Power supply circuit and power supply equipment

Abstract

The utility model relates to a power supply circuit and power supply equipment, a first control branch, a second control branch and a self-locking branch are arranged in the power supply circuit, so that when a key switch is in a starting gear, an external power supply supplies power to the first control branch and the second control branch at the same time, and the self-locking branch is conducted; the external power supply can stably and continuously supply power to the second control branch and the external electric equipment through the self-locking branch, the complexity of the power supply circuit is reduced, the cost of the power supply circuit is reduced, the maintenance of the power supply circuit is facilitated, the application range of the power supply circuit controlled to be conducted through the key switch can be effectively enlarged, and the power supply circuit is convenient to use. And the universality of the power supply circuit is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power supply, and in particular to a power supply circuit and a power supply device. Background Art

[0002] In real life, the main application scenario of the key switch is to control the conduction or disconnection of the power supply circuit, such as the key switch of a vehicle. However, in most application scenarios where the key switch is used to control the conduction or disconnection of the power supply circuit, the power supply circuit is too complicated, which increases the cost of the power supply circuit and is not conducive to the maintenance of the power supply circuit. In addition, the power supply circuit is different in different application scenarios, resulting in the power supply circuit controlled by the key switch not being universal. Utility Model Content

[0003] In order to achieve the above objectives, the present disclosure provides a power supply circuit and a power supply device.

[0004] A first aspect of the present disclosure provides a power supply circuit, the power supply circuit comprising: a key switch, a power supply branch, a self-locking branch, a first control branch, a second control branch, a power supply terminal and a power supply terminal, the key switch comprising a start gear;

[0005] The key switch is connected to the power supply branch, the first control branch and the power supply end, and is used to enable the first control branch and the power supply end to form a first path, and the power supply branch and the power supply end to form a second path when in the start gear;

[0006] The power supply branch is also connected to the second control branch and the power supply end, and is used to enable the power supply end to supply power to the second control branch and the power supply end when the second path is formed;

[0007] The self-locking branch is connected to the second control branch and the power supply end, and is used to be turned on when the first path and the second path are formed, so that the power supply end supplies power to the second control branch and the power supply end through the self-locking branch;

[0008] The power supply branch is further used to stop supplying power to the second control branch and the power supply end when the power supply end supplies power to the second control branch and the power supply end through the self-locking branch.

[0009] Optionally, the key switch further includes a working gear;

[0010] The key switch is further used to maintain the first path between the first control branch and the power supply end and disconnect the second path between the power supply branch and the power supply end when in the working gear;

[0011] The power supply branch is used to stop supplying power to the second control branch and the power supply end when the second path is disconnected;

[0012] The self-locking branch is also connected to the power supply end, and is used to supply power to the second control branch and the power supply end when the second path is disconnected.

[0013] Optionally, the power supply end includes a first power supply end and a second power supply end, the first end of the key switch is connected to the first end of the power supply branch, the second end of the key switch is connected to the first end of the first control branch, and the third end of the key switch is connected to the first power supply end;

[0014] The second end of the power supply branch is connected to the first end of the second control branch and the power supply end;

[0015] The second end of the first control branch is connected to the second end of the second control branch and the second power supply end;

[0016] The first end of the self-locking branch is connected to the first power supply end, and the second end of the self-locking branch is connected to the first end of the second control branch and the power supply end.

[0017] Optionally, the key switch is used to, when in the starting gear, connect the third end of the key switch to the first end of the key switch and the second end of the key switch to form the first path between the first control branch and the first power supply end, and to form the second path between the power supply branch and the first power supply end.

[0018] Optionally, the key switch is also used to connect the third end of the key switch to the second end of the key switch when in the working gear, so as to maintain the first path between the first control branch and the first power supply end.

[0019] Optionally, the first control branch includes a coil of a first relay, the second control branch includes a coil of a second relay, and the self-locking branch includes a normally open contact of the first relay and a normally open contact of the second relay;

[0020] One end of the normally open contact of the first relay and the normally open contact of the second relay connected in series is connected to the first power supply end, and the other end is connected to the first end of the coil of the second relay and the power supply end;

[0021] A first end of the coil of the first relay is connected to a second end of the key switch, and a second end of the coil of the first relay is connected to a second end of the coil of the second relay and the second power supply end.

[0022] Optionally, the power supply circuit further includes a switch component;

[0023] The switch component is connected to the power supply branch, the self-locking branch and the second control branch, and is used to disconnect when receiving a control signal sent by an external device, so that the power supply branch stops supplying power to the second control branch, or the self-locking branch stops supplying power to the second control branch.

[0024] Optionally, the switch assembly includes at least one self-controlled switch;

[0025] The first end of the self-controlled switch is connected to the first end of the second control branch, and the second end of the self-controlled switch is connected to the second end of the power supply branch and the second end of the self-locking branch;

[0026] The self-controlled switch is used to disconnect upon receiving the control signal sent by the external device, so that the power supply branch stops supplying power to the second control branch, or the self-locking branch stops supplying power to the second control branch.

[0027] Optionally, the switch assembly includes a control assembly, and the control assembly includes a third relay and a controller;

[0028] The coil of the third relay is connected to the controller, the first end of the normally closed contact of the third relay is connected to the first end of the second control branch, and the second end of the normally closed contact of the third relay is connected to the second end of the power supply branch and the second end of the self-locking branch;

[0029] The controller is used to, upon receiving the control signal sent by the external device, turn on the branch where the coil of the third relay is located, so that the normally closed contact of the third relay is disconnected, the power supply branch stops supplying power to the second control branch, or the self-locking branch stops supplying power to the second control branch.

[0030] A second aspect of the present disclosure provides a power supply device, the device comprising: the power supply circuit described in the first aspect of the present disclosure.

[0031] Through the above technical solution, the power supply circuit includes: a key switch, a power supply branch, a self-locking branch, a first control branch, a second control branch, a power supply end and a power supply end, wherein the key switch includes a start gear; the key switch is connected to the power supply branch, the first control branch and the power supply end, and is used to form a first path between the first control branch and the power supply end, and a second path between the power supply branch and the power supply end when the key switch is in the start gear; the power supply branch is also connected to the second control branch and the power supply end, and is used to enable the power supply end to supply power to the second control branch and the power supply end when the second path is formed; the self-locking branch is connected to the second control branch and the power supply end, and is used to conduct when the first path and the second path are formed, so that the power supply end supplies power to the second control branch and the power supply end through the self-locking branch; the power supply branch is also used to stop supplying power to the second control branch and the power supply end when the power supply end supplies power to the second control branch and the power supply end through the self-locking branch. In this way, by setting the first control branch, the second control branch and the self-locking branch in the power supply circuit, when the key switch is in the start position, the external power supply supplies power to the first control branch and the second control branch at the same time, and the self-locking branch is turned on, so that the external power supply can stably and continuously supply power to the second control branch and the external electrical equipment through the self-locking branch, thereby reducing the complexity of the power supply circuit, thereby reducing the cost of the power supply circuit, facilitating the maintenance of the power supply circuit, and can effectively increase the scope of use of the power supply circuit controlled by the key switch, which is beneficial to improving the versatility of the power supply circuit.

[0032] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0034] Figure 1 is a schematic diagram of a power supply circuit according to an exemplary embodiment of the present disclosure;

[0035] Figure 2 According to this disclosure Figure 1 A schematic diagram of a power supply circuit shown in the illustrated embodiment;

[0036] Figure 3 According to this disclosure Figure 1 A schematic diagram of another power supply circuit shown in the illustrated embodiment;

[0037] Figure 4 According to this disclosure Figure 2 A schematic diagram of a power supply circuit shown in the illustrated embodiment;

[0038] Figure 5 The figure is a block diagram of a power supply device according to an exemplary embodiment of the present disclosure.

[0039] Description of Reference Numerals

[0040] 101 key switch 102 power supply branch

[0041] 103 Self-locking branch 104 First control branch

[0042] 105 Second control branch K1 First relay

[0043] K2 Second relay 106 switch assembly DETAILED DESCRIPTION

[0044] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0045] Figure 1 is a schematic diagram of a power supply circuit according to an exemplary embodiment of the present disclosure, such as Figure 1 As shown, the power supply circuit may include: a key switch 101, a power supply branch 102, a self-locking branch 103, a first control branch 104, a second control branch 105, a power supply end and a power supply end, wherein the key switch 101 includes a start gear; the key switch 101 may be connected to the power supply branch 102, the first control branch 104 and the power supply end, and is used to enable the first control branch 104 to form a first path with the power supply end, and the power supply branch 102 to form a second path with the power supply end when in the start gear; the power supply branch 102 may also be connected to the second control branch 105 and the power supply end , used to enable the power supply end to supply power to the second control branch 105 and the power supply end when the second path is formed; the self-locking branch 103 can be connected to the second control branch 105 and the power supply end, and is used to be turned on when the first path and the second path are formed, so that the power supply end supplies power to the second control branch 105 and the power supply end through the self-locking branch 103; the power supply branch 102 can also be used to stop supplying power to the second control branch 105 and the power supply end when the power supply end supplies power to the second control branch 105 and the power supply end through the self-locking branch 103.

[0046] In addition, the key switch 101 may also include a working gear; the key switch 101 may also be used to maintain the first path between the first control branch 104 and the power supply end, and disconnect the second path between the power supply branch 102 and the power supply end when in the working gear; the power supply branch 102 may be used to stop supplying power to the second control branch 105 and the power supply end when the second path is disconnected; the self-locking branch 103 may also be connected to the power supply end, and be used to supply power to the second control branch 105 and the power supply end when the second path is disconnected.

[0047] It should be noted that the power supply end can be used to connect an external power supply, the power supply end can be used to connect an external electrical device, the key switch 101 and the self-locking branch 103 can be connected to the external power supply through the power supply end, and the power supply branch 102 and the self-locking branch 103 can be connected to the external electrical device through the power supply end. When the key switch 101 is in the start position, the first control branch 104 can form a first path with the power supply end, and the power supply branch 102 can form a second path with the power supply end. The external power supply can provide voltage to the first control branch 104 through the first path, and the external power supply can provide voltage to the second control branch 105 and the external electrical device through the second path, so that the external power supply can provide voltage to the first control branch 104 and the second control branch 105 at the same time. The time that the key switch 101 is in the start position can be a few seconds (for example, 2s or 3s), and the external power supply cannot be continuously connected through the second path. The first control branch 104 and the second control branch 105 can control the self-locking branch 103 to be turned on when the external power supply simultaneously supplies voltage to the first control branch 104 and the second control branch 105, so that the external power supply can supply voltage to the second control branch 105 and the external power supply through the self-locking branch 103, and stop supplying voltage to the second control branch 105 and the external power supply through the second path, so that the external power supply can continuously supply power to the second control branch 105 and the external power supply through the power supply circuit. When the key switch 101 is in the working position, the first path formed between the first control branch 104 and the power supply end is maintained, and the second path formed between the power supply branch 102 and the power supply end is disconnected. The external power supply can provide voltage to the first control branch 104 through the first path. When the key switch 101 is in the working position, the external power supply can simultaneously provide voltage to the first control branch 104 and the second control branch 105, so that the first control branch 104 and the second control branch 105 control the self-locking branch 103 to be turned on. The external power supply can supply power to the second control branch 105 and the power supply end through the self-locking branch 103, and the external power supply can stably and continuously supply power to the external electrical equipment through the power supply circuit.

[0048] Optionally, Figure 1 For example, the power supply end may include a first power supply end and a second power supply end, the first end of the key switch 101 can be connected to the first end of the power supply branch 102, the second end of the key switch 101 can be connected to the first end of the first control branch 104, and the third end of the key switch 101 can be connected to the first power supply end; the second end of the power supply branch 102 can be connected to the first end of the second control branch 105 and the power supply end; the second end of the first control branch 104 can be connected to the second end of the second control branch 105 and the second power supply end; the first end of the self-locking branch 103 can be connected to the first power supply end, and the second end of the self-locking branch 103 can be connected to the first end of the second control branch 105 and the power supply end.

[0049] The key switch 101 is used for, when in the starting gear, the third end of the key switch 101 can be connected to the first end of the key switch 101 and the second end of the key switch 101, so as to form the first path between the first control branch 104 and the first power supply end, and to form the second path between the power supply branch 102 and the first power supply end. The key switch 101 is also used for, when in the working gear, the third end of the key switch 101 is connected to the second end of the key switch 101, so as to maintain the first path between the first control branch 104 and the first power supply end. The first power supply end can be used to connect the positive pole of an external power supply, and the second power supply end can be used to connect the negative pole of an external power supply.

[0050] It should be noted that, when the key switch 101 is in the start position, the third end of the key switch 101 can be connected to the first end of the key switch 101 and the second end of the key switch 101 to form a first path between the first control branch 104 and the positive electrode of the external power supply, and a second path between the power supply branch 102 and the positive electrode of the external power supply. The positive electrode of the external power supply can supply power to the first control branch 104 through the first path, and the positive electrode of the external power supply can supply power to the second control branch 105 and the external electrical equipment through the second path. When the positive electrode of the external power supply supplies power to the first control branch 104 and the second control branch 105 at the same time, the first control branch 104 and the second control branch 105 are connected. 104 and the second control branch 105 can control the self-locking branch 103 to be turned on, and the positive electrode of the external power supply can supply power to the second control branch 105 and the external power device through the self-locking branch 103. When the positive electrode of the external power supply supplies power to the second control branch 105 and the external power device through the self-locking branch 103, the positive electrode of the external power supply stops supplying power to the second control branch 105 and the external power device through the second path. When the positive electrode of the external power supply supplies power to the first control branch 104 and the second control branch 105 at the same time, the self-locking branch 103 can be kept turned on, so that the positive electrode of the external power supply can stably and continuously supply power to the external power device through the power supply circuit. When the key switch 101 is in the working position, the third end of the key switch 101 is connected to the second end of the key switch 101, maintaining the first path between the first control branch 104 and the first power supply end. The external power supply can supply power to the first control branch 104 through the first path, so that the positive pole of the external power supply supplies power to the first control branch 104 and the second control branch 105 at the same time.

[0051] The above technical scheme can set the first control branch, the second control branch and the self-locking branch in the power supply circuit, so that when the key switch is in the starting position, the external power supply supplies power to the first control branch and the second control branch at the same time, and the self-locking branch is turned on, so that the external power supply can stably and continuously supply power to the second control branch and the external electrical equipment through the self-locking branch, thereby reducing the complexity of the power supply circuit, thereby reducing the cost of the power supply circuit, facilitating the maintenance of the power supply circuit, and can effectively increase the scope of use of the power supply circuit controlled by the key switch, which is beneficial to improving the versatility of the power supply circuit.

[0052] Figure 2 According to this disclosure Figure 1 The embodiment shown is a schematic diagram of a power supply circuit, such as Figure 2As shown, the first control branch 104 may include a coil of a first relay K1, the second control branch 105 may include a coil of a second relay K2, and the self-locking branch 103 may include a normally open contact of the first relay K1 and a normally open contact of the second relay K2; the normally open contact of the first relay K1 may be connected in series with the normally open contact of the second relay K2 at one end thereof and connected to the first power supply terminal, and the other end thereof may be connected to the first end of the coil of the second relay K2 and the power supply terminal; the first end of the coil of the first relay K1 may be connected to the second end of the coil of the second relay K2 and the second power supply terminal.

[0053] It should be noted that, when the key switch 101 is in the starting gear (i.e., the START gear), the third end of the key switch 101 can be connected to the first end of the key switch 101 and the second end of the key switch 101, the positive pole of the external power supply can supply power to the coil of the first relay K1 through the second end of the key switch 101, and the positive pole of the external power supply can supply power to the coil of the second relay K2 and the external electrical equipment through the first end of the key switch 101. When the coil of the first relay K1 and the coil of the second relay K2 are energized at the same time, the normally open contact of the first relay K1 and the normally open contact of the second relay K2 are closed to make the self-locking branch 103 conductive, the positive pole of the external power supply can supply power to the coil of the second relay K2 and the external electrical equipment through the self-locking branch 103, and stop supplying power to the coil of the second relay K2 and the external electrical equipment through the first end of the key switch 101, so that the coil of the second relay K2 can be continuously energized, so that the normally open contact of the second relay K2 is continuously in a closed state, and the self-locking branch 103 is kept conductive. When the key switch 101 is in the working position (i.e., the ON position), the third end of the key switch 101 can be connected to the second end of the key switch 101, and the positive electrode of the external power supply can supply power to the coil of the first relay K1 through the second end of the key switch 101. The positive electrode of the external power supply can supply power to the coil of the second relay K2 and the external electrical equipment through the self-locking branch 103, so that the coil of the first relay K1 and the coil of the second relay K2 are energized at the same time, and the normally open contacts of the first relay K1 and the normally open contacts of the second relay K2 are controlled to be closed, so as to keep the self-locking branch 103 conducting.

[0054] The above technical scheme can set the first control branch, the second control branch and the self-locking branch in the power supply circuit, so that when the key switch is in the starting position, the external power supply supplies power to the first control branch and the second control branch at the same time, and the self-locking branch is turned on, so that the external power supply can stably and continuously supply power to the second control branch and the external electrical equipment through the self-locking branch, thereby reducing the complexity of the power supply circuit, thereby reducing the cost of the power supply circuit, facilitating the maintenance of the power supply circuit, and can effectively increase the scope of use of the power supply circuit controlled by the key switch, which is beneficial to improving the versatility of the power supply circuit.

[0055] Figure 3 According to this disclosure Figure 1 The embodiment shown is a schematic diagram of another power supply circuit, such as Figure 3 As shown, the power supply circuit may further include a switch component 106; the switch component 106 is connected to the power supply branch 102, the self-locking branch 103 and the second control branch 105, and is used to disconnect when receiving a control signal sent by an external device, so that the power supply branch 102 stops supplying power to the second control branch 105, or the self-locking branch 103 stops supplying power to the second control branch 105.

[0056] In one embodiment, the switch assembly 106 may include at least one self-controlled switch; a first end of the self-controlled switch is connected to a first end of the second control branch 105, and a second end of the self-controlled switch is connected to a second end of the power supply branch 102 and a second end of the self-locking branch 103; the self-controlled switch is used to disconnect when receiving the control signal sent by the external device, so that the power supply branch 102 stops supplying power to the second control branch 105, or the self-locking branch 103 stops supplying power to the second control branch 105. The self-controlled switch may be a triode such as a MOS tube (Metal-Oxide-Semiconductor Field-Effect Transistor), a BJT tube (Bipolar Junction Transistor), and an IGBT tube (Insulate-Gate Bipolar Transistor).

[0057] In another embodiment, the switch component 106 may include a control component, which may include a third relay and a controller; the coil of the third relay is connected to the controller, the first end of the normally closed contact of the third relay is connected to the first end of the second control branch 105, and the second end of the normally closed contact of the third relay is connected to the second end of the power supply branch 102 and the second end of the self-locking branch 103; the controller is used to, when receiving the control signal sent by the external device, turn on the branch where the coil of the third relay is located, so that the normally closed contact of the third relay is disconnected, the power supply branch 102 stops supplying power to the second control branch 105, or the self-locking branch 103 stops supplying power to the second control branch 105.

[0058] It should be noted that the external device can be a device for receiving a fault signal of an external electrical device. When receiving the fault signal, the control signal is sent to the switch component 106. When receiving the control signal, the switch component 106 is disconnected, and the external power supply stops supplying power to the second control branch 105, so that the self-locking branch 103 is disconnected, and the external power supply stops supplying power to the external electrical device through the power supply circuit; the external device can also be a device for receiving the remaining power consumption of the external power supply. When it is determined that the remaining power consumption of the external power supply is less than or equal to the preset remaining power consumption, it is determined that the external power supply is over-discharged, and a control signal is sent to the switch component 106. When receiving the control signal, the switch component 106 is disconnected, and the external power supply stops supplying power to the second control branch 105, so that the self-locking branch 103 is disconnected; the external device can also be a device for remotely controlling the power supply circuit to power off.

[0059] For example, Figure 4 As shown, Figure 4 According to this disclosure Figure 2The illustrated embodiment shows a schematic diagram of a power supply circuit, the controller may be an AGV (Automated Guided Vehicle) controller, the AGV controller may be used to receive control signals sent by a scheduling device, the external power-consuming device may be an AGV power-consuming device, the external power supply may be an AGV power supply, the external device may be a scheduling device, the coil of the third relay is connected to the AGV controller, the first end of the normally closed contact of the third relay is connected to the first end of the coil of the second relay K2, the second end of the normally closed contact of the third relay is connected to the second end of the power supply branch 102 and the normally open contact of the second relay K2, the AGV controller is also connected to the AGV power supply, the positive pole of the AGV power supply may be connected to the first power supply end, the AGV power supply The negative pole of can be connected to the second power supply end, the AGV power supply supplies power to the AGV electrical equipment through the power supply circuit, the AGV power supply can be connected to the AGV controller, and provide voltage to the AGV controller. When the dispatching device receives the battery over-discharge warning signal, it sends a control signal to the AGV controller. When the AGV controller receives the control signal, it provides voltage to the coil of the third relay, the coil of the third relay is energized, the normally closed contact of the third relay is disconnected, the AGV power supply stops supplying power to the coil of the second relay K2, and the normally open contact of the second relay K2 is disconnected, so that the AGV power supply stops supplying power to the AGV electrical equipment through the power supply circuit. The external device can also be a fire-fighting device, and the AGV controller can also be used to receive the control signal sent by the fire-fighting device. When the fire-fighting device receives the fire alarm signal, it sends a control signal to the AGV controller, so that the AGV power supply stops supplying power to the AGV electrical equipment through the power supply circuit.

[0060] The above technical scheme can be achieved by setting a switch component in the power supply circuit. The switch component is connected to the power supply branch, the self-locking branch and the second control branch. When the switch component receives a control signal sent by an external device, it is disconnected to stop the external power supply from supplying power to the second control branch. The self-locking branch is disconnected, and the power supply circuit can be disconnected remotely controlled by an external device, thereby improving the operating efficiency and safety of the power supply circuit.

[0061] Figure 5 is a block diagram of a power supply device according to an exemplary embodiment of the present disclosure. Figure 5 As shown, the power supply device may include: Figure 1-Figure 4 A power supply circuit as described in any one of the preceding claims.

[0062] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0063] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0064] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A power supply circuit, characterized in that: The power supply circuit comprises: a key switch, a power supply branch, a self-locking branch, a first control branch, a second control branch, a power supply end and a power supply end, and the key switch comprises a start gear; The key switch is connected to the power supply branch, the first control branch and the power supply end, and is used to enable the first control branch and the power supply end to form a first path, and the power supply branch and the power supply end to form a second path when in the start gear; The power supply branch is also connected to the second control branch and the power supply end, and is used to enable the power supply end to supply power to the second control branch and the power supply end when the second path is formed; The self-locking branch is connected to the second control branch and the power supply end, and is used to be turned on when the first path and the second path are formed, so that the power supply end supplies power to the second control branch and the power supply end through the self-locking branch; The power supply branch is further used to stop supplying power to the second control branch and the power supply end when the power supply end supplies power to the second control branch and the power supply end through the self-locking branch.

2. The power supply circuit according to claim 1, characterized in that: The key switch also includes a working gear; The key switch is further used to maintain the first path between the first control branch and the power supply end and disconnect the second path between the power supply branch and the power supply end when in the working gear; The power supply branch is used to stop supplying power to the second control branch and the power supply end when the second path is disconnected; The self-locking branch is also connected to the power supply end, and is used to supply power to the second control branch and the power supply end when the second path is disconnected.

3. The power supply circuit according to claim 2, characterized in that: The power supply end includes a first power supply end and a second power supply end, the first end of the key switch is connected to the first end of the power supply branch, the second end of the key switch is connected to the first end of the first control branch, and the third end of the key switch is connected to the first power supply end; The second end of the power supply branch is connected to the first end of the second control branch and the power supply end; The second end of the first control branch is connected to the second end of the second control branch and the second power supply end; The first end of the self-locking branch is connected to the first power supply end, and the second end of the self-locking branch is connected to the first end of the second control branch and the power supply end.

4. The power supply circuit according to claim 3, characterized in that: The key switch is used to connect the third end of the key switch to the first end of the key switch and the second end of the key switch when in the starting gear, so as to form the first path between the first control branch and the first power supply end, and to form the second path between the power supply branch and the first power supply end.

5. The power supply circuit according to claim 4, characterized in that: The key switch is also used for connecting the third end of the key switch to the second end of the key switch when in the working gear, so as to maintain the first path between the first control branch and the first power supply end.

6. The power supply circuit according to claim 3, characterized in that: The first control branch includes a coil of a first relay, the second control branch includes a coil of a second relay, and the self-locking branch includes a normally open contact of the first relay and a normally open contact of the second relay; One end of the normally open contact of the first relay and the normally open contact of the second relay connected in series is connected to the first power supply end, and the other end is connected to the first end of the coil of the second relay and the power supply end; A first end of the coil of the first relay is connected to a second end of the key switch, and a second end of the coil of the first relay is connected to a second end of the coil of the second relay and the second power supply end.

7. The power supply circuit according to claim 2, characterized in that: The power supply circuit also includes a switch component; The switch component is connected to the power supply branch, the self-locking branch and the second control branch, and is used to disconnect when receiving a control signal sent by an external device, so that the power supply branch stops supplying power to the second control branch, or the self-locking branch stops supplying power to the second control branch.

8. The power supply circuit according to claim 7, characterized in that: The switch assembly includes at least one self-controlled switch; The first end of the self-controlled switch is connected to the first end of the second control branch, and the second end of the self-controlled switch is connected to the second end of the power supply branch and the second end of the self-locking branch; The self-controlled switch is used to disconnect upon receiving the control signal sent by the external device, so that the power supply branch stops supplying power to the second control branch, or the self-locking branch stops supplying power to the second control branch.

9. The power supply circuit according to claim 7, characterized in that: The switch assembly includes a control assembly, and the control assembly includes a third relay and a controller; The coil of the third relay is connected to the controller, the first end of the normally closed contact of the third relay is connected to the first end of the second control branch, and the second end of the normally closed contact of the third relay is connected to the second end of the power supply branch and the second end of the self-locking branch; The controller is used to, upon receiving the control signal sent by the external device, turn on the branch where the coil of the third relay is located, so that the normally closed contact of the third relay is disconnected, the power supply branch stops supplying power to the second control branch, or the self-locking branch stops supplying power to the second control branch.

10. A power supply device, characterized in that: The device comprises: the power supply circuit as described in any one of claims 1 to 9 above.

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