Power supply automatic protection circuit, electronic equipment and household appliance

Abstract

The invention relates to an automatic power supply protection circuit, electronic equipment and household appliance equipment. The automatic power supply protection circuit comprises a first power supply branch, a second power supply branch and an automatic protection branch, one end of the first power supply branch and one end of the second power supply branch are connected with the power input end, and the other end of the first power supply branch and the other end of the second power supply branch are connected with the power output end. One end of the automatic protection branch is connected with the power supply input end, and the other end of the automatic protection branch is connected with the control end of the power supply switching unit; when the power supply input end receives a high first signal, the automatic protection branch circuit pulls down the voltage of the control end of the power supply switching unit, and the second power supply branch circuit is cut off, so that the first signal of the power supply input end flows to the power supply output end through the first power supply branch circuit. A voltage conversion unit in the first power supply branch converts the first signal into a lower second signal. The power supply automatic protection circuit can adaptively select the output branch output to the post-stage circuit based on the power supply input condition, and stable output of the specified voltage is realized.

Description

Technical Field

[0001] The present application relates to the technical field of integrated circuits, and in particular to an automatic power protection circuit, electronic equipment, and household appliances. Background Art

[0002] As described in the background technology section above, the power supply voltages required by the various circuits in existing household appliances are different. In the scenario where one power supply is used to power multiple circuits, the subsequent circuits are often damaged by the impact of high-voltage signals because the previous circuits are powered by high voltage. Using electronic chips to monitor the power supply voltages of the power supplies of the various circuits will greatly increase the cost. Therefore, there is an urgent need for a power supply circuit that can automatically realize power supply protection for the subsequent circuits. Summary of the Invention

[0003] Based on this, it is necessary to provide an automatic power protection circuit, electronic equipment and household appliance that can stably protect the subsequent circuit at any time to address the above technical problems.

[0004] In a first aspect, the present application provides a power supply automatic protection circuit, comprising:

[0005] A first power supply branch, a second power supply branch and an automatic protection branch, wherein the first power supply branch includes a voltage conversion unit and the second power supply branch includes a power supply switching unit;

[0006] One end of the first power supply branch is connected to the power input end, and the other end of the first power supply branch is connected to the power output end;

[0007] One end of the second power supply branch is connected to the power input end, and the other end of the second power supply branch is connected to the power output end;

[0008] One end of the automatic protection branch is connected to the power input end, and the other end of the automatic protection branch is connected to the control end of the power supply switching unit;

[0009] When the power input terminal receives a first signal, the automatic protection branch lowers the voltage of the control terminal of the power switching unit, and the second power supply branch is cut off, so that the first signal of the power input terminal flows to the power output terminal via the first power supply branch, and the voltage conversion unit is used to convert the first signal into a second signal, wherein the voltage of the second signal is lower than the voltage of the first signal;

[0010] When the power input terminal receives a second signal, the second power supply branch is turned on, and the second signal of the power input terminal flows to the power output terminal via the second power supply branch.

[0011] In one embodiment, the invention further comprises: a control component, wherein the control component is connected to the control terminal of the power supply switching unit;

[0012] When the power input terminal receives the first signal, the control component sends a low-level signal to the control terminal of the power switching unit, and the second power supply branch is cut off, so that the first signal of the power input terminal flows to the power output terminal via the first power supply branch, and the voltage conversion unit is used to convert the first signal into a second signal;

[0013] When the power input end receives the second signal, the control component sends a high-level signal to the control end of the power switching unit, and the second power supply branch is turned on, so that the second signal of the power input end flows to the power output end via the second power supply branch.

[0014] In one embodiment, the power supply switching unit includes a field effect transistor and a first transistor;

[0015] The source of the field effect tube is connected to the power input end, the gate of the field effect tube is connected to the power output end, the gate of the field effect tube is connected to the collector of the first transistor, the emitter of the first transistor is grounded, and the base of the first transistor is respectively connected to the control component and the other end of the automatic protection branch.

[0016] In one embodiment, the automatic protection branch includes a protection level limiting unit and a level pulling-down unit;

[0017] One end of the protection level limiting unit is connected to the power input end, and the other end of the protection level limiting unit is connected to the control end of the level pull-down unit;

[0018] An input end of the level pull-down unit is connected to a control end of the power supply switching unit, and an output end of the level pull-down unit is grounded.

[0019] In one embodiment, the protection level limiting unit includes a voltage stabilizing diode, a first resistor, and a second resistor; the level pull-down unit includes a second transistor;

[0020] The cathode of the voltage stabilizing diode is connected to the power input terminal, the anode of the voltage stabilizing diode is connected to the base of the second transistor via the first resistor, and the base of the second transistor is grounded via the second resistor;

[0021] The collector of the second transistor is connected to the control end of the power supply switching unit, and the emitter of the second transistor is grounded.

[0022] In one embodiment, the control component includes a microprocessor unit and a third resistor;

[0023] The micro-processing unit is connected to the control terminal of the power supply switching unit through the third resistor.

[0024] In one embodiment, the power supply switching unit further includes a fourth resistor and a fifth resistor;

[0025] The gate of the field effect tube is connected to the power input terminal through the fourth resistor;

[0026] The collector of the first transistor is connected to the gate of the field effect transistor through the fifth resistor.

[0027] In one embodiment, the first signal is a 12V signal, and the second signal is a 5V signal.

[0028] In a second aspect, the present application further provides an electronic device, which includes the automatic power protection circuit described in the first aspect.

[0029] In a third aspect, the present application further provides a household appliance, which includes the electronic device described in the second aspect.

[0030] In summary, the present application proposes a power supply automatic protection circuit, electronic equipment and household appliance, comprising: a first power supply branch, a second power supply branch and an automatic protection branch; one end of the first power supply branch and the second power supply branch are both connected to the power supply input end, and the other ends of the first power supply branch and the second power supply branch are both connected to the power supply output end; one end of the automatic protection branch is connected to the power supply input end, and the other end of the automatic protection branch is connected to the control end of the power supply switching unit; when the power supply input end receives a higher first signal, the automatic protection branch lowers the voltage of the control end of the power supply switching unit, and the second power supply branch is cut off, so that the first signal at the power supply input end flows to the power supply output end via the first power supply branch, and the voltage conversion unit in the first power supply branch converts the first signal into a lower second signal. The power supply automatic protection circuit provided in the present application can adaptively select the output branch to be output to the subsequent circuit based on the power supply input situation, so as to achieve a stable output of a specified voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A structural block diagram of a power supply automatic protection circuit in one embodiment;

[0032] Figure 2 1 is a circuit diagram of an automatic power protection circuit in one embodiment;

[0033] Figure 3 FIG. 1 is a diagram showing the internal structure of an electronic device in one embodiment.

[0034] Summary of reference numerals:

[0035] First power supply branch 110; second power supply branch 120; automatic protection branch 130; control component 140. DETAILED DESCRIPTION

[0036] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0038] It will be understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor without departing from the scope of this application. The first resistor and the second resistor are both resistors, but they are not the same resistor.

[0039] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if there is transmission of electrical signals or data between the connected circuits, modules, units, etc.

[0040] It is understood that “at least one” refers to one or more, “a plurality” refers to two or more, and “at least a portion of an element” refers to a portion or all of an element.

[0041] As used herein, the singular forms "a," "an," and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include," "comprising," "having," and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Furthermore, the term "and / or" as used in this specification includes any and all combinations of the relevant listed items.

[0042] In one embodiment, Figure 1 As shown, a power supply automatic protection circuit is provided, comprising:

[0043] A first power supply branch 110, a second power supply branch 120, and an automatic protection branch 130 are provided. The first power supply branch 110 includes a voltage conversion unit, and the second power supply branch 120 includes a power supply switching unit. One end of the first power supply branch 110 is connected to the power input terminal, and the other end of the first power supply branch 110 is connected to the power output terminal. One end of the second power supply branch 120 is connected to the power input terminal, and the other end of the second power supply branch 120 is connected to the power output terminal.

[0044] In this embodiment, if Figure 2 As shown, the power input terminal of the power automatic protection circuit is the VCC-1 terminal, and the power output terminal is the VCC-2 terminal. The power automatic protection circuit is arranged between the power supply and the subsequent circuit. It should be noted that in a specific application scenario, the power supply can be a power supply that directly provides a voltage signal, or it can be a controller or other circuit element that indirectly provides a voltage signal. This embodiment does not limit the specific type of the power supply connected to the power input terminal, and can be configured based on the needs of the actual application scenario. Similarly, the subsequent circuit in this embodiment can also be any component or circuit in an electronic device that requires a specified voltage signal control, and the subsequent circuit can be determined based on the actual application scenario.

[0045] In this embodiment, the voltage signal received at the power input is transmitted to the power output via the first power supply branch 110 or the second power supply branch 120. When the power switching unit in the second power supply branch 120 is in the on state, the voltage signal received at the power input is transmitted to the power output via the second power supply branch 120. When the power switching unit in the second power supply branch 120 is in the off state, the voltage signal received at the power input is transmitted to the power output via the first power supply branch 110.

[0046] In a specific embodiment, the real-time state of the power switching unit is determined by a voltage signal at a control terminal of the power switching unit. When the voltage signal at the control terminal of the power switching unit is a high-level signal, the power switching unit enters an on-state. When the voltage signal at the control terminal of the power switching unit is a low-level signal, the power switching unit enters an off-state.

[0047] In this embodiment, one end of the automatic protection branch 130 is connected to the power input terminal, and the other end of the automatic protection branch 130 is connected to the control terminal of the power switching unit. Automatic protection branch 130 is used to monitor the voltage value of the voltage signal at the power input terminal. When the voltage value of the voltage signal at the power input terminal exceeds a preset voltage limit value, automatic protection branch 130 directly lowers the voltage at the control terminal of the power switching unit, causing the power switching unit to enter a cutoff state, thereby cutting off the second power supply branch 120. The voltage signal at the power input terminal is transmitted to the power output terminal via the first power supply branch 110.

[0048] The preset voltage limit value can be implemented by configuring the specific structure and connection relationship of the power supply components of the automatic protection branch 130. The specific value of the voltage limit value can be configured based on the needs of the actual application scenario. For example, the preset voltage limit value can be configured to 7V.

[0049] When the power input end receives the first signal, the automatic protection branch 130 lowers the voltage of the control end of the power supply switching unit, and the second power supply branch 120 is cut off, so that the first signal of the power input end flows to the power output end via the first power supply branch 110, and the voltage conversion unit is used to convert the first signal into a second signal, wherein the voltage of the second signal is less than the voltage of the first signal.

[0050] When the power input terminal receives the second signal, the second power supply branch 120 is turned on, and the second signal at the power input terminal flows to the power output terminal via the second power supply branch 120 .

[0051] In this embodiment, when the power voltage received at the power input terminal is a high-voltage signal, namely, a first signal, the automatic protection branch 130 lowers the voltage at the control terminal of the power switching unit to cut off the second power supply branch 120, thereby allowing the first signal to flow from the first power supply branch 110 to the power output terminal. As the first signal passes through the first power supply branch 110, it flows through the voltage conversion unit, which performs precise voltage conversion processing, converting the first signal into the second signal required by the subsequent circuit.

[0052] When the power voltage received at the power input terminal is a low voltage signal, i.e., the second signal, the automatic protection branch 130 will not affect the voltage at the control terminal of the power switching unit. The second power supply branch 120 is normally turned on, and the second signal is directly transmitted to the power output terminal through the second power supply branch 120.

[0053] It should be noted that the specific values ​​of the first signal and the second signal in this embodiment can be configured according to the needs of the actual application scenario. For example, the first signal can be configured as a 12V voltage signal, and the second signal can be configured as a 5V voltage signal or a 3.3V voltage signal.

[0054] In summary, this embodiment provides a power supply automatic protection circuit, which can realize real-time monitoring of the voltage signal at the power supply input terminal, and when the voltage signal at the power supply input terminal exceeds the preset limit value, immediately lower the voltage of the power supply switching unit control terminal, thereby realizing the conduction control of the power supply branch, so that the high-voltage signal is converted by the voltage conversion unit into the low-voltage signal required by the subsequent circuit through the first power supply branch 110 including the voltage conversion unit, so as to ensure the safety of the subsequent circuit. In actual application scenarios, the power supply required by the system of the electronic device is usually a relatively low-voltage signal, but due to the control timing problem of the front-end circuit, the electrical signal provided by the power supply often switches back and forth between the high-voltage signal and the low-voltage signal. By configuring the power supply automatic protection circuit in this embodiment in the front power supply circuit of the system of the electronic device, it is possible to effectively prevent the high-voltage signal from directly entering the subsequent system circuit, and prevent the high-voltage signal from directly burning the subsequent system circuit.

[0055] In one embodiment, Figure 1 As shown, the power automatic protection circuit further includes: a control component 140, wherein the control component 140 is connected to the control end of the power supply switching unit.

[0056] When the power input end receives the first signal, the control component 140 sends a low-level signal to the control end of the power switching unit, and the second power supply branch 120 is cut off, so that the first signal of the power input end flows to the power output end via the first power supply branch 110, and the voltage conversion unit is used to convert the first signal into a second signal.

[0057] When the power input terminal receives the second signal, the control component 140 sends a high-level signal to the control terminal of the power switching unit, and the second power supply branch 120 is turned on, so that the second signal of the power input terminal flows to the power output terminal through the second power supply branch 120.

[0058] In this embodiment, the power supply automatic protection circuit can also be used in conjunction with a control component 140 that can send high-level signals and low-level signals. The control component 140 in this embodiment can be a controller, a control chip, or a control circuit. For example, the control component 140 in this embodiment can be a microcontroller unit (MCU). Figure 2 As shown, the level signal control terminal MCU_CTRL of the micro control unit can output a corresponding high level signal or a low level signal according to the size of the electrical signal received by the power input terminal.

[0059] For example, assume that the first signal is a 12V voltage signal and the second signal is a 5V voltage signal.

[0060] When the power input terminal signal receives a 12V voltage signal, the control component 140 can send a low-level signal to the control terminal of the power supply switching unit to cut off the power supply switching unit, and then cut off the second power supply branch 120, so that the 12V voltage signal is converted into a 5V voltage signal through the voltage conversion unit of the first power supply branch 110 and then output to the subsequent circuit.

[0061] When the power input terminal signal receives a 5V voltage signal, the control component 140 can send a high-level signal to the control terminal of the power supply switching unit to turn on the power supply switching unit, thereby turning on the second power supply branch 120, so that the 12V voltage signal is converted into a 5V voltage signal through the voltage conversion unit of the first power supply branch 110 and then output to the subsequent circuit.

[0062] This embodiment is configured with a control component 140 that can adaptively output a high level or a low level according to the size of the input voltage at the power input end, so as to achieve the power supply effect of providing a stable low-voltage signal to the subsequent circuit. In actual use scenarios, the voltage of the control end of the power switching unit is preferentially controlled by the control component 140. When the working state of the control component 140 is disturbed and cannot stably output a low-level signal, the automatic protection branch 130 directly realizes the lowering of the level signal of the control end of the power switching unit. The automatic protection branch 130 in this embodiment, combined with the control component 140, can achieve dual protection for power supply switching for the subsequent circuit, so as to further improve the reliability of the automatic power protection circuit.

[0063] In one embodiment, Figure 2 As shown, the power supply switching unit includes a field effect tube and a first transistor, wherein the field effect tube is MOS1 and the first transistor is Q1.

[0064] The source of the field effect transistor is connected to the power input end, the gate of the field effect transistor is connected to the power output end, the gate of the field effect transistor is connected to the collector of the first transistor, the emitter of the first transistor is grounded, and the base of the first transistor is respectively connected to the control component 140 and the other end of the automatic protection branch 130.

[0065] In this embodiment, MOS1 can be a P-channel enhancement mode MOS transistor, and Q1 can be an NPN transistor. It should be noted that the specific transistor types of the field effect transistor and the first transistor in this embodiment can be determined according to the circuit requirements in the actual application scenario.

[0066] In this embodiment, the base of the first transistor serves as the control terminal of the power supply switching unit and is connected to the control component 140 and the automatic protection branch 130 respectively.

[0067] In actual application, when the base of the first transistor receives a low-level signal sent by the control component 140 or is pulled down by the automatic protection branch 130, it will enter the cut-off state, thereby causing the gate voltage of the field effect transistor to be pulled up. At this time, the field effect transistor enters the cut-off state, thereby cutting off the second power supply branch 120.

[0068] When the base of the first transistor receives a high-level signal sent by the control component 140, the first transistor will be in a saturated state, and the first transistor will be turned on, so that the voltage at the gate of the field-effect transistor will be pulled down, and the field-effect transistor will enter the on-state. The voltage signal at the power input end will be directly transmitted to the power output end through the field-effect transistor.

[0069] In a specific embodiment, when the second power supply branch 120 is turned on, no current is input to the voltage conversion unit, and the voltage conversion unit does not work.

[0070] In one embodiment, Figure 2 As shown, the automatic protection branch 130 includes a protection level limiting unit and a level pull-down unit. One end of the protection level limiting unit is connected to the power input terminal, and the other end is connected to the control terminal of the level pull-down unit. The input terminal of the level pull-down unit is connected to the control terminal of the power switching unit, and the output terminal of the level pull-down unit is grounded.

[0071] In this embodiment, the protection level limiting unit is directly connected to the power input terminal, and is used to convert the high voltage signal output from the power input terminal into a suitable protection level.

[0072] The level pull-down unit is used to determine whether to pull down the control terminal of the power supply switching unit according to the output signal of the protection level limiting unit. The output signal of the protection level limiting unit changes according to the voltage value of the signal output by the power input terminal.

[0073] In this embodiment, when the protection level limiting unit receives a high voltage signal, it outputs a control signal subjected to voltage reduction and limiting processing to the control terminal of the pull-down unit, so that the level pulling-down unit pulls down the voltage of the control terminal of the power supply switching unit.

[0074] In one embodiment, Figure 2 As shown, the protection level limiting unit includes a voltage regulator diode, a first resistor and a second resistor, and the level pull-down unit includes a second transistor, wherein the voltage regulator diode is D1, the first resistor is R1, the second resistor is R2, and the second transistor is Q2.

[0075] The cathode of the voltage stabilizing diode is connected to the power input terminal, the anode of the voltage stabilizing diode is connected to the base of the second transistor through the first resistor, and the base of the second transistor is grounded through the second resistor.

[0076] The collector of the second transistor is connected to the control end of the power supply switching unit, and the emitter of the second transistor is grounded.

[0077] In this embodiment, the voltage stabilizing diode D1 is used to configure a suitable protection level. The first resistor and the second resistor are used to set the static operating point of the second transistor and provide current limiting.

[0078] In one embodiment, Figure 2 As shown, the control component 140 includes a micro-processing unit and a third resistor, wherein the micro-processing unit is connected to the control end of the power switching unit through the third resistor, and the third resistor is R3.

[0079] The third resistor in this embodiment is used to provide current limiting for the level signal control terminal MCU_CTRL of the microprocessor unit to prevent the current output by the level signal control terminal MCU_CTRL from impacting the second transistor and causing damage to the second transistor.

[0080] In one embodiment, Figure 2 As shown, the power supply switching unit also includes a fourth resistor and a fifth resistor, wherein the gate of the field effect tube is connected to the power input terminal through the fourth resistor, and the collector of the first transistor is connected to the gate of the field effect tube through the fifth resistor. The fourth resistor is R4 and the fifth resistor is R5.

[0081] In this embodiment, the fourth resistor is a pull-up bias resistor, and the fifth resistor is used to provide current limiting for the field-effect transistor. When the first transistor is in the off state, the gate of the field-effect transistor receives the high-voltage signal from the power input terminal through the fourth resistor, thereby pulling up the gate voltage of the field-effect transistor and turning off the field-effect transistor. The fifth resistor is used to prevent the current at the collector of the first transistor from impacting the gate of the field-effect transistor, thereby preventing damage to the field-effect transistor.

[0082] In summary, this embodiment provides an automatic power supply protection circuit. By simultaneously configuring a control component and an automatic protection branch, it can stably and reliably receive a high-voltage signal at the power input terminal, so that the high-voltage signal is limited by the voltage conversion unit and converted into a low-voltage signal, thereby effectively protecting the subsequent system circuit and preventing the subsequent circuit from being affected by the high-voltage signal and burning. The automatic power supply protection circuit provided by this embodiment has a simple structure and does not require the configuration of additional voltage monitoring equipment. When applied to electronic equipment, it can effectively reduce the use of complex power supplies, thereby greatly reducing the cost of configuring power supply circuits for electronic equipment.

[0083] In one embodiment, an electronic device is provided, comprising the automatic power protection circuit of the aforementioned embodiment. It should be noted that the automatic power protection circuit is disposed within the power circuit within the electronic device, and the actual configuration location of the automatic power protection circuit can be adaptively configured according to the needs of the actual application scenario.

[0084] For example, the automatic power protection circuit can be set between the external power interface and the chip power interface of the electronic device, wherein the power input end of the automatic power protection circuit is connected to the external power interface, and the power output end is connected to the chip power interface.

[0085] In one embodiment, an electronic device is provided. The electronic device may be a terminal, and its internal structure diagram may be as follows: Figure 3 As shown. The electronic device includes a processor, memory, an input / output interface, a communication interface, a display unit, and an input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are connected to the system bus via the input / output interface. The processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The input / output interface of the electronic device is used to exchange information between the processor and external devices. The communication interface of the electronic device is used to communicate with external terminals via wired or wireless means. The wireless means can be achieved via Wi-Fi, a mobile cellular network, NFC (near field communication), or other technologies. The display unit of the electronic device is used to form a visually visible image and can be a display screen, a projection device, or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the electronic device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the electronic device casing, or an external keyboard, touchpad or mouse.

[0086] Those skilled in the art will understand that Figure 3 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the electronic device to which the solution of the present application is applied. The specific electronic device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0087] In one embodiment, an electrical device is further provided, comprising the electronic device in the aforementioned embodiment.

[0088] In the description of this specification, reference to the terms "some embodiments" or "other embodiments" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0089] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0090] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A power supply automatic protection circuit, characterized in that: include: A first power supply branch, a second power supply branch and an automatic protection branch, wherein the first power supply branch includes a voltage conversion unit, and the second power supply branch includes a power supply switching unit; One end of the first power supply branch is connected to the power input end, and the other end of the first power supply branch is connected to the power output end; One end of the second power supply branch is connected to the power input end, and the other end of the second power supply branch is connected to the power output end; One end of the automatic protection branch is connected to the power input end, and the other end of the automatic protection branch is connected to the control end of the power supply switching unit; When the power input terminal receives the first signal, the automatic protection branch pulls down the voltage of the control terminal of the power switching unit, and the second power supply branch is cut off, so that the first signal of the power input terminal flows to the power output terminal via the first power supply branch, and the voltage conversion unit is used to convert the first signal into a second signal, wherein the voltage of the second signal is less than the voltage of the first signal; When the power input terminal receives a second signal, the second power supply branch is turned on, and the second signal at the power input terminal flows to the power output terminal via the second power supply branch.

2. The circuit according to claim 1, characterized in that Also includes: A control component, wherein the control component is connected to a control terminal of the power supply switching unit; When the power input terminal receives the first signal, the control component sends a low-level signal to the control terminal of the power switching unit, and the second power supply branch is cut off, so that the first signal of the power input terminal flows to the power output terminal via the first power supply branch, and the voltage conversion unit is used to convert the first signal into a second signal; When the power input terminal receives the second signal, the control component sends a high level signal to the control terminal of the power switching unit, and the second power supply branch is turned on, so that the second signal of the power input terminal flows to the power output terminal via the second power supply branch.

3. The circuit according to claim 2, characterized in that The power supply switching unit includes a field effect transistor and a first triode; The source of the field effect tube is connected to the power input end, the gate of the field effect tube is connected to the power output end, the gate of the field effect tube is connected to the collector of the first transistor, the emitter of the first transistor is grounded, and the base of the first transistor is respectively connected to the control component and the other end of the automatic protection branch.

4. The circuit according to claim 1, characterized in that The automatic protection branch includes a protection level limiting unit and a level pull-down unit; One end of the protection level limiting unit is connected to the power input end, and the other end of the protection level limiting unit is connected to the control end of the level pull-down unit; An input end of the level pull-down unit is connected to a control end of the power supply switching unit, and an output end of the level pull-down unit is grounded.

5. The circuit according to claim 4, characterized in that The protection level limiting unit includes a voltage stabilizing diode, a first resistor and a second resistor; the level pull-down unit includes a second transistor; The cathode of the voltage stabilizing diode is connected to the power input terminal, the anode of the voltage stabilizing diode is connected to the base of the second transistor through the first resistor, and the base of the second transistor is grounded through the second resistor; The collector of the second transistor is connected to the control end of the power supply switching unit, and the emitter of the second transistor is grounded.

6. The circuit according to claim 2, characterized in that The control component includes a microprocessing unit and a third resistor; The micro-processing unit is connected to the control end of the power supply switching unit through the third resistor.

7. The circuit according to claim 3, characterized in that The power supply switching unit further includes a fourth resistor and a fifth resistor; The gate of the field effect tube is connected to the power input terminal through the fourth resistor; The collector of the first transistor is connected to the gate of the field effect transistor through the fifth resistor.

8. The circuit according to claim 1, characterized in that The first signal is a 12V signal, and the second signal is a 5V signal.

9. An electronic device, characterized in that: The electronic device comprises the automatic power protection circuit according to any one of claims 1 to 8.

10. A household appliance, characterized in that: The household appliance includes the electronic device according to claim 9.

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