A low dropout linear regulator and a power supply device

Abstract

An embodiment of the present application discloses a low dropout linear regulator and a power supply device. The low dropout linear regulator includes a voltage dividing module, a switching module, a feedback module, and an energy storage module. The first end of the voltage dividing module is connected to the positive pole of the input power supply and the first end of the switching module. The second end of the voltage dividing module is connected to the second end of the switching module and the first end of the feedback module. The third end of the switching module is connected to the second end of the feedback module and the first end of the energy storage module. The second end of the energy storage module is connected to the third end of the voltage dividing module and the negative pole of the input power supply. Among them, the connection point between the third end of the switching module, the second end of the feedback module, and the first end of the energy storage module is the first connection point. The switching module is used to switch the switch state based on the voltage across the feedback module. Through the above method, the function of the low dropout linear regulator can be realized with a relatively simple circuit structure, and the cost is relatively low.

Description

Technical Field

[0001] This application relates to the technical field of electronic circuits, and particularly to a low dropout regulator and a power supply device. Background Art

[0002] In power supply, the low dropout regulator (LDO) is widely used in different output voltage domains due to its advantages of few peripheral components, low output noise, small output ripple, and simple circuit structure.

[0003] In the prior art, the function of the low dropout regulator is usually realized by a buck converter circuit (Buck circuit) or by a transformer plus rectification. However, for the buck converter circuit, its circuit structure is relatively complex and difficult to implement. For the transformer plus rectification method, it will lead to an overly large volume and high cost of the low dropout regulator. Summary of the Invention

[0004] The embodiments of this application aim to provide a low dropout regulator and a power supply device, which can realize the function of the low dropout regulator through a relatively simple circuit structure and have a low cost.

[0005] To achieve the above object, in a first aspect, this application provides a low dropout regulator, including:

[0006] A voltage division module, a switching module, a feedback module, and an energy storage module;

[0007] The first end of the voltage division module is connected to the positive pole of the input power supply and the first end of the switching module. The second end of the voltage division module is connected to the second end of the switching module and the first end of the feedback module. The third end of the switching module is connected to the second end of the feedback module and the first end of the energy storage module. The second end of the energy storage module is connected to the third end of the voltage division module and the negative pole of the input power supply. Among them, the connection point between the third end of the switching module, the second end of the feedback module, and the first end of the energy storage module is the first connection point;

[0008] The switching module is used to switch the switch state based on the voltage across the feedback module to control the connection state between the positive pole of the input power supply and the first connection point. Among them, the voltage at the first end of the feedback module is the voltage division of the input power supply by the voltage division module, and the voltage at the second end is the voltage at the first connection point.

[0009] In an optional manner, the voltage division module includes a first resistor and a second resistor connected in series;

[0010] The non - series end of the first resistor is connected to the positive pole of the input power supply. The connection point between the first resistor and the second resistor is connected to the second end of the switch module. The non - series end of the second resistor is connected to the negative pole of the input power supply.

[0011] In an alternative embodiment, the voltage - dividing module further includes a zener diode;

[0012] The anode of the zener diode is connected to the negative pole of the input power supply, and the cathode of the zener diode is connected to the non - series end of the second resistor.

[0013] In an alternative embodiment, the switch module includes a first switching transistor;

[0014] The control end of the first switching transistor is connected to the second end of the voltage - dividing module. The first end of the first switching transistor is connected to the first connection point, and the second end of the first switching transistor is connected to the positive pole of the input power supply.

[0015] In an alternative embodiment, the switch module further includes a third resistor and a clamping diode;

[0016] The first end of the third resistor is connected to the cathode of the clamping diode and the control end of the first switching transistor. The second end of the third resistor is connected to the second end of the voltage - dividing module. The anode of the clamping diode is connected to the first connection point.

[0017] In an alternative embodiment, the feedback module includes a fourth resistor and a first capacitor connected in parallel;

[0018] The first end of the circuit formed by the parallel connection of the fourth resistor and the first capacitor is connected to the second end of the voltage - dividing module and the second end of the switch module. The second end of the circuit formed by the parallel connection of the fourth resistor and the first capacitor is connected to the first connection point.

[0019] In an alternative embodiment, the energy - storage module includes a second capacitor;

[0020] Both ends of the second capacitor are respectively connected to the first connection point and the negative pole of the input power supply.

[0021] In an alternative embodiment, the low - dropout linear regulator further includes a current - limiting module;

[0022] Both ends of the current - limiting module are respectively connected to the input power supply and the first end of the switch module. The current - limiting module is used to limit the current input to the first end of the switch module.

[0023] In an alternative embodiment, the current - limiting module includes a fifth resistor and a first diode;

[0024] The first end of the fifth resistor is connected to the positive electrode of the input power supply, the second end of the fifth resistor is connected to the anode of the first diode, and the cathode of the first diode is connected to the first end of the switch module.

[0025] In an alternative embodiment, the low dropout linear regulator further includes a third capacitor;

[0026] Both ends of the third capacitor are respectively connected to the positive electrode and the negative electrode of the input power supply.

[0027] In a second aspect, an embodiment of the present application provides a power supply device including the low dropout linear regulator described in any one of the above.

[0028] The beneficial effects of the embodiments of the present application are as follows: The low dropout linear regulator provided by the present application includes a voltage dividing module, a switch module, a feedback module and an energy storage module. Among them, the first end of the voltage dividing module is connected to the positive electrode of the input power supply and the first end of the switch module, the second end of the voltage dividing module is connected to the first end of the switch module and the first end of the feedback module, the second end of the voltage dividing module is connected to the second end of the switch module and the first end of the feedback module, the third end of the switch module is connected to the second end of the feedback module and the first end of the energy storage module, the second end of the energy storage module is connected to the third end of the voltage dividing module and the negative electrode of the input power supply, the connection point among the third end of the switch module, the second end of the feedback module and the first end of the energy storage module is the first connection point, and the voltage at the first connection point is used as the supply voltage for the subsequent load. Therefore, when the voltage at the first connection point changes (increases or decreases), this change will act on the switch module at the same time, causing the switch module to switch its switch state to reversely regulate the voltage at the first connection point, so as to keep the output voltage stable, that is, the function of the low dropout linear regulator is realized. Moreover, each of the above modules can be implemented by a simple hardware circuit, and the cost is relatively low. Description of the Drawings

[0029] One or more embodiments are illustrated by way of example by pictures in the corresponding drawings. These exemplary illustrations do not limit the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, unless otherwise stated, and the drawings in the figures do not constitute a proportional limitation.

[0030] Figure 1 It is a schematic structural diagram of the low dropout linear regulator provided by the embodiment of the present application;

[0031] Figure 2 It is a schematic structural diagram of the low dropout linear regulator provided by another embodiment of the present application;

[0032] Figure 3Schematic diagram of the circuit structure of the low dropout linear regulator provided by the embodiment of the present application;

[0033] Figure 4 Characteristic curve diagram of the IGBT switch tube provided by the embodiment of the present application. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0035] Please refer to Figure 1 , Figure 1 Schematic diagram of the structure of the low dropout linear regulator provided by the embodiment of the present application. As Figure 1 shown, the low dropout linear regulator includes a voltage dividing module 10, a switching module 20, a feedback module 30 and an energy storage module 40. Among them, the first end of the voltage dividing module 10 is connected to the positive pole of the input power supply 200 and the first end of the switching module 20, the second end of the voltage dividing module 10 is connected to the second end of the switching module 20 and the first end of the feedback module 30, the second end of the energy storage module 40 is connected to the third end of the voltage dividing module 10 and the negative pole of the input power supply 200, and the third end of the switching module 20 is connected to the second end of the feedback module 30 and the first end of the energy storage module 40 at a first connection point P1.

[0036] Specifically, the switching state of the switching module 20 is determined by the voltage across the feedback module 30. The switching state of the switching module 20 includes both the conduction or cutoff of the switching module 20 and the conduction degree of the switching module 20. In other words, the voltage across the feedback module 30 can control the switching module 20 to be in a conducting or cutoff state. At the same time, it can also control the magnitude of the current flowing through the switching module 20.

[0037] Among them, the voltage at the end of the feedback module 30 connected to the voltage dividing module 10 is the voltage division of the input power supply 200 by the voltage dividing module 30, and the end of the feedback module 30 connected to the first connection point P1 is the voltage at the first connection point P1.

[0038] Moreover, the switching state of the switch module 20 determines the connection state between the positive pole of the input power supply 200 and the first connection point P1. When the switch module 20 is fully conducting, the voltage of the first connection point P1 is the voltage of the input power supply 200. When the conduction degree of the switch module 20 is between conduction and cutoff, the voltage of the first connection point P1 is the voltage of the input power supply 200 minus the voltage drop of the switch module 20. When the switch module 20 is fully cutoff, the connection between the first connection point P1 and the input power supply 200 is disconnected.

[0039] In practical applications, when the voltage at the first connection point P1 changes (increases or decreases), this voltage change will act on the switch module 20 simultaneously, causing the switch module 20 to switch its switching state. Furthermore, since the switch module 20 switches its switching state, the connection state between the input power supply 200 and the energy storage module 40 also changes accordingly, so as to reverse-regulate the voltage at the first connection point P1, thereby keeping the output voltage stable, that is, realizing the function of a low dropout linear regulator.

[0040] For example, when the first connection point P1 is used to connect a load with a relatively large required supply voltage, this will cause the voltage at the first connection point P1 to decrease. Then, since the voltage at one end of the feedback module 30 connected to the voltage dividing module 10 remains unchanged, the change value of the voltage difference across the feedback module 30 acts on the switch module 20, causing the conduction degree of the switch module 20 to increase, that is, the equivalent resistance of the switch module 20 becomes smaller, so the voltage input from the input power supply 200 to the first connection point P1 increases, thus realizing the regulation process of the voltage at the first connection point P1 and keeping the voltage at the first connection point P1 relatively stable.

[0041] It should be noted that the hardware structure of the low dropout linear regulator 100 as Figure 1 shown is only an example. Moreover, the low dropout linear regulator 100 may have more or fewer components than those shown in the figure, two or more components may be combined, or different component configurations may be adopted. The various components shown in the figure may be implemented in hardware, software, or a combination of hardware and software including one or more signal processing and / or application specific integrated circuits.

[0042] For example, in one embodiment, as Figure 2 shown, the low dropout linear regulator 100 further includes a current limiting module 50. The first end of the current limiting module 50 is connected to the first end of the voltage dividing module 10 and the positive pole of the input power supply 200, and the second end of the current limiting module 50 is connected to the first end of the switch module 20. Specifically, the current limiting module 50 is used to limit the voltage at the first end of the input switch module 20 to prevent the switch module 20 from being damaged due to an excessive input power supply 200, thereby playing a protective role for the switch module 20.

[0043] For a better understanding of the present application, taking Figure 3 the circuit structure of the low dropout linear regulator shown as an example for further illustration.

[0044] As Figure 3 shown, in an embodiment, the voltage dividing module 10 includes a first resistor R1 and a second resistor R2. The first resistor R1 and the second resistor R2 are connected in series and connected to the second connection point P2. One end of the first resistor R1 that is not connected to the second resistor R2 is connected to the positive electrode VIN+ of the input power supply 200, and one end of the second resistor R2 that is not connected to the first resistor R1 is connected to the negative electrode VIN- of the input power supply 200.

[0045] The voltage at the second connection point P2 is the voltage division of the input power supply 200 on the second resistor R2, and this voltage division is also the voltage at one end of the feedback module 30.

[0046] Furthermore, the voltage dividing module 10 further includes a zener diode DW1. The anode of the zener diode DW1 is connected to the negative electrode VIN- of the input power supply 200, and the cathode of the zener diode DW1 is connected to the non-series end of the second resistor R2 (that is, the end of the second resistor R2 that is not connected to the first resistor R1).

[0047] The zener diode DW1 is used to provide a reference voltage at the second connection point P2. When the voltage division of the positive electrode VIN+ of the input power supply 200 on the zener diode DW1 is less than the reverse breakdown voltage of the zener diode DW1, at this time, the reverse resistance of the zener diode DW1 is very large and the reverse current is extremely small, so the voltage at the second connection point P2 is basically 0. Only when the voltage division of the positive electrode VIN+ of the input power supply 200 on the zener diode DW1 is greater than the reverse breakdown voltage of the zener diode DW1, at this time, the zener diode DW1 is reversely broken down, the current of the zener diode DW1 can vary within a large range, while the voltage across it remains basically unchanged, thus providing a stable reference voltage.

[0048] In an embodiment, the switching module 20 includes a first switching tube. Still taking Figure 3 the circuit of the low dropout linear regulator shown as an example, wherein the first switching tube corresponds to the IGBT switching tube Q1.

[0049] The gate of the IGBT switching tube Q1 is connected to the second end of the voltage dividing module 10, that is, the gate of the IGBT switching tube Q1 is connected to the second connection point P2. The emitter of the IGBT switching tube Q1 is connected to the first connection point P1, and the collector of the IGBT switching tube Q1 is connected to the positive electrode VIN+ of the power supply 200. Among them, the first connection point P1 is also the positive electrode VOUT+ of the output power supply, that is, the voltage at the first connection point P1 can be used to provide a power supply voltage for the subsequent load.

[0050] Please refer to Figure 4 , Figure 4 , which is the characteristic curve graph of the IGBT switch provided by the embodiment of the present application. As Figure 4 shown, wherein, the horizontal axis represents the voltage between the gate and the emitter of the IGBT switch, and the vertical axis represents the current when the IGBT switch is working. It can be seen that the working voltage of the IGBT switch is between 5V and 12V. Therefore, its voltage range is wide, and the current flowing through the IGBT switch can be controlled by controlling the voltage between the gate and the emitter of the IGBT switch. At the same time, for products operating in a high-voltage environment, such as products in an environment above 600V, the IGBT switch can usually also be selected.

[0051] It should be understood that the first switch tube can be selected from one of a triode, a MOS tube, and an IGBT switch tube.

[0052] Taking the first switch tube as a triode as an example, at this time, the base of the triode is the control end of the first switch tube, the emitter of the triode is the first end of the first switch tube, and the collector of the triode is the second end of the first switch tube.

[0053] Taking the first switch tube as a MOS tube as an example, at this time, the gate of the MOS tube is the control end of the second switch tube, the source of the MOS tube is the first end of the second switch tube, and the drain of the MOS tube is the second end of the second switch tube.

[0054] Taking the first switch tube as an IGBT switch tube as an example, at this time, the gate of the IGBT switch tube is the control end of the second switch tube, the emitter of the IGBT switch tube is the first end of the second switch tube, and the collector of the IGBT switch tube is the second end of the second switch tube.

[0055] Optionally, please refer to Figure 3 again. The switching module 10 further includes a third resistor R3 and a clamping diode DW2. Among them, the first end of the third resistor R3 is connected to the cathode of the clamping diode DW2 and the gate of the IGBT switch tube Q1, the second end of the third resistor R3 is connected to the second end of the voltage dividing module, and the anode of the clamping diode DW2 is connected to the first connection point P1.

[0056] The third resistor R3 is used to limit the current of the gate of the IGBT switch tube Q1 to prevent the current of the gate of the IGBT switch tube Q1 from being too large and damaging the IGBT switch tube Q1. The clamping diode DW2 is used to clamp the voltage between the gate and the emitter of the IGBT switch tube to clamp the voltage between the gate and the emitter of the IGBT switch tube within 12V, that is, within the working voltage range of the IGBT switch tube Q1, to protect the IGBT switch tube Q1.

[0057] In some embodiments, the feedback module includes a fourth resistor R4 and a first capacitor C1. The first end of the circuit formed by the parallel connection of the fourth resistor R4 and the first capacitor C1 is connected to the second end of the voltage division module 10 and the second end of the switch module 20, and the second end of the circuit formed by the parallel connection of the fourth resistor R4 and the first capacitor C1 is connected to the first connection point P1. That is, the first end of the fourth resistor R4 and the first end of the first capacitor C1 are both connected to the first connection point P1, and the second end of the fourth resistor R4 and the second end of the first capacitor C1 are both connected to the second connection point P2.

[0058] The fourth resistor R4 is used as a feedback resistor, that is, the voltage across the fourth resistor R4 is almost equal to the voltage between the gate and the emitter of the IGBT switch Q1. The first capacitor C1 is used to filter the voltage at the first connection point P1 to filter out the interference signals in the voltage at the first connection point P1.

[0059] Optionally, the energy storage module 40 includes a second capacitor C2. The two ends of the second capacitor C2 are respectively connected to the first connection point P1 and the negative electrode VIN- of the input power supply 200 (which is also the negative electrode VOUT- of the output power supply).

[0060] The second capacitor C2 plays a role in energy storage and filtering. On the one hand, through the charging and discharging process of the second capacitor C2, the voltage at the first connection point P1 can become smooth during the rising and falling processes. On the other hand, it also filters the voltage at the first connection point P1 to filter out the high-frequency interference in the voltage at the first connection point P1.

[0061] Optionally, the current limiting module 50 includes a fifth resistor R5 and a first diode D1. Among them, the first end of the fifth resistor R5 is connected to the positive electrode VIN+ of the input power supply 200, the second end of the fifth resistor R5 is connected to the anode of the first diode D1, and the cathode of the first diode D1 is connected to the first end of the switch module 20, that is, the cathode of the first diode D1 is connected to the collector of the IGBT switch Q1.

[0062] The fifth resistor R5 plays a current limiting role, and the fifth resistor R5 can limit the current of the collector of the IGBT switch Q1. The first diode D1 is used to prevent the subsequent voltage from affecting the input voltage conversely. For example, when the first connection point P1 is connected to a load and the voltage at the first connection point P1 fluctuates due to reasons such as abnormal load, the first diode D1 can prevent the fluctuation from being transmitted to the positive electrode VIN+ of the input power supply 200 to protect the input power supply 200.

[0063] Further, the low dropout linear regulator further includes a third capacitor C3. The two ends of the third capacitor C3 are respectively connected to the positive electrode VIN+ and the negative electrode VIN- of the input power supply 200.

[0064] The third capacitor C3 is also used for energy storage and filtering, and its function is similar to that of the second capacitor C2. It is within the scope easily understood by those skilled in the art and will not be elaborated here.

[0065] In practical applications, when the positive electrode VOUT+ and the negative electrode VOUT- of the output power supply are not connected to the subsequent load, and at the moment of just powering on, the input power supply 200 forms a reference voltage greater than 0 at the second connection point P2 through the voltage division of the first resistor R1 and the second resistor R2. At this time, the voltage at the first connection point P1 is 0, so the voltage across the fourth resistor R4 is 0, that is, the voltage difference between the gate and the emitter of the IGBT switch Q1 is greater than the turn-on voltage of the IGBT switch Q1, and the IGBT switch Q1 conducts. At the same time, due to the current limiting of the fifth resistor R5 and the time required for the second capacitor C2 to charge, the voltage at the first connection point P1 gradually rises.

[0066] Subsequently, as the voltage at the first connection point P1 rises and the voltage at the second connection point P2 remains unchanged, the voltage difference between the first connection point P1 and the second connection point P2 gradually decreases, the voltage between the gate and the emitter of the IGBT switch Q1 gradually decreases, resulting in a gradual decrease in the conduction degree of the IGBT switch Q1. However, due to the energy storage effect of the second capacitor C2, the voltage at the first connection point P1 will still keep rising until the voltage at the first connection point P1 is almost equal to the voltage at the second connection point P2, and the IGBT switch Q1 turns off.

[0067] Furthermore, when the positive electrode VOUT+ and the negative electrode VOUT- of the output power supply are not connected to the subsequent load, the electric energy stored in the second capacitor C2 will be released to provide the supply voltage for the subsequent load. At this time, the voltage at the first connection point P1 will decrease, while the voltage at the second connection point P2 remains unchanged. Therefore, the voltage between the gate and the emitter of the IGBT switch Q1 gradually increases, the conduction degree of the IGBT switch Q1 increases, the amount of charge that the input power supply 200 charges the second capacitor C2 increases, and the electric energy stored in the second capacitor C2 can be increased, which causes the voltage at the first connection point P1 to increase. In other words, by controlling the conduction degree of the IGBT switch Q1, a dynamic balance process can be achieved between the electric energy discharged by the second capacitor C2 and the electric energy used by the input power supply 200 to charge the second capacitor C2, so that the voltage at the first connection point P1 remains relatively stable. Conversely, when the supply voltage required by the subsequent load decreases and the discharge speed of the second capacitor C2 slows down, it will also be fed back to the IGBT switch Q1 at the same time, and by controlling the conduction degree of the IGBT switch Q1, the charging speed of the second capacitor C2 can be slowed down, and a relatively stable output voltage can also be maintained at the first connection point P1.

[0068] It can be seen that as the required power supply voltage of the connected load varies, the conduction degree of the IGBT switch Q1 will be correspondingly changed to keep the voltage at the first connection point P1 stable. That is, while realizing the voltage regulation and step-down functions, this low-dropout linear regulator can also be applicable to different types of loads, with strong adaptability. And, from Figure 3 it can be known that the low-dropout linear regulator adopted all uses common small electrical components and has a small volume. At the same time, it is realized through a pure hardware circuit and does not need to use a dedicated chip, etc., with a low cost.

[0069] This application also provides a power supply device, which includes the low-dropout linear regulator in any of the above embodiments. Among them, in one embodiment, the power supply device can be an LDO power supply, that is, a switching power supply realized through an LDO.

[0070] The low-dropout linear regulator 100 provided in this application includes a voltage division module 10, a switching module 20, a feedback module 30, and an energy storage module 40. Among them, the first end of the voltage division module 10 is connected to the positive pole of the input power supply 200 and the first end of the switching module 20, the second end of the voltage division module 10 is connected to the first end of the switching module 20 and the first end of the feedback module 30, the second end of the voltage division module 10 is connected to the second end of the switching module 20 and the first end of the feedback module 30, the third end of the switching module 20 is connected to the second end of the feedback module 30 and the first end of the energy storage module 40, the second end of the energy storage module 40 is connected to the third end of the voltage division module 10 and the negative pole of the input power supply 200, and the connection point among the third end of the switching module 20, the second end of the feedback module 30, and the first end of the energy storage module 40 is the first connection point P1, and the voltage at the first connection point P1 is used as the power supply voltage for the subsequent load. Therefore, when the voltage at the first connection point P1 changes (increases or decreases), this change will act on the switching module 20 at the same time, causing the switching module 20 to switch its switching state to reversely regulate the voltage at the first connection point P1, so as to keep the output voltage stable, that is, the function of the low-dropout linear regulator is realized. And, each of the above modules can be realized through a simple hardware circuit, with a low cost.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting them; under the idea of the present application, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order, and there are many other changes in different aspects of the present application as described above. For the sake of brevity, they are not provided in detail; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A low dropout linear regulator, characterized in that, including: a voltage division module, a switching module, a feedback module and an energy storage module; the voltage division module includes a first resistor and a second resistor connected in series; the non-series end of the first resistor is connected to the positive pole of the input power supply, the connection point between the first resistor and the second resistor is the second connection point, and the non-series end of the second resistor is connected to the negative pole of the input power supply; the switching module includes a first switching tube; the control end of the first switching tube is connected to the second connection point, the first end of the first switching tube is connected to the first connection point, and the second end of the first switching tube is connected to the positive pole of the input power supply; the feedback module includes a fourth resistor and a first capacitor connected in parallel; the first end of the circuit after the fourth resistor and the first capacitor are connected in parallel is connected to the second connection point, and the second end of the circuit after the fourth resistor and the first capacitor are connected in parallel is connected to the first connection point; the energy storage module includes a second capacitor; both ends of the second capacitor are respectively connected to the first connection point and the negative pole of the input power supply; the switching module is used to switch the switch state based on the voltage across the feedback module to control the connection state between the positive pole of the input power supply and the first connection point, wherein the voltage at the first end of the feedback module is the voltage at the second connection point, and the voltage at the second end is the voltage at the first connection point.

2. The low dropout linear regulator according to claim 1, characterized in that the voltage division module further includes a zener diode; the anode of the zener diode is connected to the negative pole of the input power supply, and the cathode of the zener diode is connected to the non-series end of the second resistor.

3. The low dropout linear regulator according to claim 1, characterized in that the switching module further includes a third resistor and a clamping diode; the first end of the third resistor is connected to the cathode of the clamping diode and the control end of the first switching tube, the second end of the third resistor is connected to the second connection point, and the anode of the clamping diode is connected to the first connection point.

4. The low dropout linear regulator according to any one of claims 1-3, characterized in that the low dropout linear regulator further includes a current limiting module; both ends of the current limiting module are respectively connected to the input power supply and the second end of the first switching tube, and the current limiting module is used to limit the current input to the second end of the first switching tube.

5. The low dropout linear regulator according to claim 4, characterized in that the current limiting module includes a fifth resistor and a first diode; the first end of the fifth resistor is connected to the positive pole of the input power supply, the second end of the fifth resistor is connected to the anode of the first diode, and the cathode of the first diode is connected to the second end of the first switching tube.

6. The low dropout linear regulator according to claim 1, characterized in that the low dropout linear regulator further includes a third capacitor; both ends of the third capacitor are respectively connected to the positive pole and the negative pole of the input power supply.

7. A power supply device, characterized in that, including the low dropout linear regulator according to any one of claims 1-6.

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