Switching Power Supply

Abstract

The invention provides a switching power supply, comprising: a hot-swap detector, a first-stage output negative feedback module, a second-stage output negative feedback module, a second-stage output negative feedback module, and a power chip; wherein the power chip, the load, and the hot-swap detector are connected in series in sequence; the first-stage output negative feedback module, the second-stage output negative feedback module, and the second-stage output negative feedback module are connected in parallel, and one end after the parallel connection is connected to one end of the power chip through a negative feedback resistor; the hot-swap detector is used to input a generated first current signal into the first-stage output negative feedback module, the second-stage output negative feedback module, and the second-stage output negative feedback module when a load is connected; the power chip is used to output the voltage of one of the first-stage output negative feedback module, the second-stage output negative feedback module, and the second-stage output negative feedback module as an output voltage according to different loads to meet the working voltage of the load.

Description

Technical Field

[0001] The present invention relates to the field of circuits, and in particular to a switching power supply. Background Art

[0002] In engineering applications, industrial touch screens often require a variety of different voltages such as 12V, 5V, and 3.3V, but the adapters currently on the market can only output a constant voltage, and thus cannot automatically adjust the output voltage value according to the load. The above problems bring great inconvenience to actual engineering applications. At the same time, when there is no load connected, the power supply will consume a certain amount of power because some of its own components are still working, which is not conducive to energy saving.

[0003] There is currently no effective solution to the above-mentioned problems in the related art. Summary of the invention

[0004] The embodiment of the present invention provides a switching power supply to at least solve the problem in the related art that the adapter can only output a constant voltage, resulting in the inability to automatically adjust the output voltage value according to different loads.

[0005] According to one embodiment of the present invention, a switching power supply is provided, comprising: a hot-swap detector, a first-stage output negative feedback module, a second-stage output negative feedback module, a second-stage output negative feedback module, and a power chip; wherein the power chip, the load, and the hot-swap detector are connected in series in sequence; the first-stage output negative feedback module, the second-stage output negative feedback module, and the second-stage output negative feedback module are connected in parallel, and one end of the parallel connection is connected to one end of the power chip through a negative feedback resistor; the hot-swap detector is used to input the generated first current signal into the first-stage output negative feedback module, the second-stage output negative feedback module, and the second-stage output negative feedback module when a load is connected; the power chip is used to output the voltage of one of the first-stage output negative feedback module, the second-stage output negative feedback module, and the second-stage output negative feedback module as an output voltage according to different loads to meet the working voltage of the load.

[0006] Optionally, the switching power supply also includes: a first relay and a first MOS tube; one end of the first relay is connected to one end of the hot plug detector for receiving the generated first current signal; the other end of the first relay is connected to the gate of the first MOS tube, and another end of the first relay is connected to a first resistor for receiving an input voltage; the drain of the first MOS tube receives the input voltage, the source of the first MOS tube is connected to a second resistor in parallel and one end of a power chip, and the other end of the second resistor is grounded.

[0007] Optionally, the first current controller in the first-stage output negative feedback module is used to receive the first current signal generated by the power chip and is connected to one end of the second relay, one end of the second relay connected in parallel with the third relay is connected to the source of the second MOS tube, the other end of the second relay connected in parallel with the third relay is grounded, and outputs a second current signal; another end of the third relay is used to receive the third current signal generated by the power chip; the gate input voltage of the second MOS tube, the drain of the second MOS tube is connected to the first negative feedback resistor, the first negative feedback resistor is connected in parallel to the power chip and the In the circuit of the load; the drain of the seventh MOS tube in the first-stage output negative feedback module is connected to one end of the eleventh resistor, the other end of the eleventh resistor is connected to the gate of the second MOS tube, the gate of the seventh MOS tube is connected to one end of the seventh relay and the eighth relay connected in parallel, the other ends of the seventh relay and the eighth relay connected in parallel are connected to one end of the twelfth resistor, and the other end of the twelfth resistor is connected to the input voltage; the end of the eleventh resistor connected to the gate of the second MOS tube is connected to the thirteenth resistor and the fourteenth resistor in parallel, the other end of the fourteenth resistor is grounded, and the other end of the thirteenth resistor is connected to the input voltage.

[0008] Optionally, the gate of the third MOS tube in the second-stage output negative feedback module is connected to one end of the fourth relay, the other end of the fourth relay is connected to one end of the third resistor, the other end of the third resistor is grounded, and another end of the fourth relay is used to receive the second current signal output by the first-stage output negative feedback; the drain of the third MOS tube is connected to one end of the fourth resistor, the other end of the fourth resistor is connected to the gate of the fourth MOS tube; the source of the third MOS tube is connected to the fifth resistor and the sixth resistor connected in series, and the other end of the sixth resistor is connected to the input voltage; the source of the fourth MOS tube in the second-stage output negative feedback module is connected to the fifth resistor and the sixth resistor connected in series The second current controller is connected to the ninth relay and one end of the fifteenth resistor. The second current controller connected in series, the ninth relay and the fifteenth resistor are connected in parallel with the tenth relay, and one end of the parallel connection is grounded; the drain of the fourth MOS tube is connected to the sixteenth resistor, and the other end of the sixteenth resistor receives the input voltage; the other end of the tenth relay is connected to the source of the fourth MOS tube; the source of the fourth MOS tube is also connected to the gate of the eighth MOS tube, the source of the eighth MOS tube is grounded, and outputs a fourth current signal; the drain of the eighth MOS tube is connected to one end of the second negative feedback resistor, and the other end of the second negative feedback is connected to the input voltage.

[0009] Optionally, the gate of the fifth MOS transistor in the third-stage output negative feedback module is connected to one end of the fifth relay and the sixth relay connected in parallel. The other end of the fifth relay and the sixth relay connected in parallel is connected to the seventh resistor. The other end of the seventh circuit is connected to the input voltage. The other end of the fifth relay is used to receive the second current signal. The drain of the fifth MOS transistor is connected to one end of the eighth resistor. The other end of the eighth resistor is connected to the gate of the sixth MOS transistor. The source of the fifth MOS transistor is connected to one end of the ninth resistor and the tenth resistor connected in series. The other end of the ninth resistor and the tenth resistor connected in series is connected to the input voltage.

[0010] Optionally, one ends of the first negative feedback resistor, the second negative feedback resistor, and the third negative feedback resistor are connected in parallel and then connected to the negative feedback resistor.

[0011] Optionally, the first resistor, the third resistor, the seventh resistor, and the second resistor are current-limiting resistors.

[0012] Optionally, the eleventh resistor, the thirteenth resistor, and the fourteenth resistor satisfy the following relationship:

[0013] R01 = R11 * R14 / (R11 + R14);

[0014] Vgs2 = R01 / (R01 + R13) * VInPut, and Vgs2 < Vtm2;

[0015] Wherein, R11 is the resistance value of the eleventh resistor, R14 is the resistance value of the fourteenth resistor, R13 is the resistance value of the thirteenth resistor; VInPut is the input voltage of the thirteenth resistor; Vgs2 is the voltage of the gate of the second MOS transistor relative to the source, and Vtm2 is the conduction voltage of the second MOS transistor.

[0016] Optionally, the fourth resistor, the fifth resistor, and the sixth resistor satisfy the following relationship:

[0017] R02 = R4 * R6 / (R4 + R6);

[0018] Vgs4 = R02 / (R02 + R5) * VInPut, and Vgs4 < Vtm4; At the same time, it satisfies that Vgs4 = R6 / (R6 + R5) * VInPut, and Vgs4 > Vtm5;

[0019] Wherein, R4 is the resistance value of the fourth resistor, R5 is the resistance value of the fifth resistor, R6 is the resistance value of the sixth resistor; VInPut is the input voltage of the fifth resistor; Vgs4 is the voltage of the gate of the fourth MOS transistor relative to the source, and Vtm4 is the conduction voltage of the fourth MOS transistor.

[0020] Optionally, the eighth resistor, the ninth resistor, and the tenth resistor satisfy the following relationship:

[0021] R03 = R8 * R9 / (R8 + R9);

[0022] Vgs6 = R03 / (R03 + R10) * VInPut, and Vgs6 < Vtm6; At the same time, it satisfies that Vgs6 = R9 / (R9 + R10) * VInPut, and Vgs6 > Vtm6;

[0023] Wherein, R8 is the resistance value of the eighth resistor, R9 is the resistance value of the ninth resistor, R10 is the resistance value of the tenth resistor; VInPut is the input voltage of the tenth resistor; Vgs6 is the voltage of the gate of the sixth MOS transistor relative to the source, and Vtm6 is the conduction voltage of the sixth MOS transistor.

[0024] Through the present invention, in the case where a load is connected, the hot plug detector inputs the generated first current signal into the first-stage output negative feedback module, the second-stage output negative feedback module, and the second-stage output negative feedback module; and then the power supply chip outputs the voltage of one of the first-stage output negative feedback module, the second-stage output negative feedback module, and the second-stage output negative feedback module according to the different loads as the output voltage to satisfy the working voltage of the load, realizing automatically adjusting the voltage required by the output load according to the different loads, solving the problem in the related art that the adapter can only output a constant voltage, resulting in the inability to automatically adjust the output voltage value according to the different loads, achieving the effects of reducing the engineering quantity and being more energy-saving. Description of the Drawings

[0025] The drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and the schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0026] Figure 1 is a schematic structural diagram of a switching power supply according to an embodiment of the present invention;

[0027] Figure 2 is an optional schematic structural diagram of a switching power supply according to an embodiment of the present invention;

[0028] Figure 3 is a schematic circuit diagram of the first-stage output negative feedback module according to this embodiment;

[0029] Figure 4 is a schematic circuit diagram of the second-stage output negative feedback module according to this embodiment;

[0030] Figure 5 is a schematic circuit diagram of the third-stage output negative feedback module according to this embodiment. Detailed Embodiments

[0031] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0032] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0033] Example 1

[0034] In this embodiment, a switching power supply is provided. Figure 1 is a schematic diagram of the structure of a switching power supply according to an embodiment of the present invention. Figure 1 As shown, the switching power supply includes: a hot-swap detector, a first-stage output negative feedback module, a second-stage output negative feedback module, a second-stage output negative feedback module, and a power chip; wherein the power chip, the load, and the hot-swap detector are connected in series end to end; the first-stage output negative feedback module, the second-stage output negative feedback module, and the second-stage output negative feedback module are connected in parallel, and one end of the parallel connection is connected to one end of the power chip through a negative feedback resistor;

[0035] A hot-swap detector, used for inputting the generated first current signal into the first-stage output negative feedback module, the second-stage output negative feedback module, and the second-stage output negative feedback module when a load is connected;

[0036] The power chip is used to output the voltage of the first-stage output negative feedback module, the second-stage output negative feedback module, and one of the third-stage output negative feedback modules as the output voltage to meet the working voltage of the load according to different loads.

[0037] like Figure 2 As shown, the switching power supply in this embodiment also includes: a first relay (KA1) and a first MOS (M1); one end of the first relay (KA1) is connected to one end of the hot plug detector for receiving the generated first current signal (D); the other end of the first relay (KA1) is connected to the gate of the first MOS tube (M1), and another end of the first relay (KA1) is connected to the first resistor (R1) for receiving the input voltage; the drain of the first MOS tube (M1) receives the input voltage, the source of the first MOS tube (M1) is connected to the second resistor (R2) in parallel and one end of the power chip, and the other end of the second resistor (R2) is grounded;

[0038] Figure 3 is a circuit diagram of the first-stage output negative feedback module according to this embodiment, such as Figure 3As shown, the first current controller in the first-stage output negative feedback module is used to receive the first current signal (D) generated by the power chip and is connected to one end of the second relay (KA2), one end of the second relay (KA2) and the third relay (KA3) in parallel is connected to the source of the second MOS tube (M2), the other end of the second relay (KA2) and the third relay (KA3) in parallel is grounded, and outputs the second current signal (A); another end of the third relay (KA3) is used to receive the third current signal (F) generated by the power chip; the gate input voltage of the second MOS tube (M2), the drain of the second MOS tube (M2) is connected to the first negative feedback resistor (FB1), and the first negative feedback resistor (FB1) is connected in parallel to the circuit of the power chip and the load connected in series; the first-stage output negative feedback module is used to receive the first current signal (D) generated by the power chip and the drain of the second MOS tube (M2) is connected to the first negative feedback resistor (FB1), and the first negative feedback resistor (FB1) is connected in parallel to the circuit of the power chip and the load connected in series; the first-stage output negative feedback module is used to receive the third current signal (F) generated by the power chip; the gate input voltage of the second MOS tube (M2), ... first-stage output negative feedback module is used to receive the third current signal (F The drain of the seventh MOS tube (M7) in the module is connected to one end of the eleventh resistor (R11), the other end of the eleventh resistor (R11) is connected to the gate of the second MOS tube (M2), the gate of the seventh MOS tube (M7) is connected to one end of the seventh relay (KA7) and the eighth relay (KA8) connected in parallel, the other end of the seventh relay (KA7) and the eighth relay (KA8) connected in parallel is connected to one end of the twelfth resistor (R12), and the other end of the twelfth resistor (R12) is connected to the input voltage; the end of the eleventh resistor (R11) connected to the gate of the second MOS tube (M2) is connected to the thirteenth resistor (R13) and the fourteenth resistor (R14) connected in parallel, the other end of the fourteenth resistor (R14) is grounded, and the other end of the thirteenth resistor (R13) is connected to the input voltage.

[0039] Figure 4 is a circuit diagram of the second-stage output negative feedback module according to this embodiment, such as Figure 4As shown, the gate of the third MOS tube (M3) in the second-stage output negative feedback module is connected to one end of the fourth relay (KA4), the other end of the fourth relay (KA4) is connected to one end of the third resistor (R3), the other end of the third resistor (R3) is grounded, and another end of the fourth relay (KA4) is used to receive the second current signal (A) output by the first-stage output negative feedback; the drain of the third MOS tube (M3) is connected to one end of the fourth resistor (R4), the other end of the fourth resistor (R4) is connected to the gate of the fourth MOS tube (M4); the source of the third MOS tube (M3) is connected to the fifth resistor (R5) and the sixth resistor (R6) connected in series, and the other end of the sixth resistor (R6) is connected to the input voltage; the source of the fourth MOS tube (M4) in the second-stage output negative feedback module is connected to the second current control signal (A) connected in series. A controller, a ninth relay (KA9) and one end of a fifteenth resistor (R15) are connected, a second current controller connected in series, the ninth relay (KA9) and the fifteenth resistor (R15) are connected in parallel with a tenth relay (KA10), and one end of the parallel connection is grounded; the drain of the fourth MOS tube (M4) is connected to the sixteenth resistor (R16), and the other end of the sixteenth resistor (R16) receives an input voltage; the other end of the tenth relay (KA10) is connected to the source of the fourth MOS tube (M4); the source of the fourth MOS tube (M4) is also connected to the gate of the eighth MOS tube (M8), the source of the eighth MOS tube (M8) is grounded, and outputs a fourth current signal (B); the drain of the eighth MOS tube (M8) is connected to one end of a second negative feedback resistor (FB2), and the other end of the second negative feedback is connected to the input voltage.

[0040] Figure 5 is a circuit diagram of the third-stage output negative feedback module according to this embodiment, such as Figure 5 As shown, the gate of the fifth MOS tube in the third-stage output negative feedback module is connected to one end of the fifth relay and the sixth relay connected in parallel, the other ends of the fifth relay and the sixth relay connected in parallel are connected to the seventh resistor, the other end of the seventh circuit is connected to the input voltage, and another end of the fifth relay is used to receive the second current signal; the drain of the fifth MOS tube is connected to one end of the eighth resistor, the other end of the eighth resistor is linked to the gate of the sixth MOS tube, the source of the fifth MOS tube is connected to one end of the ninth resistor and the tenth resistor connected in series, and the other ends of the ninth resistor and the tenth resistor connected in series are connected to the input voltage.

[0041] It should be noted that one end of the first negative feedback resistor (FB1), the second negative feedback resistor (FB2) and the third negative feedback resistor (FB3) are connected in parallel and then connected to the negative feedback resistor (FB).

[0042] Among them, the first resistor (R1), the third resistor (R3), the seventh resistor (R7) and the second resistor (R8) are current limiting resistors.

[0043] Among them, the second relay (KA2) conducts for a preset duration under the trigger of the first current controller, and the ninth relay (KA9) conducts for a preset duration under the trigger of the second current controller. In a specific application scenario, it can be: when the first current controller receives the current signal D, it generates a current pulse to keep the second current relay (KA2) conducting for 0.5S; after the fifth MOS transistor (M5) conducts, the second current controller generates a current pulse to keep the ninth current relay (KA9) conducting for 0.5S.

[0044] In addition, the eleventh resistor (R11), the thirteenth resistor (R13), and the fourteenth resistor (R14) satisfy the following relationship:

[0045] R01 = R11 * R14 / (R11 + R14);

[0046] Vgs2 = R01 / (R01 + R13) * VInPut, and Vgs2 < Vtm2;

[0047] Among them, R11 is the resistance value of the eleventh resistor, R14 is the resistance value of the fourteenth resistor, R13 is the resistance value of the thirteenth resistor; VInPut is the input voltage of the thirteenth resistor; Vgs2 is the voltage of the gate of the second MOS transistor relative to the source, and Vtm2 is the conduction voltage of the second MOS transistor.

[0048] In addition, the fourth resistor (R4), the fifth resistor (R5), and the sixth resistor (R6) satisfy the following relationship:

[0049] R02 = R4 * R6 / (R4 + R6);

[0050] Vgs4 = R02 / (R02 + R5) * VInPut, and Vgs4 < Vtm4; at the same time, it satisfies that Vgs4 = R6 / (R6 + R5) * VInPut, and Vgs4 > Vtm4;

[0051] Among them, R4 is the resistance value of the fourth resistor, R5 is the resistance value of the fifth resistor, R6 is the resistance value of the sixth resistor; VInPut is the input voltage of the fifth resistor; Vgs4 is the voltage of the gate of the fourth MOS transistor relative to the source, and Vtm4 is the conduction voltage of the fourth MOS transistor.

[0052] In addition, the eighth resistor (R8), the ninth resistor (R9), and the tenth resistor (R10) satisfy the following relationship:

[0053] R03 = R8 * R9 / (R8 + R9);

[0054] Vgs6 = R03 / (R03 + R10) * VInPut, and Vgs6 < Vtm6; at the same time, it satisfies that Vgs6 = R9 / (R9 + R10) * VInPut, and Vgs6 > Vtm6;

[0055] Among them, R8 is the resistance value of the eighth resistor, R9 is the resistance value of the ninth resistor, and R10 is the resistance value of the tenth resistor; VInPut is the input voltage of the tenth resistor; Vgs6 is the voltage of the gate of the sixth MOS transistor relative to the source, and Vtm6 is the conduction voltage of the sixth MOS transistor.

[0056] Case (1), when no load is connected, since there is no current signal D, the first current relay (KA1) is disconnected, resulting in the non-conduction of the first MOS transistor (M1), the power input voltage Vin is 0, and the entire switching power supply does not work;

[0057] Case (2), when a load is connected, the hot plug detector generates a current signal D, and the first current relay (KA1) conducts, so that the first MOS transistor (M1) conducts, and the power supply chip obtains an input voltage Vin approximately equal to VInPut (determined by the resistor R2); at the same time, since the first current controller obtains the current signal D, it generates a current pulse signal to make the second current relay (KA2) conduct for 0.5 s, and the third MOS transistor (M3) conducts, and the power supply chip outputs the voltage of the first-stage negative feedback module; at this time, if the output voltage can meet the load working voltage, a current signal F (the third current signal) is generated, and the third current relay (KA3) conducts. After 0.5 s, since the third current relay (KA3) conducts, the third MOS transistor (M3) remains in the conducting state, and the power supply chip stably outputs the first-stage voltage. At this time, since the current signal A is continuously generated, the fourth current relay (KA4) and the fifth relay (KA5) are in the conducting state, the third MOS transistor (M3) and the fifth MOS transistor (M5) are in the conducting state, Vgs4 = R02 / (R02 + R5) * VInPut, Vgs6 = R03 / (R03 + R10) * VInPut. From the relationship between the noted resistors, it can be seen that at this time, the MOS transistors M4 and M6 are disconnected (Vgs < Vtm, MOS is disconnected), so the voltages of the second-stage output negative feedback module and the third-stage output negative feedback module are 0;

[0058] In case (3), when the voltage of the first-stage negative feedback module does not meet the working voltage of the load, the current signal F is 0, and the third current relay (KA3) is disconnected. After 0.5s, since the second current relay (KA2) is also disconnected, the second MOS tube (M2) is disconnected. At this time, the power chip stops working temporarily. At the same time, since the second MOS tube (M2) is disconnected, the current signal A is 0, the fourth current relay (KA4) is disconnected, the third MOS tube (M3) is disconnected, Vgs4=R6 / (R6+R5)*VInPut>Vtm4, the fourth MOS tube (M4) is turned on. It can be seen from the above relay turn-on condition that the ninth current relay (KA9) is turned on, thereby the eighth MOS tube (M8) is turned on, and the power chip outputs the voltage of the second-stage negative feedback module. At this time, a current signal B is generated, the second current relay (KA2) is turned on, the seventh MOS tube (M7) is turned on, Vgs2=R01 / (R01+R13)*VInPut, and it can be seen from the relationship between the above resistors that the second MOS tube (M2) is disconnected, and similarly, the MOS tube M6 is disconnected, so at this time the power chip only generates the output voltage of the second-stage negative feedback module.

[0059] In case (4), if the voltage of the second-stage negative feedback module does not meet the normal working voltage of the load, the current signal F is 0, the tenth current relay (KA10) is disconnected, and then the ninth relay (KA9) is turned on for 0.5s and then disconnected, so that the fifth MOS tube (M5) and the eighth MOS tube (M8) are disconnected, and the power chip stops working temporarily. At the same time, due to the disconnection of the third MOS tube (M3) and the eighth MOS tube (M8), the current signals A and B (the fourth current signal) are both 0, Vgs6 = R9 / (R9+R10), and it can be seen from the relationship between the resistors that the sixth MOS tube (M6) is turned on (VInPut>Vtm6MOS tube is turned on), and the power chip outputs the voltage of the third-stage negative feedback module to generate a current signal C. The third current relay (KA3) is turned on, and the seventh MOS tube (M7) is turned on, Vgs2 = R01 / (R01+R2)VInPut, and it can be seen from the relationship between the resistors that the second MOS tube (M2) is disconnected, and the voltage of the first-stage negative feedback module is not output. Similarly, from situation (3), when the second MOS tube (M2) is disconnected, the voltage of the second-stage negative feedback module is also not output. Therefore, at this time, the power chip only generates the voltage of the third-stage negative feedback module.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A switching power supply, characterized in that: include: A hot-swap detector, a first-stage output negative feedback module, a second-stage output negative feedback module, a third-stage output negative feedback module, and a power chip; wherein the power chip, the load, and the hot-swap detector are connected in series end to end; the first-stage output negative feedback module, the second-stage output negative feedback module, and the third-stage output negative feedback module are connected in parallel, and one end of the parallel connection is connected to one end of the power chip through a main negative feedback resistor; The hot plug detector is used to input the generated first current signal into the first-stage output negative feedback module when a load is connected; The power chip is used to output the voltage of one of the first-stage output negative feedback module, the second-stage output negative feedback module, and the third-stage output negative feedback module as an output voltage to meet the working voltage of the load according to the different loads; The first current controller in the first-stage output negative feedback module is used to receive the first current signal generated by the power chip and is connected to one end of the second relay, one end of the second relay connected in parallel with the third relay is connected to the source of the second MOS tube, the other end of the second relay connected in parallel with the third relay is grounded, and outputs the second current signal; another end of the third relay is used to receive the third current signal generated by the power chip; the gate input voltage of the second MOS tube, the drain of the second MOS tube is connected to the first negative feedback resistor, and the first negative feedback resistor is connected in parallel to the circuit of the power chip and the load connected in series; The drain of the seventh MOS tube in the first-stage output negative feedback module is connected to one end of the eleventh resistor, the other end of the eleventh resistor is connected to the gate of the second MOS tube, the gate of the seventh MOS tube is connected to one end of the seventh relay and the eighth relay connected in parallel, the other ends of the seventh relay and the eighth relay connected in parallel are connected to one end of the twelfth resistor, and the other end of the twelfth resistor is connected to the input voltage; the end of the eleventh resistor connected to the gate of the second MOS tube is connected to the connection point of the thirteenth resistor and the fourteenth resistor connected in series, the other end of the fourteenth resistor is grounded, and the other end of the thirteenth resistor is connected to the input voltage; The gate of the third MOS tube in the second-stage output negative feedback module is connected to one end of the fourth relay, the other end of the fourth relay is connected to one end of the third resistor, the other end of the third resistor is connected to the input voltage, and another end of the fourth relay is used to receive the second current signal output by the first-stage output negative feedback module; the drain of the third MOS tube is connected to one end of the fourth resistor, the other end of the fourth resistor is connected to the gate of the fourth MOS tube, and the end of the fourth resistor connected to the gate of the fourth MOS tube is connected to the connection point of the fifth resistor and the sixth resistor connected in series; the source of the third MOS tube is connected to one end of the fifth resistor and the sixth resistor connected in series, and the other end of the fifth resistor and the sixth resistor connected in series is connected to the input voltage; The source of the fourth MOS tube in the second-stage output negative feedback module is connected to the second current controller, the ninth relay and one end of the fifteenth resistor connected in series, and the second current controller, the ninth relay and the fifteenth resistor connected in series are connected in parallel with the tenth relay, and one end of the parallel connection is grounded; the drain of the fourth MOS tube is connected to the sixteenth resistor, and the other end of the sixteenth resistor receives the input voltage; the other end of the tenth relay is connected to the source of the fourth MOS tube; the source of the fourth MOS tube is also connected to the gate of the eighth MOS tube, the source of the eighth MOS tube is grounded, and outputs a fourth current signal; the drain of the eighth MOS tube is connected to one end of the second negative feedback resistor, and the other end of the second negative feedback resistor is connected to the input voltage; The gate of the fifth MOS tube in the third-stage output negative feedback module is connected to one end of the fifth relay and the sixth relay connected in parallel, the other ends of the fifth relay and the sixth relay connected in parallel are connected to the seventh resistor, the other end of the seventh resistor is connected to the input voltage, and another end of the fifth relay is used to receive the second current signal; the drain of the fifth MOS tube is connected to one end of the eighth resistor, the other end of the eighth resistor is connected to the gate of the sixth MOS tube, the end of the eighth resistor connected to the gate of the sixth MOS tube is connected to the connection point of the ninth resistor and the tenth resistor connected in series, the source of the fifth MOS tube is connected to one end of the ninth resistor and the tenth resistor connected in series, and the other ends of the ninth resistor and the tenth resistor connected in series are connected to the input voltage; one end of the sixth MOS tube is grounded and outputs the fifth current signal, the other end of the sixth MOS tube is connected to one end of the third negative feedback resistor, and the other end of the third negative feedback resistor is connected to the input voltage.

2. The switching power supply according to claim 1, characterized in that: The switching power supply also includes: a first relay and a first MOS tube; one end of the first relay is connected to one end of the hot plug detector for receiving the generated first current signal; the other end of the first relay is connected to the gate of the first MOS tube, and another end of the first relay is connected to a first resistor for receiving an input voltage; the drain of the first MOS tube receives the input voltage, the source of the first MOS tube is connected to a second resistor in parallel and one end of a power chip, and the other end of the second resistor is grounded.

3. The switching power supply according to claim 1, characterized in that: One end of the first negative feedback resistor, the second negative feedback resistor and the third negative feedback resistor are connected in parallel to the main negative feedback resistor.

4. The switching power supply according to claim 2, characterized in that: The first resistor, the third resistor, the seventh resistor and the second resistor are current limiting resistors.

5. The switching power supply according to claim 1, characterized in that: The eleventh resistor, the thirteenth resistor and the fourteenth resistor satisfy the following relationship: R01=R11*R14 / (R11+R14); Vgs2=R01 / (R01+R13)*VInPut, and Vgs2 <Vtm2; Wherein, R11 is the resistance value of the eleventh resistor, R14 is the resistance value of the fourteenth resistor, and R13 is the resistance value of the thirteenth resistor; VInPut is the input voltage of the thirteenth resistor; Vgs2 is the voltage of the gate of the second MOS transistor relative to the source, and Vtm2 is the conduction voltage of the second MOS transistor.

6. The switching power supply according to claim 1, characterized in that: The fourth resistor, the fifth resistor, and the sixth resistor satisfy the following relationship: R02 = R4 * R6 / (R4 + R6); Vgs4 = R02 / (R02 + R5) * VInPut, and Vgs4 < Vtm4; at the same time, Vgs4 = R6 / (R6 + R5) * VInPut, and Vgs4 > Vtm4; Wherein, R4 is the resistance value of the fourth resistor, R5 is the resistance value of the fifth resistor, and R6 is the resistance value of the sixth resistor; VInPut is the input voltage of the fifth resistor; Vgs4 is the voltage of the gate of the fourth MOS transistor relative to the source, and Vtm4 is the conduction voltage of the fourth MOS transistor.

7. The switching power supply according to claim 1, characterized in that: The eighth resistor, the ninth resistor, and the tenth resistor satisfy the following relationship: R03 = R8 * R9 / (R8 + R9); Vgs6 = R03 / (R03 + R10) * VInPut, and Vgs6 < Vtm6; at the same time, Vgs6 = R9 / (R9 + R10) * VInPut, and Vgs6 > Vtm6; Wherein, R8 is the resistance value of the eighth resistor, R9 is the resistance value of the ninth resistor, and R10 is the resistance value of the tenth resistor; VInPut is the input voltage of the tenth resistor; Vgs6 is the voltage of the gate of the sixth MOS transistor relative to the source, and Vtm6 is the conduction voltage of the sixth MOS transistor.

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