Cascode cascade type switching device with current limiting structure and electronic equipment
By introducing a current-limiting depletion-type MOSFET into a common-source cascaded switching device, the problems of unstable turn-on current and speed are solved, and stable voltage stress control and fast turn-off of the secondary-side synchronous transistor in the circuit are achieved, thereby improving the performance of the switching device.
Patent Information
- Application Number
- CN202422533817.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-18
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2034-10-18
AI Technical Summary
Traditional cascaded common-source and common-gate switching devices cannot adjust the turn-on current and speed when turned on, resulting in unstable turn-on current changes and reducing the ability to control the voltage stress of the secondary-side synchronous transistor in the circuit.
In cascaded common-source and common-gate switching devices, a current-limiting depletion-mode MOSFET is introduced. The gate current of the high-voltage depletion-mode MOSFET is controlled by the current-limiting structure, so that it remains constant when turned on and achieves fast turn-off when turned off, thereby reducing turn-off losses.
Effective control of turn-on current and speed improves the voltage stress control capability of the secondary-side synchronous transistor in the circuit, achieves rapid turn-off, and reduces turn-off losses.
Smart Images
Figure CN223514878U_ABST
Abstract
Description
[Technical Field]
[0001] This utility model belongs to the field of semiconductor manufacturing technology, and in particular relates to a common source cascade type switching device with a current limiting structure. [Background Technology]
[0002] A cascaded cascaded cascaded cascaded cascaded switching device is constructed by using a low-voltage enhancement-mode (EMF) MOSFET and a high-voltage depletion-mode (DSM) MOSFET in a common-source, common-gate configuration. The drain of the DSM serves as the drain (D) of the switching device, the gate (G) of the DSM serves as the gate (G) of the switching device, and the source (S) of the DSM serves as the source (S) of the switching device, ultimately achieving enhancement-mode functionality. The structure of the cascaded ... Figure 1 As shown.
[0003] Common-source cascaded switching devices combine enhanced operation, easy drive, excellent reverse recovery characteristics, and high reliability, making them one of the mainstream structures for commercial power devices. However, traditional common-source cascaded switching devices cannot adjust the turn-on current (current through the external resistor R) or turn-on speed during turn-on. Furthermore, because the gate voltage of the high-voltage depletion-mode MOSFET changes continuously during the turn-on phase, the turn-on current also changes continuously, making it impossible to guarantee the stability of the turn-on speed and reducing the ability to control the voltage stress on the secondary-side synchronous transistor in the circuit.
[0004] Therefore, there is a need to provide a common-source cascaded switching device with better voltage stress control capability. [Utility Model Content]
[0005] The present invention aims to solve the above problems and provides a common-source cascaded switching device with better voltage stress control capability.
[0006] This common-source, common-gate cascaded switching device includes:
[0007] The gate terminal is used to receive the voltage signal from the driver.
[0008] The source and drain terminals are used to form a switching channel for an external load, and two semiconductor channels are provided between the source and drain terminals;
[0009] A low-voltage enhancement-mode field-effect transistor (LVFET) is provided, wherein the gate of the LVFET serves as the gate terminal of a switching device for receiving a voltage signal from a driver; the drain of the LVFET is connected to the source of a high-voltage depletion-mode field-effect transistor (DHMT); the source of the LVFET serves as the source terminal of the switching device; and the source of the LVFET is connected to the gate of the DHMT through a current-limiting structure.
[0010] The high-voltage depletion-type field-effect transistor, wherein the drain of the high-voltage field-effect transistor serves as the drain terminal of the switching device;
[0011] The current limiting structure includes a current-limiting depletion-type field-effect transistor (FET), the gate of which is connected to the gate of the high-voltage depletion-type FET, the drain of which is connected to the source of the low-voltage enhancement-type FET, and the source of which is connected to the gate of the high-voltage depletion-type FET.
[0012] In the switching device of this embodiment, the current limiting structure further includes a current limiting resistor. One end of the current limiting resistor is connected to the gate of the high-voltage depletion-type field-effect transistor, and the other end of the current limiting resistor is connected to the source of the current-limiting depletion-type field-effect transistor.
[0013] In the switching 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.
[0014] 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 value.
[0015] In the switching 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.
[0016] 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.
[0017] 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.
[0018] In the switching device of this embodiment, the structure of the current-limiting depletion-type field-effect transistor and the high-voltage depletion-type field-effect transistor includes, but is not limited to, metal-oxide-semiconductor field-effect transistor, metal-insulator-semiconductor field-effect transistor, metal-semiconductor field-effect transistor, and high electron mobility transistor.
[0019] In the switching device of this embodiment, 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.
[0020] This utility model also provides an electronic device using the above-described common-source cascaded switching device with current-limiting structure.
[0021] Compared to existing technologies, the cascaded common-source cascode switching device of this invention is equipped with a current-limiting structure featuring a current-limiting depletion-mode MOSFET. When the switching device is turned on, this current-limiting depletion-mode MOSFET effectively controls the magnitude of the turn-on current (the gate current of the high-voltage depletion-mode MOSFET) (this turn-on current does not change with the gate voltage of the high-voltage depletion-mode MOSFET), thereby effectively controlling the turn-on speed of the switching device and improving the control capability over the voltage stress of the secondary-side synchronous transistor in the circuit. Furthermore, the switching device can achieve a larger gate current of the high-voltage depletion-mode MOSFET during the turn-off phase, thereby achieving a faster turn-off speed and reducing turn-off losses. This effectively solves the technical problem of limited control capability over the voltage stress of the secondary-side synchronous transistor in existing switching devices. [Attached Image Description]
[0022] Figure 1 A schematic diagram of the structure of an existing cascaded enhancement-type switching device with common source and common gate;
[0023] Figure 2 This is a schematic diagram of the first embodiment of the common-source cascaded switching device with current-limiting structure of the present invention.
[0024] Figure 3 This is a schematic diagram showing the variation curves of the gate voltage Vg_HEMT1 and the gate current Ig_HEMT1 of the high-voltage depletion-mode field-effect transistor in the cascaded common-source cascode switching device with current-limiting structure of this utility model.
[0025] Figure 4 This is a schematic diagram of the second embodiment of the common-source cascaded switching device with current-limiting structure of this utility model.
Detailed Implementation Methods
[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0027] This utility model discloses a common-source, common-gate cascaded switching device with a current-limiting structure. Please refer to [reference needed]. Figure 2 , Figure 2 This is a schematic diagram of the first embodiment of the common-source cascaded switching device with current-limiting structure of this utility model.
[0028] The switching device 20 includes a gate terminal 21, a source terminal 22, a drain terminal 23, a low-voltage enhancement-mode field-effect transistor 24, a high-voltage depletion-mode field-effect transistor 25, and a current-limiting structure 26. The gate terminal 21 is used to receive the voltage signal from the driver; the source terminal 22 and the drain terminal 23 are used to form a switching channel for an external load, and two semiconductor channels (the low-voltage enhancement-mode field-effect transistor 24 and the high-voltage depletion-mode field-effect transistor 25) are provided between the source terminal 22 and the drain terminal 23.
[0029] The gate 241 of the low-voltage enhancement-mode field-effect transistor 24 serves as the gate terminal 21 of the switching device 20, used to receive the voltage signal from the driver; the drain 243 of the low-voltage enhancement-mode field-effect transistor 24 is connected to the source 252 of the high-voltage depletion-mode field-effect transistor 25, the source 242 of the low-voltage enhancement-mode field-effect transistor 24 serves as the source terminal 22 of the switching device 20, the source 242 of the low-voltage enhancement-mode field-effect transistor 24 is connected to the gate 251 of the high-voltage depletion-mode field-effect transistor 25 through the current limiting structure 26; the drain 253 of the high-voltage depletion-mode field-effect transistor 25 serves as the drain terminal 23 of the switching device 20.
[0030] The current limiting structure 26 includes a current limiting depletion type field-effect transistor (FET). The gate 261 of the current limiting depletion type FET is connected to the gate of the high-voltage depletion type FET 25. The drain 263 of the current limiting depletion type FET is connected to the source 242 of the low-voltage enhancement type FET 24. The source 262 of the current limiting depletion type FET is connected to the gate 251 of the high-voltage depletion type FET 25.
[0031] In the switching device of this invention 20, the threshold voltage Vth_HEMT2 of the current-limiting depletion-type field-effect transistor should be greater than the threshold voltage Vth_HEMT1 of the high-voltage depletion-type field-effect transistor 25. Here, the threshold voltage 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).
[0032] When the switching device 20 is turned on, the gate voltage Vg_HEMT1 of the high-voltage depletion field-effect transistor 25 increases. However, the gate voltage Vg_HEMT1 of the high-voltage depletion field-effect transistor 25 is less than the threshold voltage Vth_HEMT2 of the current-limiting depletion field-effect transistor. Therefore, when the high-voltage depletion field-effect transistor 25 is turned on, the current-limiting depletion field-effect transistor is still in a high-resistance state.
[0033] Because the current-limiting depletion-type field-effect transistor (FET) has an internal gate-source resistor R_HEMT2, before the gate voltage Vg_HEMT1 of the high-voltage depletion-type FET 25 reaches the threshold voltage Vth_HEMT2 of the current-limiting FET, the gate current Ig_HEMT1 of the high-voltage depletion-type FET 25 is equal to the drain-source leakage current of the current-limiting FET, approximately Vth_HEMT2 / R_HEMT2. This gate current is a constant value; therefore, the gate current Ig_HEMT1 of the high-voltage depletion-type FET 25 is determined by the threshold voltage Vth_HEMT2 of the current-limiting FET and the gate-source resistor R_HEMT2.
[0034] During the turn-on process of switching device 20, the curves showing the changes in gate voltage Vg_HEMT1 and gate current Ig_HEMT1 of high-voltage depletion-mode field-effect transistor 25 are as follows: Figure 3 As shown in the figure, 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 constant value. At this time, the user can effectively control the turn-on speed of the switching device 20 through this gate current Ig_HEMT1.
[0035] The gate voltage Vg_HEMT1 of the high-voltage depletion field-effect transistor 25 continues to increase under the discharge action of the high-voltage depletion 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 field-effect transistor 25 is greater than or equal to the threshold voltage Vth_HEMT2 of the current-limiting depletion field-effect transistor, the current-limiting depletion field-effect transistor is in a low-resistance state.
[0036] When the switching device 20 is turned off, the gate voltage Vg_HEMT1 of the high-voltage depletion-type field-effect transistor 25 is always greater than or equal to the threshold voltage Vth_HEMT2 of the current-limiting depletion-type field-effect transistor. The current-limiting depletion-type field-effect transistor is always in a low-resistance state. At this time, the current of the current-limiting depletion-type field-effect transistor is at its maximum, thereby achieving a faster turn-off speed and reducing turn-off losses.
[0037] Therefore, in this embodiment, the switching device 20 can control the turn-on current and thus the turn-on speed through a current-limiting depletion-type field-effect transistor during the turn-on phase, thereby improving the switching device's ability to control the voltage stress on the secondary-side synchronous transistor in the circuit.
[0038] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the second embodiment of the common-source cascaded switching device with current-limiting structure of this utility model.
[0039] The switching device 40 in this embodiment includes a gate terminal 41, a source terminal 42, and a drain terminal 43. Based on the first embodiment, the current limiting structure 46 of the switching device 40 includes a current-limiting depletion-type field-effect transistor 461 and a current-limiting resistor 462. One end of the current-limiting resistor 462 is connected to the gate of the high-voltage depletion-type field-effect transistor 45, and the other end of the current-limiting resistor 462 is connected to the source of the current-limiting depletion-type field-effect transistor 461. The gate of the current-limiting depletion-type field-effect transistor 461 is connected to the gate of the high-voltage depletion-type field-effect transistor 45, and the drain of the current-limiting depletion-type field-effect transistor 461 is connected to the source of the low-voltage enhancement-type field-effect transistor 44.
[0040] In the switching device of this invention, the threshold voltage Vth_HEMT2 of the current-limiting depletion-type field-effect transistor 461 should be greater than the threshold voltage Vth_HEMT1 of the high-voltage depletion-type field-effect transistor 45. Here, the threshold voltage 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).
[0041] When the switching device 40 is turned on, the gate voltage Vg_HEMT1 of the high-voltage depletion field-effect transistor 45 increases. However, the gate voltage Vg_HEMT1 of the high-voltage depletion field-effect transistor 45 is less than the threshold voltage Vth_HEMT2 of the current-limiting depletion field-effect transistor 461. Therefore, when the high-voltage depletion field-effect transistor 45 is turned on, the current-limiting depletion field-effect transistor is still in a high-resistance state.
[0042] In this embodiment, a current-limiting resistor 462 is provided between the gate of the high-voltage depletion-type field-effect transistor 45 and the source of the current-limiting depletion-type field-effect transistor 461. Thus, before the gate voltage Vg_HEMT1 of the high-voltage depletion-type field-effect transistor 45 reaches the threshold voltage Vth_HEMT2 of the current-limiting depletion-type field-effect transistor 461, the gate current Ig_HEMT1 of the high-voltage depletion-type field-effect transistor 45 is equal to Vth_HEMT2 / (R_HEMT2+Rg). That is, the constant current value of the high-voltage depletion-type field-effect transistor 45 in the high-impedance state is determined by the threshold voltage Vth_HEMT2 of the current-limiting depletion-type field-effect transistor 461, the gate-source resistance R_HEMT2 of the current-limiting depletion-type field-effect transistor 461, and the resistance value Rg of the current-limiting resistor 462. At this time, the user can effectively control the turn-on speed of the switching device 40 through this gate current Ig_HEMT1.
[0043] The gate voltage Vg_HEMT1 of the high-voltage depletion field-effect transistor 45 continues to increase under the discharge action of the high-voltage depletion field-effect transistor 25. When the gate voltage Vg_HEMT1 of the high-voltage depletion field-effect transistor 45 is greater than or equal to the threshold voltage Vth_HEMT2 of the current-limiting depletion field-effect transistor 461, the current-limiting depletion field-effect transistor 461 is turned on and is in a low-resistance state.
[0044] When the switching device 40 is turned off, the gate voltage Vg_HEMT1 of the high-voltage depletion field-effect transistor 45 is greater than or equal to the threshold voltage Vth_HEMT2 of the current-limiting depletion field-effect transistor 461. The current-limiting depletion field-effect transistor 461 is in a low-resistance state. At this time, the current of the current-limiting depletion field-effect transistor 461 is at its maximum, thereby achieving a faster turn-off speed and reducing turn-off losses.
[0045] In this way, the user can adjust the turn-on current of the switching device through the current-limiting resistor 462, thereby controlling the turn-on speed of the switching device 40, without needing to adjust the parameters of the current-limiting depletion-type field-effect transistor 461 to set a specific turn-on speed. If the user wants to reduce the gate current Ig_HEMT1 of the high-voltage depletion-type field-effect transistor 45, they only need to increase the resistance value Rg of the current-limiting resistor 462, without needing to adjust the parameters of the current-limiting depletion-type field-effect transistor 461.
[0046] The current-limiting structure of the switching device in this embodiment can be fabricated through external packaging integration. The structures of the current-limiting depletion-type field-effect transistor (FET) and the high-voltage depletion-type FET in the current-limiting structure include, but are not limited to, metal-oxide-semiconductor field-effect transistors (MOSFETs), metal-insulator-semiconductor field-effect transistors (MISFETs), metal-semiconductor field-effect transistors (MESFETs), and high electron mobility transistors (HEMTs). The materials of the current-limiting depletion-type FET and the high-voltage depletion-type FET include, but are not limited to, gallium nitride, silicon carbide, and silicon.
[0047] The aforementioned current-limiting depletion-mode MOSFET can be integrated into the same chip as a high-voltage depletion-mode MOSFET, or it can be integrated into the same chip as a low-voltage enhancement-mode MOSFET. Furthermore, the current-limiting depletion-mode MOSFET, the high-voltage depletion-mode MOSFET, and the low-voltage enhancement-mode MOSFET can also be packaged into a single device.
[0048] This invention also provides an electronic device with a common-source cascaded switching device having the above-mentioned current-limiting structure. The specific working principle of this electronic device is the same as or similar to that of the electronic device with the common-source cascaded switching device having the above-mentioned current-limiting structure. For details, please refer to the relevant descriptions in the specific embodiments of the common-source cascaded switching device having the above-mentioned current-limiting structure.
[0049] This invention discloses a cascaded common-source cascode switching device with a current-limiting structure incorporating a current-limiting depletion-mode MOSFET. When the switching device is turned on, this current-limiting depletion-mode MOSFET effectively controls the magnitude of the turn-on current (the gate current of the high-voltage depletion-mode MOSFET) (this turn-on current does not change with the gate voltage of the high-voltage depletion-mode MOSFET), thereby effectively controlling the turn-on speed of the switching device and improving the control capability over the voltage stress of the secondary-side synchronous transistor in the circuit. Furthermore, during the turn-off phase, the switching device can achieve a larger gate current of the high-voltage depletion-mode MOSFET, thereby achieving a faster turn-off speed and reducing turn-off losses. This effectively solves the technical problem of limited control capability over the voltage stress of the secondary-side synchronous transistor in existing switching devices.
[0050] Although the present invention has been disclosed through the above embodiments, the scope of protection of the present invention is not limited thereto. Any deductions, substitutions, etc., made to the above components without departing from the concept of the present invention shall fall within the scope of the claims of the present invention.
Claims
1. A cascaded common-source switch with a current-limiting structure, characterized in that, include: The gate terminal is used to receive the voltage signal from the driver. The source and drain terminals are used to form a switching channel for an external load, and two semiconductor channels are provided between the source and drain terminals; A low-voltage enhancement-mode field-effect transistor (LVFET), wherein the gate of the LVFET serves as the gate terminal of a switching device for receiving a voltage signal from a driver. The drain of the low-voltage enhancement-mode field-effect transistor is connected to the source of the high-voltage depletion-mode field-effect transistor. The source of the low-voltage enhancement-mode field-effect transistor serves as the source terminal of the switching device, and the source of the low-voltage enhancement-mode field-effect transistor is connected to the gate of the high-voltage depletion-mode field-effect transistor through a current-limiting structure. The high-voltage depletion-type field-effect transistor, wherein the drain of the high-voltage depletion-type field-effect transistor serves as the drain terminal of the switching device; The current limiting structure includes a current-limiting depletion-type field-effect transistor (FET), the gate of which is connected to the gate of the high-voltage depletion-type FET, the drain of which is connected to the source of the low-voltage enhancement-type FET, and the source of which is connected to the gate of the high-voltage depletion-type FET.
2. The cascaded switching device with a current-limiting structure according to claim 1, characterized in that, The current limiting structure also includes a current limiting resistor, one end of which is connected to the gate of the high-voltage depletion-type field-effect transistor, and the other end of which is connected to the source of the current-limiting depletion-type field-effect transistor.
3. The cascaded switching device with a current-limiting structure according to claim 2, 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.
4. The cascaded switching device with a current-limiting structure according to claim 3, characterized in that, 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 value.
5. The cascaded switching device with a 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 field-effect transistor, the gate-source internal resistance of the current-limiting depletion field-effect transistor, and the current-limiting resistor.
6. The cascaded switching device with a current-limiting structure according to claim 3, characterized in that, 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.
7. The cascaded switching device with a current-limiting structure according to claim 3, characterized in that, 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.
8. The cascaded switching device with a current-limiting structure according to claim 1, characterized in that, The current-limiting depletion-type field-effect transistor and the high-voltage depletion-type field-effect transistor include metal-oxide-semiconductor field-effect transistors, metal-insulator-semiconductor field-effect transistors, metal-semiconductor field-effect transistors, and high electron mobility transistors.
9. An electronic device, characterized in that, The electronic device includes any of the common-source cascaded switching devices with a current-limiting structure as described in claims 1-8.