Power input interface protection circuit and power supply

Abstract

A power input interface protection circuit and a power supply relate to the technical field of power supplies. The circuit comprises a protection module, an anti-reverse connection module and a filtering module. The protection module is used for being connected with an input power supply and protecting working voltage and working current output by the input power supply; the reverse connection prevention module is connected to the overcurrent protection module and is used for disconnecting the connection with the input power supply when the input power supply is reversely connected with the protection module; and the filtering module is connected to the anti-reverse-connection module and is used for filtering the working voltage and the working current output by the input power supply and outputting the working voltage and the working current so as to supply power to a load connected with the filtering module.

Description

Technical Field

[0001] This application relates to the field of power supply technology, specifically to a power input interface protection circuit and a power supply. Background Technology

[0002] In DC power supplies, input protection circuits are incorporated into the input interface to address potential issues such as high-voltage pulses, short circuits, reverse polarity, and signal interference. These circuits aim to protect the power supply and subsequent circuitry from potential power problems and damage.

[0003] Existing protection circuits typically protect against two or three of the aforementioned problems, and their improper placement results in an overall inadequate protection effect. Utility Model Content

[0004] This application provides a more complete and better protective circuit for a power input interface, and a power supply equipped with the power input interface protection circuit.

[0005] According to a first aspect of this application, one embodiment provides a power input interface protection circuit, comprising:

[0006] A protection module is connected to the input power supply and is used to protect the operating voltage and operating current output by the input power supply.

[0007] A reverse connection protection module is connected to the protection module and is used to disconnect the connection with the input power supply when the input power supply is reversed with the protection module.

[0008] A filtering module, connected to the reverse connection protection module, is used to filter the operating voltage and operating current output by the input power supply, and output the operating voltage and operating current to supply power to the load connected to the filtering module.

[0009] In one embodiment, the protection module includes an overvoltage protection module and an overcurrent protection module; the overvoltage protection module is used to absorb the surge voltage when the operating voltage generates a surge voltage; the overcurrent protection module is used to reduce the operating current when the operating current is overcurrent.

[0010] In one embodiment, the overvoltage protection module includes a front-end voltage suppression module and a back-end voltage suppression module;

[0011] The first terminal of the pre-stage voltage suppression module is connected to the positive terminal of the input power supply, the second terminal of the pre-stage voltage suppression module is connected to the negative terminal of the input power supply, and the third terminal of the pre-stage voltage suppression module is grounded.

[0012] The first terminal of the subsequent voltage suppression module is connected to the positive terminal of the input power supply, and the second terminal of the subsequent voltage suppression module is connected to the negative terminal of the input power supply.

[0013] In one embodiment, the front-end voltage suppression module includes varistor RT1 and varistor RT2; the back-end voltage suppression module includes transient voltage suppressor D2;

[0014] The first end of the varistor RT1 is connected to the positive terminal of the input power supply, the second end of the varistor RT2 is connected to the negative terminal of the input power supply, and the second ends of the varistor RT1 and the second ends of the varistor RT2 are connected to ground.

[0015] The first terminal of the transient voltage suppressor D2 is connected to the positive terminal of the input power supply, and the second terminal of the transient voltage suppressor D2 is connected to the negative terminal of the input power supply.

[0016] In one embodiment, the overcurrent protection module includes a fuse F1, the first end of which is connected to the positive terminal of the input power supply, and the second end of which is connected to the first terminal of the pre-amplifier voltage suppression module.

[0017] Alternatively, the first end of the fuse F1 is connected to the first end of the front-stage voltage suppression module, and the second end of the fuse F1 is connected to the first end of the rear-stage voltage suppression module;

[0018] Alternatively, the first end of the fuse F1 is connected to the first end of the subsequent voltage suppression module, and the second end of the fuse F1 is connected to the reverse connection protection module.

[0019] In one embodiment, the reverse connection protection module includes a capacitor C5, a control chip U1, and a switching transistor Q1;

[0020] The first end of capacitor C5 is connected to the protection module, the second end of capacitor C5 is connected to the charge pump input terminal of control chip U1, the drive output terminal of control chip U1 is connected to the gate of switch Q1, the source of switch Q1 is connected to the first end of capacitor C5, and the drain of switch Q1 is connected to the filter module.

[0021] In one embodiment, the filtering module includes an EMI filtering module for filtering out common-mode interference and differential-mode interference of the operating voltage and operating current.

[0022] In one embodiment, the EMI filtering module includes capacitors C1, C2, and C6, and a common-mode inductor L2. The first terminal of capacitor C2 is connected to the drain of the switching transistor Q1, and the second terminal of capacitor C2 is connected to the negative terminal of the input power supply. The input terminal of the common-mode inductor L2 is connected to the first terminal of capacitor C2, the output terminal of the common-mode inductor L2 is connected to the first terminal of capacitor C1, the common-mode terminal of the common-mode inductor L2 is connected to the second terminal of capacitor C2, and the ground terminal of the common-mode inductor L2 is connected to the second terminal of capacitor C6. The second terminal of capacitor C1 and the first terminal of capacitor C6 are grounded.

[0023] In one embodiment, the EMI filtering module further includes a high-frequency filtering module, which includes capacitor C3, capacitor C4, and inductor L1; the first end of capacitor C3 is connected to the first end of capacitor C1, the second end of capacitor C3 is connected to the second end of capacitor C6, the first end of capacitor L1 is connected to the first end of capacitor C3, the second end of inductor L1 is connected to the first end of capacitor C4, and the second end of capacitor C4 is connected to the second end of capacitor C3.

[0024] According to a second aspect, one embodiment provides a power supply, comprising:

[0025] Input power supply, used to output operating current and operating voltage;

[0026] A power input interface protection circuit is provided, which is connected to the input power supply. The power input interface protection circuit adopts the power input interface protection circuit described in any of the above embodiments.

[0027] According to the power input interface protection circuit and power supply of the above embodiments, the circuit includes a protection module, a reverse connection protection module, and a filtering module connected in sequence. The protection module is connected to the input power supply and protects the operating voltage and current output by the input power supply. The reverse connection protection module disconnects when the input power supply is reversed, thus disconnecting the subsequent circuit and preventing damage to it. Finally, the filtering module filters the circuit. This application places the protection module at the very beginning of the circuit, enabling it to absorb transient high voltage and current from the input power supply immediately, ensuring that subsequent modules are protected from direct impacts of large high voltage or large current, thus protecting the safety of the entire circuit. Placing the reverse connection protection module after the overcurrent protection module prevents damage to components in the reverse connection protection module due to excessive current when the current is already limited. The filtering module is located at the end of the circuit and is used to prevent noise interference from the preceding modules from affecting the normal operation of subsequent equipment, thereby filtering out residual noise and interference signals and ensuring the stability of the output power supply. This provides a power input interface protection circuit with complete functions, a reasonable layout, and optimal protection effect. Attached Figure Description

[0028] Figure 1 This is a circuit diagram of a diode reverse connection protection circuit in the prior art;

[0029] Figure 2 This is a schematic diagram of the power input interface protection circuit in one embodiment;

[0030] Figure 3 This is a schematic diagram of the protection module in one embodiment;

[0031] Figure 4 This is a schematic diagram of the overvoltage protection module in one embodiment;

[0032] Figure 5 This is a circuit diagram of a power input interface protection circuit in one embodiment. Figure 1 ;

[0033] Figure 6 This is a circuit diagram of a power input interface protection circuit in one embodiment. Figure 2 ;

[0034] Figure 7 This is a circuit diagram of a power input interface protection circuit in one embodiment. Figure 3 ;

[0035] Figure 8 This is a schematic diagram of the structure of a filtering module in one embodiment;

[0036] Figure 9 This is a schematic diagram of the power supply structure in another embodiment. Detailed Implementation

[0037] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. Similar elements in different embodiments are referred to by related similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the present application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present application are not shown or described in the specification. This is to avoid obscuring the core parts of the present application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0038] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments, and the operational steps involved in each embodiment can also be rearranged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the specification and drawings are only for clearly describing a particular embodiment and do not imply that they represent the necessary components and / or order.

[0039] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0040] Please refer to Figure 1 In reverse connection protection circuits, a diode reverse connection protection circuit is generally used. A diode D1 is connected in series at the positive input terminal of the power supply. The diode's forward conduction and reverse cutoff characteristics are used for reverse connection protection. When the power supply is reverse connected, diode D1 is reverse cut off, the power supply cannot form a circuit, and the subsequent circuit will not work. This can effectively prevent the subsequent circuit from burning out due to reverse connection. However, since the forward voltage drop of diode D1 is generally 0.7V, the diode will heat up significantly during normal operation, resulting in considerable power loss.

[0041] This application provides a power input interface protection circuit suitable for 5V, 12V, 24V, and other power supplies. The circuit includes a protection module, a reverse connection protection module, and a filtering module connected in sequence. Connecting these modules in this order allows for optimal utilization of each module's function, achieving the best protection effect. This will be described in detail below.

[0042] Please refer to Figure 2One embodiment provides a power input interface protection circuit 100, which includes a protection module 110, a reverse connection protection module 120, and a filtering module 130 connected in sequence.

[0043] In one embodiment, the protection module 110 is connected to the input power supply and is used to protect the operating voltage and operating current output by the input power supply. The reverse connection protection module 120 is connected to the protection module 110 and is used to disconnect from the input power supply when the input power supply is reverse-connected. The filtering module 130 is connected to the reverse connection protection module 120 and is used to filter the operating voltage and operating current output by the input power supply, and output the operating voltage and operating current to power the load connected to the filtering module 130.

[0044] Please refer to Figure 3 In one embodiment, the protection module 110 includes an overvoltage protection module 111 and an overcurrent protection module 112. The overvoltage protection module 111 is used to absorb surge voltage when the operating voltage generates a surge voltage. The overcurrent protection module 112 is used to reduce the operating current when the operating current is excessive. The order of the overvoltage protection module 111 and the overcurrent protection module 112 is not limited.

[0045] It should be noted that in this embodiment, the protection module 110 is placed at the very beginning of the circuit. The overvoltage protection module 111 within the protection module 110 can absorb surge voltages or transient high voltages from the input power supply immediately, ensuring that subsequent modules are protected from direct impacts of large high voltages and safeguarding the entire circuit. Simultaneously, the overcurrent protection module 112 within the protection module 110 limits excessive current caused by abnormal current, preventing high currents that might be triggered by surge voltages from affecting other modules. The reverse connection protection module 120 prevents reverse connection of the input power supply. By placing the reverse connection protection module 120 after the protection module 110, components within the reverse connection protection module 120 (such as switching transistors) will not be damaged by excessive current when the current is already limited. The filter module 130 is located at the very end of the circuit and is used to prevent noise interference from affecting the normal operation of subsequent equipment, thereby filtering out residual noise and interference signals and ensuring the stability of the output power supply.

[0046] Please refer to Figure 4In one embodiment, the overvoltage protection module 111 includes a pre-stage voltage suppression module 1111 and a post-stage voltage suppression module 1112. The pre-stage voltage suppression module 1111 is used to reduce the voltage amplitude of the surge voltage to absorb it. The post-stage voltage suppression module 1112 is used to absorb the residual surge voltage to reduce it to a safe threshold. When a surge voltage acts on the circuit, the pre-stage voltage suppression module 1111 quickly reduces its resistance value to absorb most of the surge voltage, preventing it from being further transmitted to the subsequent circuit. Simultaneously, the post-stage voltage suppression module 1112 also responds quickly, reducing its resistance to a low value to absorb the remaining residual voltage, ensuring that the voltage does not exceed the safe range that the circuit can withstand.

[0047] Please refer to Figure 5 In one embodiment, the front-end voltage suppression module 1111 includes varistor RT1 and varistor RT2, and the rear-end voltage suppression module 1112 includes transient voltage suppressor D2. The first terminal of varistor RT1 is connected to the first terminal of the front-end voltage suppression module 1111, the second terminal of varistor RT2 is connected to the second terminal of the front-end voltage suppression module 1111, and the second terminals of varistor RT1 and RT2 are connected to the third terminal of the front-end voltage suppression module 1111. The first terminal of transient voltage suppressor D2 is connected to the first terminal of the rear-end voltage suppression module 1112, and the second terminal of transient voltage suppressor D2 is connected to the second terminal of the rear-end voltage suppression module 1112.

[0048] It should be noted that varistor RT1 and RT2 are components whose resistance drops rapidly when the voltage exceeds their set threshold. When the voltage is below a certain value, the resistance of varistor RT1 and RT2 is very high and does not affect the circuit operation; when the voltage exceeds the safe range, varistor RT1 and RT2 will rapidly reduce their resistance and divert most of the current, thereby absorbing and weakening the surge voltage. In this embodiment, varistor RT1 and RT2 serve as the surge protection front-end, with a large current carrying capacity, absorbing most of the surge voltage first.

[0049] Transient voltage suppressor D2 is a component specifically designed to suppress transient voltages. It typically responds rapidly when the voltage reaches a certain threshold, limiting the voltage within a safe range. In the absence of overvoltage, it maintains high impedance (i.e., non-conductive). When a surge voltage occurs, the impedance of transient voltage suppressor D2 drops rapidly, quickly absorbing the instantaneous large current and clamping the voltage to a safe level. In this embodiment, transient voltage suppressor D2 acts as a downstream stage to absorb any remaining residual voltage energy.

[0050] When a surge voltage is applied, varistor RT1, varistor RT2 and transient voltage suppressor D2 all rapidly change the impedance between their terminals from high impedance to low impedance to absorb a large instantaneous current, clamping the voltage across the terminals to a safe value, thereby protecting downstream circuit components from the impact of transient high voltage spike pulses.

[0051] Please refer to Figure 5 , Figure 6 and Figure 7 In one embodiment, the overcurrent protection module 112 includes a fuse F1. If the overcurrent protection module 112 is located before the overvoltage protection module 111, the first end of the fuse F1 is connected to the positive terminal of the input power supply, and the second end of the fuse F1 is connected to the first end of the preceding voltage suppression module 1111, i.e., the first end of the varistor RT1. If the overcurrent protection module 112 is located between the preceding voltage suppression module 1111 and the following voltage suppression module 1112, the first end of the fuse F1 is connected to the first end of the preceding voltage suppression module 1111, i.e., the first end of the varistor RT1, and the second end of the fuse F1 is connected to the first end of the following voltage suppression module 1112, i.e., the first end of the transient voltage suppressor D2. If the overcurrent protection module 112 is located after the overvoltage protection module 111, the first end of the fuse F1 is connected to the first end of the following voltage suppression module 1112, i.e., the first end of the transient voltage suppressor D2, and the second end of the fuse F1 is connected to the reverse connection protection module 120.

[0052] It should be noted that during normal operation, fuse F1 exhibits a low-resistance state. When a short circuit or overload occurs, the current flowing through fuse F1 increases instantaneously, causing it to become high-resistance. The downstream operating current decreases rapidly. After the fault is cleared, fuse F1 cools down and returns to its low-resistance state, thus completing the overcurrent protection for the circuit. As a passive component, fuse F1 requires no additional power supply or control circuitry. It can quickly interrupt overcurrent, protecting the circuit, and its manufacturing and maintenance costs are very low.

[0053] Please refer to Figure 5 , Figure 6 and Figure 7In one embodiment, the reverse connection protection module 120 includes a capacitor C5 and a control chip U1 with a switching transistor Q1. If the overcurrent protection module 112 is located before the overvoltage protection module 111, the first terminal of capacitor C5 is connected to the first terminal of transient voltage suppressor D2; if the overcurrent protection module 112 is located between the preceding voltage suppression module 1111 and the following voltage suppression module 1112, the first terminal of capacitor C5 is connected to the first terminal of transient voltage suppressor D2; if the overcurrent protection module 112 is located after the overvoltage protection module 111, the first terminal of capacitor C5 is connected to the second terminal of fuse F1. The second terminal of capacitor C5 is connected to the charge pump input terminal of the control chip U1 (i.e.,...). Figure 5 , Figure 6 and Figure 7 The VCAP port in the control chip U1 (i.e., the drive output terminal of the control chip U1) Figure 5 , Figure 6 and Figure 7 The GATE port in the circuit is connected to the gate of the switching transistor Q1 (i.e., Figure 5 , Figure 6 and Figure 7 The G port in the circuit), the source of the switching transistor Q1 (i.e. Figure 5 , Figure 6 and Figure 7 The S port in the circuit is connected to the positive terminal of the input power supply, and the drain of the switching transistor Q1 (i.e., the S port) is connected to the positive terminal of the input power supply. Figure 5 , Figure 6 and Figure 7 The D port in the circuit is connected to the filter module 130. The enable terminal of the control chip U1 (i.e., port D) is connected to the filter module 130. Figure 5 , Figure 6 and Figure 7 The EN port of the diode and the anode and input power supply terminal of the diode (i.e., Figure 5 , Figure 6 and Figure 7 The ANODE port in the circuit is connected to the second terminal of fuse F1, and the ground terminal of control chip U1 (i.e., the ground terminal of the control chip U1). Figure 5 , Figure 6 and Figure 7 The GND port in the control chip is grounded, and the anode of the diode (i.e., Figure 5 , Figure 6 and Figure 7 The CATHODE port in the circuit is connected to the drain of the switching transistor Q1.

[0054] In one embodiment, the control chip U1 is an SCT53600, which is a diode controller. The input terminal of the control chip U1 has a dedicated detection circuit to monitor the polarity of the input voltage. Under normal circumstances, there is a positive potential difference (e.g., +12V or +5V) between the positive terminal of the input voltage and the reference ground (GND). If the input power supply is reversed (positive and negative terminals reversed), the control chip U1 detects the reversed potential relationship at the input terminal (e.g., -12V or -5V) and thus determines that it is reversed. The control chip U1 is responsible for controlling the operation of the entire reverse connection protection circuit, and turns off the switching transistor Q1 when a reverse connection is detected.

[0055] In one embodiment, the switching transistor Q1 is an N-type metal-oxide-semiconductor (NMOS) transistor. The circuit is turned on and off by controlling the gate voltage of the switching transistor Q1. The gate of the switching transistor Q1 controls its switching state. During normal operation, the control chip U1 provides the required gate drive voltage to the switching transistor Q1 through capacitor C5, enabling Q1 to conduct and allowing current to flow through the circuit. In reverse connection mode, the control chip U1 quickly turns off the switching transistor Q1, thereby cutting off the current and protecting the circuit. When the circuit is normally conducting, the control chip U1 maintains the switching transistor Q1 at a small forward voltage drop (approximately 20mV), which reduces conduction losses, lowers heat generation, and prevents overheating damage to the device.

[0056] In one embodiment, capacitor C5 is an external charge pump capacitor, which is an energy storage element. It stores energy in the circuit and provides the energy required to drive the gate of switch Q1. Through the charge pump, capacitor C5 can provide sufficient voltage to drive the gate of switch Q1, thereby turning on switch Q1.

[0057] Please refer to Figure 8 In one embodiment, the filtering module 130 includes an EMI filtering module 131 and a high-frequency filtering module 132. The EMI filtering module 131 is used to filter out common-mode interference and differential-mode interference of the operating voltage or operating current, and the high-frequency filtering module 132 is used to filter out high-frequency interference of the operating voltage or operating current.

[0058] Please refer to Figure 5 , Figure 6 or Figure 7In one embodiment, the EMI filtering module 131 includes capacitors C1, C2, and C6, and a common-mode inductor L2. The first terminal of capacitor C2 is connected to the drain of the switching transistor Q1, and the second terminal of capacitor C2 is connected to the negative terminal of the input power supply. The input terminal of common-mode inductor L2 is connected to the first terminal of capacitor C2, the output terminal of common-mode inductor L2 is connected to the first terminal of capacitor C1, the common-mode terminal of common-mode inductor L2 is connected to the second terminal of capacitor C2, and the ground terminal of common-mode inductor L2 is connected to the second terminal of capacitor C6. The second terminals of capacitor C1 and the first terminals of capacitor C6 are grounded.

[0059] It should be noted that capacitor C2, acting as an X capacitor, is used to eliminate differential-mode interference. The X capacitor reduces the voltage difference between the two conductors, filtering out high-frequency differential-mode interference. Capacitors C1 and C6, acting as Y capacitors, are used to eliminate common-mode interference. Y capacitors provide a low-impedance path, filtering out interference signals between the power line and ground, thus reducing the impact of common-mode noise. Inductor L2, acting as a common-mode inductor, is used to eliminate common-mode interference, preventing high-frequency signals from common-mode noise sources such as power lines and signal lines from flowing into the device. Especially when current flows simultaneously between two lines, the common-mode inductor provides high impedance, suppressing common-mode noise.

[0060] Please refer to Figure 5 , Figure 6 or Figure 7 In one embodiment, the high-frequency filtering module 132 includes capacitor C3, capacitor C4, and inductor L1. The first end of capacitor C3 is connected to the first end of capacitor C1, the second end of capacitor C3 is connected to the second end of capacitor C6, the first end of capacitor L1 is connected to the first end of capacitor C3, the second end of inductor L1 is connected to the first end of capacitor C4, and the second end of capacitor C4 is connected to the second end of capacitor C3.

[0061] It should be noted that capacitors C3 and C4, along with inductor L1, form a π-type filter to suppress high-frequency noise interference. Capacitors C3 and C4 guide high-frequency noise to ground by providing a low-impedance path, while inductor L1 blocks high-frequency signals from passing through, thus effectively filtering high-frequency noise from the signal path. The design of the π-type filter gives it a strong attenuation capability for high-frequency signals.

[0062] Please refer to Figure 9 In another embodiment, a power supply 10 is provided, which includes an input power supply 11 and a power input interface protection circuit 100. The input power supply can be a 5V, 12V, or 24V power supply, etc., used to output operating current and operating voltage. The power input interface protection circuit 100 adopts the power input interface protection circuit 100 of any of the above embodiments. Since the power input interface protection circuit 100 has been clearly described in the above embodiments, it will not be repeated here.

[0063] The above-described specific examples are for illustrative purposes only and are not intended to limit the scope of this invention. Those skilled in the art to which this invention pertains can make various simple deductions, modifications, or substitutions based on the concept of this invention.

Claims

1. A power input interface protection circuit, characterized in that, Includes protection modules, reverse connection protection modules, and filtering modules: The protection module is used to connect to the input power supply and to protect the operating voltage and operating current output by the input power supply; wherein, the protection module includes an overvoltage protection module and an overcurrent protection module; the overvoltage protection module is used to absorb the surge voltage when the operating voltage generates a surge voltage; the overcurrent protection module is used to reduce the operating current when the operating current is overcurrent; The reverse connection protection module is used to disconnect the input power supply when the input power supply is reverse-connected to the protection module; wherein, the reverse connection protection module includes a capacitor C5, a control chip U1, and a switching transistor Q1; the first end of the capacitor C5 is connected to the protection module, the second end of the capacitor C5 is connected to the charge pump input terminal of the control chip U1, the drive output terminal of the control chip U1 is connected to the gate of the switching transistor Q1, the source of the switching transistor Q1 is connected to the first end of the capacitor C5, and the drain of the switching transistor Q1 is connected to the filter module; The filtering module is connected to the reverse connection protection module and is used to filter the operating voltage and operating current output by the input power supply, and output the operating voltage and operating current to supply power to the load connected to the filtering module; wherein, the filtering module includes an EMI filtering module and a high-frequency filtering module, the EMI filtering module is used to filter out common-mode interference and differential-mode interference of the operating voltage or operating current, and the high-frequency filtering module is used to filter out high-frequency interference of the operating voltage or operating current.

2. The power input interface protection circuit as described in claim 1, characterized in that, The overvoltage protection module includes a front-stage voltage suppression module and a rear-stage voltage suppression module; The first terminal of the pre-stage voltage suppression module is connected to the positive terminal of the input power supply, the second terminal of the pre-stage voltage suppression module is connected to the negative terminal of the input power supply, and the third terminal of the pre-stage voltage suppression module is grounded. The first terminal of the subsequent voltage suppression module is connected to the positive terminal of the input power supply, and the second terminal of the subsequent voltage suppression module is connected to the negative terminal of the input power supply.

3. The power input interface protection circuit as described in claim 2, characterized in that, The front-end voltage suppression module includes varistor RT1 and varistor RT2; the back-end voltage suppression module includes transient voltage suppressor D2; The first end of the varistor RT1 is connected to the positive terminal of the input power supply, the second end of the varistor RT2 is connected to the negative terminal of the input power supply, and the second ends of the varistor RT1 and the second ends of the varistor RT2 are connected to ground. The first terminal of the transient voltage suppressor D2 is connected to the positive terminal of the input power supply, and the second terminal of the transient voltage suppressor D2 is connected to the negative terminal of the input power supply.

4. The power input interface protection circuit as described in claim 3, characterized in that, The overcurrent protection module includes a fuse F1, the first end of which is connected to the positive terminal of the input power supply, and the second end of which is connected to the first terminal of the pre-stage voltage suppression module. Alternatively, the first end of the fuse F1 is connected to the first end of the front-stage voltage suppression module, and the second end of the fuse F1 is connected to the first end of the rear-stage voltage suppression module; Alternatively, the first end of the fuse F1 is connected to the first end of the subsequent voltage suppression module, and the second end of the fuse F1 is connected to the reverse connection protection module.

5. The power input interface protection circuit as described in claim 4, characterized in that, The EMI filtering module includes capacitors C1, C2, and C6, and a common-mode inductor L2. The first terminal of capacitor C2 is connected to the drain of the switching transistor Q1, and the second terminal of capacitor C2 is connected to the negative terminal of the input power supply. The input terminal of common-mode inductor L2 is connected to the first terminal of capacitor C2, the output terminal of common-mode inductor L2 is connected to the first terminal of capacitor C1, the common-mode terminal of common-mode inductor L2 is connected to the second terminal of capacitor C2, and the ground terminal of common-mode inductor L2 is connected to the second terminal of capacitor C6. The second terminal of capacitor C1 and the first terminal of capacitor C6 are grounded.

6. The power input interface protection circuit as described in claim 4, characterized in that, The high-frequency filtering module includes capacitor C3, capacitor C4, and inductor L1; the first end of capacitor C3 is connected to the first end of capacitor C1, the second end of capacitor C3 is connected to the second end of capacitor C6, the first end of inductor L1 is connected to the first end of capacitor C3, the second end of inductor L1 is connected to the first end of capacitor C4, and the second end of capacitor C4 is connected to the second end of capacitor C3.

7. A power supply, characterized in that, include: Input power supply, used to output operating current and operating voltage; A power input interface protection circuit is provided, wherein the power input interface protection circuit is connected to the input power supply, and the power input interface protection circuit adopts the power input interface protection circuit as described in any one of claims 1-6.

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