Direct current input circuit and control method thereof

Abstract

The application relates to a direct current input circuit and a control method thereof. The circuit comprises a voltage acquisition module for acquiring an input voltage of the voltage protection circuit; a voltage abnormality protection module connected with the voltage acquisition module, for detecting whether the input voltage acquired by the voltage acquisition module is abnormal, and disconnecting the circuit from a load to protect the load in the case that the input voltage is detected to be abnormal. The application solves the technical problem that the direct current input circuit has high complexity and it is difficult to realize overvoltage and undervoltage protection at the same time.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a DC input circuit and its control method. Background Technology

[0002] DC input devices have very strict requirements for input voltage. Reverse connection of the power supply usually leads to damage to the device. Therefore, most DC input devices are designed with reverse connection protection circuits. Overvoltage can also cause abnormal operation of electrical equipment. Overvoltage is divided into overvoltage and undervoltage. DC-powered products often damage components on the PCB board due to overvoltage, affecting normal use. Undervoltage, or insufficient voltage, usually causes the electrical equipment to malfunction.

[0003] In related technologies, the design of DC input circuits has reduced the reliability, stability and applicability of the circuit in pursuit of low cost, while increasing the complexity of the circuit. False overvoltage or undervoltage may occur, leading to false shutdown. Furthermore, related technologies are also difficult to achieve simultaneous protection against overvoltage and undervoltage.

[0004] There is currently no effective solution to the problem of high complexity in DC input circuits, making it difficult to achieve simultaneous overvoltage and undervoltage protection. Summary of the Invention

[0005] This application provides a DC input circuit and its control method to solve the technical problems of high complexity of DC input circuits and difficulty in achieving simultaneous overvoltage and undervoltage protection.

[0006] According to one aspect of an embodiment of this application, this application provides a DC input circuit, including:

[0007] A voltage acquisition module is used to acquire the input voltage of the voltage protection circuit;

[0008] A voltage anomaly protection module, connected to the voltage acquisition module, is used to detect whether the input voltage acquired by the voltage acquisition module is abnormal, and disconnect the circuit from the load when an abnormal input voltage is detected, so as to protect the load.

[0009] Optionally, the voltage acquisition module includes:

[0010] The first voltage divider resistor has one end connected to the positive input terminal of the circuit, and the other end connected to the first current limiting resistor and the second voltage divider resistor respectively. The first current limiting resistor and the second voltage divider resistor are connected in parallel.

[0011] The second voltage divider resistor is connected to the negative input terminal of the circuit;

[0012] The first current-limiting resistor is connected to both the filter capacitor and the positive input terminal of the voltage follower.

[0013] The voltage follower has its output terminal connected to the second current-limiting resistor;

[0014] The second current-limiting resistor is connected to the AD port of the controller;

[0015] The controller is connected to the negative input terminal of the circuit.

[0016] Optionally, the voltage anomaly protection module includes:

[0017] The third current-limiting resistor has one end connected to the controller and the other end connected to the base of the transistor;

[0018] The transistor's emitter is connected to the negative input terminal of the circuit, and its collector is connected to the fourth current-limiting resistor.

[0019] The fourth current-limiting resistor is connected to both the relay and the fifth current-limiting resistor.

[0020] The relay is connected to the load and is used to control the disconnection and connection of the circuit with the load;

[0021] The fifth current-limiting resistor is connected to the positive terminal of the first light-emitting diode;

[0022] The negative terminal of the first light-emitting diode is connected to the negative input terminal of the circuit.

[0023] Optionally, the circuit further includes a voltage conversion module, which is connected to the controller of the voltage acquisition module and is used to step down the input voltage to provide power to the controller.

[0024] Optionally, the circuit further includes a reverse connection protection module for detecting whether the input voltage is reverse connected and protecting the circuit in the event of a reverse connection.

[0025] Optionally, the reverse connection protection module includes:

[0026] The sixth current-limiting resistor is connected to the negative terminal of the second light-emitting diode;

[0027] The positive terminal of the second LED is connected to the negative input terminal of the circuit. It is used to conduct and emit light when the input voltage is reverse voltage, so as to indicate that the input voltage has a reverse connection abnormality.

[0028] The first diode has its positive terminal connected to the positive input terminal of the circuit and its negative terminal connected to the first voltage divider resistor of the voltage acquisition module, which is used to protect the voltage acquisition module in the event of reverse connection.

[0029] The second diode has its positive terminal connected to the positive input terminal of the circuit and its negative terminal connected to the voltage conversion module, and is used to protect the voltage conversion module in the event of reverse connection.

[0030] The pull-down resistor has one end connected to the base of the transistor in the voltage abnormality protection module through the third current-limiting resistor, and the other end connected to the negative input terminal of the circuit. It is used to pull down the base voltage of the transistor in the event of reverse connection so that the transistor is in the off state.

[0031] According to another aspect of the embodiments of this application, this application provides a control method for a DC input circuit, including:

[0032] The input voltage is acquired using a voltage acquisition module, and the input voltage is then detected.

[0033] If an overvoltage or undervoltage abnormality is detected in the input voltage, the control voltage abnormality protection module disconnects from the load to protect the load.

[0034] Optionally, the method further includes voltage detection in the following manner:

[0035] If the voltage value of the input voltage is detected to be less than or equal to a first threshold, and the duration of the voltage value being less than or equal to the first threshold is greater than or equal to a target time threshold, the current state of the input voltage is determined to be a continuous low voltage.

[0036] If the voltage value of the input voltage is detected to be less than or equal to a first threshold, and the duration of the voltage value being less than or equal to the first threshold is less than the target time threshold, the current state of the input voltage is determined to be a false low voltage.

[0037] If the voltage value of the input voltage is detected to be greater than or equal to a second threshold, and the duration of the voltage value being greater than or equal to the second threshold is greater than or equal to the target time threshold, the current state of the input voltage is determined to be a continuous high voltage, wherein the second threshold is greater than the first threshold;

[0038] If the input voltage value is detected to be greater than or equal to a second threshold, and the duration of the voltage value being greater than or equal to the second threshold is less than the target time threshold, the current state of the input voltage is determined to be a false high voltage.

[0039] Optionally, the step of controlling the voltage abnormality protection module to disconnect from the load in the event of an overvoltage or undervoltage abnormality detected in the input voltage, in order to protect the load, includes:

[0040] When the input voltage is continuously high or continuously low, the relay between the input voltage and the load is turned off to protect the load.

[0041] Optionally, in the event of reverse voltage connection, the method further includes issuing a reverse connection warning and protecting the circuit in the following manner:

[0042] A reverse connection reminder is provided by emitting light through an LED, wherein the positive terminal of the LED is connected to the negative input terminal of the DC input circuit, and the negative terminal is connected to the positive input terminal of the DC input circuit.

[0043] The voltage acquisition module is protected by cutting off the reverse voltage through the first diode, wherein the positive terminal of the first diode is connected to the positive input terminal of the DC input circuit, and the negative terminal is connected to the negative input terminal of the DC input circuit and the voltage acquisition module.

[0044] The voltage conversion module is protected by cutting off the reverse voltage through the second diode, wherein the positive terminal of the second diode is connected to the positive input terminal of the DC input circuit, and the negative terminal is connected to the voltage conversion module.

[0045] The base voltage of the transistor in the voltage abnormality protection module is lowered by a pull-down resistor, thereby turning off the transistor and protecting the voltage abnormality protection module. One end of the pull-down resistor is connected to the negative input terminal of the DC input circuit, and the other end is connected to the base of the transistor in the voltage abnormality protection module.

[0046] Compared with related technologies, the technical solutions provided in this application have the following advantages:

[0047] This application provides a DC input circuit, including a voltage acquisition module for acquiring the input voltage of the voltage protection circuit; and a voltage anomaly protection module connected to the voltage acquisition module for detecting whether the input voltage acquired by the voltage acquisition module is abnormal, and disconnecting the circuit from the load when an abnormal input voltage is detected, thereby protecting the load. This application solves the technical problems of high complexity in DC input circuits and difficulty in achieving simultaneous overvoltage and undervoltage protection. Attached Figure Description

[0048] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0049] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0050] Figure 1 This is a schematic diagram of an optional DC input circuit according to an embodiment of this application;

[0051] Figure 2 This is a flowchart of an optional DC input circuit control method provided according to an embodiment of this application.

[0052] Reference numerals: R1 - First voltage divider resistor; R2 - Second voltage divider resistor; H - Positive input terminal of DC input circuit; L - Negative input terminal of DC input circuit; R a1 - First current-limiting resistor; R a2 -Second current-limiting resistor; R a3 -Third current-limiting resistor; R a4 - Fourth current-limiting resistor; R a5 - Fifth current-limiting resistor; R a6 -Sixth current-limiting resistor; C r - Filter capacitor; A- Voltage follower; MCU- Controller; U in -Input voltage; U o - Output voltage; Q2 - Transistor; K - Relay; LED1 - First LED; LED2 - Second LED; Ub - Transistor base voltage; Uc - Transistor collector voltage; D1 - First diode; D2 - Second diode; R b - Pull-down resistor. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] In the following description, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustration and has no specific meaning in itself. Therefore, "module" and "part" may be used interchangeably.

[0055] DC input devices have very strict requirements for input voltage. Reverse connection of the power supply usually leads to damage to the device. Therefore, most DC input devices are designed with reverse connection protection circuits. Overvoltage can also cause abnormal operation of electrical equipment. Overvoltage is divided into overvoltage and undervoltage. DC-powered products often damage components on the PCB board due to overvoltage, affecting normal use. Undervoltage, or insufficient voltage, usually causes the electrical equipment to malfunction.

[0056] In related technologies, the design of DC input circuits has reduced the reliability, stability and applicability of the circuit in pursuit of low cost, while increasing the complexity of the circuit. False overvoltage or undervoltage may occur, leading to false shutdown. Furthermore, related technologies are also difficult to achieve simultaneous protection against overvoltage and undervoltage.

[0057] To address the problems mentioned in the background art, according to one aspect of the embodiments of this application, an embodiment of a DC input circuit is provided, the DC input circuit comprising:

[0058] A voltage acquisition module is used to acquire the input voltage of the voltage protection circuit;

[0059] A voltage anomaly protection module, connected to the voltage acquisition module, is used to detect whether the input voltage acquired by the voltage acquisition module is abnormal, and disconnect the circuit from the load when an abnormal input voltage is detected, so as to protect the load.

[0060] Compared to existing technologies, the DC input circuit provided in this application can achieve simultaneous overvoltage and undervoltage protection with lower complexity. The following is based on... Figure 1 The specific circuit connections of this DC input circuit are explained.

[0061] Optionally, such as Figure 1 As shown, the voltage acquisition module includes:

[0062] The first voltage divider resistor R1 has one end connected to the positive input terminal H of the circuit, and the other end connected to the first current limiting resistor R. a1 The second voltage divider resistor R2 is connected, and the first current limiting resistor R a1 The second voltage divider resistor R2 is connected in parallel;

[0063] The second voltage divider resistor R2 is connected to the negative input terminal L of the circuit;

[0064] The first current-limiting resistor R a1 , respectively with filter capacitor C r Connect to the positive input (+) terminal of voltage follower A;

[0065] The voltage follower A has its output terminal connected to the second current-limiting resistor R. a2 connect;

[0066] The second current-limiting resistor R a2 It connects to the AD port of the controller MCU;

[0067] The controller MCU is connected to the negative input terminal L of the circuit.

[0068] In this embodiment of the application, the first current-limiting resistor R a1 and filter capacitor C r An RC low-pass filter circuit can be formed to filter out interference signals.

[0069] In this embodiment, the voltage between the positive and negative input terminals of the circuit is the input voltage U. in The voltage across the load is the output voltage U of the DC input circuit. o R1 and R2 are voltage divider resistors used to reduce the voltage of the input voltage follower A.

[0070] In this embodiment, the output of the voltage follower is connected to the (-) input terminal and participates in voltage control as a feedback signal.

[0071] Optionally, such as Figure 1 As shown, the voltage anomaly protection module includes:

[0072] Third current-limiting resistor R a3 One end is connected to the controller MCU, and the other end is connected to the base of transistor Q2;

[0073] The emitter of transistor Q2 is connected to the negative input terminal L of the circuit, and the collector is connected to the fourth current-limiting resistor R. a4 connect;

[0074] The fourth current-limiting resistor R a4 They are respectively connected to relay K and the fifth current-limiting resistor R. a5 connect;

[0075] The relay K is connected to the load and is used to control the disconnection and connection between the circuit and the load;

[0076] The fifth current-limiting resistor R a5 It is connected to the positive terminal of the first light-emitting diode LED1;

[0077] The negative terminal of the first light-emitting diode LED1 is connected to the negative input terminal L of the circuit.

[0078] In this embodiment, the voltage anomaly protection module described above can disconnect the relay to protect the circuit in the event of overvoltage or undervoltage. Specifically, when overvoltage or undervoltage occurs, the MCU outputs a low level, the base voltage Ub of transistor Q2 approaches zero, transistor Q2 is turned off, and the collector voltage Uc of the transistor approaches the input voltage U. in At this time, the relay is disconnected, and the output voltage U o The voltage is set to zero to protect the load, and the first LED (LED1) illuminates to indicate a voltage anomaly. When the input voltage is within the normal range, the MCU outputs a high level, and the base voltage Ub of transistor Q2 is close to the input voltage U. in When transistor Q2 is saturated and conducting, the collector voltage Uc of the transistor is close to zero. At this time, the relay closes, and the output voltage U... o equal to U in The circuit is working normally.

[0079] Optionally, such as Figure 1 As shown, the circuit also includes a voltage conversion module, which is connected to the controller of the voltage acquisition module and is used to step down the input voltage to provide power to the controller.

[0080] In this embodiment, the operating voltage of the MCU and basic peripheral circuits is typically +5V or +3.3V, while the input voltage is much higher than +5V. Therefore, a voltage conversion module is needed to step down the voltage. Most voltage conversion modules have a wide input voltage range and can output a stable voltage even when the input voltage is too high or too low. However, high-power loads often fail to operate normally due to excessively high or low voltage. Therefore, this application proposes to perform voltage detection on the input voltage and cut off the load power supply when overvoltage or undervoltage occurs, thereby protecting the circuit.

[0081] Optionally, the circuit further includes a reverse connection protection module for detecting whether the input voltage is reverse connected and protecting the circuit in the event of a reverse connection.

[0082] Specifically, such as Figure 1 As shown, the reverse connection protection module includes:

[0083] Sixth current-limiting resistor R a6 It is connected to the negative terminal of the second light-emitting diode LED2;

[0084] The positive terminal of the second light-emitting diode LED2 is connected to the negative input terminal L of the circuit. It is used to conduct and emit light when the input voltage is reverse voltage, so as to indicate that the input voltage has a reverse connection abnormality.

[0085] The first diode D1 has its positive terminal connected to the positive input terminal H of the circuit, and its negative terminal connected to the first voltage divider resistor R1 of the voltage acquisition module, which is used to protect the voltage acquisition module in the event of reverse connection.

[0086] The second diode D2 has its positive terminal connected to the positive input terminal H of the circuit and its negative terminal connected to the voltage conversion module, which is used to protect the voltage conversion module in the event of reverse connection.

[0087] Pull-down resistor R b One end is connected to the third current-limiting resistor R. a3 The transistor Q2 is connected to its base, and the other end is connected to the negative input terminal L of the circuit. This is used to pull down the base voltage of the transistor Q2 in the event of a reverse connection, so that the transistor Q2 is in the off state.

[0088] The following is a complete explanation of the entire operation process of the DC input circuit.

[0089] When the Uin input is positive, i.e., no reverse connection has occurred:

[0090] The voltage follower sends the voltage UA at point A to the AD port of the MCU. The MCU determines whether the input voltage Uin is too high or too low. When the voltage is normal, the MCU outputs a high level to control Q2 to saturate and conduct, and the relay K closes.

[0091] The MCU's overvoltage and undervoltage detection process includes continuous undervoltage, continuous overvoltage, false undervoltage, and false overvoltage. When the high voltage duration exceeds the target time threshold, it is judged as continuous overvoltage. In this case, relay K needs to be shut down to implement overvoltage protection, and LED1 illuminates to indicate an overvoltage fault. When the high voltage duration is below the target time threshold, it is judged as false overvoltage, and relay K does not need to be shut down. When the low voltage (undervoltage) duration exceeds the target time threshold, it is judged as continuous undervoltage. In this case, relay K needs to be shut down to implement undervoltage (undervoltage) protection, and LED1 illuminates to indicate an overvoltage fault. When the low voltage duration is below the target time threshold, it is judged as false undervoltage, and relay K does not need to be shut down.

[0092] The MCU records the entire process of an overvoltage fault, including detailed information such as the fault voltage, fault time, and duration, which facilitates fault analysis and equipment repair by maintenance personnel.

[0093] When the Uin input is negative, i.e., reverse connection occurs:

[0094] LED2 is lit. The presence of diodes D1 and D2 protects the voltage acquisition and conversion modules in the event of reverse connection. Pull-down resistor R... bThe presence of the transistor Q2 causes the base voltage Ub to be zero, so Q2 is turned off. The collector voltage Uc approaches Uin, the relay K is disconnected, the output voltage Uo is equal to 0, and the load is protected.

[0095] The above enables automatic detection and protection against reverse connection and overvoltage.

[0096] Based on the aforementioned DC input circuit, this application proposes a control method for the DC input circuit, such as... Figure 2 As shown, the method includes:

[0097] Step S202: The input voltage is acquired using a voltage acquisition module and the input voltage is detected.

[0098] Step S204: If an overvoltage or undervoltage abnormality is detected in the input voltage, the voltage abnormality protection module is controlled to disconnect from the load to protect the load.

[0099] In this embodiment of the application, the process of MCU determining overvoltage and undervoltage includes: continuous low voltage, continuous high voltage, false low voltage, and false high voltage.

[0100] Specifically, the method further includes voltage detection in the following manner:

[0101] If the voltage value of the input voltage is detected to be less than or equal to a first threshold, and the duration of the voltage value being less than or equal to the first threshold is greater than or equal to a target time threshold, the current state of the input voltage is determined to be a continuous low voltage.

[0102] If the voltage value of the input voltage is detected to be less than or equal to a first threshold, and the duration of the voltage value being less than or equal to the first threshold is less than the target time threshold, the current state of the input voltage is determined to be a false low voltage.

[0103] If the voltage value of the input voltage is detected to be greater than or equal to a second threshold, and the duration of the voltage value being greater than or equal to the second threshold is greater than or equal to the target time threshold, the current state of the input voltage is determined to be a continuous high voltage, wherein the second threshold is greater than the first threshold;

[0104] If the input voltage value is detected to be greater than or equal to a second threshold, and the duration of the voltage value being greater than or equal to the second threshold is less than the target time threshold, the current state of the input voltage is determined to be a false high voltage.

[0105] Accordingly, the step of controlling the voltage abnormality protection module to disconnect from the load in the event of an overvoltage or undervoltage abnormality detected in the input voltage, in order to protect the load, includes:

[0106] When the input voltage is continuously high or continuously low, the relay between the input voltage and the load is turned off to protect the load.

[0107] In this embodiment, an input voltage less than or equal to a first threshold is determined to be low voltage (undervoltage), and an input voltage greater than or equal to a second threshold is determined to be high voltage. When the high voltage duration exceeds a target time threshold, it is determined to be continuous overvoltage, and relay K needs to be turned off to achieve overvoltage protection; LED1 lights up to indicate an overvoltage fault. When the high voltage duration is less than the target time threshold, it is determined to be false overvoltage, and relay K does not need to be turned off. When the low voltage (undervoltage) duration exceeds the target time threshold, it is determined to be continuous low voltage (undervoltage), and relay K needs to be turned off to achieve low voltage (undervoltage) protection; LED1 lights up to indicate an overvoltage fault. When the low voltage duration is less than the target time threshold, it is determined to be false low voltage (undervoltage), and relay K does not need to be turned off. The first threshold is less than the second threshold, and the first threshold, second threshold, and target time threshold can be set according to actual needs.

[0108] Optionally, in the event of reverse voltage connection, the method further includes issuing a reverse connection warning and protecting the circuit in the following manner:

[0109] A reverse connection reminder is provided by emitting light through an LED, wherein the positive terminal of the LED is connected to the negative input terminal of the DC input circuit, and the negative terminal is connected to the positive input terminal of the DC input circuit.

[0110] The voltage acquisition module is protected by cutting off the reverse voltage through the first diode, wherein the positive terminal of the first diode is connected to the positive input terminal of the DC input circuit, and the negative terminal is connected to the negative input terminal of the DC input circuit and the voltage acquisition module.

[0111] The voltage conversion module is protected by cutting off the reverse voltage through the second diode, wherein the positive terminal of the second diode is connected to the positive input terminal of the DC input circuit, and the negative terminal is connected to the voltage conversion module.

[0112] The base voltage of the transistor in the voltage abnormality protection module is lowered by a pull-down resistor, thereby turning off the transistor and protecting the voltage abnormality protection module. One end of the pull-down resistor is connected to the negative input terminal of the DC input circuit, and the other end is connected to the base of the transistor in the voltage abnormality protection module.

[0113] In this embodiment of the application, when the Uin input is negative, i.e., when reverse connection occurs:

[0114] LED2 is lit. The presence of diodes D1 and D2 protects the voltage acquisition and conversion modules in the event of reverse connection. Pull-down resistor R... b The presence of the transistor Q2 causes the base voltage Ub to be zero, so Q2 is turned off. The collector voltage Uc approaches Uin, the relay K is disconnected, the output voltage Uo is equal to 0, and the load is protected.

[0115] The above enables automatic detection and protection against reverse connection and overvoltage.

[0116] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A DC input circuit, characterized in that, include: The voltage acquisition module is used to acquire the input voltage of the voltage protection circuit. A voltage anomaly protection module, connected to the voltage acquisition module, is used to detect whether the input voltage acquired by the voltage acquisition module is abnormal, and disconnect the circuit from the load when an abnormal input voltage is detected, so as to protect the load. The circuit also includes a reverse connection protection module, which includes: The sixth current-limiting resistor is connected to the negative terminal of the second light-emitting diode; The positive terminal of the second LED is connected to the negative input terminal of the circuit. It is used to conduct and emit light when the input voltage is reverse voltage, so as to indicate that the input voltage has a reverse connection abnormality. The first diode has its positive terminal connected to the positive input terminal of the circuit and its negative terminal connected to the first voltage divider resistor of the voltage acquisition module, which is used to protect the voltage acquisition module in the event of reverse connection. The second diode has its positive terminal connected to the positive input terminal of the circuit and its negative terminal connected to the voltage conversion module, and is used to protect the voltage conversion module in the event of reverse connection. The pull-down resistor has one end connected to the base of the transistor in the voltage abnormality protection module through the third current-limiting resistor, and the other end connected to the negative input terminal of the circuit. It is used to pull down the base voltage of the transistor to zero in the event of reverse connection, so that the transistor is in the cut-off state, the relay is disconnected, and the output voltage is equal to zero, so as to protect the load. The voltage acquisition module includes: The first voltage divider resistor has one end connected to the positive input terminal of the circuit, and the other end connected to the first current limiting resistor and the second voltage divider resistor respectively. The first current limiting resistor and the second voltage divider resistor are connected in parallel. The second voltage divider resistor is connected to the negative input terminal of the circuit; The first current-limiting resistor is connected to both the filter capacitor and the positive input terminal of the voltage follower. The voltage follower has its output terminal connected to the second current-limiting resistor; The second current-limiting resistor is connected to the AD port of the controller; The controller is connected to the negative input terminal of the circuit.

2. The circuit according to claim 1, characterized in that, The voltage anomaly protection module includes: The third current-limiting resistor has one end connected to the controller and the other end connected to the base of the transistor; The transistor's emitter is connected to the negative input terminal of the circuit, and its collector is connected to the fourth current-limiting resistor. The fourth current-limiting resistor is connected to both the relay and the fifth current-limiting resistor. The relay is connected to the load and is used to control the disconnection and connection of the circuit with the load; The fifth current-limiting resistor is connected to the positive terminal of the first light-emitting diode; The negative terminal of the first light-emitting diode is connected to the negative input terminal of the circuit.

3. The circuit according to claim 1, characterized in that, The circuit also includes a voltage conversion module, which is connected to the controller of the voltage acquisition module and is used to step down the input voltage to provide power to the controller.

4. A control method for a DC input circuit, characterized in that, include: The input voltage is acquired using a voltage acquisition module, and the input voltage is then detected. If an overvoltage or undervoltage abnormality is detected in the input voltage, the control voltage abnormality protection module disconnects from the load to protect the load. In the event of reverse voltage connection, the method further includes issuing a reverse connection warning and protecting the circuit in the following manner: A reverse connection reminder is provided by emitting light through an LED, wherein the positive terminal of the LED is connected to the negative input terminal of the DC input circuit, and the negative terminal is connected to the positive input terminal of the DC input circuit. The voltage acquisition module is protected by cutting off the reverse voltage through the first diode, wherein the positive terminal of the first diode is connected to the positive input terminal of the DC input circuit, and the negative terminal is connected to the negative input terminal of the DC input circuit and the voltage acquisition module. The voltage conversion module is protected by cutting off the reverse voltage through the second diode, wherein the positive terminal of the second diode is connected to the positive input terminal of the DC input circuit, and the negative terminal is connected to the voltage conversion module. The base voltage of the transistor in the voltage abnormality protection module is lowered by a pull-down resistor, thereby turning off the transistor and protecting the voltage abnormality protection module. One end of the pull-down resistor is connected to the negative input terminal of the DC input circuit, and the other end is connected to the base of the transistor in the voltage abnormality protection module. This is used to pull down the base voltage of the transistor to zero in the event of a reverse connection, so that the transistor is in the off state, the relay is disconnected, and the output voltage is equal to zero, thereby protecting the load. The method further includes voltage detection in the following manner: If the voltage value of the input voltage is detected to be less than or equal to a first threshold, and the duration of the voltage value being less than or equal to the first threshold is greater than or equal to a target time threshold, the current state of the input voltage is determined to be a continuous low voltage. If the voltage value of the input voltage is detected to be less than or equal to a first threshold, and the duration of the voltage value being less than or equal to the first threshold is less than the target time threshold, the current state of the input voltage is determined to be a false low voltage. If the voltage value of the input voltage is detected to be greater than or equal to a second threshold, and the duration of the voltage value being greater than or equal to the second threshold is greater than or equal to the target time threshold, the current state of the input voltage is determined to be a continuous high voltage, wherein the second threshold is greater than the first threshold; If the input voltage value is detected to be greater than or equal to a second threshold, and the duration of the voltage value being greater than or equal to the second threshold is less than the target time threshold, the current state of the input voltage is determined to be a false high voltage.

5. The method according to claim 4, characterized in that, The step of controlling the voltage anomaly protection module to disconnect from the load in the event of an overvoltage or undervoltage anomaly detected in the input voltage, in order to protect the load, includes: When the input voltage is continuously high or continuously low, the relay between the input voltage and the load is turned off to protect the load.

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