Buck converter and power supply apparatus

Abstract

The invention discloses a buck converter and a power supply device. The buck converter comprises a first MOS tube, a second MOS tube, an inductor, an electric signal detection module and a switch control module. The electric signal detection module is used for acquiring a first electric signal of the drain electrode of the second MOS transistor and a second electric signal of the source electrode of the second MOS transistor, identifying the current characteristic of a loop where the inductor is located according to the first electric signal and the second electric signal, and when the current characteristic meets a preset condition, outputting the current characteristic of the loop. A turn-off signal used for turning off the second MOS tube is output; the preset condition comprises a condition representing that an input power supply is damaged after inductive current flows into the voltage input end; and the switch control module is used for controlling the second MOS tube to be turned off when receiving a turn-off signal. According to the invention, reverse current can be prevented from hitting back to the voltage input end, and the chip and peripheral passive components can be prevented from being damaged due to overhigh voltage of the voltage input end, so that the performance of the buck converter can be improved.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a buck converter and a power supply device. Background Art

[0002] When the buck converter is in FCCM (Forced Continuous Conduction Mode) mode, if the output voltage is too high, reverse current may be generated, and the reverse current can easily return to the input, causing the input voltage to be too high. This phenomenon may cause the following problems: (1) Reverse current loss, that is, under light load or no-load conditions, the inductor current will flow in the reverse direction, increasing losses; (2) Reverse current noise: The flow of reverse current may introduce additional electromagnetic interference. It can be seen that the reverse current generated by the buck converter in FCCM mode can easily affect the performance of the buck converter. Summary of the invention

[0003] In view of this, the present application provides a buck converter and a power supply device to solve the problem that the buck converter generates a reverse current in the FCCM mode, which easily affects the performance of the buck converter.

[0004] A buck converter provided in the present application includes a first MOS tube, a second MOS tube, an inductor, an electrical signal detection module and a switch control module; The drain of the first MOS tube is connected to the voltage input terminal, and the source is respectively connected to the first end of the inductor, the first detection end of the electrical signal detection module and the drain of the second MOS tube; the second end of the inductor is connected to the voltage output terminal; the source of the second MOS tube is connected to the second detection end of the electrical signal detection module; the output end of the electrical signal detection module is connected to the gate of the second MOS tube through the switch control module; The electrical signal detection module is used to obtain a first electrical signal of the drain of the second MOS transistor and a second electrical signal of the source of the second MOS transistor, identify the current characteristics of the loop where the inductor is located according to the first electrical signal and the second electrical signal, and output a shutdown signal for shutting down the second MOS transistor when the current characteristics meet a preset condition; the preset condition includes a condition indicating that the inductor current will damage the input power supply after flowing into the voltage input terminal; The switch control module is used to control the second MOS tube to turn off when receiving a shutdown signal.

[0005] Optionally, the first electrical signal includes the drain voltage of the second MOS tube, and the second electrical signal includes the source voltage of the second MOS tube; the electrical signal detection module is used to obtain the difference between the drain voltage and the source voltage, and if the difference is greater than a preset protection threshold, the shutdown signal is output.

[0006] Optionally, the electrical signal detection module includes a voltage difference acquisition unit and a first comparator; the first input end of the voltage difference acquisition unit serves as the first detection end of the electrical signal detection module, connected to the drain of the second MOS tube, the second input end serves as the second detection end of the electrical signal detection module, connected to the source of the second MOS tube, and the output end is connected to the first input end of the first comparator; the second input end of the first comparator is used to access the protection threshold, and the output end is connected to the control end of the switch control module, used to output the shutdown signal; the voltage difference acquisition unit is used to obtain the difference between the drain voltage and the source voltage; the first comparator is used to output the shutdown signal when the difference is greater than a preset protection threshold.

[0007] Optionally, the first electrical signal includes a drain voltage of the second MOS tube, and the second electrical signal includes a source voltage of the second MOS tube; the electrical signal detection module is used to output the shutdown signal when the drain voltage is greater than the source voltage.

[0008] Optionally, the electrical signal detection module includes a second comparator; the first input end of the second comparator serves as the first detection end of the electrical signal detection module, connected to the drain of the second MOS tube, the second input end serves as the second detection end of the electrical signal detection module, connected to the source of the second MOS tube, and the output end is connected to the control end of the switch control module, for outputting the shutdown signal.

[0009] Optionally, the switch control module includes a switch unit; the control end of the switch unit is connected to the output end of the electrical signal detection module, the first end is connected to the gate of the second MOS tube, and the second end is used to access the turn-on voltage of the second MOS tube, and is used to disconnect when the control end thereof is connected to the shutdown signal.

[0010] Optionally, the buck converter further includes a capacitor; a first end of the capacitor is connected to the voltage output end, and a second end of the capacitor is grounded.

[0011] Optionally, the control end of the switch control module is connected to the output end of the electrical signal detection module, and the first end is used to access the conduction voltage; the buck converter also includes a first inverting unit and a second inverting unit; the first end of the first inverting unit is used to access the conduction voltage, and the second end is connected to the gate of the first MOS tube; the first end of the second inverting unit is respectively connected to the first end of the second inverting unit and the control end of the switch control module, and the second end is connected to the gate of the first MOS tube; the second end of the second inverting unit is connected to the gate of the second MOS tube; the first inverting unit and the second inverting unit are used to assist each other to turn on one of the first MOS tube and the second MOS tube when the switch control module is turned on, and turn off the other of the first MOS tube and the second MOS tube.

[0012] The present application also provides a power supply device, which includes at least one buck converter of any one of the above types.

[0013] In the above-mentioned buck converter and power supply device of the present application, the electrical signal detection module can obtain the first electrical signal of the drain of the second MOS tube and the second electrical signal of the source of the second MOS tube, identify the current characteristics of the loop where the inductor is located according to the first electrical signal and the second electrical signal, and output a shutdown signal for shutting down the second MOS tube when the current characteristics meet the preset condition that characterizes that the inductor current will damage the input power supply after flowing into the voltage input terminal. When receiving the shutdown signal, the switch control module controls the second MOS tube to shut down to exit the working mode in which one of the first MOS tube and the second MOS tube is turned on and the other is turned off. At this time, the inductor current becomes zero, which can prevent the reverse current from returning to the voltage input terminal, and the voltage at the voltage input terminal stops rising and remains in a stable state, which can prevent the voltage at the voltage input terminal from being too high to damage the chip and peripheral passive components, thereby improving the performance of the buck converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] 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 those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 It is a schematic diagram of the buck converter structure during the research process of this application; Figure 2 It is a schematic diagram of the change of electrical signals of the buck converter during the research process of this application; Figure 3 is a schematic diagram of the structure of a buck converter according to an embodiment of the present application; Figure 4is a schematic diagram of electrical signal changes of a buck converter according to an embodiment of the present application; Figure 5 is a schematic diagram of the structure of a buck converter according to another embodiment of the present application; Figure 6 is a schematic diagram of the structure of a buck converter according to another embodiment of the present application; Figure 7 is a schematic diagram of the structure of a buck converter according to another embodiment of the present application; Figure 8 is a schematic diagram of the structure of a buck converter according to another embodiment of the present application; Fig. 9 It is a schematic diagram of the structure of a buck converter according to another embodiment of the present application. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application are clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In the absence of conflict, the following embodiments and their technical features can be combined with each other.

[0017] by Figure 1 The simplified schematic diagram of the buck converter shown in the figure explains the change process of its input voltage and output voltage. Figure 1 Where Vin is the input voltage and Vout is the output voltage. In FCCM mode, the buck converter always forces the inductor current to flow continuously in both directions regardless of the load. This means that even if the load is light or the inductor current becomes negative (flowing in the reverse direction), the switch will still switch at the predetermined frequency. For example, refer to Figure 1 As shown in Figure 1, when the output voltage Vout is too high, it may cause the current in the inductor L to flow in the opposite direction (i.e., reverse current). The reverse current IL at the inductor L will return to the input through the low-side switch or the freewheeling diode, such as reference Figure 2 shown.

[0018] When the reverse current returns to the input, it will be re-injected into the input power supply. If the capacitor at the input cannot effectively absorb the reverse current, the input voltage will rise, or even be too high to damage the chip and peripheral passive components. Therefore, the reverse current generated by the buck converter in FCCM mode can easily affect the performance of the buck converter and may also damage the corresponding chip or power supply equipment.

[0019] In view of the above problems, the present application provides a first aspect of a buck converter, referring to Figure 3As shown, the buck converter includes a first MOS transistor Q1 , a second MOS transistor Q2 , an inductor L, an electrical signal detection module 100 and a switch control module 200 .

[0020] The drain of the first MOS transistor Q1 is connected to the voltage input terminal Vin, and the source is respectively connected to the first end of the inductor L, the first detection end of the electrical signal detection module 100 and the drain of the second MOS transistor Q2; the second end of the inductor L is connected to the voltage output terminal Vout. The source of the second MOS transistor Q2 is connected to the second detection end of the electrical signal detection module 100. The output end of the electrical signal detection module 100 is connected to the gate of the second MOS transistor Q2 through the switch control module 200. Optionally, the control end of the switch control module 200 is connected to the output end of the electrical signal detection module 100, the first end is used to access the conduction voltage, and the second end is connected to the gate of the second MOS transistor Q2. When the buck converter is working normally, one of the first MOS transistor Q1 and the second MOS transistor Q2 is turned on and the other is turned off, so that the inductor L is continuously turned on to achieve voltage conversion.

[0021] The electrical signal detection module 100 is used to obtain a first electrical signal of the drain of the second MOS transistor Q2 and a second electrical signal of the source of the second MOS transistor Q2, identify the current characteristics of the loop where the inductor L is located according to the first electrical signal and the second electrical signal, and output a shutdown signal for shutting down the second MOS transistor Q2 when the current characteristics meet the preset conditions. The preset conditions include the condition that the inductor current will damage the input power supply after flowing into the voltage input terminal Vin; optionally, the preset conditions include the inductor current direction condition that the inductor current flows from the near voltage output terminal Vout of the inductor L to the far voltage output terminal Vout of the inductor L; optionally, the preset conditions include the condition that the inductor current has a certain threshold value, and the current flows into the voltage input terminal and damages the input power supply.

[0022] The switch control module 200 is used to control the second MOS transistor Q2 to turn off when receiving the shutdown signal, so as to exit the working mode in which one of the first MOS transistor Q1 and the second MOS transistor Q2 is turned on and the other is turned off. Figure 4 As shown by the middle dotted line, the inductor current becomes zero, preventing the reverse current from flowing back to the voltage input terminal Vin, and the voltage Vin at the voltage input terminal Vin stops rising and can be kept in a stable state, thereby preventing the voltage Vin at the voltage input terminal Vin from being too high and damaging the chip and peripheral passive components; Figure 4 Where Vin is the input voltage, Vout is the output voltage, and IL represents the current flowing through the inductor L.

[0023] Furthermore, the electrical signal detection module 100 can also stop outputting the shutdown signal when the current characteristic exceeds the range of the preset condition (that is, does not meet the preset condition) to enable the second MOS tube Q2 to work normally. At this time, one of the first MOS tube Q1 and the second MOS tube Q2 is turned on and the other is turned off, and this cycle is repeated to make the inductor L continuously turned on, and the buck converter performs the voltage conversion work normally.

[0024] Optionally, the shutdown signal may include a signal for stopping providing a turn-on voltage to the gate of the second MOS transistor Q2, or may include other signals for shutting down the second MOS transistor Q2.

[0025] In the above-mentioned buck converter, the electrical signal detection module 100 can obtain a first electrical signal of the drain of the second MOS transistor Q2 and a second electrical signal of the source of the second MOS transistor Q2, identify the current characteristics of the loop where the inductor L is located according to the first electrical signal and the second electrical signal, and output a shutdown signal for shutting down the second MOS transistor Q2 when the current characteristics meet the preset condition that the inductor current will damage the input power supply after flowing into the voltage input terminal. When receiving the shutdown signal, the switch control module 200 controls the second MOS transistor Q2 to shut down, so as to exit the working mode in which one of the first MOS transistor Q1 and the second MOS transistor Q2 is turned on and the other is turned off. At this time, the inductor current becomes zero, which can prevent the reverse current from flowing back to the voltage input terminal Vin, and the voltage Vin of the voltage input terminal Vin stops rising and remains in a stable state, which can prevent the voltage Vin of the voltage input terminal Vin from being too high to damage the chip and peripheral passive components, thereby improving the performance of the buck converter.

[0026] In some embodiments, the first electrical signal includes the drain voltage of the second MOS transistor Q2, and the second electrical signal includes the source voltage of the second MOS transistor Q2. The electrical signal detection module 100 is used to obtain the difference between the drain voltage and the source voltage, and if the difference between the drain voltage and the source voltage is greater than a preset protection threshold, a shutdown signal is output to enable the switch control module 200 to shut down the second MOS transistor Q2 according to the shutdown signal.

[0027] Optionally, the protection threshold can be set according to factors such as the maximum current flowing through the inductor L. If the difference between the drain voltage and the source voltage is greater than the protection threshold, it indicates that the inductor current will damage the input power supply after flowing into the voltage input terminal Vin. At this time, the second MOS tube Q2 needs to be turned off to prevent the inductor current from flowing into the voltage input terminal Vin. Optionally, the protection threshold can also be called an overcurrent protection value of a negative current, which can be set to I0*k1, where I0 represents the maximum current flowing through the inductor L, and k1 represents a preset coefficient, which can be 1.5 or the like.

[0028] In one example, reference Figure 5As shown, the electrical signal detection module 100 includes a voltage difference acquisition unit 110 and a first comparator 120 .

[0029] The first input end of the voltage difference acquisition unit 110 serves as the first detection end of the electrical signal detection module 100, and is connected to the drain of the second MOS tube Q2. The second input end serves as the second detection end of the electrical signal detection module 100, and is connected to the source of the second MOS tube Q2. The output end is connected to the first input end (such as the positive input end) of the first comparator 120; the second input end (such as the negative input end) of the first comparator 120 is used to access the protection threshold, and the output end is connected to the control end of the switch control module 200, and is used to output the shutdown signal.

[0030] The voltage difference acquisition unit 110 is used to acquire the difference between the drain voltage and the source voltage; the first comparator 120 is used to output the shutdown signal when the difference is greater than a preset protection threshold. Optionally, the voltage difference acquisition unit 110 can be implemented using components such as a difference circuit.

[0031] In some embodiments, the first electrical signal includes the drain voltage of the second MOS transistor Q2, and the second electrical signal includes the source voltage of the second MOS transistor Q2. The electrical signal detection module 100 is used to output the shutdown signal when the drain voltage is greater than the source voltage. Here, the drain voltage of the second MOS transistor Q2 is greater than the source voltage, indicating that the inductor current is about to flow into the voltage input terminal Vin. At this time, the shutdown signal is output to shut down the second MOS transistor Q2, which can effectively prevent the inductor current from continuing to flow into the voltage input terminal Vin.

[0032] In some examples, reference Figure 6 As shown, the electrical signal detection module 100 includes a second comparator 130. The first input terminal (such as the positive input terminal) of the second comparator 130 serves as the first detection terminal of the electrical signal detection module 100, connected to the drain of the second MOS tube Q2, the second input terminal (such as the negative input terminal) serves as the second detection terminal of the electrical signal detection module 100, connected to the source of the second MOS tube Q2, and the output terminal is connected to the control terminal of the switch control module 200, for outputting the shutdown signal. This example can use a relatively simple structure to implement the voltage detection function of the electrical signal detection module 100, which can simplify the circuit structure of the corresponding buck converter.

[0033] In some embodiments, reference Figure 7 and Figure 8As shown, the switch control module 200 includes a switch unit 210. The control end of the switch unit 210 is connected to the output end of the electrical signal detection module 100, the first end is connected to the gate of the second MOS transistor Q2, and the second end is used to access the conduction voltage of the second MOS transistor Q2. The switch unit 210 is used to disconnect when the control end thereof is connected to the shutdown signal, so as to stop connecting the conduction voltage to the second MOS transistor Q2, thereby shutting down the second MOS transistor Q2.

[0034] In some examples, the switch unit 210 may be implemented using components such as a switch tube; in other examples, the switch unit 210 may also be implemented using other switch components.

[0035] In some embodiments, reference Fig. 9 As shown, the buck converter further includes a capacitor Cout; a first end of the capacitor Cout is connected to the voltage output end Vout, and a second end of the capacitor Cout is grounded.

[0036] In some examples, the control end of the switch control module 200 is connected to the output end of the electrical signal detection module 100, and the first end is used to access the conduction voltage. The buck converter also includes a first inverting unit 310 and a second inverting unit 320. The first end of the first inverting unit 310 is respectively connected to the first end of the second inverting unit 320 and the control end of the switch control module 200, and the second end is connected to the gate of the first MOS tube Q1; the second end of the second inverting unit 320 is connected to the gate of the second MOS tube Q2; the first inverting unit 310 and the second inverting unit 320 are used to assist each other to turn on one of the first MOS tube Q1 and the second MOS tube Q2 when the switch control module 200 is turned on (such as the switch unit 210 is turned on), and turn off the other of the first MOS tube Q1 and the second MOS tube Q2.

[0037] Furthermore, when the control terminal of the switch control module 200 receives a shutdown signal, the on signal received by the second MOS transistor Q2 can be disconnected to at least shut down the second MOS transistor Q2.

[0038] Specifically, the first inverting unit 310 and the second inverting unit 320 may respectively include at least one inverter, one of the first inverting unit 310 and the second inverting unit 320 includes an odd number of inverters, and the other includes an even number of inverters, so that after the conduction signal is connected through the switch control module 200, one of the first MOS tube Q1 and the second MOS tube Q2 is turned on and the other is turned off.

[0039] In the above buck converter, the electrical signal detection module 100 can obtain a first electrical signal of the drain of the second MOS transistor Q2 and a second electrical signal of the source of the second MOS transistor Q2, identify the current characteristics of the loop where the inductor L is located according to the first electrical signal and the second electrical signal, and output a shutdown signal for shutting down the second MOS transistor Q2 when the current characteristics meet the preset condition that the inductor current will damage the input power supply after flowing into the voltage input terminal. When receiving the shutdown signal, the switch control module 200 controls the second MOS transistor Q2 to shut down, so as to exit the working mode in which one of the first MOS transistor Q1 and the second MOS transistor Q2 is turned on and the other is turned off. At this time, the inductor current becomes zero, which can prevent the reverse current from returning to the voltage input terminal Vin, and the voltage Vin of the voltage input terminal Vin stops rising and remains in a stable state, which can prevent the voltage Vin of the voltage input terminal Vin from being too high to damage the chip and peripheral passive components, thereby improving the performance of the buck converter.

[0040] A second aspect of the present application provides a power supply device, which includes at least one buck converter as described in any of the above embodiments.

[0041] The above-mentioned power supply device includes the buck converter described in any of the above-mentioned embodiments, and has all the beneficial effects of the buck converter described in any of the above-mentioned embodiments, which will not be repeated here.

[0042] Although the present application has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art based on reading and understanding this specification and the accompanying drawings. The present application includes all such modifications and variations and is limited only by the scope of the appended claims. In particular, with respect to the various functions performed by the above-mentioned components, the terms used to describe such components are intended to correspond to any component (unless otherwise indicated) that performs the specified function of the component (e.g., it is functionally equivalent), even if it is not structurally equivalent to the disclosed structure that performs the function in the exemplary implementation of the present specification shown herein.

[0043] That is, the above description is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the specification and drawings of the present application, such as the mutual combination of technical features between the embodiments, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

[0044] In addition, in the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, for structural elements with the same or similar characteristics, the present application may use the same or different reference numerals for identification. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0045] In this application, the word "exemplary" is used to mean "used as an example, illustration or description". Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or more advantageous than other embodiments. In order to enable any technician in the field to implement and use the present application, the present application provides the above description. In the above description, various details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present application can be implemented without using these specific details. In other embodiments, well-known structures and processes will not be elaborated in detail to avoid unnecessary details that make the description of the present application obscure. Therefore, the present application is not intended to be limited to the embodiments shown, but is consistent with the widest range of principles and features disclosed in the present application.

Claims

1. A buck converter, characterized in that: The buck converter includes a first MOS tube, a second MOS tube, an inductor, an electrical signal detection module and a switch control module; The drain of the first MOS tube is connected to the voltage input terminal, and the source is respectively connected to the first end of the inductor, the first detection end of the electrical signal detection module and the drain of the second MOS tube; the second end of the inductor is connected to the voltage output terminal; the source of the second MOS tube is connected to the second detection end of the electrical signal detection module; the output end of the electrical signal detection module is connected to the gate of the second MOS tube through the switch control module; The electrical signal detection module is used to obtain a first electrical signal of the drain of the second MOS transistor and a second electrical signal of the source of the second MOS transistor, identify the current characteristics of the loop where the inductor is located according to the first electrical signal and the second electrical signal, and output a shutdown signal for shutting down the second MOS transistor when the current characteristics meet a preset condition; the preset condition includes a condition indicating that the inductor current will damage the input power supply after flowing into the voltage input terminal; The switch control module is used to control the second MOS tube to turn off when receiving a shutdown signal.

2. The buck converter according to claim 1, characterized in that The first electrical signal includes a drain voltage of the second MOS transistor, and the second electrical signal includes a source voltage of the second MOS transistor; The electrical signal detection module is used to obtain the difference between the drain voltage and the source voltage, and output the shutdown signal if the difference is greater than a preset protection threshold.

3. The buck converter according to claim 2, characterized in that The electrical signal detection module includes a voltage difference acquisition unit and a first comparator; The first input end of the voltage difference acquisition unit is used as the first detection end of the electrical signal detection module, connected to the drain of the second MOS tube, the second input end is used as the second detection end of the electrical signal detection module, connected to the source of the second MOS tube, and the output end is connected to the first input end of the first comparator; the second input end of the first comparator is used to access the protection threshold, and the output end is connected to the control end of the switch control module, so as to output the shutdown signal; The voltage difference acquisition unit is used to acquire the difference between the drain voltage and the source voltage; the first comparator is used to output the shutdown signal when the difference is greater than a preset protection threshold.

4. The buck converter according to claim 1, wherein: The first electrical signal includes a drain voltage of the second MOS transistor, and the second electrical signal includes a source voltage of the second MOS transistor; The electrical signal detection module is used to output the shutdown signal when the drain voltage is greater than the source voltage.

5. The buck converter according to claim 4, characterized in that The electrical signal detection module includes a second comparator; The first input end of the second comparator serves as the first detection end of the electrical signal detection module, connected to the drain of the second MOS tube; the second input end serves as the second detection end of the electrical signal detection module, connected to the source of the second MOS tube; the output end is connected to the control end of the switch control module, and is used to output the shutdown signal.

6. The buck converter according to claim 1, wherein: The switch control module includes a switch unit; The control end of the switch unit is connected to the output end of the electrical signal detection module, the first end is connected to the gate of the second MOS tube, and the second end is used to access the conduction voltage of the second MOS tube and to disconnect when the control end thereof is connected to the shutdown signal.

7. The buck converter according to claim 1, wherein: The buck converter also includes a capacitor; The first end of the capacitor is connected to the voltage output end, and the second end is grounded.

8. The buck converter according to claim 1, wherein: The control end of the switch control module is connected to the output end of the electrical signal detection module, and the first end is used to access the conduction voltage; the buck converter also includes a first inverting unit and a second inverting unit; The first end of the first inverting unit is used to access the conduction voltage, and the second end is connected to the gate of the first MOS tube; the first end of the second inverting unit is respectively connected to the first end of the second inverting unit and the control end of the switch control module, and the second end is connected to the gate of the first MOS tube; the second end of the second inverting unit is connected to the gate of the second MOS tube; The first inverting unit and the second inverting unit are used to assist each other to turn on one of the first MOS tube and the second MOS tube and turn off the other of the first MOS tube and the second MOS tube when the switch control module is turned on.

9. A power supply device, characterized in that: The power supply device comprises at least one buck converter according to any one of claims 1 to 8.

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