Auxiliary power supply starting circuit with high input voltage, switching power supply and electronic equipment

Abstract

The utility model provides an auxiliary power supply starting circuit with high input voltage, a switching power supply and electronic equipment. The circuit comprises a pre-starting circuit and a pre-charging circuit, the pre-charging circuit comprises a constant current charging circuit, an energy storage circuit and a protection circuit. The constant current charging circuit comprises a first NMOS tube and a first resistor. The input end of the pre-starting circuit is electrically connected with an input power supply, and the output end is electrically connected with the input end of the protection circuit; a first output end of the protection circuit is electrically connected with a grid electrode of the first NMOS tube, and a second output end of the protection circuit is electrically connected with a second end of the first resistor; the drain electrode of the first NMOS tube is electrically connected with an input power supply, and the source electrode is electrically connected with the first end of the first resistor; the first end of the energy storage circuit is electrically connected with the second end of the first resistor and the power supply end of the power supply control chip, and the second end is grounded. According to the auxiliary power supply starting circuit with the high input voltage, the constant-current charging circuit can be started through the pre-starting circuit to charge the energy storage circuit, and rapid starting of the auxiliary power supply is achieved.

Description

Technical Field

[0001] This application relates to the field of auxiliary power supply technology, and in particular to auxiliary power supply startup circuits, switching power supplies, and electronic devices with high input voltage. Background Technology

[0002] The auxiliary power supply is responsible for providing a stable low-voltage power supply to the control circuits in electronic devices, ensuring that the electronic devices can operate quickly and reliably before the main power supply is fully powered on. Therefore, the startup time of the auxiliary power supply directly affects the startup speed of the electronic devices.

[0003] Existing auxiliary power supply startup circuits use RC circuits, which start the auxiliary power supply through the charging process of resistors and capacitors. However, when the input voltage is high, the resistance R in the RC circuit is large, and the charging time of the RC circuit is long, resulting in a longer startup time and a slower startup speed for the auxiliary power supply. Utility Model Content

[0004] In view of this, the purpose of this application is to provide an auxiliary power supply startup circuit, a switching power supply and electronic equipment with high input voltage, which can start a constant current charging circuit to charge the energy storage circuit through a pre-start circuit, thereby achieving rapid startup of the auxiliary power supply.

[0005] In a first aspect, embodiments of this application provide an auxiliary power supply startup circuit with a high input voltage. The high input voltage auxiliary power supply startup circuit includes a pre-startup circuit and a pre-charge circuit; the pre-charge circuit includes a constant current charging circuit, an energy storage circuit, and a protection circuit; the constant current charging circuit includes a first NMOS transistor and a first resistor; wherein...

[0006] The input terminal of the pre-start circuit is electrically connected to the input power supply, and the output terminal of the pre-start circuit is electrically connected to the input terminal of the protection circuit; the first output terminal of the protection circuit is electrically connected to the gate of the first NMOS transistor, and the second output terminal of the protection circuit is electrically connected to the second terminal of the first resistor; the drain of the first NMOS transistor is electrically connected to the input power supply, and the source of the first NMOS transistor is electrically connected to the first terminal of the first resistor; the first terminal of the energy storage circuit is electrically connected to the second terminal of the first resistor and the power supply terminal of the power control chip, respectively, and the second terminal of the energy storage circuit is grounded.

[0007] Secondly, embodiments of this application provide a switching power supply, which includes a power control chip, a self-powered circuit, and the high input voltage auxiliary power start-up circuit described in the first aspect.

[0008] The first input terminal of the self-powered circuit is electrically connected to the input power supply, the second input terminal of the self-powered circuit is electrically connected to the second output terminal of the power control chip, and the output terminal of the self-powered circuit is electrically connected to the power supply terminal of the power control chip.

[0009] Thirdly, embodiments of this application provide an electronic device, which includes the switching power supply described in the second aspect.

[0010] The high input voltage auxiliary power supply startup circuit, switching power supply, and electronic device provided in this application include a pre-startup circuit and a pre-charge circuit. The pre-charge circuit includes a constant current charging circuit, an energy storage circuit, and a protection circuit. The constant current charging circuit includes a first NMOS transistor and a first resistor. The input terminal of the pre-startup circuit is electrically connected to the input power supply, and the output terminal of the pre-startup circuit is electrically connected to the input terminal of the protection circuit. The first output terminal of the protection circuit is electrically connected to the gate of the first NMOS transistor, and the second output terminal of the protection circuit is electrically connected to the second terminal of the first resistor. The drain of the first NMOS transistor is electrically connected to the input power supply, and the source of the first NMOS transistor is electrically connected to the first terminal of the first resistor. The first terminal of the energy storage circuit is electrically connected to the second terminal of the first resistor and the power supply terminal of the power control chip, and the second terminal of the energy storage circuit is grounded. Thus, the high input voltage auxiliary power supply startup circuit provided in this application can start the constant current charging circuit through the pre-startup circuit to charge the energy storage circuit, achieving rapid startup of the auxiliary power supply.

[0011] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This illustration shows one of the structural schematic diagrams of an auxiliary power supply startup circuit with high input voltage provided in an embodiment of this application;

[0014] Figure 2 A schematic diagram of a pre-start circuit provided in an embodiment of this application is shown;

[0015] Figure 3 A schematic diagram of a pre-charging circuit provided in an embodiment of this application is shown;

[0016] Figure 4 This is a second schematic diagram of the structure of an auxiliary power supply startup circuit with high input voltage provided in an embodiment of this application;

[0017] Figure 5 A schematic diagram of a switching power supply provided in an embodiment of this application is shown.

[0018] Explanation of key component symbols:

[0019] 100 - High input voltage auxiliary power supply startup circuit; 110 - Pre-start circuit; 120 - Pre-charge circuit; 121 - Constant current charging circuit; 122 - Energy storage circuit; 123 - Protection circuit; 210 - Power control chip; Q1 - First NMOS transistor; R1 - First resistor; R2 - Second resistor; C1 - First capacitor; Z1 - First Zener diode; R3 - Third resistor; Z2 - Second Zener diode; R4 - Fourth resistor; C2 - Second capacitor; Z3 - Third Zener diode; 130 - Shutdown circuit; R5 - Fifth resistor; Q2 - First transistor; 200 - Switching power supply; 220 - Self-powered circuit. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0022] In the description of this utility model, it should be noted that the terms "inner" and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first" and "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0023] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0024] To enable those skilled in the art to utilize the content of this application and in conjunction with the specific application scenario of "starting up an auxiliary power supply," the following implementation is provided. For those skilled in the art, the general principles defined herein can be applied to other embodiments and application scenarios without departing from the spirit and scope of this application. Although this application primarily describes "starting up an auxiliary power supply," it should be understood that this is merely an exemplary embodiment.

[0025] It is worth noting that prior to this application, existing auxiliary power supply startup circuits used RC circuits to start the auxiliary power supply through the charging process of resistors and capacitors. However, when the input voltage is high, the resistance R in the RC circuit is large, and the charging time of the RC circuit is long, resulting in a longer startup time and slower startup speed for the auxiliary power supply.

[0026] To overcome the above-mentioned defects, embodiments of this application provide an auxiliary power supply startup circuit with high input voltage, a switching power supply, and electronic equipment, which can start the constant current charging circuit to charge the energy storage circuit through the pre-start circuit, thereby achieving rapid startup of the auxiliary power supply.

[0027] Please see Figure 1 , Figure 1 This is one of the structural schematic diagrams of a high input voltage auxiliary power supply startup circuit provided in an embodiment of this application. For example... Figure 1 As shown, the high input voltage auxiliary power supply startup circuit 100 provided in this application embodiment includes a pre-startup circuit 110 and a pre-charge circuit 120; the pre-charge circuit 120 includes a constant current charging circuit 121, an energy storage circuit 122, and a protection circuit 123; the constant current charging circuit 121 includes a first NMOS transistor Q1 and a first resistor R1; wherein,

[0028] The input terminal of the pre-start circuit 110 is electrically connected to the input power supply, and the output terminal of the pre-start circuit 110 is electrically connected to the input terminal of the protection circuit 123. The first output terminal of the protection circuit 123 is electrically connected to the gate of the first NMOS transistor Q1, and the second output terminal of the protection circuit 123 is electrically connected to the second terminal of the first resistor R1. The drain of the first NMOS transistor Q1 is electrically connected to the input power supply, and the source of the first NMOS transistor Q1 is electrically connected to the first terminal of the first resistor R1. The first terminal of the energy storage circuit 122 is electrically connected to the second terminal of the first resistor R1 and the power supply terminal of the power control chip 210, respectively, and the second terminal of the energy storage circuit 122 is grounded.

[0029] In this embodiment, the pre-start circuit 110 is used to provide a driving voltage to the first NMOS transistor Q1 through the second output terminal of the protection circuit 123 when the input power supply outputs a high-voltage start-up input voltage, thereby turning on the first NMOS transistor Q1 and starting the constant current charging circuit 121 in the pre-charge circuit 120. In a preferred embodiment of this application, the driving voltage of the first NMOS transistor Q1 is approximately 12V.

[0030] In this embodiment, the constant current charging circuit 121 is composed of a first NMOS transistor Q1 and a first resistor R1. After the pre-startup circuit 110 turns on the first NMOS transistor Q1, it charges the energy storage circuit 122 with a constant current through the input voltage of the input power supply, thereby improving the charging speed of the energy storage circuit 122. Specifically, when current flows through the first resistor R1, a voltage drop is formed across the first resistor R1, which reduces the voltage V from the gate to the source of the first NMOS transistor Q1. GS This causes the first NMOS transistor Q1 to enter the linear region of critical conduction, thereby reducing the current flowing through the first resistor R1. The voltage across the first resistor R1 decreases synchronously, which in turn increases the gate-to-source voltage V of the first NMOS transistor Q1. GS Ultimately, due to the negative feedback mechanism, the drain-to-source current I of the first NMOS transistor Q1 is increased. DS It is maintained at a constant value. In a preferred embodiment of this application, the first NMOS transistor Q1 is an enhancement-mode NMOS transistor, and the withstand voltage of the first NMOS transistor Q1 is approximately the sum of the maximum input voltage of the input power supply and the derating voltage margin. DS The empirical value is approximately 50mA. The typical resistance of the first resistor R1 is approximately 120Ω, or 6V / I. DS .

[0031] In this embodiment, the energy storage circuit 122 is used to store electrical energy until the stored electrical energy can continuously supply power to the power supply terminal VCC of the power control chip 210 at the supply voltage for a period of time, so as to start the power control chip 210, that is, to start the auxiliary power supply.

[0032] In this embodiment, the protection circuit 123 is used to protect the first NMOS transistor Q1 to prevent damage to the first NMOS transistor Q1.

[0033] In one possible implementation, the embodiments provided in this application are described below. Figure 1 An example of a possible circuit structure for the pre-start circuit 110 is provided. Please refer to [link / reference]. Figure 2 , Figure 2 This is a schematic diagram of a pre-start circuit 110 provided in an embodiment of this application. Figure 2 As shown, the pre-start circuit 110 includes a second resistor R2 and a first capacitor C1; wherein, the first end of the second resistor R2 is electrically connected to the input power supply, and the second end of the second resistor R2 is electrically connected to the first end of the first capacitor C1 and the input end of the protection circuit 123 respectively; the second end of the first capacitor C1 is grounded.

[0034] In a preferred embodiment of this application, the pre-start circuit 110 is an RC charging circuit composed of a second resistor R2 and a first capacitor C1. The second resistor R1 charges the first capacitor C1 when the input power supply outputs a high-voltage start-up input voltage, causing the voltage across the first capacitor C1 to rise and drive the first NMOS transistor Q1 to start the constant current charging circuit 121 in the pre-charge circuit 120. Specifically, since the first NMOS transistor Q1 requires very little energy to turn on, the first capacitor C1 can be a small-value capacitor to reduce the start-up time of the pre-start circuit 110. In a preferred embodiment of this application, the capacitance value of the first capacitor C1 is approximately 0.1 μF.

[0035] Furthermore, such as Figure 2 As shown, the pre-start circuit 110 also includes a first Zener diode Z1; wherein, the positive terminal of the first Zener diode Z1 is electrically connected to the first terminal of the first capacitor C1, and the negative terminal of the first Zener diode Z1 is electrically connected to the second terminal of the first capacitor Z1.

[0036] In this embodiment, the first Zener diode Z1 is used to protect the first capacitor C1, ensuring that the voltage across the first capacitor C1 does not exceed the Zener voltage of the first Zener diode Z1. In a preferred embodiment of this application, the Zener voltage of the first Zener diode Z1 is approximately the sum of the startup voltage of the power control chip 210 and the drive voltage of the first NMOS transistor Q1. Additionally, the second resistor R2 is used to ensure that the current flowing through the first Zener diode Z1 does not exceed its maximum safe current capacity.

[0037] In one possible implementation, the embodiments provided in this application are described below. Figure 1 An example of a possible circuit structure for the pre-charge circuit 120 is provided. Please refer to [link / reference]. Figure 3 , Figure 3 This is a schematic diagram of a pre-charging circuit 120 provided in an embodiment of this application. Figure 3 As shown, the protection circuit 123 includes a third resistor R3; wherein, the first end of the third resistor R3 is electrically connected to the output terminal of the pre-start circuit 110, and the second end of the third resistor R3 is electrically connected to the gate of the first NMOS transistor.

[0038] In this embodiment, the third resistor R3 is used as the driving resistor for the first NMOS transistor Q1. In a preferred embodiment, the resistance of the third resistor R3 is approximately 10Ω.

[0039] Furthermore, such as Figure 3 As shown, the protection circuit 123 also includes a second Zener diode Z2 and a fourth resistor R4; wherein, the positive terminal of the second Zener diode Z2 is electrically connected to the second terminal of the third resistor R3, and the negative terminal of the second Zener diode Z2 is electrically connected to the first terminal of the fourth resistor R4; the second terminal of the fourth resistor R4 is electrically connected to the second terminal of the first resistor R1.

[0040] In this embodiment, the second Zener diode Z2 is used to protect the first NMOS transistor Q1, ensuring the gate-to-source voltage V of the first NMOS transistor Q1. GS The first NMOS transistor Q1 will not be damaged due to excessive voltage. The fourth resistor R4 is used to ensure that the current flowing through the second Zener diode Z2 does not exceed its maximum safe current value. In a preferred embodiment of this application, the Zener diode Z2's Zener voltage is approximately the sum of the drive voltage of the first NMOS transistor Q1 (approximately 12V) and the derating voltage margin.

[0041] Furthermore, such as Figure 3 As shown, the energy storage circuit 122 includes a second capacitor C2 and a third Zener diode Z3; wherein, the first end of the second capacitor C2 is electrically connected to the second end of the first resistor R1, and the second end of the second capacitor C2 is grounded; the first end of the third Zener diode Z3 is electrically connected to the first end of the second capacitor C2, and the second end of the third Zener diode Z3 is electrically connected to the second end of the second capacitor C2.

[0042] In this embodiment, the second capacitor C2 supplies power to the power control chip 210 after charging reaches its startup voltage, enabling the power control chip 210 to operate normally. The third Zener diode Z3 protects the power control chip 210, ensuring that the power supply terminal voltage of the power control chip 210 is not damaged due to excessive voltage. In a preferred embodiment of this application, the capacitance value of the second capacitor C2 is approximately the minimum capacitance value that ensures the sum of the static power consumption and drive power consumption supplied to the input pin of the power control chip 210 during the soft-start time of the auxiliary circuit, which is approximately 100 times the capacitance value of the first capacitor C1; the Zener diode Z3's Zener voltage is approximately the maximum operating voltage of the power control chip 210.

[0043] Calculations show that the start-up time of the auxiliary power supply start-up circuit has changed from the traditional RC start-up circuit start-up time of 3×R1×C2 to 3×R1×C1 + 1 / 2×C2×U. VCC / (6 / R4), since the latter time is very small and can be ignored, and C2>>C1, the auxiliary power supply startup time can be reduced by about 99%, which greatly improves the startup speed of the auxiliary power supply.

[0044] In one possible embodiment, the following is an example illustrating a possible circuit structure of the high input voltage auxiliary power supply startup circuit 100 provided in this application embodiment. Please refer to... Figure 4 , Figure 4 This is a second schematic diagram of a high input voltage auxiliary power supply startup circuit provided in an embodiment of this application. Figure 4 As shown, the high input voltage auxiliary power supply startup circuit 100 also includes a shutdown circuit 130; wherein, the input terminal of the shutdown circuit 130 is electrically connected to the first output terminal of the power control chip 210, and the output terminal of the shutdown circuit 130 is electrically connected to the output terminal of the pre-start circuit 110.

[0045] In this embodiment, the shutdown circuit 130 is used to control the pre-start circuit 110 to shut down after the power control chip 210 is started, so as to avoid the auxiliary power start circuit 100 with high input voltage after the auxiliary power is started repeatedly starting the power control chip 210 and causing device damage.

[0046] Furthermore, such as Figure 4 As shown, the shutdown circuit 130 includes a fifth resistor R5 and a first transistor Q2; wherein, the first end of the fifth resistor R5 is electrically connected to the first output terminal of the power control chip 210, and the second end of the fifth resistor R5 is electrically connected to the base of the first transistor Q2; the collector of the first transistor Q2 is electrically connected to the output terminal of the pre-start circuit 110, and the emitter of the first transistor Q2 is grounded.

[0047] In this embodiment, the first output terminal of the power control chip 210 outputs a high-level signal when it is turned on, controlling the emitter and collector of the first transistor Q2 to conduct, pulling the output voltage of the startup circuit 110 down to near 0V, thereby turning off the first NMOS transistor Q1. This prevents the auxiliary power startup circuit 100 with a high input voltage from repeatedly starting the power control chip 210 after the auxiliary power supply is started, thus avoiding damage to the device. The fifth resistor R5 is used to limit the current flowing to the base of the first transistor Q2 to protect the first transistor Q2 from damage by excessive base current.

[0048] This application provides a high input voltage auxiliary power supply startup circuit, including a pre-start circuit and a pre-charge circuit. The pre-charge circuit includes a constant current charging circuit, an energy storage circuit, and a protection circuit. The constant current charging circuit includes a first NMOS transistor and a first resistor. The input terminal of the pre-start circuit is electrically connected to the input power supply, and the output terminal of the pre-start circuit is electrically connected to the input terminal of the protection circuit. The first output terminal of the protection circuit is electrically connected to the gate of the first NMOS transistor, and the second output terminal of the protection circuit is electrically connected to the second terminal of the first resistor. The drain of the first NMOS transistor is electrically connected to the input power supply, and the source of the first NMOS transistor is electrically connected to the first terminal of the first resistor. The first terminal of the energy storage circuit is electrically connected to the second terminal of the first resistor and the power supply terminal of the power control chip, and the second terminal of the energy storage circuit is grounded. Thus, the high input voltage auxiliary power supply startup circuit provided in this application can start the constant current charging circuit through the pre-start circuit to charge the energy storage circuit, achieving rapid startup of the auxiliary power supply.

[0049] This application also provides a switching power supply. Please refer to [link to relevant documentation]. Figure 5 , Figure 5 This is a schematic diagram of a switching power supply provided in an embodiment of this application. Figure 5 As shown, the switching power supply 200 includes a power control chip 210, a self-powered circuit 220, and an auxiliary power start-up circuit 100 with high input voltage as described above.

[0050] The first input terminal of the self-powered circuit 220 is electrically connected to the input power supply, the second input terminal of the self-powered circuit 220 is electrically connected to the second output terminal of the power control chip 210, and the output terminal of the self-powered circuit 220 is electrically connected to the power supply terminal of the power control chip 210.

[0051] In this embodiment, the power control chip 210 is used to send a PWM control signal to the second input terminal of the self-powered circuit 220 through the second output terminal after successful startup, so as to control the self-powered circuit 220 to supply power to the power supply terminal of the power control chip 210 through the input power.

[0052] In this embodiment, the self-powered circuit 220 is used to supply power to the power supply terminal of the power control chip 210 through an input power source according to the PWM control signal sent by the power control chip 210. Taking a flyback auxiliary power supply as an example, the self-powered circuit 220 includes a transformer, and the power control chip 210 outputs a PWM signal to control the auxiliary winding of the transformer to conduct and continuously supply power to the power supply terminal of the power control chip 210.

[0053] Here, this application embodiment also provides an electronic device, which includes as follows: Figure 5 The aforementioned switching power supply 200. This electronic device may be a charging module, an inverter, etc.

[0054] Finally, it should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other. The above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and are not intended to limit it. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in this application, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A high input voltage auxiliary power supply startup circuit, characterized in that, The high input voltage auxiliary power supply startup circuit includes a pre-startup circuit and a pre-charge circuit; the pre-charge circuit includes a constant current charging circuit, an energy storage circuit, and a protection circuit; the constant current charging circuit includes a first NMOS transistor and a first resistor; wherein, The input terminal of the pre-start circuit is electrically connected to the input power supply, and the output terminal of the pre-start circuit is electrically connected to the input terminal of the protection circuit; the first output terminal of the protection circuit is electrically connected to the gate of the first NMOS transistor, and the second output terminal of the protection circuit is electrically connected to the second terminal of the first resistor; the drain of the first NMOS transistor is electrically connected to the input power supply, and the source of the first NMOS transistor is electrically connected to the first terminal of the first resistor; the first terminal of the energy storage circuit is electrically connected to the second terminal of the first resistor and the power supply terminal of the power control chip, respectively, and the second terminal of the energy storage circuit is grounded.

2. The high input voltage auxiliary power supply startup circuit according to claim 1, characterized in that, The pre-start circuit includes a second resistor and a first capacitor; wherein, the first end of the second resistor is electrically connected to the input power supply, and the second end of the second resistor is electrically connected to the first end of the first capacitor and the input end of the protection circuit respectively; the second end of the first capacitor is grounded.

3. The auxiliary power supply startup circuit with high input voltage according to claim 2, characterized in that, The pre-start circuit further includes a first Zener diode; wherein the positive terminal of the first Zener diode is electrically connected to the first terminal of the first capacitor, and the negative terminal of the first Zener diode is electrically connected to the second terminal of the first capacitor.

4. The auxiliary power supply startup circuit with high input voltage according to claim 1, characterized in that, The protection circuit includes a third resistor; wherein, the first end of the third resistor is electrically connected to the output terminal of the pre-start circuit, and the second end of the third resistor is electrically connected to the gate of the first NMOS transistor.

5. The high input voltage auxiliary power supply startup circuit according to claim 4, characterized in that, The protection circuit further includes a second Zener diode and a fourth resistor; wherein the anode of the second Zener diode is electrically connected to the second terminal of the third resistor, and the cathode of the second Zener diode is electrically connected to the first terminal of the fourth resistor; the second terminal of the fourth resistor is electrically connected to the second terminal of the first resistor.

6. The high input voltage auxiliary power supply startup circuit according to claim 5, characterized in that, The energy storage circuit includes a second capacitor and a third Zener diode; wherein, the first terminal of the second capacitor is electrically connected to the second terminal of the first resistor, and the second terminal of the second capacitor is grounded; the first terminal of the third Zener diode is electrically connected to the first terminal of the second capacitor, and the second terminal of the third Zener diode is electrically connected to the second terminal of the second capacitor.

7. The auxiliary power supply startup circuit with high input voltage according to claim 1, characterized in that, The high input voltage auxiliary power supply startup circuit also includes a shutdown circuit; wherein, the input terminal of the shutdown circuit is electrically connected to the first output terminal of the power control chip, and the output terminal of the shutdown circuit is electrically connected to the output terminal of the pre-startup circuit.

8. The auxiliary power supply startup circuit with high input voltage according to claim 7, characterized in that, The shutdown circuit includes a fifth resistor and a first transistor; wherein, the first end of the fifth resistor is electrically connected to the first output terminal of the power control chip, and the second end of the fifth resistor is electrically connected to the base of the first transistor; the collector of the first transistor is electrically connected to the output terminal of the pre-start circuit, and the emitter of the first transistor is grounded.

9. A switching power supply, characterized in that, The switching power supply includes a power control chip, a self-powered circuit, and an auxiliary power start-up circuit with high input voltage as described in any one of claims 1 to 8. The first input terminal of the self-powered circuit is electrically connected to the input power supply, the second input terminal of the self-powered circuit is electrically connected to the second output terminal of the power control chip, and the output terminal of the self-powered circuit is electrically connected to the power supply terminal of the power control chip.

10. An electronic device, characterized in that, Including the switching power supply as described in claim 9.

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