Linear MOS switch tube for hot plugging

Abstract

The invention provides a linear MOS switching tube for hot plugging, which relates to the technical field of power electronics, and comprises a Zener diode D1, an LDMOS M1, an LDMOS M2, a shield gate trench MOS switching tube SGT1, an LDMOS M3 and a shield gate trench MOS switching tube SGT2, the drain electrode of the LDMOS M1 is electrically connected with the grid electrode of a resistor R2 and the grid electrode of the LDMOS M2, the source electrode of the LDMOS M1 is electrically connected with the source electrode of the LDMOS M2, the drain electrode of the LDMOS M2 is electrically connected with the source electrode of a resistor R3 and the source electrode of the LDMOS M3, and the source electrode of the resistor R3 and the source electrode of the LDMOS M3 are electrically connected with the grid electrode of the resistor R2 and the grid electrode of the LDMOS M3. The resistor R3 is electrically connected with the grid electrode of the shield grid groove MOS switch tube SGT1, the drain electrode of the shield grid groove MOS switch tube SGT1 is electrically connected with the drain electrode of the shield grid groove MOS switch tube SGT2, the grid electrode of the shield grid groove MOS switch tube SGT2 is electrically connected with the source electrode of the LDMOS M3, and the source electrode of the shield grid groove MOS switch tube SGT2 is electrically connected with the drain electrode of the LDMOS M3. According to the invention, rapid response and accurate control of transient current and voltage fluctuation in the hot plug process are realized through the high-efficiency linear MOS switch tube.

Description

Technical Field

[0001] The invention relates to the technical field of power electronics, and in particular to a linear MOS switch tube for hot plugging. Background Art

[0002] In modern electronic devices, hot-swap technology is widely used because it facilitates plug-and-play of devices. However, the surge current problem associated with the hot-swap process has always been a key factor restricting the stability and reliability of the device. When a device is connected to or disconnected from the power supply during hot-swap, a large transient current, namely surge current, is generated due to the capacitive effect of the power line and the instantaneous change of the load. This surge current usually has a short duration, ranging from hundreds of microseconds to more than ten milliseconds, but its peak current may be much higher than the normal operating current, posing a severe challenge to the electronic components in the circuit.

[0003] MOSFET (Metal Oxide Semiconductor Field Effect Transistor), as a linear MOS switch tube, plays an important role in hot-swap circuits. However, when facing surge current, the safe operating area (SOA) of traditional MOSFET devices is often limited, and they are easily damaged due to exceeding the tolerance limit. SOA defines the range in which MOSFET can safely operate under specific conditions (such as voltage, current and temperature). Exceeding this range may cause device failure.

[0004] Therefore, a linear MOS switch tube for hot swap is proposed. Summary of the invention

[0005] The present specification provides a linear MOS switch tube for hot plugging, which realizes rapid response and precise control of transient current and voltage fluctuations during hot plugging through a high-efficiency linear MOS switch tube (especially a shielded gate trench MOS switch tube).

[0006] This specification provides a linear MOS switch tube for hot swapping, including: A Zener diode D1, an LDMOS M1, an LDMOS M2, a shielded gate trench MOS switch tube SGT1, an LDMOS M3, and a shielded gate trench MOS switch tube SGT2, wherein the cathode of the Zener diode D1 is electrically connected to the resistor R2, the anode of the Zener diode D1 is electrically connected to the resistor R1 and the gate of the LDMOS M1, respectively, the drain of the LDMOS M1 is electrically connected to the resistor R2 and the gate of the LDMOS M2, the source of the LDMOS M1 is electrically connected to the source of the LDMOS M2, the drain of the LDMOS M2 is electrically connected to the resistor R3 and the source of the LDMOS M3, respectively, the resistor R3 is electrically connected to the gate of the shielded gate trench MOS switch tube SGT1, the drain of the shielded gate trench MOS switch tube SGT1 is electrically connected to the drain of the shielded gate trench MOS switch tube SGT2, the gate of the shielded gate trench MOS switch tube SGT2 is electrically connected to the LDMOS The source of the shielded gate trench MOS switch tube SGT2 is electrically connected to the drain of the LDMOS M3.

[0007] Optionally, the unit quantity ratio of the shielded gate trench MOS switch tube SGT1 to the shielded gate trench MOS switch tube SGT2 is 1:19.

[0008] Optionally, the start-up process includes: when the drain of the linear mos is equal to the power supply voltage, vg1 starts to rise from 0V, the Zener diode D1 is not turned on, the LDMOS M1 is turned off, the LDMOS M2 is turned on, the resistor R3 limits the drain discharge of the LDMOS M2, and the gate of the shielded gate trench MOS switch tube SGT1 is charged through vg1; vg2 is equal to the on-state voltage drop of the LDMOS M2, and the LDMOS M2 remains turned off.

[0009] Optionally, the start-up process also includes: when vg1 reaches the Miller platform of the shielded gate trench MOS switch tube SGT1, the shielded gate trench MOS switch tube SGT1 operates above the zero temperature point, and the temperature and current are negatively fed back; the surge current is borne by the shielded gate trench MOS switch tube SGT1.

[0010] Optionally, the start-up process also includes: when vg1 exceeds the Miller platform, the Zener diode D1 is turned on, the voltage drop of the resistor R1 causes the LDMOS M1 to be turned on, and the LDMOS M2 to be turned off, vg2=vg1, and the LDMOS M3 is turned off. vg1 charges the gate of the shielded gate trench MOS switch tube SGT2 through the resistor R3 to limit the current, and the shielded gate trench MOS switch tube SGT2 is turned on.

[0011] In this specification, a fast response and precise control of transient current and voltage fluctuations during hot plugging are achieved through high-efficiency linear MOS switch tubes (especially shielded gate trench MOS switch tubes). The power supply voltage is monitored in real time through sampling resistors, and the Zener diodes, triodes and other components in the control module are used to ensure the stable operation of the circuit at different voltage levels. In particular, effective management of the gate voltage of the linear MOS switch tube is achieved, further improving the reliability and safety of the circuit. In addition, the circuit also has the characteristics of simple structure, easy integration, and strong adaptability. It is suitable for the hot plug protection needs of a variety of electronic equipment, effectively extending the service life of the equipment and reducing maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0013] Figure 1 A schematic diagram of a linear MOS switch tube for hot swapping provided in an embodiment of this specification; Figure 2 A schematic diagram of the structure of a protection circuit for hot plugging provided in an embodiment of this specification.

[0014] The accompanying drawings illustrate: 100, power supply; 200, sampling resistor; 300, control module; 400, linear MOS switch tube; 500, load. DETAILED DESCRIPTION

[0015] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0016] The following is combined with Figure 1-2 The exemplary embodiments of the present invention are described more fully. However, the exemplary embodiments can be implemented in various forms, and it should not be understood that the present invention is limited to the embodiments set forth herein. On the contrary, providing these exemplary embodiments can make the present invention more comprehensive and complete, and it is more convenient to fully convey the inventive concept to those skilled in the art. The same reference numerals in the figures represent the same or similar elements, components or parts, and thus their repeated description will be omitted.

[0017] Under the premise of being consistent with the technical concept of the present invention, the features, structures, characteristics or other details described in a specific embodiment do not exclude that they can be combined in one or more other embodiments in a suitable manner.

[0018] In the description of specific embodiments, the features, structures, characteristics or other details described in the present invention are intended to enable those skilled in the art to fully understand the embodiments. However, it does not exclude that those skilled in the art can practice the technical solutions of the present invention without one or more of the specific features, structures, characteristics or other details.

[0019] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0020] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0021] The term "and / or" or "and / or" includes all combinations of any one or more of the associated listed items.

[0022] Figure 1 A schematic diagram of a linear MOS switch tube for hot swapping provided in an embodiment of this specification includes: A Zener diode D1, an LDMOS M1, an LDMOS M2, a shielded gate trench MOS switch tube SGT1, an LDMOS M3, and a shielded gate trench MOS switch tube SGT2, wherein the cathode of the Zener diode D1 is electrically connected to the resistor R2, the anode of the Zener diode D1 is electrically connected to the resistor R1 and the gate of the LDMOS M1, respectively, the drain of the LDMOS M1 is electrically connected to the resistor R2 and the gate of the LDMOS M2, the source of the LDMOS M1 is electrically connected to the source of the LDMOS M2, the drain of the LDMOS M2 is electrically connected to the resistor R3 and the source of the LDMOS M3, respectively, the resistor R3 is electrically connected to the gate of the shielded gate trench MOS switch tube SGT1, the drain of the shielded gate trench MOS switch tube SGT1 is electrically connected to the drain of the shielded gate trench MOS switch tube SGT2, the gate of the shielded gate trench MOS switch tube SGT2 is electrically connected to the LDMOS The source of the shielded gate trench MOS switch tube SGT2 is electrically connected to the drain of the LDMOS M3.

[0023] In the specific implementation of this specification, the Zener diode D1 is used as a voltage stabilizing element in the circuit, and its negative electrode realizes the limitation and adjustment of the current through a precision resistor R2 to ensure the stable operation of the circuit. The positive electrode of D1 is doubly connected. On the one hand, after the voltage is divided by the resistor R1, it is directly connected to the gate of LDMOS M1 to provide a control voltage for M1; on the other hand, the positive electrode of D1 is also directly connected to the gate of LDMOS M1. Such a design enhances the flexibility and response speed of voltage control. As an amplifying and switching element, the drain of LDMOS M1 not only forms a feedback loop with the resistor R2 to adjust its own working state, but also connects to the gate of the next LDMOS M2 to realize the cascade amplification of the signal. The drain of LDMOS M2 outputs a further amplified signal, which is not only load matched through the resistor R3, but also acts directly on the gate of the shielded gate trench MOS switch tube SGT1 as a control signal. As a high-performance switching device, the drain of SGT1 is connected to the drain of another MOS switch tube SGT2 of the same type, and they jointly assume the switching function in the circuit. In particular, resistor R3 is not only connected between the drain of M2 and the gate of SGT1, but also plays a role in current limiting and protection, ensuring that the gate voltage of SGT1 is within a safe range. The gate of SGT2 is designed quite cleverly, and it is directly connected to the source of LDMOS M3. In this way, the working state of M3 can directly affect the switching behavior of SGT2, forming a closed-loop control system.

[0024] In general, through the coordinated work of Zener diode D1, LDMOS M1 to M3, and shielded gate trench MOS switch tubes SGT1 and SGT2, accurate amplification, regulation, and efficient switching control of the input signal are achieved, providing stable and reliable power management and signal processing capabilities for various electronic devices.

[0025] Optionally, the unit quantity ratio of the shielded gate trench MOS switch tube SGT1 to the shielded gate trench MOS switch tube SGT2 is 1:19.

[0026] In the specific implementation of this specification, the fine control of current and voltage is achieved by accurately configuring the ratio of the number of shielded gate trench MOS switch tubes SGT1 and SGT2. Specifically, the unit number ratio of shielded gate trench MOS switch tubes SGT1 and SGT2 in the control unit is set to 1:19. This configuration means that for every SGT1 switch tube, there are 19 SGT2 switch tubes working with it. Such a design is not arbitrary, but is based on the system's comprehensive consideration of current distribution, voltage regulation, and surge current protection during hot plugging.

[0027] SGT1 is evenly distributed in the total area of ​​the entire linear MOS. During the hot plug process, when the surge current comes, only SGT1 in the linear MOS is turned on. Since the number of SGT1 is small and the distribution is even, it can effectively limit the surge current and provide a large heat dissipation space. In addition, SGT1 works above the zero temperature point, and there is a negative feedback relationship between its current and temperature: as the temperature increases, the SGT1 current will decrease; and the decrease in current will cause the temperature to drop. In this way, all SGT1s work in a self-current balancing state, effectively avoiding the generation of hot spots and thermal failures. After the surge is over, SGT2 is turned on again, thereby reducing the total RdsON (on-resistance) of the linear MOS.

[0028] Optionally, the start-up process includes: when the drain of the linear mos is equal to the power supply voltage, vg1 starts to rise from 0V, the Zener diode D1 is not turned on, the LDMOS M1 is turned off, the LDMOS M2 is turned on, the resistor R3 limits the drain discharge of the LDMOS M2, and the gate of the shielded gate trench MOS switch tube SGT1 is charged through vg1; vg2 is equal to the on-state voltage drop of the LDMOS M2, and the LDMOS M2 remains turned off.

[0029] In a specific embodiment of the present specification, when the drain of the linear MOS reaches its rated value, the control signal vg1 starts to gradually rise from 0V. At this stage, the Zener diode D1 has not yet turned on, so it will not have a significant impact on the circuit. Due to the low initial value of vg1, LDMOS M1 is in the off state, which means that its internal channel is not formed and the current cannot pass. At the same time, LDMOS M2 is in the on state. This is because during the rise of vg1, although M1 is turned off, the gate of M2 may receive a sufficiently high voltage through other channels (such as the bias circuit inside the system) to enable it to turn on. After M2 is turned on, its drain begins to discharge, and this discharge process is limited by resistor R3. The presence of R3 not only protects M2 from damage by excessive current, but also ensures the smooth progress of the discharge process. As the drain of M2 discharges, the gate of the shielded gate trench MOS switch tube SGT1 is charged through vg1 (which has gradually risen at this time). This charging process causes the gate voltage of SGT1 to gradually increase. When it reaches the threshold voltage, a channel is formed inside SGT1 and current begins to flow, marking the start of SGT1.

[0030] It is worth noting that at this stage, the value of another control signal vg2 is equal to the conduction voltage drop of LDMOS M2. Since M2 is in the on state, its conduction voltage drop is a relatively small value, which means that vg2 is not enough to turn on another shielded gate trench MOS switch tube SGT2 (or other related components). Therefore, while SGT1 is turned on, SGT2 remains in the off state, ensuring the orderly distribution of current and voltage in the system.

[0031] Optionally, the start-up process also includes: when vg1 reaches the Miller platform of the shielded gate trench MOS switch tube SGT1, the shielded gate trench MOS switch tube SGT1 operates above the zero temperature point, and the temperature and current are negatively fed back; the surge current is borne by the shielded gate trench MOS switch tube SGT1.

[0032] In the specific implementation of the present specification, when vg1 (gate control voltage) gradually rises and reaches the Miller Plateau stage of the shielded gate trench MOS switch tube SGT1, the start-up process of the entire hot-swap control system enters a critical period. The Miller Plateau is a unique phenomenon of the MOS switch tube during the start-up process. It occurs when the gate voltage is close to but has not yet fully reached the threshold voltage. At this time, the drain current begins to increase significantly, but the growth of the gate voltage becomes slow. At this stage, the working state of the shielded gate trench MOS switch tube SGT1 becomes particularly special. Due to the existence of the Miller effect, a dynamic capacitor feedback network is formed between the gate and drain of SGT1, which causes a slight change in the gate voltage to cause a significant change in the drain current. More importantly, at this time, the operating point of SGT1 is exactly in its zero temperature coefficient region (or zero temperature point), which means that at this operating point, the temperature and current of SGT1 show a negative feedback relationship. The existence of a negative feedback mechanism is an important advantage for hot-swap control systems. It means that when current fluctuations or surge currents occur in the system, SGT1 can automatically adjust its operating state to limit the increase in current and reduce temperature rise, thereby protecting itself from overheating damage. Specifically, when surge current occurs, the temperature of SGT1 rises, but because it is above the zero temperature point, its internal resistance increases accordingly, thereby limiting further increases in current. This self-regulation mechanism helps maintain system stability and reliability.

[0033] Optionally, the start-up process also includes: when vg1 exceeds the Miller platform, the Zener diode D1 is turned on, the voltage drop of the resistor R1 causes the LDMOS M1 to be turned on, and the LDMOS M2 to be turned off, vg2=vg1, and the LDMOS M3 is turned off. vg1 charges the gate of the shielded gate trench MOS switch tube SGT2 through the resistor R3 to limit the current, and the shielded gate trench MOS switch tube SGT2 is turned on.

[0034] In a specific embodiment of the present specification, when vg1 (gate control voltage) successfully crosses the Miller platform and continues to rise, the start-up process of the hot-swap control system enters the next critical stage. At this point, a significant change is that the Zener diode D1 begins to conduct. The conduction of D1 is due to the increase of vg1, which makes the voltage across it reach the breakdown voltage of D1, thereby triggering the voltage regulation characteristics of D1. After the Zener diode D1 is turned on, its stable voltage output generates a voltage drop through the resistor R1. This voltage drop provides a sufficiently high voltage for the gate of LDMOS M1, causing M1 to change from the off state to the on state. The conduction of M1 means that its internal channel is formed and current begins to pass, which further affects other components in the circuit. At the same time, due to the conduction of M1, the gate voltage of LDMOS M2 begins to drop, causing M2 to change from the on state to the off state. This change is rapid because the gate voltage of M2 is directly affected by the drain current of M1, and the conduction of M1 provides a low potential reference point for the gate of M2. As M2 is turned off, the current that originally flowed through M2 to resistor R3 is cut off. At this time, the value of vg2 (another gate control voltage) is no longer affected by the M2 conduction voltage drop, but is directly equal to vg1. This is because after M2 is turned off, the circuit between its drain and gate is disconnected, vg2 loses its original voltage source, and instead follows the change of vg1. At the same time as M2 is turned off, LDMOS M3 is also in the off state. This is because before M1 is turned on, M3 may have been in the off state due to the initial low value of vg1, and the turn-on of M1 does not provide enough gate voltage for M3 to turn it on. Finally, as vg1 continues to rise, it charges the gate of the shielded gate trench MOS switch tube SGT2 through resistor R3. This charging process causes the gate voltage of SGT2 to gradually increase. When it reaches the threshold voltage, the internal channel of SGT2 is formed, and the current begins to pass, marking the turn-on of SGT2.

[0035] This LinearMOS controls the opening of the shielded gate trench MOS switch tube SGT1 and the shielded gate trench MOS switch tube SGT2. When it needs to withstand surge current, only a small part is opened. The current limiting simultaneously lowers the zero temperature point, prevents thermal failure of the device, and widens the SOA. After the surge, the shielded gate trench MOS switch tube SGT1 and the shielded gate trench MOS switch tube SGT2 are fully opened to provide a regular size of on-resistance.

[0036] Figure 2 A schematic diagram of a hot-swap protection circuit provided in an embodiment of the present specification includes: a power supply, a sampling resistor, a linear MOS switch tube, a control module, and a load; The power supply is electrically connected to the sampling resistor, the sampling resistor is electrically connected to the control module and the linear MOS switch tube respectively, the linear MOS switch tube is electrically connected to the control module and the load respectively, the control module is electrically connected to the load, and the load and the power supply are both grounded.

[0037] In the specific implementation of this specification, the power supply is used as the energy source of the entire circuit, and the power supply is responsible for providing a stable voltage output to provide the necessary power support for the normal operation of other components. The sampling resistor is connected in series between the power supply and the subsequent circuit to monitor the change of the power supply voltage in real time. By measuring the voltage drop on the sampling resistor, the actual output voltage of the power supply can be accurately obtained to provide key data for subsequent control and protection operations. As the core switching element in the circuit, the linear MOS switch tube has the advantages of fast response speed, low power consumption, and high control accuracy. It switches the on-off state of the circuit quickly and accurately according to the instructions of the control module to achieve effective control of current and voltage. The control module is the brain of the entire circuit, responsible for receiving the voltage information provided by the sampling resistor and making decisions based on this information. It uses internal logic circuits and algorithms to calculate appropriate control signals to adjust the working state of the linear MOS switch tube, thereby achieving protection of the circuit.

[0038] The electrical connection between these components constitutes the core of this circuit. The power supply is connected to the subsequent circuit through the sampling resistor, and the sampling resistor is connected to the control module and the linear MOS switch tube. The linear MOS switch tube is not only connected to the control module, but also to the load to form a closed-loop control system. There is also an electrical connection between the control module and the load to achieve the functions of load voltage regulation and circuit protection.

[0039] Through accurate monitoring of power supply voltage, fast-response linear MOS switch tubes, and intelligent control modules and control units, an efficient and stable hot-swap protection system is formed. The system can effectively suppress transient current and voltage fluctuations generated during hot-swap, thereby protecting circuits and equipment from damage and improving system reliability and safety.

[0040] In this specification, a fast response and precise control of transient current and voltage fluctuations during hot plugging are achieved through high-efficiency linear MOS switch tubes (especially shielded gate trench MOS switch tubes). The power supply voltage is monitored in real time through sampling resistors, and the Zener diodes, triodes and other components in the control module are used to ensure the stable operation of the circuit at different voltage levels. In particular, effective management of the gate voltage of the linear MOS switch tube is achieved, further improving the reliability and safety of the circuit. In addition, the circuit also has the characteristics of simple structure, easy integration, and strong adaptability. It is suitable for the hot plug protection needs of a variety of electronic equipment, effectively extending the service life of the equipment and reducing maintenance costs.

[0041] The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the present invention is not inherently related to any specific computer, virtual device or electronic device, and various general devices can also implement the present invention. The above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0042] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0043] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A linear MOS switch tube for hot swap, characterized in that: include: A Zener diode D1, an LDMOS M1, an LDMOS M2, a shielded gate trench MOS switch tube SGT1, an LDMOS M3, and a shielded gate trench MOS switch tube SGT2, wherein the cathode of the Zener diode D1 is electrically connected to the resistor R2, the anode of the Zener diode D1 is electrically connected to the resistor R1 and the gate of the LDMOS M1, respectively, the drain of the LDMOS M1 is electrically connected to the resistor R2 and the gate of the LDMOS M2, the source of the LDMOS M1 is electrically connected to the source of the LDMOS M2, the drain of the LDMOS M2 is electrically connected to the resistor R3 and the source of the LDMOS M3, respectively, the resistor R3 is electrically connected to the gate of the shielded gate trench MOS switch tube SGT1, the drain of the shielded gate trench MOS switch tube SGT1 is electrically connected to the drain of the shielded gate trench MOS switch tube SGT2, the gate of the shielded gate trench MOS switch tube SGT2 is electrically connected to the LDMOS The source of the shielded gate trench MOS switch tube SGT2 is electrically connected to the drain of the LDMOS M3.

2. The linear MOS switch tube for hot swapping according to claim 1, characterized in that: The ratio of the number of units of the shielded gate trench MOS switch transistor SGT1 to the number of units of the shielded gate trench MOS switch transistor SGT2 is 1:

19.

3. The linear MOS switch tube for hot swapping according to claim 2, characterized in that: The start-up process includes: when the drain of the linear mos is equal to the power supply voltage, vg1 starts to rise from 0V, the Zener diode D1 is not turned on, the LDMOS M1 is turned off, the LDMOS M2 is turned on, the resistor R3 limits the drain discharge of the LDMOS M2, and the gate of the shielded gate trench MOS switch tube SGT1 is charged through vg1; vg2 is equal to the on-state voltage drop of the LDMOS M2, and the LDMOS M2 remains turned off.

4. The linear MOS switch tube for hot swapping according to claim 3, characterized in that: The start-up process also includes: when vg1 reaches the Miller platform of the shielded gate trench MOS switch tube SGT1, the shielded gate trench MOS switch tube SGT1 operates above the zero temperature point, and the temperature and current are negatively fed back; the surge current is borne by the shielded gate trench MOS switch tube SGT1.

5. The linear MOS switch tube for hot swapping according to claim 4, characterized in that: The start-up process also includes: when vg1 exceeds the Miller platform, the Zener diode D1 is turned on, the voltage drop of the resistor R1 causes the LDMOS M1 to be turned on, and the LDMOS M2 to be turned off, vg2=vg1, and the LDMOS M3 is turned off. vg1 charges the gate of the shielded gate trench MOS switch tube SGT2 through the resistor R3 to limit the current, and the shielded gate trench MOS switch tube SGT2 is turned on.

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