Cascode cascade type switching device with voltage dividing and current limiting structure

Abstract

The invention discloses a cascode cascade type switching device with a voltage dividing and current limiting structure. The cascode cascade type switching device comprises a grid end, a source end, a drain end, a low-voltage enhanced field effect transistor, a high-voltage depletion field effect transistor and the current limiting structure. The current-limiting structure comprises a plurality of current-limiting depletion type field-effect tubes and a current-limiting resistor, and when the switching device is turned on, the grid electrode and source electrode voltage of the current-limiting depletion type field-effect tubes can limit the source electrode and drain electrode voltage of the adjacent current-limiting depletion type field-effect tubes. The breakdown caused by overlarge voltage of the source electrode and the drain electrode of the current-limiting depletion type field effect transistor is avoided, and the working reliability of the current-limiting depletion type field effect transistor and the whole switching device is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a common-source and common-gate cascade type switch device with a voltage-dividing and current-limiting structure. Background Art

[0002] The common-source and common-gate cascade switching device is composed of a low-voltage enhancement-type field-effect transistor and a high-voltage depletion-type field-effect transistor in a common-source and common-gate manner. Figure 1 It is a common-source and common-gate cascade switching device with a current limiting structure, in which the drain of the high-voltage depletion-type field effect transistor 15 is the drain 13 of the switching device, the gate of the low-voltage enhancement-type field effect transistor 14 is the gate 11 of the switching device, and the source of the low-voltage enhancement-type field effect transistor 14 is the source 12 of the switching device, thereby finally realizing an enhanced function.

[0003] Figure 1 The common-source and common-gate cascade switching device also has a current-limiting depletion-type field effect transistor 16 as a current-limiting structure between the source of the low-voltage enhancement-type field effect transistor 14 and the gate of the high-voltage depletion-type field effect transistor 15. The current-limiting structure can effectively control the size of the turn-on current when the gate voltage of the high-voltage depletion-type field effect transistor 15 changes, thereby stably controlling the turn-on speed of the switching device and improving the control capability of the voltage stress of the secondary-side synchronous tube in the circuit.

[0004] However, when a smaller turn-on current or turn-on speed is required, it is necessary to reduce the absolute value of the threshold voltage of the current limiting depletion type field effect transistor 16, such as reducing the gate dielectric thickness of the current limiting depletion type field effect transistor 16; this will reduce the reliability of the current limiting depletion type field effect transistor 16, and thus affect the reliability of the entire switching device.

[0005] Therefore, it is necessary to provide a common-source and common-gate cascade switch device with a current limiting structure and higher reliability. Summary of the invention

[0006] The present invention aims to solve the above-mentioned problem. The present invention provides a common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure and high reliability.

[0007] The common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure comprises: A gate terminal, used to receive a voltage signal from a driver; A source terminal and a drain terminal, used to form a switch channel of an external load, two semiconductor channels are arranged between the source terminal and the drain terminal; A low-voltage enhancement type field effect transistor, wherein the gate of the low-voltage enhancement type field effect transistor serves as the gate terminal of the switching device and is used to receive the voltage signal of the driver; the drain of the low-voltage enhancement type field effect transistor is connected to the source of the high-voltage depletion type field effect transistor, the source of the low-voltage enhancement type field effect transistor serves as the source terminal of the switching device, and the source of the low-voltage enhancement type field effect transistor is connected to the gate of the high-voltage depletion type field effect transistor through a current limiting structure; The high-voltage depletion-type field effect transistor, the drain of the high-voltage depletion-type field effect transistor serves as the drain end of the switching device; The current limiting structure includes multiple current limiting depletion type field effect transistors and current limiting resistors, the gate of the first current limiting depletion type field effect transistor is connected to the gate of the high voltage depletion type field effect transistor, the source of the first current limiting depletion type field effect transistor is connected to the gate of the high voltage depletion type field effect transistor through the current limiting resistor, the gate of the nth current limiting depletion type field effect transistor is connected to the source of the n-1th current limiting depletion type field effect transistor, the source of the nth current limiting depletion type field effect transistor is connected to the drain of the n-1th current limiting depletion type field effect transistor, and the drain of the last current limiting depletion type field effect transistor is connected to the source of the low voltage enhancement type field effect transistor, wherein n is a positive integer greater than 1.

[0008] In the switch device of this embodiment, the threshold voltage of the current-limiting depletion-type field effect transistor is greater than the threshold voltage of the high-voltage depletion-type field effect transistor.

[0009] In the switch device of this embodiment, the threshold voltages of the plurality of current-limiting depletion-type field effect transistors are equal.

[0010] In the switching device of this embodiment, when the switching device is turned on, the gate voltage of the high-voltage depletion-type field effect transistor increases; when the gate voltage of the high-voltage depletion-type field effect transistor is less than the threshold voltage of the current-limiting depletion-type field effect transistor, the gate current of the high-voltage depletion-type field effect transistor is a constant current value.

[0011] In the switch device of this embodiment, the constant current value is determined by the threshold voltage of the current limiting depletion type field effect transistor, the gate-source internal resistance of the current limiting depletion type field effect transistor, and the current limiting resistor.

[0012] In the switch device of this embodiment, when the gate voltage of the high-voltage depletion-type field effect transistor is less than the threshold voltage of the current-limiting depletion-type field effect transistor, the gate-source voltage of the current-limiting depletion-type field effect transistor is equal to the threshold voltage, and the source-drain voltage of the nth current-limiting depletion-type field effect transistor is equal to the gate-source voltage of the n+1th current-limiting depletion-type field effect transistor, wherein n is a positive integer greater than 0; The source-drain voltage of the last current-limiting depletion-type field effect transistor is determined by the gate voltage of the high-voltage depletion-type field effect transistor, the threshold voltage of the current-limiting depletion-type field effect transistor, and the number of the current-limiting depletion-type field effect transistors.

[0013] In the switching device of this embodiment, when the switching device is turned on, the gate voltage of the high-voltage depletion-type field effect transistor increases; when the gate voltage of the high-voltage depletion-type field effect transistor is greater than or equal to the threshold voltage of the current limiting depletion-type field effect transistor, the current limiting depletion-type field effect transistor is in a low resistance state.

[0014] In the switching device of this embodiment, when the switching device is turned off, the gate voltage of the high-voltage depletion-type field effect transistor is greater than or equal to the threshold voltage of the current-limiting depletion-type field effect transistor, and the current-limiting depletion-type field effect transistor is in a low resistance state.

[0015] In the switching device of this embodiment, the structures of the current limiting depletion-type field effect transistor and the high-voltage depletion-type field effect transistor include but are not limited to metal-oxide semiconductor field effect transistors, metal-insulator-semiconductor field effect transistors, metal semiconductor field effect transistors, and high electron mobility transistors.

[0016] In the switch device of this embodiment, the materials of the current limiting depletion-mode field effect transistor and the high-voltage depletion-mode field effect transistor include but are not limited to gallium nitride, silicon carbide, and silicon.

[0017] Compared with the prior art, the common source and common gate cascade switch device with a voltage-dividing current-limiting structure of the present invention is provided with a plurality of current-limiting depletion-type field effect tubes and current-limiting resistors as the current-limiting structure. When the current-limiting depletion-type field effect tube is turned on, the gate-source voltage (threshold voltage) of the current-limiting depletion-type field effect tube can limit the source-drain voltage of the adjacent current-limiting depletion-type field effect tube, thereby avoiding the breakdown caused by the excessive source-drain voltage of the current-limiting depletion-type field effect tube, thereby affecting the reliability of the current-limiting depletion-type field effect tube. In this way, the user can reduce the gate current of the high-voltage depletion-type field effect tube by reducing the threshold voltage of the current-limiting depletion-type field effect tube, and will not affect the working reliability of the current-limiting depletion-type field effect tube and the entire switch device, effectively solving the technical problem of poor working reliability of the existing common source and common gate cascade switch device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a common-source and common-gate cascade type switch device with a current limiting structure; Figure 2 It is a structural schematic diagram of a common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure of the present invention; Figure 3It is a schematic diagram of the change curves of the gate voltage Vg_HEMT1 and the gate current Ig_HEMT1 of the high-voltage depletion-type field effect transistor in the common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0020] The present invention discloses a common source and common gate cascade type switch device with a voltage dividing and current limiting structure, please refer to Figure 2 , Figure 2 It is a structural schematic diagram of a common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure of the present invention.

[0021] The switch device 20 includes a gate terminal 21, a source terminal 22, a drain terminal 23, a low voltage enhancement type field effect transistor 24, a high voltage depletion type field effect transistor 25 and a current limiting structure 26. The gate terminal 21 is used to receive a voltage signal from a driver; the source terminal 22 and the drain terminal 23 are used to form a switch channel for an external load, and two semiconductor channels (a low voltage enhancement type field effect transistor 24 and a high voltage depletion type field effect transistor 25) are arranged between the source terminal 22 and the drain terminal 23.

[0022] The gate of the low-voltage enhancement type field effect transistor 24 serves as the gate terminal 21 of the switching device 20, and is used to receive the voltage signal of the driver; the drain of the low-voltage enhancement type field effect transistor 24 is connected to the source of the high-voltage depletion type field effect transistor 25, and the source of the low-voltage enhancement type field effect transistor 24 serves as the source terminal 22 of the switching device 20, and the source of the low-voltage enhancement type field effect transistor 24 is connected to the gate of the high-voltage depletion type field effect transistor 25 through the current limiting structure 26; the drain of the high-voltage depletion type field effect transistor 25 serves as the drain terminal 23 of the switching device 20.

[0023] The current limiting structure 26 includes multiple current limiting depletion type field effect transistors and current limiting resistors 262, the gate of the first current limiting depletion type field effect transistor 2611 is connected to the gate of the high voltage depletion type field effect transistor, the source of the first current limiting depletion type field effect transistor 2611 is connected to the gate of the high voltage depletion type field effect transistor through the current limiting resistor 262, the gate of the nth current limiting depletion type field effect transistor is connected to the source of the n-1th current limiting depletion type field effect transistor, the source of the nth current limiting depletion type field effect transistor is connected to the drain of the n-1th current limiting depletion type field effect transistor, and the drain of the last current limiting depletion type field effect transistor 261n is connected to the source of the low voltage enhancement type field effect transistor 24, where n is a positive integer greater than 1. For example, the gate of the second current limiting depletion type field effect transistor 2612 is connected to the source of the first current limiting depletion type field effect transistor 2611, the source of the second current limiting depletion type field effect transistor 2612 is connected to the drain of the first current limiting depletion type field effect transistor 2611, the gate of the last current limiting depletion type field effect transistor 261n is connected to the source of the second to last current limiting depletion type field effect transistor 2613, the source of the last current limiting depletion type field effect transistor 261n is connected to the drain of the second to last current limiting depletion type field effect transistor 2613, and the drain of the last current limiting depletion type field effect transistor 261n is connected to the source of the low voltage enhancement type field effect transistor 24.

[0024] The threshold voltage of the current limiting depletion type field effect transistor in the switch device of the present invention 20 should be greater than the threshold voltage Vth_HEMT1 of the high voltage depletion type field effect transistor 25. The threshold voltage here refers to the maximum gate voltage of the current limiting depletion type field effect transistor in a high resistance state (this voltage can be adjusted within a certain range).

[0025] Please refer to Figure 1 For example, by reducing the threshold voltage (source-gate threshold voltage) of the current-limiting depletion-type field effect transistor 16, the turn-on current of the switching device can be reduced, and the gate current of the high-voltage depletion-type field effect transistor 15 can be equal to Vth_HEMT2 / R_HEMT2, where Vth_HEMT2 is the threshold voltage of the current-limiting depletion-type field effect transistor, and R_HEMT2 is the gate-source internal resistance of the current-limiting depletion-type field effect transistor.

[0026] However, when the absolute value of the gate voltage of the high-voltage depletion-type field effect transistor 15 is too high, the source-drain voltage of the current-limiting depletion-type field effect transistor 16 will be too large, which may cause the current-limiting depletion-type field effect transistor to break down and affect the working stability of the current-limiting depletion-type field effect transistor and the entire switching device.

[0027] In this embodiment, the threshold voltages of the plurality of current limiting depletion type field effect transistors are equal, so that when the switch device 20 starts to turn on, the gate voltage Vg_HEMT1 of the high voltage depletion type field effect transistor 25 increases, but the gate voltage Vg_HEMT1 of the high voltage depletion type field effect transistor 25 is less than the threshold voltage of the current limiting depletion type field effect transistor. Therefore, when the high voltage depletion type field effect transistor 25 is turned on, each current limiting depletion type field effect transistor is still in a high resistance state, that is, the source gate voltage of each current limiting depletion type field effect transistor is the threshold voltage. At this time, the gate current of the high-voltage depletion-type field effect transistor is a constant current value, which is determined by the threshold voltage of the current-limiting depletion-type field effect transistor, the gate-source internal resistance of the current-limiting depletion-type field effect transistor, and the current-limiting resistor 262. The gate current of the high-voltage depletion-type field effect transistor 25 can be equal to Vth_HEMT2 / (R_HEMT2+Rg), where Vth_HEMT2 is the threshold voltage of the current-limiting depletion-type field effect transistor, R_HEMT2 is the gate-source internal resistance of the current-limiting depletion-type field effect transistor, and Rg is the resistance value of the current-limiting resistor 262.

[0028] Since the source-drain voltage of the nth current-limiting depletion-type field effect transistor is equal to the gate-source voltage of the n+1th current-limiting depletion-type field effect transistor, the source-drain voltages of the other current-limiting depletion-type field effect transistors except the last current-limiting depletion-type field effect transistor are also threshold voltages. The source-drain voltage of the last current-limiting depletion-type field effect transistor is equal to the gate voltage of the high-voltage depletion-type field effect transistor minus the voltage of the current-limiting resistor 262 and the source-gate voltages of the other current-limiting depletion-type field effect transistors. If the switch device is provided with five current-limiting depletion-type field effect transistors, the source-drain voltage of the last current-limiting depletion-type field effect transistor is equal to the gate voltage of the high-voltage depletion-type field effect transistor minus the voltage of the current-limiting resistor 262 and the source-drain voltages of the four current-limiting depletion-type field effect transistors.

[0029] Therefore, Figure 1 The gate voltage of the high-voltage depletion-type field effect transistor when it is turned on is -20V. If the current limiting structure of a single current limiting depletion-type field effect transistor is adopted, a current limiting resistor is connected between the source of the single current limiting depletion-type field effect transistor and the gate of the high-voltage depletion-type field effect transistor, then the voltage division of the current limiting resistor is -2V, and the source-drain voltage of the current limiting depletion-type field effect transistor is -18V.

[0030] If adopted Figure 2After the current limiting structure of multiple current limiting depletion type field effect tubes in this embodiment, the source drain voltage of the last current limiting depletion type field effect tube can be determined by the gate voltage of the high voltage depletion type field effect tube, the threshold voltage of the current limiting depletion type field effect tube and the number of the current limiting depletion type field effect tubes. If five current limiting depletion type field effect tubes are provided, and the source gate threshold voltage of each current limiting depletion type field effect tube is -2v, then the voltage division of the current limiting resistor 262 is -2v, and the source drain voltage of the first four current limiting depletion type field effect tubes is also -2v, then the source drain voltage of the last current limiting depletion type field effect tube is -10v, and the absolute value of this voltage is relatively low, which can effectively prevent the last current limiting depletion type field effect tube from being broken down (it is difficult to withstand the source drain voltage of -18V), thereby affecting the reliability of the current limiting depletion type field effect tube.

[0031] Since the source-drain voltage of the current-limiting depletion-type field effect transistor can be effectively controlled, the gate current of the high-voltage depletion-type field effect transistor 25 can be adjusted by adjusting the threshold voltage of the current-limiting depletion-type field effect transistor, for example, by reducing the threshold voltage of the current-limiting depletion-type field effect transistor (without reducing the reliability of the current-limiting depletion-type field effect transistor) and increasing the number of current-limiting depletion-type field effect transistors at the same time (reducing the absolute value of the source-drain voltage of the last current-limiting depletion-type field effect transistor) to reduce the gate current of the high-voltage depletion-type field effect transistor 25.

[0032] During the process of turning on the switch device 20, the gate voltage Vg_HEMT1 of the high-voltage depletion-type field effect transistor 25 and the gate current Ig_HEMT1 of the high-voltage depletion-type field effect transistor 25 are shown in FIG. Figure 3 As shown in the figure, it can be seen that when the gate voltage Vg_HEMT1 of the high-voltage depletion-type field effect transistor 25 is less than the threshold voltage Vth_HEMT2 of the current-limiting depletion-type field effect transistor, the gate current Ig_HEMT1 (turn-on current) of the high-voltage depletion-type field effect transistor 25 is a certain value. At this time, the user can effectively control the turn-on speed of the switch device 20 through the gate current Ig_HEMT1.

[0033] The gate voltage Vg_HEMT1 of the high-voltage depletion-type field effect transistor 25 continues to increase under the discharge effect of the high-voltage depletion-type field effect transistor 25 (the absolute value of the gate voltage gradually approaches zero). When the gate voltage Vg_HEMT1 of the high-voltage depletion-type field effect transistor 25 is greater than or equal to the threshold voltage Vth_HEMT2 of the current-limiting depletion-type field effect transistor, the first current-limiting depletion-type field effect transistor 2611 is turned on, and the first current-limiting depletion-type field effect transistor 2611 is in a low resistance state. Subsequently, the gate voltages of other current-limiting depletion-type field effect transistors will also be greater than the threshold voltage Vth_HEMT2 of the current-limiting depletion-type field effect transistor. 2 (the source-drain voltage when the current limiting depletion-type field effect transistor is turned on is approximately equal to the gate-source voltage when the next current limiting depletion-type field effect transistor is turned on), the current limiting depletion-type field effect transistors are turned on in sequence according to the numbering order, such as the first current limiting depletion-type field effect transistor 2611, the second current limiting depletion-type field effect transistor 2612, the second to last current limiting depletion-type field effect transistor 2613 and the last current limiting depletion-type field effect transistor 261n are turned on in sequence, at which time the current limiting depletion-type field effect transistors are in a low resistance state, which effectively avoids the situation where some current limiting depletion-type field effect transistors are still in a high resistance state after some current limiting depletion-type field effect transistors are turned on.

[0034] When the switch device 20 is turned off, the gate voltage Vg_HEMT1 of the high-voltage depletion-type field effect transistor 25 is greater than or equal to the threshold voltage of all current-limiting depletion-type field effect transistors, and all current-limiting depletion-type field effect transistors are in a low resistance state. At this time, the current of the current-limiting depletion-type field effect transistor is the largest, thereby achieving a faster turn-off speed and reducing turn-off loss.

[0035] Since the switch device of this embodiment mainly generates a constant gate turn-on current through the threshold voltage of the current-limiting depletion-type field effect tube, the gate-source internal resistance of the current-limiting depletion-type field effect tube, and the current-limiting resistor, a fault (such as a short circuit, etc.) in one of the current-limiting depletion-type field effect tubes will not significantly affect the current limiting effect. At the same time, the gate voltage of multiple current-limiting depletion-type field effect tubes can effectively limit the source-drain voltage of the current-limiting depletion-type field effect tube, effectively avoiding the breakdown caused by the excessive source-drain voltage of the current-limiting depletion-type field effect tube, and improving the working stability of the current-limiting depletion-type field effect tube and the entire switch device.

[0036] Therefore, the switch device 20 in this embodiment can control the turn-on current and thus the turn-on speed through the current limiting depletion type field effect transistor in the turn-on stage, and can reduce the source-drain voltage of the depletion type field effect transistor by adjusting the number of the current limiting depletion type field effect transistors. In addition, the switch device 20 can achieve a large current in the turn-off stage, thereby achieving a faster turn-off speed and reducing the turn-off loss; thereby improving the working reliability of the current limiting depletion type field effect transistor and the entire switch device.

[0037] The current limiting structure of the switch device of this embodiment can be made by external packaging integration. The structures of the current limiting depletion type field effect transistor and the high voltage depletion type field effect transistor in the current limiting structure include but are not limited to metal-oxide semiconductor field effect transistor (MOSFET, Metal-Oxide-Semiconductor Field Effect Transistor), metal-insulator-semiconductor field effect transistor (MISFET, Metal Insulation Semiconductor Field Effect Transistor), metal semiconductor field effect transistor (MESFET, Metal-Semiconductor Field Effect Transistor), and high electron mobility transistor (HEMT, High Electron Mobility Transistor). The materials of the current limiting depletion type field effect transistor and the high voltage depletion type field effect transistor include but are not limited to gallium nitride, silicon carbide, and silicon.

[0038] The above-mentioned current limiting depletion type field effect transistor can be integrated with the high-voltage depletion type field effect transistor in the same chip, and can also be integrated with the low-voltage enhancement type field effect transistor in the same chip. Furthermore, the current limiting depletion type field effect transistor, the high-voltage depletion type field effect transistor and the low-voltage enhancement type field effect transistor can also be set as one device through packaging.

[0039] The common source and common gate cascade switch device with a voltage-dividing current-limiting structure of the present invention is provided with a plurality of current-limiting depletion-type field effect tubes and a current-limiting resistor as a current-limiting structure. When the current-limiting depletion-type field effect tube is turned on, the gate-source voltage (threshold voltage) of the current-limiting depletion-type field effect tube can limit the source-drain voltage of the adjacent current-limiting depletion-type field effect tube, thereby avoiding the breakdown caused by the excessive source-drain voltage of the current-limiting depletion-type field effect tube, thereby affecting the reliability of the current-limiting depletion-type field effect tube. In this way, the user can reduce the turn-on current of the high-voltage depletion-type field effect tube by reducing the threshold voltage of the current-limiting depletion-type field effect tube, and will not affect the working reliability of the current-limiting depletion-type field effect tube and the entire switch device, effectively solving the technical problem of poor working reliability of the existing common source and common gate cascade switch device.

[0040] Although the present invention is disclosed through the above embodiments, the protection scope of the present invention is not limited thereto. Without departing from the concept of the present invention, several deductions and replacements of the above components will fall within the scope of the claims of the present invention.

Claims

1. A common source and common gate cascade switch device with a voltage-dividing and current-limiting structure, characterized in that: include: A gate terminal, used to receive a voltage signal from a driver; A source terminal and a drain terminal, used to form a switch channel of an external load, two semiconductor channels are arranged between the source terminal and the drain terminal; A low voltage enhancement type field effect transistor, wherein the gate of the low voltage enhancement type field effect transistor serves as the gate terminal of the switching device and is used to receive a voltage signal from a driver; The drain of the low voltage enhancement type field effect transistor is connected to the source of the high voltage depletion type field effect transistor, the source of the low voltage enhancement type field effect transistor serves as the source terminal of the switch device, and the source of the low voltage enhancement type field effect transistor is connected to the gate of the high voltage depletion type field effect transistor through a current limiting structure; The high-voltage depletion-type field effect transistor, the drain of the high-voltage depletion-type field effect transistor serves as the drain end of the switching device; The current limiting structure includes multiple current limiting depletion type field effect transistors and current limiting resistors, the gate of the first current limiting depletion type field effect transistor is connected to the gate of the high voltage depletion type field effect transistor, the source of the first current limiting depletion type field effect transistor is connected to the gate of the high voltage depletion type field effect transistor through the current limiting resistor, the gate of the nth current limiting depletion type field effect transistor is connected to the source of the n-1th current limiting depletion type field effect transistor, the source of the nth current limiting depletion type field effect transistor is connected to the drain of the n-1th current limiting depletion type field effect transistor, and the drain of the last current limiting depletion type field effect transistor is connected to the source of the low voltage enhancement type field effect transistor, wherein n is a positive integer greater than 1.

2. The common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure according to claim 1, characterized in that: The threshold voltage of the current limiting depletion type field effect transistor is greater than the threshold voltage of the high voltage depletion type field effect transistor.

3. The common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure according to claim 2, characterized in that: The threshold voltages of the plurality of current-limiting depletion-type field effect transistors are equal.

4. The common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure according to claim 3, characterized in that: When the switch device is turned on, the gate voltage of the high-voltage depletion-type field effect transistor increases; when the gate voltage of the high-voltage depletion-type field effect transistor is less than the threshold voltage of the current-limiting depletion-type field effect transistor, the gate current of the high-voltage depletion-type field effect transistor is a constant current value.

5. The common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure according to claim 4, characterized in that: The constant current value is determined by the threshold voltage of the current limiting depletion type field effect transistor, the gate-source internal resistance of the current limiting depletion type field effect transistor, and the current limiting resistor.

6. The common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure according to claim 3, characterized in that: When the gate voltage of the high-voltage depletion-type field effect transistor is less than the threshold voltage of the current-limiting depletion-type field effect transistor, the gate-source voltage of the current-limiting depletion-type field effect transistor is equal to the threshold voltage, and the source-drain voltage of the nth current-limiting depletion-type field effect transistor is equal to the gate-source voltage of the n+1th current-limiting depletion-type field effect transistor, wherein n is a positive integer greater than 0; The source-drain voltage of the last current-limiting depletion-type field effect transistor is determined by the gate voltage of the high-voltage depletion-type field effect transistor, the threshold voltage of the current-limiting depletion-type field effect transistor, and the number of the current-limiting depletion-type field effect transistors.

7. The common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure according to claim 3, characterized in that: When the switch device is turned on, the gate voltage of the high-voltage depletion-type field effect transistor increases; when the gate voltage of the high-voltage depletion-type field effect transistor is greater than or equal to the threshold voltage of the current limiting depletion-type field effect transistor, the current limiting depletion-type field effect transistor is in a low resistance state.

8. The common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure according to claim 3, characterized in that: When the switch device is turned off, the gate voltage of the high-voltage depletion-type field effect transistor is greater than or equal to the threshold voltage of the current-limiting depletion-type field effect transistor, and the current-limiting depletion-type field effect transistor is in a low resistance state.

9. The common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure according to claim 1, characterized in that: The structures of the current-limiting depletion-type field effect transistor and the high-voltage depletion-type field effect transistor include but are not limited to metal-oxide semiconductor field effect transistors, metal-insulator-semiconductor field effect transistors, metal semiconductor field effect transistors, and high electron mobility transistors.

10. The common-source and common-gate cascade switch device with a voltage-dividing and current-limiting structure according to claim 1, characterized in that: The materials of the current limiting depletion mode field effect transistor and the high voltage depletion mode field effect transistor include but are not limited to gallium nitride, silicon carbide, and silicon.

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