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CN-115360668-B - DC input circuit and control method thereof

CN115360668BCN 115360668 BCN115360668 BCN 115360668BCN-115360668-B

Abstract

The application relates to a direct current input circuit and a control method thereof, wherein the circuit comprises a voltage acquisition module and a voltage abnormality protection module, wherein the voltage acquisition module is used for acquiring input voltage of a voltage protection circuit, and the voltage abnormality protection module is connected with the voltage acquisition module and used for detecting whether the input voltage acquired by the voltage acquisition module is abnormal or not and disconnecting the circuit from a load under the condition that the input voltage is detected to be abnormal so as to protect the load. The application solves the technical problems that the DC input circuit has high complexity and is difficult to realize overvoltage and undervoltage protection simultaneously.

Inventors

  • LIANG SHANG

Assignees

  • 珠海格力电器股份有限公司

Dates

Publication Date
20260508
Application Date
20220825

Claims (5)

  1. 1. A direct current input circuit, comprising: The voltage acquisition module is used for acquiring the input voltage of the voltage protection circuit; The voltage abnormality protection module is connected with the voltage acquisition module and is used for detecting whether the input voltage acquired by the voltage acquisition module is abnormal or not, and disconnecting a circuit from a load under the condition that the input voltage is detected to be abnormal so as to protect the load; The circuit also includes an anti-reverse connection module, the anti-reverse connection module including: The sixth current limiting resistor is connected with the cathode of the second light emitting diode; The positive electrode of the second light-emitting diode is connected with the negative electrode input end of the circuit and is used for conducting and emitting light under the condition that the input voltage is reverse voltage so as to prompt that the reverse connection abnormality occurs in the input voltage; The positive electrode of the first diode is connected with the positive electrode input end of the circuit, and the negative electrode of the first diode is connected with the first voltage dividing resistor of the voltage acquisition module and used for protecting the voltage acquisition module under the condition of reverse connection; The positive electrode of the second diode is connected with the positive electrode input end of the circuit, and the negative electrode of the second diode is connected with the voltage conversion module and used for protecting the voltage conversion module under the condition of reverse connection; One end of the pull-down resistor is connected with the base electrode of the triode of the voltage abnormality protection module through a third current limiting resistor, and the other end of the pull-down resistor is connected with the negative input end of the circuit and is used for pulling down the base voltage of the triode to zero under the condition of reverse connection so as to enable the triode to be in a cut-off state, disconnect a relay and enable the output voltage to be equal to zero and be used for protecting a load; Wherein, the voltage acquisition module includes: one end of the first voltage dividing resistor is connected with the positive electrode input end of the circuit, the other end of the first voltage dividing resistor is connected with the first current limiting resistor and the second voltage dividing resistor respectively, and the first current limiting resistor and the second voltage dividing resistor are connected in parallel; the second voltage dividing resistor is connected with the negative electrode input end of the circuit; The first current limiting resistor is respectively connected with the filter capacitor and the positive input end of the voltage follower; The output end of the voltage follower is connected with the second current limiting resistor; The second current limiting resistor is connected with the AD port of the controller; and the controller is connected with the negative electrode input end of the circuit.
  2. 2. The circuit of claim 1, wherein the voltage anomaly protection module comprises: One end of the third current limiting resistor is connected with the controller, and the other end of the third current limiting resistor is connected with the base electrode of the triode; the emitting electrode of the triode is connected with the negative input end of the circuit, and the collecting electrode of the triode is connected with a fourth current limiting resistor; the fourth current limiting resistor is respectively connected with the relay and the fifth current limiting resistor; The relay is connected with the load and used for controlling disconnection and connection of the circuit and the load; the fifth current limiting resistor is connected with the anode of the first light emitting diode; the negative electrode of the first light-emitting diode is connected with the negative electrode input end of the circuit.
  3. 3. The circuit of claim 1, further comprising a voltage conversion module coupled to the controller of the voltage acquisition module for providing power to the controller after the input voltage is stepped down.
  4. 4. A control method of a direct current input circuit, comprising: Collecting input voltage by using a voltage collecting module and detecting the input voltage; under the condition that overvoltage abnormality or undervoltage abnormality of the input voltage is detected, a voltage abnormality protection module is controlled to disconnect the load so as to protect the load; in the event of a voltage reversal, the method further comprises issuing a reversal reminder and protection circuit in the following manner: The LED emits light to carry out reverse connection reminding, wherein the anode of the LED is connected with the cathode input end of the direct current input circuit, and the cathode of the LED is connected with the anode input end of the direct current input circuit; The reverse voltage is cut off through a first diode to protect a voltage acquisition module, wherein the positive electrode of the first diode is connected with the positive electrode input end of the direct current input circuit, and the negative electrode of the first diode is connected with the negative electrode input end of the direct current input circuit and the voltage acquisition module; the reverse voltage is cut off through a second diode, and the voltage conversion module is protected, wherein the positive electrode of the second diode is connected with the positive electrode input end of the direct current input circuit, and the negative electrode of the second diode is connected with the voltage conversion module; The base voltage of the triode of the voltage abnormality protection module is pulled down through a pull-down resistor, so that the triode is cut off to protect the voltage abnormality protection module, wherein one end of the pull-down resistor is connected with the negative input end of the direct current input circuit, the other end of the pull-down resistor is connected with the base of the triode of the voltage abnormality protection module, and the pull-down resistor is used for pulling down the base voltage of the triode to zero under the condition of reverse connection so as to enable the triode to be in a cut-off state, disconnect a relay, enable the output voltage to be equal to zero and be used for protecting a load; Wherein the method further comprises performing voltage detection in the following manner: Determining that the current state of the input voltage is continuously low voltage when the voltage value of the input voltage is detected to be smaller than or equal to a first threshold value and the duration time of the voltage value smaller than or equal to the first threshold value is larger than or equal to a target time threshold value; determining that the current state of the input voltage is a false low voltage if the voltage value of the input voltage is detected to be smaller than or equal to a first threshold value and the duration of the voltage value smaller than or equal to the first threshold value is smaller than the target time threshold value; determining that the current state of the input voltage is continuously high voltage when the voltage value of the input voltage is detected to be greater than or equal to a second threshold value, and the duration time of the voltage value being greater than or equal to the second threshold value is greater than or equal to the target time threshold value, wherein the second threshold value is greater than the first threshold value; And if the voltage value of the input voltage is detected to be larger than or equal to a second threshold value and the duration time of the voltage value larger than or equal to the second threshold value is smaller than the target time threshold value, determining that the current state of the input voltage is a false high voltage.
  5. 5. The method of claim 4, wherein controlling a voltage anomaly protection module to disconnect from a load to protect the load if an overvoltage anomaly or an undervoltage anomaly is detected in the input voltage comprises: in case the input voltage is at a continuously high voltage or a continuously low voltage, a relay between the input voltage and the load is turned off to protect the load.

Description

DC input circuit and control method thereof Technical Field The present application relates to the field of electronic circuits, and in particular, to a dc input circuit and a control method thereof. Background The requirement of the dc input device on the input voltage is very strict, and the power supply is reversed, which usually leads to the damage of the device, so that in most dc input devices, a reverse connection protection circuit is designed. Meanwhile, the overvoltage can cause abnormal operation of electric equipment, and the overvoltage is divided into over-high voltage and over-low voltage. The direct current power supply type products often cause the damage of components and parts on the PCB board because of input voltage is too high, influence user's normal use. Too low a voltage, i.e., an under voltage, typically results in the consumer not functioning properly. In the related art, the design of the dc input circuit reduces the reliability, stability and applicability of the circuit due to pursuing low cost, but rather improves the complexity of the circuit, false overvoltage or undervoltage may occur to cause false turn-off, and the related art is difficult to realize simultaneous protection of overvoltage and undervoltage. Aiming at the problems that the direct current input circuit has high complexity and is difficult to realize overvoltage and undervoltage protection, no effective solution is proposed at present. Disclosure of Invention The application provides a direct current input circuit and a control method thereof, which are used for solving the technical problems that the direct current input circuit is high in complexity and difficult to realize overvoltage and undervoltage protection simultaneously. According to an aspect of an embodiment of the present application, there is provided a dc input circuit including: The voltage acquisition module is used for acquiring the input voltage of the voltage protection circuit; The voltage abnormality protection module is connected with the voltage acquisition module and is used for detecting whether the input voltage acquired by the voltage acquisition module is abnormal or not, and disconnecting the circuit from the load under the condition that the input voltage is detected to be abnormal so as to protect the load. Optionally, the voltage acquisition module includes: one end of the first voltage dividing resistor is connected with the positive electrode input end of the circuit, the other end of the first voltage dividing resistor is connected with the first current limiting resistor and the second voltage dividing resistor respectively, and the first current limiting resistor and the second voltage dividing resistor are connected in parallel; the second voltage dividing resistor is connected with the negative electrode input end of the circuit; The first current limiting resistor is respectively connected with the filter capacitor and the positive input end of the voltage follower; The output end of the voltage follower is connected with the second current limiting resistor; The second current limiting resistor is connected with the AD port of the controller; and the controller is connected with the negative electrode input end of the circuit. Optionally, the voltage abnormality protection module includes: One end of the third current limiting resistor is connected with the controller, and the other end of the third current limiting resistor is connected with the base electrode of the triode; the emitting electrode of the triode is connected with the negative input end of the circuit, and the collecting electrode of the triode is connected with a fourth current limiting resistor; the fourth current limiting resistor is respectively connected with the relay and the fifth current limiting resistor; The relay is connected with the load and used for controlling disconnection and connection of the circuit and the load; the fifth current limiting resistor is connected with the anode of the first light emitting diode; the negative electrode of the first light-emitting diode is connected with the negative electrode input end of the circuit. Optionally, the circuit further includes a voltage conversion module, where the voltage conversion module is connected to the controller of the voltage acquisition module, and is configured to provide a power supply for the controller after reducing the input voltage. Optionally, the circuit further comprises an anti-reverse connection module for detecting whether reverse connection occurs to the input voltage and protecting the circuit in case of reverse connection. Optionally, the anti-reverse connection module includes: The sixth current limiting resistor is connected with the cathode of the second light emitting diode; The positive electrode of the second light-emitting diode is connected with the negative electrode input end of the circuit and is used for conducting and emitting light under the condit