Direct current input protection circuit and direct current power supply system

Abstract

The utility model relates to the technical field of circuit protection, in particular to a direct-current input protection circuit and a direct-current power supply system. The DC input protection circuit comprises an overcurrent protection sub-circuit, a peak voltage protection sub-circuit, a reverse connection protection sub-circuit, an overvoltage protection sub-circuit and an impact current suppression sub-circuit. The overcurrent protection sub-circuit is used for receiving external direct current power supply and turning off the circuit when the external direct current power supply exceeds a fixed current threshold value; the peak voltage protection sub-circuit is used for clamping the output voltage of the overcurrent protection sub-circuit within a fixed voltage value; the reverse connection protection sub-circuit is used for turning off the circuit when the peak voltage protection sub-circuit outputs reverse power supply; the overvoltage protection sub-circuit is used for turning off the impulse current suppression sub-circuit when the output voltage of the reverse connection protection sub-circuit exceeds a fixed voltage threshold value; the impact current suppression sub-circuit is used for suppressing impact current generated at the starting moment of external direct current power supply. The electric equipment is protected by the sub-circuits under the condition that the sub-circuits do not interfere with one another.

Description

Technical Field

[0001] This utility model relates to the field of circuit protection technology, and in particular to a DC input protection circuit and a DC power supply system. Background Technology

[0002] In the field of electronic power technology, the power supply is the heart of all electrical equipment. In DC power supply systems, some precision or expensive electrical equipment requires high safety tolerance and has stringent requirements for power supply. Therefore, various protection measures are usually configured at the power supply end to prevent damage to electrical equipment due to abnormal power supply.

[0003] However, existing technologies for protecting DC power supplies only address one or two specific power anomalies, failing to meet the needs of complex electrical equipment. Since different power supply anomalies have different underlying principles, requiring different protection mechanisms, circuit protection technologies for different situations often interfere with each other and cannot be integrated. Therefore, designing a comprehensive DC input protection circuit capable of protecting against multiple power supply anomalies is a pressing problem in this field. Utility Model Content

[0004] The purpose of this invention is to design a comprehensive DC input protection circuit that can protect against various power supply anomalies and provide comprehensive protection for electrical equipment.

[0005] To achieve the above objectives, the first aspect of this utility model provides a DC input protection circuit, including an overcurrent protection sub-circuit, a spike voltage protection sub-circuit, a reverse connection protection sub-circuit, an overvoltage protection sub-circuit, and an inrush current suppression sub-circuit; wherein:

[0006] The input terminal of the overcurrent protection sub-circuit serves as the input terminal of the DC input protection circuit, and the output terminal of the overcurrent protection sub-circuit is electrically connected to the input terminal of the spike voltage protection sub-circuit.

[0007] The output terminal of the spike voltage protection circuit is electrically connected to the input terminal of the reverse connection protection sub-circuit.

[0008] The output terminal of the reverse connection protection sub-circuit is electrically connected to the input terminal of the overvoltage protection sub-circuit and the first input terminal of the inrush current suppression sub-circuit.

[0009] The output terminal of the overvoltage protection sub-circuit is electrically connected to the second input terminal of the inrush current suppression sub-circuit.

[0010] The output terminal of the inrush current suppression sub-circuit serves as the output terminal of the DC input protection circuit.

[0011] It should be noted that the overcurrent protection sub-circuit is used to receive external DC power supply and shut down the circuit when the external DC power supply exceeds a fixed current threshold; the spike voltage protection sub-circuit is used to clamp the output voltage of the overcurrent protection sub-circuit within a fixed voltage value; the reverse connection protection sub-circuit is used to shut down the circuit when the spike voltage protection sub-circuit outputs reverse power supply; the overvoltage protection sub-circuit is used to shut down the inrush current suppression sub-circuit when the output voltage of the reverse connection protection sub-circuit exceeds a fixed voltage threshold; and the inrush current suppression sub-circuit is used to suppress the inrush current generated at the moment of startup of the external DC power supply.

[0012] The aforementioned DC input protection circuit, through the design of a circuit structure that organically combines overcurrent protection sub-circuits, peak voltage protection sub-circuits, reverse connection protection sub-circuits, overvoltage protection sub-circuits, and inrush current suppression sub-circuits, enables each sub-circuit to jointly achieve its function without causing mutual interference. This allows the DC input protection circuit to simultaneously handle overcurrent anomalies, peak voltage anomalies, reverse voltage anomalies, overvoltage anomalies, and inrush current anomalies in DC power supply input, increasing the comprehensiveness of protection for electrical equipment, improving the reliability and stability of DC output power supply, and effectively extending the service life of electrical equipment.

[0013] In one possible implementation, the overcurrent protection subcircuit includes a fuse; wherein:

[0014] The first end of the fuse serves as the positive input terminal of the overcurrent protection sub-circuit, and the second end serves as the positive output terminal of the overcurrent protection sub-circuit.

[0015] It should be noted that the fuse is used to melt and shut down the circuit when the external DC power supply exceeds its rated current.

[0016] In this implementation, the external DC power supply is output after passing through a fuse. When the current value of the external DC power supply exceeds the rated current of the fuse, the fuse will melt quickly due to the excessive heat generated by the current it carries, thus breaking the circuit and cutting off the output of the external DC power supply. This protects the electrical equipment when the external DC power supply current value is too high, preventing damage caused by the electrical equipment operating in an overloaded environment for a long time, and improving the reliability and stability of the DC output power supply.

[0017] In one possible implementation, the spike voltage protection sub-circuit includes a transient voltage suppression diode; wherein:

[0018] The first terminal of the transient voltage suppression diode serves as the positive input and positive output terminal of the peak voltage protection sub-circuit, and the second terminal serves as the negative input and negative output terminal of the peak voltage protection sub-circuit.

[0019] It should also be noted that the transient voltage suppression diode is used to be instantaneously broken down when the voltage at the input terminal of the peak voltage protection sub-circuit reaches its avalanche voltage threshold, so as to clamp the input voltage within a fixed voltage value.

[0020] In this implementation, the reverse breakdown characteristic of the transient voltage suppression diode is utilized. When the voltage of the external DC power supply exceeds its breakdown voltage, that is, when the external DC power supply reaches its avalanche voltage threshold, it quickly conducts and enters the breakdown state, absorbing the overvoltage of the external DC power supply and clamping it to the vicinity of the breakdown voltage of the transient voltage suppression diode. This achieves the suppression of the external DC power supply spike voltage, protects the normal operation of the electrical equipment, avoids damage to the electrical equipment by the spike voltage, and improves the reliability and stability of the DC output power supply.

[0021] In one possible implementation, the reverse connection protection sub-circuit includes a first current-limiting resistor, a first filter capacitor, a first Zener diode, and a first N-channel MOSFET; wherein:

[0022] The first end of the first current-limiting resistor serves as the positive input and positive output of the reverse connection protection sub-circuit, and the second end is electrically connected to the gate of the first N-channel field-effect transistor.

[0023] The first terminal of the first filter capacitor is electrically connected to the gate of the N-channel field-effect transistor, and the second terminal is electrically connected to the source of the first N-channel field-effect transistor.

[0024] The cathode of the first Zener diode is electrically connected to the gate of the first N-channel MOSFET, and the anode is electrically connected to the source of the first N-channel MOSFET.

[0025] The source of the first N-channel MOSFET serves as the negative output terminal of the reverse connection protection sub-circuit, and the drain serves as the negative input terminal of the reverse connection protection sub-circuit.

[0026] It should be noted that in the reverse connection protection sub-circuit, the path including the first current-limiting resistor, the first filter capacitor, and the first Zener diode provides a driving voltage for the first N-channel MOSFET. When the voltage is positively input to the reverse connection protection sub-circuit, the driving voltage between the gate and source of the first N-channel MOSFET is positive, thereby turning on the drain and source of the first N-channel MOSFET. This allows the reverse connection protection sub-circuit to form a conducting loop, transmitting power from the input terminal of the sub-circuit to the output terminal. When the voltage is negatively input to the reverse connection protection sub-circuit, the driving voltage between the gate and source of the first N-channel MOSFET is negative, thereby turning off the drain and source of the first N-channel MOSFET. This cuts off the reverse connection protection sub-circuit loop, preventing reverse power transmission from the input terminal of the sub-circuit to the power-consuming equipment.

[0027] In this implementation, the reverse connection protection sub-circuit is designed using the conduction characteristics of the first N-channel MOSFET. This ensures that the external DC power supply is transmitted normally to the electrical equipment when it is in the forward direction, and prevents the external DC power supply from being transmitted to the electrical equipment when it is in the reverse direction, thus avoiding damage to the electrical equipment due to reverse voltage input and improving the reliability and stability of the DC output power supply.

[0028] In one possible implementation, the overvoltage protection sub-circuit includes a first voltage divider resistor, a second voltage divider resistor, a second Zener diode, a second filter capacitor, and a second N-channel MOSFET; wherein:

[0029] The first end of the first voltage divider resistor serves as the positive input terminal of the overvoltage protection sub-circuit, and the second end is electrically connected to the gate of the second N-channel field-effect transistor.

[0030] The first terminal of the second voltage divider resistor is electrically connected to the gate of the second N-channel field-effect transistor, and the second terminal is electrically connected to the source of the second N-channel field-effect transistor.

[0031] The cathode of the second Zener diode is electrically connected to the gate of the second N-channel MOSFET, and the anode is electrically connected to the source of the second N-channel MOSFET.

[0032] The first terminal of the second filter capacitor is electrically connected to the gate of the second N-channel field-effect transistor, and the second terminal is electrically connected to the source of the second N-channel field-effect transistor.

[0033] The source of the second N-channel MOSFET serves as the negative input terminal of the overvoltage protection sub-circuit, and the drain serves as the output terminal of the overvoltage protection sub-circuit.

[0034] It should be noted that the overvoltage protection sub-circuit includes a path containing a first voltage divider resistor, a second voltage divider resistor, a second filter capacitor, and a second Zener diode to provide a driving voltage for the second N-channel MOSFET. When the input voltage exceeds the normal operating voltage range, the driving voltage between the gate and source of the second N-channel MOSFET reaches the conduction threshold of the second N-channel MOSFET, thereby turning on the drain and source of the second N-channel MOSFET. This, in turn, turns on the output terminal and the negative input terminal of the overvoltage protection sub-circuit, and the output voltage is pulled low by the negative input terminal. Finally, the overvoltage protection sub-circuit outputs a low-level signal to the inrush current suppression sub-circuit, causing the inrush current suppression sub-circuit to turn off.

[0035] In this implementation, an overvoltage protection sub-circuit is designed using the conduction characteristics of the second N-channel MOSFET. When the external DC power supply voltage is too high, the power supply transmission is cut off, preventing the electrical equipment from being damaged in an overvoltage environment, ensuring the safety of the electrical equipment, and improving the reliability and stability of the DC output power supply.

[0036] In one possible implementation, the inrush current suppression sub-circuit includes a second current-limiting resistor, a third filter capacitor, a third Zener diode, and a third N-channel MOSFET; wherein:

[0037] The first end of the second current-limiting resistor serves as the first positive input and positive output of the inrush current suppression sub-circuit, and the second end is electrically connected to the gate of the third N-channel field-effect transistor.

[0038] The first terminal of the third filter capacitor is electrically connected to the gate of the third N-channel field-effect transistor, and the second terminal is electrically connected to the source of the third N-channel field-effect transistor.

[0039] The cathode of the third Zener diode is electrically connected to the gate of the third N-channel MOSFET, and the anode is electrically connected to the source of the third N-channel MOSFET.

[0040] The source of the third N-channel MOSFET serves as the first negative input terminal of the inrush current suppression sub-circuit, the gate serves as the second input terminal of the inrush current suppression sub-circuit, and the drain serves as the negative output terminal of the inrush current suppression sub-circuit.

[0041] Specifically, in the inrush current suppression sub-circuit, the path including the second current-limiting resistor, the third filter capacitor, and the third Zener diode provides the driving voltage for the third N-channel MOSFET. During the power-on process of the external DC power supply, the driving voltage between the gate and source of the third N-channel MOSFET gradually increases as the second current-limiting resistor charges the third filter capacitor, thereby gradually reducing the on-resistance between the source and drain of the third N-channel MOSFET until the source and drain are fully connected.

[0042] It should also be noted that the gate of the third N-channel MOSFET is electrically connected to the output of the overvoltage protection sub-circuit. When the overvoltage protection sub-circuit outputs a low-level signal to the inrush current suppression sub-circuit from its output, the driving voltage between the gate and source of the third N-channel MOSFET is pulled low, and the drain and source of the third N-channel MOSFET are cut off, thereby cutting off the negative output of the inrush current suppression sub-circuit.

[0043] In this implementation, to avoid a large inrush current being generated on the DC input protection circuit at the moment of external DC power supply, which could damage circuit components, an inrush current suppression sub-circuit is designed. This sub-circuit suppresses the inrush current during the external DC power supply power-on process by the on-resistance between the source and drain of the third N-channel MOSFET. Furthermore, by combining the conduction characteristics of the N-channel MOSFET with the energy storage characteristics of the capacitor, the on-resistance between the source and drain of the third N-channel MOSFET adapts to the changing characteristics of the inrush current. This achieves the suppression of the peak inrush current at the initial moment of power-on through the on-resistance, and the resistance value of the on-resistance gradually decreases as the inrush current decreases. Finally, after the inrush current disappears, the on-resistance decreases to full conduction. While effectively suppressing the inrush current, this reduces the power transmission power loss of the DC input protection circuit and improves the reliability and stability of the DC output power supply.

[0044] In one possible implementation, the inrush current suppression sub-circuit further includes a third current-limiting resistor; wherein:

[0045] The first end of the third current-limiting resistor is electrically connected to the gate of the third N-channel MOSFET, and the second end is electrically connected to the source of the third N-channel MOSFET.

[0046] In this implementation, the third current-limiting resistor and the third filter capacitor form an RC parallel circuit, which makes the charging process of the second current-limiting resistor to the third filter capacitor smoother, and the rise of the driving voltage between the gate and source of the third N-channel MOSFET smoother. This prevents overshoot or oscillation between the gate and source of the third N-channel MOSFET, enhances the stability of the inrush current suppression sub-circuit, and improves the circuit's effect of suppressing the inrush current generated at the moment of power-on of the external DC power supply.

[0047] In one possible implementation, the DC input protection circuit further includes a filter sub-circuit; wherein:

[0048] The input terminal of the filter sub-circuit is electrically connected to the output terminal of the inrush current suppression sub-circuit, and the output terminal of the filter sub-circuit serves as the output terminal of the DC input protection circuit.

[0049] In this implementation, the filter sub-circuit is used to filter out the ripple and noise of its input voltage, so that the DC input protection circuit outputs a stable and smooth voltage, thereby improving the reliability and stability of the DC output power supply.

[0050] In one possible implementation, the filter sub-circuit includes a fourth filter capacitor; wherein:

[0051] The first end of the fourth filter capacitor serves as the positive input and positive output of the filter sub-circuit, and the second end serves as the negative input and negative output of the filter sub-circuit.

[0052] A second aspect of this utility model provides a DC power supply system, comprising a DC power supply and a DC input protection circuit as described in any implementation of the first aspect; wherein:

[0053] The output terminal of the DC power supply is electrically connected to the input terminal of the DC input protection circuit, and the output terminal of the DC input protection circuit serves as the output terminal of the DC power supply system.

[0054] It should also be noted that the DC power supply is used to output DC power; the DC input protection circuit is used to receive the DC power and transmit the DC power to the external electrical equipment, so as to protect the external electrical equipment when the DC power supply is abnormal.

[0055] The DC input protection circuit and DC power supply system provided by this utility model have at least the following advantages compared with the prior art:

[0056] By designing a circuit structure that organically combines overcurrent protection subcircuits, spike voltage protection subcircuits, reverse connection protection subcircuits, overvoltage protection subcircuits, and inrush current suppression subcircuits, each subcircuit can work together to achieve its function without causing mutual interference. This allows the DC input protection circuit to simultaneously handle overcurrent anomalies, spike voltage anomalies, reverse voltage anomalies, overvoltage anomalies, and inrush current anomalies in DC power supply input, increasing the comprehensiveness of protection for electrical equipment, improving the reliability and stability of DC output power supply, and effectively extending the service life of electrical equipment. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the structure of a DC input protection circuit provided in an embodiment of the present invention;

[0058] Figure 2 This is a schematic diagram of an overcurrent protection sub-circuit provided in an embodiment of the present invention;

[0059] Figure 3 This is a schematic diagram of a peak voltage protection sub-circuit provided in an embodiment of the present invention;

[0060] Figure 4 This is a schematic diagram of the reverse connection protection sub-circuit provided in an embodiment of the present invention;

[0061] Figure 5 This is a schematic diagram of an overvoltage protection sub-circuit provided in an embodiment of the present invention;

[0062] Figure 6 This is a schematic diagram of the structure of an inrush current suppression sub-circuit provided in an embodiment of the present invention;

[0063] Figure 7 This is a schematic diagram of the structure of a filter sub-circuit provided in an embodiment of the present invention;

[0064] Among them: 100, overcurrent protection sub-circuit; 110, peak voltage protection sub-circuit; 120, reverse connection protection sub-circuit; 130, overvoltage protection sub-circuit; 140, inrush current suppression sub-circuit; 150, filter sub-circuit. Detailed Implementation

[0065] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0066] The following detailed descriptions are exemplary and intended to provide further detailed explanation of the present invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings are used to distinguish different objects and not to describe a particular order.

[0067] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0068] See Figure 1 This utility model embodiment provides a DC input protection circuit, including an overcurrent protection sub-circuit 100, a spike voltage protection sub-circuit 110, a reverse connection protection sub-circuit 120, an overvoltage protection sub-circuit 130, an inrush current suppression sub-circuit 140, and a filter sub-circuit 150; wherein:

[0069] The input terminal of the overcurrent protection sub-circuit 100 serves as the input terminal of the DC input protection circuit, and the output terminal of the overcurrent protection sub-circuit 100 is electrically connected to the input terminal of the spike voltage protection sub-circuit 110.

[0070] The output terminal of the spike voltage protection sub-circuit 110 is electrically connected to the input terminal of the reverse connection protection sub-circuit 120;

[0071] The output terminal of the reverse connection protection sub-circuit 120 is electrically connected to the input terminal of the overvoltage protection sub-circuit 130 and the first input terminal of the inrush current suppression sub-circuit 140.

[0072] The output terminal of the overvoltage protection sub-circuit 130 is electrically connected to the second input terminal of the inrush current suppression sub-circuit 140;

[0073] The output terminal of the inrush current suppression sub-circuit 140 is electrically connected to the input terminal of the filter sub-circuit 150;

[0074] The output terminal of the filter sub-circuit 150 serves as the output terminal of the DC input protection circuit.

[0075] It should be noted that the overcurrent protection sub-circuit is used to receive external DC power supply Vi and shut down the circuit when the external DC power supply Vi exceeds a fixed current threshold; the spike voltage protection sub-circuit is used to clamp the output voltage Va of the overcurrent protection sub-circuit within a fixed voltage value; the reverse connection protection sub-circuit is used to shut down the circuit when the output Vb of the spike voltage protection sub-circuit supplies power in reverse; the overvoltage protection sub-circuit is used to shut down the inrush current suppression sub-circuit when the output voltage Vc of the reverse connection protection sub-circuit exceeds a fixed voltage threshold; the inrush current suppression sub-circuit is used to suppress the inrush current generated at the moment of startup of the external DC power supply; and the filter sub-circuit is used to filter out the ripple and noise of its input voltage Vd so that the DC input protection circuit outputs a stable and smooth voltage Vo.

[0076] See Figure 2 This utility model embodiment provides an overcurrent protection sub-circuit 100, including a fuse F1; wherein:

[0077] The first terminal of the fuse serves as the positive input terminal Vi+ of the overcurrent protection sub-circuit, and the second terminal serves as the positive output terminal Va+ of the overcurrent protection sub-circuit.

[0078] It should be noted that the fuse F1 is used to blow and shut off the circuit when the external DC power supply Vi exceeds its rated current.

[0079] In this embodiment, the external DC power supply Vi is output after passing through a fuse. When the current value of the external DC power supply Vi exceeds the rated current of the fuse F1, the fuse will melt quickly due to the excessive heat generated by the current it carries, thus breaking the circuit and cutting off the output of the external DC power supply Vi. This protects the electrical equipment when the current value of the external DC power supply Vi is too high, preventing damage caused by the electrical equipment operating in an overloaded environment for a long time.

[0080] See Figure 3This utility model embodiment provides a spike voltage protection sub-circuit 110, including a transient voltage suppression diode V1; wherein:

[0081] The first terminal of the transient voltage suppression diode V1 serves as the positive input terminal Va+ and the positive output terminal Vb+ of the peak voltage protection sub-circuit, and the second terminal serves as the negative input terminal Va- and the negative output terminal Vb- of the peak voltage protection sub-circuit.

[0082] It should also be noted that the transient voltage suppression diode V1 is used to be instantaneously broken down when the input voltage Va of the spike voltage protection sub-circuit 110 reaches its avalanche voltage threshold, so as to clamp the input voltage Va within a fixed voltage value.

[0083] In this implementation, the reverse breakdown characteristic of the transient voltage suppression diode V1 is utilized. When the voltage of the external DC power supply exceeds its breakdown voltage, that is, when the external DC power supply reaches its avalanche voltage threshold, it quickly conducts and enters the breakdown state, absorbing the overvoltage of the external DC power supply and clamping it to the vicinity of the breakdown voltage of the transient voltage suppression diode. This achieves the suppression of the external DC power supply spike voltage, protects the normal operation of the electrical equipment, avoids damage to the electrical equipment by the spike voltage, and improves the reliability and stability of the DC output power supply.

[0084] See Figure 4 This utility model embodiment provides a reverse connection protection sub-circuit 120, including a first current-limiting resistor R1, a first filter capacitor C1, a first Zener diode V2, and a first N-channel MOSFET S1; wherein:

[0085] The first end of the first current-limiting resistor R1 serves as the positive input terminal Vb+ and the positive output terminal Vc+ of the reverse connection protection sub-circuit 120, and the second end is electrically connected to the gate of the first N-channel field-effect transistor S1.

[0086] The first terminal of the first filter capacitor C1 is electrically connected to the gate of the N-channel field-effect transistor S1, and the second terminal is electrically connected to the source of the first N-channel field-effect transistor S1.

[0087] The cathode of the first Zener diode V2 is electrically connected to the gate of the first N-channel field-effect transistor S1, and the anode is electrically connected to the source of the first N-channel field-effect transistor S1;

[0088] The source of the first N-channel MOSFET S1 serves as the negative output terminal Vc- of the reverse connection protection sub-circuit 120, and the drain serves as the negative input terminal Vb- of the reverse connection protection sub-circuit.

[0089] It should be noted that in the reverse connection protection sub-circuit 120, the path including the first current-limiting resistor R1, the first filter capacitor C1, and the first Zener diode V2 provides a driving voltage for the first N-channel MOSFET S1. When the voltage is positively input to the reverse connection protection sub-circuit 120, the driving voltage between the gate and source of the first N-channel MOSFET S1 is positive, thereby turning on the drain and source of the first N-channel MOSFET S1. This allows the reverse connection protection sub-circuit 120 to form a conducting loop, transmitting the power supply Vb from the sub-circuit input terminal to the sub-circuit output terminal Vc. When the voltage is negatively input to the reverse connection protection sub-circuit 120, the driving voltage between the gate and source of the first N-channel MOSFET S1 is negative, thereby turning off the drain and source of the first N-channel MOSFET S1. This causes the reverse connection protection sub-circuit 120 to be cut off, preventing the reverse power supply Vb from the sub-circuit input terminal from being transmitted to the electrical equipment.

[0090] See Figure 5 This utility model embodiment provides an overvoltage protection sub-circuit 130, including a first voltage divider resistor R2, a second voltage divider resistor R3, a second Zener diode V3, a second filter capacitor C2, and a second N-channel MOSFET S2; wherein:

[0091] The first terminal of the first voltage divider resistor R2 serves as the positive input terminal Vc+ of the overvoltage protection sub-circuit, and the second terminal is electrically connected to the gate of the second N-channel field-effect transistor S2.

[0092] The first end of the second voltage divider resistor R3 is electrically connected to the gate of the second N-channel field-effect transistor S2, and the second end is electrically connected to the source of the second N-channel field-effect transistor S2;

[0093] The cathode of the second Zener diode V3 is electrically connected to the gate of the second N-channel MOSFET S2, and the anode is electrically connected to the source of the second N-channel MOSFET S2;

[0094] The first terminal of the second filter capacitor C2 is electrically connected to the gate of the second N-channel field-effect transistor S2, and the second terminal is electrically connected to the source of the second N-channel field-effect transistor S2;

[0095] The source of the second N-channel MOSFET S2 serves as the negative input terminal Vc- of the overvoltage protection sub-circuit, and the drain serves as the output terminal off of the overvoltage protection sub-circuit 130.

[0096] It should be noted that the overvoltage protection sub-circuit 130 includes a path containing the first voltage divider resistor R2 and the second voltage divider resistor R3, the second filter capacitor C2, and the second Zener diode V3, which provides a driving voltage for the second N-channel MOSFET S2. When the input voltage Vc+ exceeds the normal operating voltage range, the driving voltage between the gate and source of the second N-channel MOSFET S2 reaches the conduction threshold of the second N-channel MOSFET S2, thereby turning on the drain and source of the second N-channel MOSFET S2. This causes the output terminal off of the overvoltage protection sub-circuit 130 to conduct with the negative input terminal Vc-. The output voltage off is pulled low by the negative input terminal Vc-, ultimately causing the overvoltage protection sub-circuit 130 to output a low-level signal off to the inrush current suppression sub-circuit, causing the inrush current suppression sub-circuit 140 to turn off.

[0097] See Figure 6 This utility model embodiment provides an inrush current suppression sub-circuit 140, including a second current-limiting resistor R4, a third current-limiting resistor R5, a third filter capacitor C3, a third Zener diode V4, and a third N-channel MOSFET S3; wherein:

[0098] The first end of the second current-limiting resistor R4 serves as the first positive input terminal Vc+ and the positive output terminal Vd+ of the inrush current suppression sub-circuit 140, and the second end is electrically connected to the gate of the third N-channel field-effect transistor S3.

[0099] The first end of the third current-limiting resistor R5 is electrically connected to the gate of the third N-channel field-effect transistor S3, and the second end is electrically connected to the source of the third N-channel field-effect transistor S3.

[0100] The first terminal of the third filter capacitor C3 is electrically connected to the gate of the third N-channel field-effect transistor S3, and the second terminal is electrically connected to the source of the third N-channel field-effect transistor S3.

[0101] The cathode of the third Zener diode V4 is electrically connected to the gate of the third N-channel field-effect transistor S1, and the anode is electrically connected to the source of the third N-channel field-effect transistor S1.

[0102] The source of the third N-channel MOSFET S1 serves as the first negative input terminal Vc- of the inrush current suppression sub-circuit 140, the gate serves as the second input terminal off of the inrush current suppression sub-circuit 140, and the drain serves as the negative output terminal Vd- of the inrush current suppression sub-circuit.

[0103] Specifically, the surge current suppression sub-circuit 140 includes a path containing a second current-limiting resistor R4, a third current-limiting resistor R5, a third filter capacitor C3, and a third Zener diode V4, which provides a driving voltage for the third N-channel MOSFET S3. During the power-on process of the external DC power supply, the driving voltage between the gate and source of the third N-channel MOSFET S3 gradually increases as the second current-limiting resistor R4 charges the third filter capacitor C3, thereby gradually reducing the on-resistance between the source and drain of the third N-channel MOSFET S3 until the source and drain are fully connected.

[0104] It should also be noted that the gate of the third N-channel MOSFET S3 is also electrically connected to the output terminal off of the overvoltage protection sub-circuit 130. When the overvoltage protection sub-circuit 130 outputs a low-level signal from the output terminal off to the inrush current suppression sub-circuit 140, the driving voltage between the gate and source of the third N-channel MOSFET S3 is pulled low, and the drain and source of the third N-channel MOSFET S3 are cut off, thereby causing the negative output terminal Vd- of the inrush current suppression sub-circuit 140 to be cut off.

[0105] See Figure 7 This utility model embodiment provides a filter sub-circuit 150, including a fourth filter capacitor C4; wherein:

[0106] The first end of the fourth filter capacitor C4 serves as the positive input terminal Vd+ and the positive output terminal Vo+ of the filter sub-circuit 150, and the second end serves as the negative input terminal Vd- and the negative output terminal Vo- of the filter sub-circuit 150.

[0107] This utility model embodiment also provides a DC power supply system, including a DC power supply and a DC input protection circuit as described in any of the above embodiments; wherein:

[0108] The output terminal of the DC power supply is electrically connected to the input terminal of the DC input protection circuit, and the output terminal of the DC input protection circuit serves as the output terminal of the DC power supply system.

[0109] It should also be noted that the DC power supply is used to output DC power; the DC input protection circuit is used to receive the DC power and transmit the DC power to the external electrical equipment, so as to protect the external electrical equipment when the DC power supply is abnormal.

[0110] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0111] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various improvements and substitutions without departing from the concept of this application, and these improvements and substitutions should also be considered within the scope of protection of this utility model. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. A DC input protection circuit, characterized in that, This includes overcurrent protection sub-circuit, spike voltage protection sub-circuit, reverse connection protection sub-circuit, overvoltage protection sub-circuit, and inrush current suppression sub-circuit; among which: The input terminal of the overcurrent protection sub-circuit serves as the input terminal of the DC input protection circuit, and the output terminal of the overcurrent protection sub-circuit is electrically connected to the input terminal of the spike voltage protection sub-circuit. The output terminal of the spike voltage protection circuit is electrically connected to the input terminal of the reverse connection protection sub-circuit. The output terminal of the reverse connection protection sub-circuit is electrically connected to the input terminal of the overvoltage protection sub-circuit and the first input terminal of the inrush current suppression sub-circuit. The output terminal of the overvoltage protection sub-circuit is electrically connected to the second input terminal of the inrush current suppression sub-circuit. The output terminal of the inrush current suppression sub-circuit serves as the output terminal of the DC input protection circuit.

2. The DC input protection circuit according to claim 1, characterized in that, The overcurrent protection subcircuit includes a fuse; wherein: The first end of the fuse serves as the positive input terminal of the overcurrent protection sub-circuit, and the second end serves as the positive output terminal of the overcurrent protection sub-circuit.

3. The DC input protection circuit according to claim 1, characterized in that, The peak voltage protection sub-circuit includes a transient voltage suppression diode; wherein: The first terminal of the transient voltage suppression diode serves as the positive input and positive output terminal of the peak voltage protection sub-circuit, and the second terminal serves as the negative input and negative output terminal of the peak voltage protection sub-circuit.

4. The DC input protection circuit according to claim 1, characterized in that, The reverse connection protection sub-circuit includes a first current-limiting resistor, a first filter capacitor, a first Zener diode, and a first N-channel MOSFET; wherein: The first end of the first current-limiting resistor serves as the positive input and positive output of the reverse connection protection sub-circuit, and the second end is electrically connected to the gate of the first N-channel field-effect transistor. The first terminal of the first filter capacitor is electrically connected to the gate of the N-channel field-effect transistor, and the second terminal is electrically connected to the source of the first N-channel field-effect transistor. The cathode of the first Zener diode is electrically connected to the gate of the first N-channel MOSFET, and the anode is electrically connected to the source of the first N-channel MOSFET. The source of the first N-channel MOSFET serves as the negative output terminal of the reverse connection protection sub-circuit, and the drain serves as the negative input terminal of the reverse connection protection sub-circuit.

5. A DC input protection circuit according to claim 1, characterized in that, The overvoltage protection sub-circuit includes a first voltage divider resistor, a second voltage divider resistor, a second Zener diode, a second filter capacitor, and a second N-channel MOSFET; wherein: The first end of the first voltage divider resistor serves as the positive input terminal of the overvoltage protection sub-circuit, and the second end is electrically connected to the gate of the second N-channel field-effect transistor. The first terminal of the second voltage divider resistor is electrically connected to the gate of the second N-channel field-effect transistor, and the second terminal is electrically connected to the source of the second N-channel field-effect transistor. The cathode of the second Zener diode is electrically connected to the gate of the second N-channel MOSFET, and the anode is electrically connected to the source of the second N-channel MOSFET. The first terminal of the second filter capacitor is electrically connected to the gate of the second N-channel field-effect transistor, and the second terminal is electrically connected to the source of the second N-channel field-effect transistor. The source of the second N-channel MOSFET serves as the negative input terminal of the overvoltage protection sub-circuit, and the drain serves as the output terminal of the overvoltage protection sub-circuit.

6. A DC input protection circuit according to claim 1, characterized in that, The inrush current suppression sub-circuit includes a second current-limiting resistor, a third filter capacitor, a third Zener diode, and a third N-channel MOSFET; wherein: The first end of the second current-limiting resistor serves as the first positive input and positive output of the inrush current suppression sub-circuit, and the second end is electrically connected to the gate of the third N-channel field-effect transistor. The first terminal of the third filter capacitor is electrically connected to the gate of the third N-channel field-effect transistor, and the second terminal is electrically connected to the source of the third N-channel field-effect transistor. The cathode of the third Zener diode is electrically connected to the gate of the third N-channel MOSFET, and the anode is electrically connected to the source of the third N-channel MOSFET. The source of the third N-channel MOSFET serves as the first negative input terminal of the inrush current suppression sub-circuit, the gate serves as the second input terminal of the inrush current suppression sub-circuit, and the drain serves as the negative output terminal of the inrush current suppression sub-circuit.

7. A DC input protection circuit according to claim 6, characterized in that, The inrush current suppression sub-circuit further includes a third current-limiting resistor; wherein: The first end of the third current-limiting resistor is electrically connected to the gate of the third N-channel MOSFET, and the second end is electrically connected to the source of the third N-channel MOSFET.

8. A DC input protection circuit according to claim 1, characterized in that, It also includes a filter sub-circuit; wherein: The input terminal of the filter sub-circuit is electrically connected to the output terminal of the inrush current suppression sub-circuit, and the output terminal of the filter sub-circuit serves as the output terminal of the DC input protection circuit.

9. A DC input protection circuit according to claim 8, characterized in that, The filter sub-circuit includes a fourth filter capacitor; wherein: The first end of the fourth filter capacitor serves as the positive input and positive output of the filter sub-circuit, and the second end serves as the negative input and negative output of the filter sub-circuit.

10. A DC power supply system, characterized in that, Includes a DC power supply and a DC input protection circuit as described in any one of claims 1 to 9; wherein: The output terminal of the DC power supply is electrically connected to the input terminal of the DC input protection circuit, and the output terminal of the DC input protection circuit serves as the output terminal of the DC power supply system.

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