, and calculates the current value flowing through the current-measuring resistor according to the voltage difference across the current-measuring resistor and the resistance value of the current-measuring resistor, to obtain the working current value of the common-source common-gate power device.

2. The cascode power device of claim 1, wherein, The absolute value of the temperature drift coefficient of the material of the current-measuring resistor is less than 200 ppm / ℃.

3. The cascode power device of claim 1, wherein, The material of the current-measuring resistor comprises titanium nitride or tantalum nitride.

4. The cascode power device of claim 1, wherein, The current-measuring resistor and the depletion-mode switch device are integrated on the same chip, and the distance between the current-measuring resistor and the depletion-mode switch device is greater than 200 μm in the horizontal distance inside the chip.

5. The cascode power device of claim 4, wherein, The current-measuring resistor is arranged on the metal interconnection layer of the depletion-mode switch device and is electrically connected with the source of the depletion-mode switch device through a wire and / or a via.

6. The cascode power device of claim 1, wherein, The source of the depletion-mode switch device is led out as a first connection terminal, the drain of the low-voltage switch device is led out as a second connection terminal, and the current-measuring resistor is electrically connected with the first connection terminal at the first end and is electrically connected with the second connection terminal at the second end.

7. The cascode power device of claim 1, wherein, The resistance value of the current-measuring resistor ranges from 0.1 mΩ to 200 mΩ.

8. The cascode power device of claim 1, wherein, The depletion-mode switch device adopts a multi-finger gate structure, and at least comprises a first depletion-mode switch device and a second depletion-mode switch device in parallel, the gate of the first depletion-mode switch device and the gate of the second depletion-mode switch device are electrically connected with the source of the low-voltage switch device, and the source of the first depletion-mode switch device and the source of the second depletion-mode switch device are electrically connected with the drain of the low-voltage switch device. The first depletion-mode switch device is located in the main current path of the common-source common-gate power device, and the second depletion-mode switch device is located in the first detection path of the common-source common-gate power device. The current-measuring resistor is located in the first detection path and is electrically connected between the source of the second depletion-mode switch device and the drain of the low-voltage switch device.

9. The cascode power device of claim 8, wherein, The source-drain resistance value of the second depletion-mode switch device is more than 100 times of the source-drain resistance value of the first depletion-mode switch device.

10. The cascode power device of claim 8, wherein, The depletion-mode switch device further comprises a third depletion-mode switch device, and the third depletion-mode switch device is in parallel with the first depletion-mode switch device and the second depletion-mode switch device. The common-source common-gate power device further comprises: a temperature-sensitive resistor, the temperature-sensitive resistor and the third depletion-mode switch device are located in the second detection path of the common-source common-gate power device, and the temperature-sensitive resistor is electrically connected between the source of the third depletion-mode switch device and the drain of the low-voltage switch device. The first end of the temperature-sensitive resistor and the second end of the temperature-sensitive resistor are configured to be electrically connected with the current detection circuit, so that the current detection circuit measures a voltage difference between the temperature-sensitive resistor; a current temperature is calculated according to a mapping relationship between a temperature of the temperature-sensitive resistor and the voltage difference and the voltage difference between the temperature-sensitive resistor; a resistance value of the current measurement resistor is corrected based on the current temperature; and a current value flowing through the current measurement resistor is calculated according to the voltage difference between the current measurement resistor and the corrected resistance value of the current measurement resistor, so as to obtain the working current value of the cascode power device.

11. The cascode power device of claim 8, wherein, The current detection circuit further comprises: A temperature-sensitive resistor is located in the first detection path and is electrically connected between the source of the second depletion-mode switching device and the drain of the low-voltage switching device, and the temperature-sensitive resistor is in series or parallel with the current measurement resistor; The first end of the temperature-sensitive resistor and the second end of the temperature-sensitive resistor are configured to be electrically connected with the current detection circuit, so that the current detection circuit measures a voltage difference between the temperature-sensitive resistor; a current temperature is calculated according to a mapping relationship between a temperature of the temperature-sensitive resistor and the voltage difference and the voltage difference between the temperature-sensitive resistor; a resistance value of the current measurement resistor is corrected based on the current temperature; and a current value flowing through the current measurement resistor is calculated according to the voltage difference between the current measurement resistor and the corrected resistance value of the current measurement resistor, so as to obtain the working current value of the cascode power device.

12. The cascode power device of claim 10 or 11, wherein, The temperature-sensitive resistor, the current measurement resistor and the depletion-mode switching device are integrated on the same chip, and the distance between the temperature-sensitive resistor and the depletion-mode switching device is less than the distance between the current measurement resistor and the depletion-mode switching device in the horizontal distance inside the chip.

13. The cascode power device of claim 1, wherein, The low-voltage switching device comprises a silicon-based N-type field effect transistor, and the depletion-mode switching device comprises a depletion-mode gallium nitride field effect transistor or a depletion-mode junction field effect transistor.

14. A current sensing method for a cascode power device, characterized by, The cascode power device comprises a low-voltage switching device, a depletion-mode switching device and a current measurement resistor, the gate of the depletion-mode switching device is electrically connected with the source of the low-voltage switching device, and the source of the depletion-mode switching device is electrically connected with the drain of the low-voltage switching device; The current measurement resistor is electrically connected between the source of the depletion-mode switching device and the drain of the low-voltage switching device, and the voltage drop of the current measurement resistor is less than the threshold voltage of the depletion-mode switching device; The current detection method comprises: Measuring a voltage difference between the current measurement resistor; According to the voltage difference between the current measurement resistor and the resistance value of the current measurement resistor, a current value flowing through the current measurement resistor is calculated, so as to obtain the working current value of the cascode power device.

15. The current detection method according to claim 14, wherein The depletion-mode switching device adopts a multi-finger gate structure, and the depletion-mode switching device comprises a first depletion-mode switching device, a second depletion-mode switching device and a third depletion-mode switching device in parallel, the gate of the first depletion-mode switching device, the gate of the second depletion-mode switching device and the gate of the third depletion-mode switching device are electrically connected with the source of the low-voltage switching device, and the source of the first depletion-mode switching device, the source of the second depletion-mode switching device and the source of the third depletion-mode switching device are electrically connected with the drain of the low-voltage switching device; The first depletion mode switch device is located in a main current path of the cascode power device, the second depletion mode switch device and the current sensing resistor are located in a first detection path of the cascode power device, and the current sensing resistor is electrically connected between a source of the second depletion mode switch device and a drain of the low-voltage switch device; the third depletion mode switch device and the temperature sensitive resistor are located in a second detection path of the cascode power device, and the temperature sensitive resistor is electrically connected between a source of the third depletion mode switch device and a drain of the low-voltage switch device; The current detection method further comprises: measuring a voltage difference across the temperature sensitive resistor; calculating a current value flowing through the current sensing resistor according to the voltage difference across the current sensing resistor and the resistance value of the current sensing resistor, to obtain the working current value of the cascode power device, comprising: calculating a current value flowing through the current sensing resistor according to the voltage difference across the current sensing resistor and the resistance value of the current sensing resistor, to obtain the working current value of the cascode power device. ​ ​

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