Direct-current power supply power-down holding circuit and direct-current power supply

Abstract

The utility model relates to the technical field of direct-current power supplies, in particular to a direct-current power supply power-down retaining circuit and a direct-current power supply. The DC power supply power-down holding circuit comprises a first energy storage circuit, a power supply control circuit and a second energy storage circuit, when the input end of a DC power supply is powered down, a capacitor in the first energy storage circuit is used for supplying power to a power supply load, the power supply load is a DCDC conversion module, the DCDC conversion module detects voltage change, and the DC power supply control circuit controls the power supply control circuit to supply power to the DC power supply load. And the second energy storage circuit supplies power to the DCDC conversion module through the power supply control circuit, so that the retention time of power failure of the power supply is prolonged. According to the DC power supply power-down holding circuit, the power-down holding time of the switching power supply is prolonged, the stability of the voltage input to the DCDC conversion module is improved, the capacitance of the capacitor in the first energy storage circuit is relatively small, the volume of the capacitor is reduced, and the cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of direct current power supply, in particular to a direct current power supply power-off holding circuit and a direct current power supply. Background Art

[0002] A DC to DC power converter, also known as a DC / DC power supply, is an electronic device that converts a DC input voltage into a DC output voltage of different voltage levels. It is widely used in various occasions that require a stable DC voltage supply.

[0003] In order to cope with short-term input voltage drops, the existing DC / DC power supply is required to have a power-off hold time. Usually, the power-off hold time is achieved by an electrolytic capacitor. The capacity of the electrolytic capacitor determines the hold time. Therefore, the capacitor voltage must ensure the hold time under the conditions of the highest input voltage and the capacity must ensure the minimum working voltage. That is, the capacitor with the highest voltage and the largest capacity is selected. As a result, the capacitor cost is very high and the volume is particularly large. Utility Model Content

[0004] The embodiments of the utility model provide a DC power supply power-off holding circuit and a DC power supply to solve the problems of high capacitor cost and large volume caused by using high-voltage and high-capacity capacitors to maintain the power-off holding time in the prior art.

[0005] In a first aspect, the utility model provides a DC power supply power-off holding circuit, comprising: a first energy storage circuit, a power supply control circuit and a second energy storage circuit, wherein the input end of the first energy storage circuit is used to input a power supply signal, the output end of the first energy storage circuit is used to connect a power supply load, the output end of the second energy storage circuit is connected to the power supply input end of the power supply control circuit, the output end of the power supply control circuit is used to connect the power supply load, the control input end of the power supply control circuit is electrically connected to the power supply load, and the power supply control circuit is used to control the second energy storage circuit to supply power to the power supply load according to a signal at its control end.

[0006] In one embodiment, the power supply control circuit includes a first power supply control branch and a second power supply control branch, the control end of the first power supply control branch is electrically connected to the power supply load, the input end of the first power supply control branch is connected to the control end of the second power supply control branch, the output end of the first power supply control branch is grounded, the input end of the second power supply control branch is connected to the output end of the second energy storage circuit, and the output end of the second power supply control branch is used to connect the power supply load.

[0007] In one embodiment, the first power supply control branch includes a protection branch and a first switch tube, one end of the protection branch is electrically connected to the power supply load, the other end of the protection branch is grounded, the control end of the first switch tube is connected to one end of the protection branch, the input end of the first switch tube is connected to the control end of the second power supply control branch, and the output end of the first switch tube is grounded.

[0008] In one embodiment, the second power supply control branch includes a voltage divider branch and a second switch tube, the input end of the voltage divider branch is connected to the output end of the second switch tube, the first output end of the voltage divider branch is connected to the control end of the second switch tube, the second output end of the voltage divider branch is connected to the input end of the first power supply control branch, the input end of the second switch tube is connected to the output end of the second energy storage circuit, and the output end of the second switch tube is used to connect the power supply load.

[0009] In one implementation, the second power supply control branch further includes a voltage stabilizing branch, an input end of the voltage stabilizing branch is grounded, and an output end of the voltage stabilizing branch is connected to a control end of the second switch tube.

[0010] In one embodiment, the second energy storage circuit includes: an anti-reverse branch, an input end of the anti-reverse branch is used to input a first power supply signal, and an output end of the anti-reverse branch is connected to a power supply input end of the power supply control circuit.

[0011] In one embodiment, the DC power supply power-off holding circuit further includes: a filter circuit, wherein a positive terminal of the filter circuit is connected to an output terminal of the second energy storage circuit, and a negative terminal of the filter circuit is grounded.

[0012] In a second aspect, this embodiment provides a DC power supply, which includes a power supply load and a DC power supply power-off holding circuit as described in the first aspect and its improvement, wherein the DC power supply power-off holding circuit is electrically connected to the power supply load.

[0013] In one embodiment, the power supply load is a DC\DC conversion module, and the DC power supply also includes: an electromagnetic compatibility circuit, the input end of the electromagnetic compatibility circuit is used to input the power supply signal, and the output end of the electromagnetic compatibility circuit is connected to the input end of the first energy storage circuit.

[0014] In one embodiment, the DC power supply further includes: a bus anti-backfeed circuit, one end of the bus anti-backfeed circuit is connected to the negative terminal of the first energy storage circuit, and the other end of the bus anti-backfeed circuit is connected to a bus for providing the power supply signal.

[0015] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0016] The DC power supply power-off holding circuit of the utility model includes: a first energy storage circuit, a power supply control circuit and a second energy storage circuit. When the input end of the DC power supply loses power, the capacitor in the first energy storage circuit is used to supply power to the power supply load, and the power supply load is a DC\DC conversion module. The DC\DC conversion module detects the voltage change and outputs the conduction signal of the power supply control circuit to the control end of the power supply control circuit. The power supply control circuit is turned on, and the second energy storage circuit supplies power to the DC\DC conversion module through the power supply control circuit to extend the power supply power-off holding time. The DC power supply power-off holding circuit of the utility model mainly uses the second energy storage circuit to supply power to the DC\DC conversion module, which improves the power-off holding time of the switching power supply and also improves the stability of the voltage input to the DC\DC conversion module. The capacitor in the first energy storage circuit only needs to maintain the conduction signal of the power supply control circuit output by the DC\DC conversion module, and the capacity is relatively small, which reduces the capacitor volume and reduces the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments of the utility model will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 It is a schematic diagram of the module structure of a DC power supply power-off holding circuit provided by an embodiment of the utility model;

[0019] Figure 2 It is a schematic diagram of the module structure of a power supply control circuit provided in one embodiment of the utility model;

[0020] Figure 3 This is a circuit connection diagram of a power supply control circuit provided by an embodiment of the utility model;

[0021] Figure 4 It is a schematic diagram of the module structure of the second energy storage circuit provided in one embodiment of the utility model;

[0022] Figure 5 It is a schematic diagram of the module structure of a filter circuit provided by an embodiment of the utility model;

[0023] Figure 6 This is a schematic diagram of the module structure of a DC power supply provided by an embodiment of the utility model;

[0024] Among them, 1. a first energy storage circuit, 2. a power supply control circuit, 3. a second energy storage circuit, 4. a power supply load, 5. a filter circuit, 6. an electromagnetic compatibility circuit, 7. a busbar anti-reverse feeding circuit, 21. a first power supply control branch, 22. a second power supply control branch, 31. an anti-reverse feeding branch, 211. a protection branch, 212. a first switch tube, 221. a voltage dividing branch, 222. a second switch tube, 223. a voltage stabilizing branch. DETAILED DESCRIPTION

[0025] In order to make the technical problems, technical solutions and beneficial effects solved by the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0026] In the description of the present invention, it should be understood that the terms "longitudinal", "radial", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In order to thoroughly understand the present invention, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by the present invention. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0029] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure belongs. It will be further understood that the terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein.

[0030] In one embodiment, if Figure 1 As shown, a module structure schematic diagram of a DC power supply power-off holding circuit is provided, including: a first energy storage circuit 1, a power supply control circuit 2 and a second energy storage circuit 3, the input end of the first energy storage circuit 1 is used to input a power supply signal, the output end of the first energy storage circuit 1 is used to connect a power supply load 4, the output end of the second energy storage circuit 3 is connected to the power supply input end of the power supply control circuit 2, the output end of the power supply control circuit 2 is used to connect the power supply load 4, the control input end of the power supply control circuit 2 is electrically connected to the power supply load 4, and the power supply control circuit 2 is used to control the second energy storage circuit 3 to supply power to the power supply load 4 according to the signal of its control end.

[0031] It is understandable that the power supply signal is provided by the power bus. The power supply load 4 is a DC\DC conversion module, which includes a processor. When the power fails, the processor can immediately detect the power failure and output a control signal to the power supply control circuit 2.

[0032] Specifically, the first energy storage circuit 1 includes an energy storage capacitor. The first energy storage circuit 1 is used to power the DC\DC conversion module when the power supply is cut off, so that the DC\DC conversion module outputs a control signal to the power supply control circuit 2; the second energy storage circuit 3 should be provided with a first power supply, and the first power supply is any power supply except the power bus. Preferably, a battery is provided at the input end of the second energy storage circuit 3. When the power supply control circuit 2 is turned on, the battery is used to power the DC\DC conversion module to extend the power-off holding time.

[0033] It can be understood that the power supply control circuit 2 can be any kind of control circuit. A switch tube can be set in the power supply control circuit 2, and the second energy storage circuit 3 can be controlled by the conduction and closing of the switch tube to supply power to the DC\DC conversion module; a relay can be set in the power supply control circuit 2, and the second energy storage circuit 3 can be controlled by the closing and opening of the relay to supply power to the DC\DC conversion module; an optocoupler can also be set in the power supply control circuit 2, and the second energy storage circuit 3 can be controlled by the conduction and closing of the optocoupler to supply power to the DC\DC conversion module.

[0034] The working process of the above-mentioned DC power supply power-off holding circuit is as follows: when the power supply fails, the energy storage capacitor in the first energy storage circuit 1 is first used to power the DC\DC conversion module. The DC\DC conversion module detects the voltage change and outputs a conduction signal of the power supply control circuit 2 to turn on the power supply control circuit 2. The second energy storage circuit 3 supplies power to the DC\DC conversion module through the power supply control circuit 2 to extend the power-off holding time. Furthermore, the power-off holding time of the circuit can be set according to the actual application situation. When the preset power-off holding time is reached, the processor can output a shutdown signal of the power supply control circuit 2 to control the power supply control circuit 2 to shut down, and the second energy storage circuit 3 cannot supply power.

[0035] The DC power supply power-off holding circuit of the present embodiment mainly utilizes the second energy storage circuit 3 to power the DC\DC conversion module, which improves the power-off holding time of the switching power supply while also improving the stability of the voltage input to the DC\DC conversion module. The capacitor in the first energy storage circuit 1 only needs to maintain the conduction signal of the DC\DC conversion module output power supply control circuit 2, and has a small capacity, which reduces the capacitor volume and reduces the cost.

[0036] like Figure 2 As shown, a schematic diagram of the module structure of a power supply control circuit 2 is provided, such as Figure 3 As shown, a circuit connection diagram of a power supply control circuit 2 is provided.

[0037] In one embodiment, if Figure 2 As shown in the above Figure 1 On the basis of the DC power supply power-off holding circuit shown, the power supply control circuit 2 includes a first power supply control branch 21 and a second power supply control branch 22, the control end of the first power supply control branch 21 is electrically connected to the power supply load 4, the input end of the first power supply control branch 21 is connected to the control end of the second power supply control branch 22, the output end of the first power supply control branch 21 is grounded, the input end of the second power supply control branch 22 is connected to the output end of the second energy storage circuit 3, and the output end of the second power supply control branch 22 is used to connect the power supply load 4.

[0038] It is understandable that the first power supply control branch 21 can be any type of control circuit, the second power supply control branch 22 can be any type of control circuit, the structure of the first power supply control branch 21 can be the same as the structure of the second power supply control branch 22, or the structure of the first power supply control branch 21 can be different from the structure of the second power supply control branch 22.

[0039] Specifically, the control end of the first power supply control branch 21 is used to input the control signal output by the processor in the DC\DC conversion module, and the output end of the second power supply control branch 22 is used to use the second energy storage circuit 3 to power the DC\DC conversion module.

[0040] The working process of the above-mentioned DC power supply power-off holding circuit is as follows: the DC\DC conversion module detects the voltage change, outputs the conduction signal of the first power supply control branch 21 to turn on the first power supply control branch 21, and after the first power supply control branch 21 is turned on, a conduction signal of the second power supply control branch 22 is generated, the second power supply control branch 22 is turned on, and the second energy storage circuit 3 supplies power to the DC\DC conversion module through the second power supply control branch 22, thereby extending the power-off holding time.

[0041] The DC power supply power-off holding circuit of this embodiment provides a first power supply control branch 21 and a second control power supply branch in the power supply control circuit 2 to implement step-by-step control, further ensuring the stability and safety of the circuit.

[0042] In one embodiment, if Figure 2 As shown, on the basis of the above embodiment, the first power supply control branch 21 includes a protection branch 211 and a first switch tube 212, one end of the protection branch 211 is electrically connected to the power supply load 4, the other end of the protection branch 211 is grounded, the control end of the first switch tube 212 is connected to one end of the protection branch 211, the input end of the first switch tube 212 is connected to the control end of the second power supply control branch 22, and the output end of the first switch tube 212 is grounded.

[0043] Specifically, the resistor R126 in the protection branch 211 is used to protect the first switch tube 212 to prevent the first switch tube 212 from breaking down. It can be understood that the first switch tube 212 is any type of switch tube, the first switch tube 212 can be a MOS tube, the first switch tube 212 can also be a triode, the first switch tube 212 can also be a field effect tube, preferably, as Figure 3 As shown, the first switch tube 212 is a MOS tube Q2.

[0044] The working process of the above-mentioned DC power supply power-off holding circuit is as follows: the DC\DC conversion module detects the voltage change and outputs a high-level signal to turn on the first switch tube 212. After the first switch tube 212 is turned on, the signal at the control end of the second power supply control branch 22 is pulled low to turn on the second power supply control branch 22.

[0045] The DC power supply power-off holding circuit of this embodiment is provided with a switch tube in the first power supply control branch 21 for control, so as to realize efficient, flexible and accurate power control and improve the stability and reliability of the circuit.

[0046] In one embodiment, if Figure 2As shown, on the basis of the above embodiment, the second power supply control branch 22 includes a voltage dividing branch 221 and a second switch tube 222, the input end of the voltage dividing branch 221 is connected to the output end of the second switch tube 222, the first output end of the voltage dividing branch 221 is connected to the control end of the second switch tube 222, the second output end of the voltage dividing branch 221 is connected to the input end of the first power supply control branch 21, the input end of the second switch tube 222 is connected to the output end of the second energy storage circuit 3, and the output end of the second switch tube 222 is used to connect the power supply load 4.

[0047] Specifically, a voltage dividing resistor is provided in the voltage dividing branch 221, and the voltage at the control end of the second switch tube 222 is reduced by the voltage dividing branch 221 to ensure that the second switch tube 222 can be turned on. It can be understood that the second switch tube 222 is any type of switch tube, the second switch tube 222 can be a MOS tube, the second switch tube 222 can also be a triode, the second switch tube 222 can also be a field effect tube, preferably, as Figure 3 As shown, the second switch tube 222 is a MOS tube Q1.

[0048] The working process of the above-mentioned DC power supply power-off holding circuit is as follows: after the first switch tube 212 is turned on, the resistor R174 and the resistor R173 in the voltage dividing branch 221 are used to divide the voltage, so that the second switch tube 222 is turned on. After the second switch tube 222 is turned on, the second energy storage circuit 3 supplies power to the DC\DC conversion module through the second switch tube 222.

[0049] The DC power supply power-off holding circuit of this embodiment sets a switch tube in the second power supply control branch 22 for control, and uses a voltage divider circuit to control the voltage of the second switch tube 222 to ensure that the second switch tube 222 can be turned on, thereby achieving efficient, flexible and precise power control and improving the stability and reliability of the circuit.

[0050] In one embodiment, if Figure 2 As shown, based on the above embodiment, the second power supply control branch 22 also includes a voltage stabilizing branch 223 , the input end of the voltage stabilizing branch 223 is grounded, and the output end of the voltage stabilizing branch 223 is connected to the control end of the second switch tube 222 .

[0051] Specifically, the voltage stabilizing branch 223 is used to stabilize the signal at the control end of the second switch tube 222. It is understandable that the voltage stabilizing branch 223 can be any voltage stabilizing circuit, preferably, Figure 3 As shown, the voltage stabilizing branch 223 is a voltage stabilizing diode ZV1.

[0052] The DC power supply power-off holding circuit of this embodiment is provided with a voltage stabilizing branch 223 to stabilize the signal at the control end of the second switch tube 222, thereby ensuring that the second switch tube 222 can be turned on and protecting the switch tube, thereby improving the reliability and stability of the circuit.

[0053] In one embodiment, if Figure 4 As shown, a schematic diagram of the module structure of a second energy storage circuit 3 is provided. Figure 1 On the basis of the DC power supply power-off holding circuit shown, the second energy storage circuit 3 includes: an anti-reverse branch 31, the input end of the anti-reverse branch 31 is used to input the first power supply signal, and the output end of the anti-reverse branch 31 is connected to the power supply input end of the power supply control circuit 2.

[0054] Specifically, the anti-reverse branch 31 is used to prevent the signal in the power supply control circuit 2 from flowing to the first power supply that provides the first power supply signal, thereby avoiding damage to the first power supply. It can be understood that the anti-reverse branch 31 of this embodiment is any kind of anti-reverse circuit. A diode can be set in the anti-reverse branch 31 to protect the first power supply, and a transistor can also be set in the anti-reverse branch 31 to protect the first power supply.

[0055] In the DC power supply power-off holding circuit of this embodiment, an anti-reverse branch 31 is provided in the second energy storage circuit 3 to protect the first power supply in the second energy storage circuit 3, which can significantly improve the circuit reliability and the durability of the power supply.

[0056] In one embodiment, if Figure 5 As shown, a schematic diagram of the module structure of a filter circuit 5 is provided. Figure 1 On the basis of the DC power supply power-off holding circuit shown, the DC power supply power-off holding circuit further includes: a filter circuit 5, the positive terminal of the filter circuit 5 is connected to the output end of the second energy storage circuit 3, and the negative terminal of the filter circuit 5 is grounded.

[0057] Specifically, a filter capacitor may be provided in the filter circuit 5 to filter the signal output by the second energy storage circuit 3 .

[0058] The working process of the above DC power supply power-off holding circuit is as follows: after the power supply control circuit 2 is turned on, the filter circuit 5 filters the signal of the second energy storage circuit 3 and then the signal flows to the power supply control circuit 2 .

[0059] The DC power supply power-off holding circuit of this embodiment is provided with a filter circuit 5 to filter the signal at the output end of the second energy storage circuit 3, thereby further improving the signal quality and the stability of the voltage input to the DC\DC conversion module.

[0060] In one embodiment, a DC power supply is provided, the DC power supply comprising a power supply load 4 and a DC power supply power-off holding circuit mentioned in any of the above embodiments, wherein the DC power supply power-off holding circuit is electrically connected to the power supply load 4.

[0061] like Figure 6 As shown, a schematic diagram of the module structure of a DC power supply is provided.

[0062] In one embodiment, if Figure 6 As shown, based on the above embodiment, the power supply load 4 is a DC\DC conversion module, and the DC power supply also includes: an electromagnetic compatibility circuit 6, the input end of the electromagnetic compatibility circuit 6 is used to input the power supply signal, and the output end of the electromagnetic compatibility circuit 6 is connected to the input end of the first energy storage circuit 1.

[0063] Specifically, the electromagnetic compatibility circuit 6 is used to suppress electromagnetic interference to ensure that the circuit can still work normally when subjected to electromagnetic interference. Devices such as TVS diodes can be set in the electromagnetic compatibility circuit 6 as surge protection circuits, and transient suppression diodes, EMI filters and other devices can also be set to suppress electromagnetic interference.

[0064] The DC power supply of this embodiment sets an electromagnetic compatibility circuit 6 between the busbar providing the power supply signal and the energy storage capacitor of the first energy storage circuit 1 to suppress electromagnetic interference, which can reduce noise interference, ensure signal quality, and improve signal accuracy and effectiveness.

[0065] In one embodiment, if Figure 6 As shown, based on the above embodiment, the DC power supply also includes: a bus anti-backfeed circuit 7, one end of the bus anti-backfeed circuit 7 is connected to the negative end of the first energy storage circuit 1, and the other end of the bus anti-backfeed circuit 7 is connected to the bus for providing the power supply signal.

[0066] Specifically, the bus anti-backflow circuit 7 is used to prevent the signal in the circuit from flowing into the bus in reverse phase. A diode can be set in the bus anti-backflow circuit 7 to protect the bus, and a switch tube can also be set in the bus anti-backflow circuit 7 to protect the bus.

[0067] In the DC power supply of this embodiment, a bus anti-backflow circuit 7 is provided between the bus and the first energy storage circuit 1 to protect the bus, which significantly improves the reliability of the circuit and the durability of the power supply and ensures the safe operation of the circuit.

[0068] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A DC power supply power-off holding circuit, characterized in that: include: A first energy storage circuit, a power supply control circuit and a second energy storage circuit, wherein the input end of the first energy storage circuit is used to input a power supply signal, the output end of the first energy storage circuit is used to connect a power supply load, the output end of the second energy storage circuit is connected to the power supply input end of the power supply control circuit, the output end of the power supply control circuit is used to connect the power supply load, the control input end of the power supply control circuit is electrically connected to the power supply load, and the power supply control circuit is used to control the second energy storage circuit to supply power to the power supply load according to a signal at its control end.

2. The DC power supply power-off holding circuit according to claim 1, characterized in that: The power supply control circuit includes a first power supply control branch and a second power supply control branch, the control end of the first power supply control branch is electrically connected to the power supply load, the input end of the first power supply control branch is connected to the control end of the second power supply control branch, the output end of the first power supply control branch is grounded, the input end of the second power supply control branch is connected to the output end of the second energy storage circuit, and the output end of the second power supply control branch is used to connect the power supply load.

3. The DC power supply power-off holding circuit as claimed in claim 2, characterized in that: The first power supply control branch includes a protection branch and a first switch tube, one end of the protection branch is electrically connected to the power supply load, the other end of the protection branch is grounded, the control end of the first switch tube is connected to one end of the protection branch, the input end of the first switch tube is connected to the control end of the second power supply control branch, and the output end of the first switch tube is grounded.

4. The DC power supply power-off holding circuit as claimed in claim 3, characterized in that: The second power supply control branch includes a voltage divider branch and a second switch tube, the input end of the voltage divider branch is connected to the output end of the second switch tube, the first output end of the voltage divider branch is connected to the control end of the second switch tube, the second output end of the voltage divider branch is connected to the input end of the first power supply control branch, the input end of the second switch tube is connected to the output end of the second energy storage circuit, and the output end of the second switch tube is used to connect the power supply load.

5. The DC power supply power-off holding circuit as claimed in claim 4, characterized in that: The second power supply control branch further includes a voltage stabilizing branch, an input end of the voltage stabilizing branch is grounded, and an output end of the voltage stabilizing branch is connected to a control end of the second switch tube.

6. The DC power supply power-off holding circuit according to claim 1, characterized in that: The second energy storage circuit includes: an anti-reverse branch, an input end of the anti-reverse branch is used to input a first power supply signal, and an output end of the anti-reverse branch is connected to a power supply input end of the power supply control circuit.

7. The DC power supply power-off holding circuit according to claim 1, characterized in that: The DC power supply power-off holding circuit further includes: a filter circuit, wherein a positive terminal of the filter circuit is connected to an output terminal of the second energy storage circuit, and a negative terminal of the filter circuit is grounded.

8. A DC power supply, characterized in that: The DC power supply comprises: a power supply load and a DC power supply power-off holding circuit as described in any one of claims 1 to 7, wherein the DC power supply power-off holding circuit is electrically connected to the power supply load.

9. The DC power supply according to claim 8, characterized in that: The power supply load is a DC\DC conversion module, and the DC power supply also includes: an electromagnetic compatibility circuit, the input end of the electromagnetic compatibility circuit is used to input the power supply signal, and the output end of the electromagnetic compatibility circuit is connected to the input end of the first energy storage circuit.

10. The DC power supply according to claim 9, characterized in that: The DC power supply further includes: a bus anti-backfeed circuit, one end of which is connected to the negative terminal of the first energy storage circuit, and the other end of which is connected to a bus for providing the power supply signal.

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