DC power failure detection circuit and device

Abstract

The embodiment of the present invention discloses a DC power failure detection circuit and device, in which one end of the first energy storage module of the circuit is used to connect the power supply and one end of the first voltage divider module, and the other end of the first energy storage module and the other end of the first voltage divider module are grounded; the power input end of the isolation unit is used to connect the power supply; one end of the second energy storage module is connected to the power output end of the isolation unit and one end of the second voltage divider module, and the other end of the second energy storage module and the other end of the second voltage divider module are grounded; the first comparison end of the comparison unit obtains the first voltage of the potential detection end of the first voltage divider module; the second comparison end of the comparison unit obtains the second voltage of the potential detection end of the second voltage divider module; the comparison result of the first voltage and the second voltage before the power supply is disconnected is opposite to the comparison result after the power supply is disconnected. This technical solution can detect the disconnection of a DC power supply of any voltage value, has a wider range of applications, and is conducive to electricity safety.

Description

Technical Field

[0001] The present invention relates to the field of circuits, and in particular to a direct current power supply failure detection circuit and equipment. Background Art

[0002] The existing power failure detection technology usually sets a comparison voltage. When the power supply voltage (or voltage division) to be detected is lower than the set value, the signal changes to detect whether the DC power supply is powered off. Disadvantages of the existing technical solutions:

[0003] 1. The comparison voltage is a fixed value and cannot meet the application environment of wide power supply voltage (for example, it is not compatible with 24V and 48V power supply systems).

[0004] 2. When the comparison voltage is set high, it is easy to trigger falsely. When the comparison voltage is set low, the detection accuracy is low (the power supply itself fluctuates). Summary of the invention

[0005] In view of the above problems, the present invention provides a DC power failure detection circuit and device.

[0006] An embodiment of the present invention provides a DC power failure detection circuit, which includes a comparison unit, a first discharge unit, a second discharge unit and an isolation unit;

[0007] The first discharge unit includes a first energy storage module and a first voltage divider module, one end of the first energy storage module is used to connect to a power source and is connected to one end of the first voltage divider module, and the other end of the first energy storage module and the other end of the first voltage divider module are grounded;

[0008] The power input terminal of the isolation unit is used to connect to the power supply;

[0009] The second discharge unit includes a second energy storage module and a second voltage divider module, one end of the second energy storage module is connected to the power output end of the isolation unit and to one end of the second voltage divider module, and the other end of the second energy storage module and the other end of the second voltage divider module are grounded;

[0010] The first comparison terminal of the comparison unit is connected to the potential detection terminal of the first voltage dividing module, and is used to obtain the first voltage of the potential detection terminal of the first voltage dividing module;

[0011] The second comparison terminal of the comparison unit is connected to the potential detection terminal of the second voltage dividing module, and is used to obtain the second voltage of the potential detection terminal of the second voltage dividing module;

[0012] The comparison result between the first voltage and the second voltage before the power supply is disconnected is opposite to the comparison result after the power supply is disconnected.

[0013] In the DC power failure detection circuit described in another embodiment of the present invention, the comparison unit is a comparator or a controller.

[0014] In the above-mentioned DC power failure detection circuit, when the comparison unit is a comparator, the positive end of the comparator is connected to the potential detection end of the first voltage divider module, the reverse end of the comparator is connected to the potential detection end of the second voltage divider module, and the first energy storage module is also used to be connected in parallel with an external load;

[0015] When the power supply is normally powered, the first voltage at the potential detection end of the first voltage dividing module is greater than the second voltage at the potential detection end of the second voltage dividing module;

[0016] The first voltage is determined according to the following formula:

[0017] U1=U*R U1 / R 11 , U1 represents the first voltage, U represents the voltage of the power supply, R U1 represents the resistance between the potential detection terminal of the first voltage divider module and the ground, R 11 Represents the total resistance of the first voltage divider module;

[0018] The second voltage is determined according to the following formula:

[0019] U2=(UU g )*R U2 / R 22 , U2 represents the second voltage, R U2 represents the resistance between the potential detection terminal of the second voltage divider module and the ground, R 22 Represents the total resistance of the second voltage divider module; U g represents the voltage across the isolation unit;

[0020] A discharge time ratio of a first discharge time of the first discharge unit to a second discharge time of the second discharge unit is less than 1;

[0021] The discharge time ratio is determined according to the following formula:

[0022] k represents the discharge time ratio, R f represents the equivalent resistance of the external load, C1 represents the equivalent capacitance of the first energy storage module, and C2 represents the equivalent capacitance of the second energy storage module.

[0023] In the above-mentioned DC power failure detection circuit, when the comparison unit is a comparator, the reverse end of the comparator is connected to the potential detection end of the first voltage divider module, the forward end of the comparator is connected to the potential detection end of the second voltage divider module, and the first energy storage module is also used to be connected in parallel with an external load;

[0024] When the power supply is normally supplied, the first voltage of the potential detection end of the first voltage dividing module is less than the second voltage of the potential detection end of the second voltage dividing module;

[0025] The first voltage is determined according to the following formula:

[0026] U1=U*R U1 / R 11 , U1 represents the first voltage, U represents the voltage of the power supply, R U1 represents the resistance between the potential detection terminal of the first voltage divider module and the ground, R 11 Represents the total resistance of the first voltage divider module;

[0027] The second voltage is determined according to the following formula:

[0028] U2=(UU g )*R U2 / R 22 , U2 represents the second voltage, R U2 represents the resistance between the potential detection terminal of the second voltage divider module and the ground, R 22 Represents the total resistance of the second voltage divider module; U g represents the voltage across the isolation unit;

[0029] A discharge time ratio of a first discharge time of the first discharge unit to a second discharge time of the second discharge unit is greater than 1;

[0030] The discharge time ratio is determined according to the following formula:

[0031] k represents the discharge time ratio, R f represents the equivalent resistance of the external load, C1 represents the equivalent capacitance of the first energy storage module, and C2 represents the equivalent capacitance of the second energy storage module.

[0032] In the above-mentioned DC power failure detection circuit, the isolation unit includes a diode, the anode of the diode serves as the power input end of the isolation unit, and the cathode of the diode serves as the power output end of the isolation unit.

[0033] In the above-mentioned DC power failure detection circuit, the first energy storage module includes a first capacitor, the positive electrode of the first capacitor is used to connect to the power supply, and the negative electrode of the first capacitor is grounded.

[0034] In the above-mentioned DC power supply power-off detection circuit, the first voltage divider module includes a first resistor and a second resistor, one end of the first resistor is connected to the positive electrode of the first capacitor, the other end of the first resistor serves as the potential detection end of the first voltage divider module and is connected to one end of the second resistor, and the other end of the second resistor is grounded.

[0035] In the above-mentioned DC power failure detection circuit, the second energy storage module includes a second capacitor, the positive electrode of the second capacitor is connected to the power output end of the isolation unit, and the negative electrode of the second capacitor is grounded.

[0036] In the above-mentioned DC power supply power-off detection circuit, the second voltage divider module includes a third resistor and a fourth resistor, one end of the third resistor is connected to the positive electrode of the second capacitor, the other end of the third resistor serves as the potential detection end of the second voltage divider module and is connected to one end of the fourth resistor, and the other end of the fourth resistor is grounded.

[0037] Still another embodiment of the present invention provides a DC power failure detection device, which includes the above-mentioned DC power failure detection circuit.

[0038] The DC power failure detection circuit disclosed in the present invention includes a comparison unit, a first discharge unit, a second discharge unit and an isolation unit, wherein the first discharge unit includes a first energy storage module and a first voltage divider module, one end of the first energy storage module is used to connect to the power supply and one end of the first voltage divider module, and the other end of the first energy storage module and the other end of the first voltage divider module are grounded; the power input end of the isolation unit is used to connect to the power supply; the second discharge unit includes a second energy storage module and a second voltage divider module, one end of the second energy storage module is connected to the power output end of the isolation unit and one end of the second voltage divider module, and the other end of the second energy storage module and the other end of the second voltage divider module are grounded; the first comparison end of the comparison unit is connected to the potential detection end of the first voltage divider module, and is used to obtain the first voltage of the potential detection end of the first voltage divider module; the second comparison end of the comparison unit is connected to the potential detection end of the second voltage divider module, and is used to obtain the second voltage of the potential detection end of the second voltage divider module; wherein the comparison result of the first voltage and the second voltage before the power supply is disconnected is opposite to the comparison result after the power supply is disconnected. This technical solution can detect the disconnection of a DC power supply of any voltage value, has a wider range of applications, and is conducive to electricity safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope of protection of the present invention. In each of the drawings, similar components are numbered similarly.

[0040] Figure 1 A functional structure diagram of a DC power failure detection circuit provided by an embodiment of the present invention is shown;

[0041] Figure 2 A schematic diagram of the circuit structure of a DC power failure detection circuit provided by an embodiment of the present invention is shown;

[0042] Figure 3 A circuit structure schematic diagram of another DC power failure detection circuit provided by an embodiment of the present invention is shown;

[0043] Figure 4 A circuit structure schematic diagram of another DC power failure detection circuit provided by an embodiment of the present invention is shown.

[0044] Description of main component symbols:

[0045] 1-comparison unit; 2-first discharge unit; 3-second discharge unit; 4-isolation unit; 21-first energy storage module; 22-first voltage divider module; 31-second energy storage module; 32-second voltage divider module; B1-comparator; C1-first capacitor; R1-first resistor; R2-second resistor; C2-second capacitor; R3-third resistor; R4-fourth resistor; M1-controller; D1-diode; R F -External load. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0047] The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0048] Hereinafter, the terms "including", "having" and their cognates, which may be used in various embodiments of the present invention, are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or adding the possibility of one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0049] Furthermore, the terms “first”, “second”, “third”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0050] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as those generally understood by those skilled in the art to which the various embodiments of the present invention belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meanings as the contextual meanings in the relevant technical field and will not be interpreted as having idealized meanings or overly formal meanings unless clearly defined in the various embodiments of the present invention.

[0051] The invention discloses a direct current power supply disconnection detection circuit, which can detect the disconnection of a direct current power supply of any voltage value, has a wider application range, and is beneficial to electricity safety.

[0052] Example 1

[0053] In this embodiment, see Figure 1 , shows a DC power failure detection circuit, which includes a comparison unit 1, a first discharge unit 2, a second discharge unit 3 and an isolation unit 4.

[0054] The first discharge unit 2 includes a first energy storage module 21 and a first voltage divider module 22, one end of the first energy storage module 21 is used to connect to a power source and one end of the first voltage divider module 22, and the other end of the first energy storage module 21 and the other end of the first voltage divider module 22 are grounded; the power input end of the isolation unit 4 is used to connect to a power source; the second discharge unit 3 includes a second energy storage module 31 and a second voltage divider module 32, one end of the second energy storage module 31 is connected to the power output end of the isolation unit and one end of the second voltage divider module 32, and the other end of the second energy storage module 31 and the other end of the second voltage divider module 32 are grounded; the first comparison end of the comparison unit 1 is connected to the potential detection end of the first voltage divider module 22, and is used to obtain a first voltage of the potential detection end of the first voltage divider module 22; the second comparison end of the comparison unit 1 is connected to the potential detection end of the second voltage divider module 32, and is used to obtain a second voltage of the potential detection end of the second voltage divider module 32, and the comparison result of the first voltage and the second voltage before the power supply is disconnected is opposite to the comparison result after the power supply is disconnected.

[0055] Exemplarily, while the first voltage is pre-set using the first voltage divider module 22 and the second voltage is pre-set using the second voltage divider module 32, the discharge speed of the second discharge unit is pre-set using the second voltage divider module 32 based on the comparison result of the pre-set first voltage and the second voltage, so that when the power supply is disconnected, the comparison result of the first voltage and the second voltage changes, thereby causing the output signal of the power-off detection result output terminal of the comparison unit 1 to change.

[0056] It can be understood that the resistance value of the second voltage divider module 32 can determine the discharge speed of the second discharge unit 3. The larger the resistance value of the second voltage divider module 32, the smaller the current, the slower the discharge speed of the second discharge unit 3, and the longer the discharge time. When the discharge time of the first discharge unit 2 is constant, the discharge time of the second discharge unit 3 can be set to be shorter than the discharge time of the first discharge unit 2 by setting the resistance value of the second voltage divider module 32, or the discharge time of the second discharge unit 3 can be set to be longer than the discharge time of the first discharge unit 2 by setting the resistance value of the second voltage divider module 32.

[0057] Exemplarily, it can be pre-set that: when the DC power supply is normally supplied, the first voltage at the potential detection end of the first voltage divider module 22 is greater than the second voltage at the potential detection end of the second voltage divider module 32, and at the same time, the discharge speed of the first discharge unit 2 is set much greater than the discharge speed of the second discharge unit 3, so that after the power is disconnected, the speed at which the first voltage decreases is much greater than the speed at which the second voltage decreases, and then, after a period of discharge, the first voltage will be less than the second voltage, that is, the comparison result of the first voltage and the second voltage changes, and the DC power supply can be determined to be powered off based on the new comparison result.

[0058] Exemplarily, it can also be pre-set that: when the DC power supply is normally supplied, the first voltage of the potential detection end of the first voltage divider module 22 is less than the second voltage of the potential detection end of the second voltage divider module 32, and at the same time, the first discharge speed of the first discharge unit 2 is set much smaller than the second discharge speed of the second discharge unit 3, so that after the power supply end is disconnected from the power supply, the speed at which the second voltage decreases is much faster than the speed at which the first voltage decreases, and then, after a period of discharge, the first voltage will be greater than the second voltage, that is, the comparison result of the first voltage and the second voltage changes, and the DC power supply can be determined to be powered off based on the new comparison result.

[0059] The DC power failure detection circuit disclosed in this embodiment includes a comparison unit 1, a first discharge unit 2, a second discharge unit 3 and an isolation unit 4, wherein the first discharge unit 2 includes a first energy storage module 21 and a first voltage divider module 22, one end of the first energy storage module 21 is used to connect to a power source and is connected to one end of the first voltage divider module 22, and the other end of the first energy storage module 21 and the other end of the first voltage divider module 22 are grounded; the power input end of the isolation unit 4 is used to connect to the power source; the second discharge unit 3 includes a second energy storage module 31 and a second voltage divider module 32, one end of the second energy storage module 31 is connected to the isolation unit 4, and connected to one end of the second voltage divider module 32, the other end of the second energy storage module 31 and the other end of the second voltage divider module 32 are grounded; the first comparison end of the comparison unit 1 is connected to the potential detection end of the first voltage divider module 22, for obtaining the first voltage of the potential detection end of the first voltage divider module 22; the second comparison end of the comparison unit is connected to the potential detection end of the second voltage divider module 32, for obtaining the second voltage of the potential detection end of the second voltage divider module 32; wherein the comparison result of the first voltage and the second voltage before the power supply is disconnected is opposite to the comparison result after the power supply is disconnected. This technical solution can detect the disconnection of a DC power supply of any voltage value, has a wider range of applications, and is conducive to electricity safety.

[0060] Example 2

[0061] For further information, see Figure 2, the comparison unit 1 may be a comparator B1.

[0062] Comparator B1 is an electronic component that outputs different voltage results at the output end by comparing the current or voltage at the two input ends. Voltage comparator B1 can be regarded as an operational amplifier with a magnification close to infinity. Voltage comparator B1 is used to compare the size of two voltages. For example, the high or low level of the output voltage is used to indicate the size relationship between the two input voltages. When the voltage at the "+" input end is higher than the voltage at the "-" input end, the output of voltage comparator B1 is a high level; when the voltage at the "+" input end is lower than the voltage at the "-" input end, the output of voltage comparator B1 is a low level. The chips that can be used as voltage comparator B1 include: LM324, LM358, uA741, TL081\2\3\4, OP07 and OP27, all of which can be made into voltage comparator B1. LM339 and LM393 are professional voltage comparators B1 with fast switching speed and small delay time, which can be used in special voltage comparison occasions.

[0063] Exemplary, such as Figure 2 As shown, the positive end "+" of the comparator B1 is connected to the potential detection end of the first voltage divider module 22, and the negative end "-" of the comparator B1 is connected to the potential detection end of the second voltage divider module 32. When the voltage drop generated by the isolation unit 4 is ignored, the first ratio of the resistance between the potential detection end of the first voltage divider module 22 and the ground to the total resistance of the first voltage divider module 22 is greater than the second ratio of the resistance between the potential detection end of the second voltage divider module 32 and the ground to the total resistance of the second voltage divider module 32, so that the first voltage of the potential detection end of the first voltage divider module 22 is greater than the second voltage of the potential detection end of the second voltage divider module 32; the discharge time of the first discharge unit 2 is less than the discharge time of the second discharge unit 3, that is, the discharge speed of the first discharge unit 2 is greater than the discharge speed of the second discharge unit 3, and when the power supply is disconnected for a period of time, the first voltage is less than the second voltage. It can be understood that one end of the first energy storage module 21 is used for one end of the external load, and the other end of the external load is grounded. The external load is an external electrical device.

[0064] Exemplary, such as Figure 3As shown, the reverse end of the comparator B1 is connected to the potential detection end of the first voltage divider module 22, and the positive end of the comparator B1 is connected to the potential detection end of the second voltage divider module 32. When the voltage drop generated by the isolation unit 4 is ignored, the first ratio of the resistance between the potential detection end of the first voltage divider module 22 and the ground to the total resistance of the first voltage divider module 22 is less than the second ratio of the resistance between the potential detection end of the second voltage divider module 32 and the ground to the total resistance of the second voltage divider module 32, so that the first voltage of the potential detection end of the first voltage divider module 22 is less than the second voltage of the potential detection end of the second voltage divider module 32; the discharge time of the first discharge unit 2 is greater than the discharge time of the second discharge unit 3, that is, the discharge speed of the first discharge unit 2 is less than the discharge speed of the second discharge unit 3, and when the power supply is disconnected for a period of time, the first voltage is greater than the second voltage. It can be understood that one end of the first energy storage module 21 is used for one end of the external load, and the other end of the external load is grounded. The external load is an external electrical device.

[0065] Furthermore, the first discharge time is determined according to the following formula:

[0066] R f Represents the equivalent resistance of the external load, R 11 represents the total resistance of the first voltage divider module, C1 represents the equivalent capacitance of the first energy storage module, E represents the initial voltage across the first energy storage module, V t Represents the voltage across the first energy storage module at any discharging time t.

[0067] Furthermore, the second discharge time is determined according to the following formula:

[0068] R 22 represents the total resistance of the second voltage divider module, C2 represents the equivalent capacitance of the second energy storage module, E represents the initial voltage across the second energy storage module, V t Represents the voltage across the second energy storage module at any discharging time t.

[0069] A discharge time ratio of a first discharge time of the first discharge unit to a second discharge time of the second discharge unit k represents the discharge time ratio, R f Represents the equivalent resistance of the external load, R 11 represents the total resistance of the first voltage divider module, C1 represents the equivalent capacitance of the first energy storage module, R 22 represents the total resistance of the second voltage divider module, and C2 represents the equivalent capacitance of the second energy storage module. F It can be understood as the external electrical equipment connected to the positive and negative ends of the power supply, and the equivalent resistance value R of the external loadf It can be understood as the equivalent resistance of the external electrical equipment at the positive and negative ends of the power supply.

[0070] It can be understood that the discharge time ratio of the first discharge time of the first discharge unit to the second discharge time of the second discharge unit is greater than 1, and the first discharge time of the first discharge unit is greater than the second discharge time of the second discharge unit. The discharge time ratio of the first discharge time of the first discharge unit to the second discharge time of the second discharge unit is less than 1, and the first discharge time of the first discharge unit is less than the second discharge time of the second discharge unit.

[0071] Furthermore, the first voltage U1 of the potential detection terminal of the first voltage dividing module 22 is equal to U*R U1 / R 11 , U represents the voltage of the power supply, R U1 represents the resistance between the potential detection terminal of the first voltage divider module and the ground, R 11 When the voltages at both ends of the isolation unit are considered, the second voltage U2 at the potential detection end of the second voltage dividing module 32 is equal to (UU g )*R U2 / R 22 , R U2 represents the resistance between the potential detection terminal of the second voltage divider module and the ground, R 22 Represents the total resistance of the second voltage divider module; U g Represents the voltage across the isolation unit.

[0072] Furthermore, the first energy storage module 21 of the first discharge unit 2 includes a first capacitor C1, the positive electrode of the first capacitor C1 is used to connect to the power supply, and the negative electrode of the first capacitor C1 is grounded. The first capacitor C1 can be understood as the sum of equivalent energy storage at both ends of the positive and negative electrodes of the power supply.

[0073] Furthermore, the first voltage divider module 22 of the first discharge unit 2 includes a first resistor R1 and a second resistor R2, one end of the first resistor R1 is connected to the positive electrode of the first capacitor C1, the other end of the first resistor R1 serves as a potential detection end of the first voltage divider module 22 and is connected to one end of the second resistor R2, and the other end of the second resistor R2 is grounded. The voltage across the first capacitor C1 is divided by the first resistor R1 and the second resistor R2, so that the voltage division accuracy is high and the adjustment is flexible.

[0074] Exemplarily, the first voltage at the potential detection terminal of the first energy storage module 21 is V in1 Indicates input voltage (such as Figure 2 As shown), R1 represents the resistance value of the first resistor R1, and R2 represents the resistance value of the second resistor R2.

[0075] Furthermore, the second energy storage module 31 of the second discharge unit 3 includes a second capacitor C2, a positive electrode of the second capacitor C2 is connected to the power output end of the isolation unit 4, and a negative electrode of the second capacitor C2 is grounded.

[0076] Further, the second voltage divider module 32 of the second discharge unit 3 includes a third resistor R3 and a fourth resistor R4, one end of the third resistor R3 is connected to the positive electrode of the second capacitor C2, the other end of the third resistor R3 is used as the potential detection end of the second voltage divider module 32, and is connected to one end of the fourth resistor R4, and the other end of the fourth resistor is grounded. The voltage across the second capacitor C2 is divided by the third resistor R3 and the fourth resistor R4, so that the voltage division accuracy is high and the adjustment is flexible.

[0077] Exemplarily, the second voltage at the potential detection terminal of the second voltage dividing module 32 is like Figure 2 As shown, when the voltage across the isolation unit 4 is ignored, V in2 The value is close to the input voltage V in1 , R3 represents the resistance value of the third resistor R3, and R4 represents the resistance value of the fourth resistor R4.

[0078] Understandably, Greater than When the first voltage V1 is greater than the second voltage V2, Less than , the first voltage V1 is less than the second voltage V2.

[0079] For example, the equivalent resistance of the external load is denoted by R f The total resistance value of the first voltage divider module 22 and the external load connected in parallel therewith is Discharge time ratio It should be less than 1, so that the discharge time of the first discharge unit 2 is shorter than the discharge time of the second discharge unit 3.

[0080] Further, it should be understood that the discharge time of the discharge circuit is t=R*C. When the capacitance remains unchanged, the discharge time can be controlled by adjusting the resistance. When the resistance remains unchanged, the discharge time can also be controlled by setting the capacitance. In addition, the discharge time can also be controlled by both capacitance and resistance. This is not limited here.

[0081] Furthermore, the isolation unit 4 includes a diode D1, the anode of the diode D1 is used as the power input end of the isolation unit 4, and is used to connect to the power supply end, and the cathode of the diode D1 is used as the power output end of the isolation unit 4, and is connected to the charging end of the second discharge unit 3. The diode D1 is used for isolation, and two internal and external voltages are formed when the DC power supply is powered off, so that the first discharge unit 2 and the second discharge unit 3 do not interfere with each other.

[0082] Example 3

[0083] In this embodiment, see Figure 4 The comparison unit 1 may be a controller M1, which is used to monitor the first voltage and the second voltage in real time, and update the output signal of the power-off detection result output terminal when the comparison result between the first voltage and the second voltage changes.

[0084] Exemplarily, the first pin of the controller M1 serves as a first comparison terminal for real-time monitoring of the first voltage, the second pin of the controller M1 serves as a second comparison terminal for real-time monitoring of the second voltage, and the third pin of the controller M1 serves as a power-off detection result output terminal. When the comparison result between the first voltage and the second voltage changes, the output signal of the power-off detection result output terminal is updated.

[0085] It is understood that the controller M1 has a built-in analog-to-digital conversion module that can convert the received analog signal into a digital signal. If the controller M1 does not have a built-in analog-to-digital conversion module, the first voltage and the second voltage can be converted into digital signals by an analog-to-digital conversion chip and then sent to the corresponding pins of the controller M1.

[0086] It can be understood that the embodiment of the present invention relates to a DC power failure detection device, which includes the DC power failure detection circuit of the embodiment of the present invention.

[0087] Exemplarily, the DC power failure detection device includes gate equipment and other electrical equipment. For example, the gate equipment can determine that the DC power is disconnected using the DC power failure detection circuit, and further, the gate equipment can automatically perform the gate opening action using the backup power supply to avoid the gate closing when the power is off.

[0088] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and a part of the module, program segment or code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or the flow diagram, and the combination of boxes in the structure diagram and / or the flow diagram, can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0089] In addition, the functional modules or units in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0090] If the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0091] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A DC power failure detection circuit, characterized in that: The circuit includes a comparison unit, a first discharge unit, a second discharge unit and an isolation unit. The first discharge unit includes a first energy storage module and a first voltage divider module, one end of the first energy storage module is used to connect to a power source and is connected to one end of the first voltage divider module, and the other end of the first energy storage module and the other end of the first voltage divider module are grounded; The power input terminal of the isolation unit is used to connect to the power supply; The second discharge unit includes a second energy storage module and a second voltage divider module, one end of the second energy storage module is connected to the power output end of the isolation unit and to one end of the second voltage divider module, and the other end of the second energy storage module and the other end of the second voltage divider module are grounded; The first comparison terminal of the comparison unit is connected to the potential detection terminal of the first voltage dividing module, and is used to obtain the first voltage of the potential detection terminal of the first voltage dividing module; The second comparison terminal of the comparison unit is connected to the potential detection terminal of the second voltage dividing module, and is used to obtain the second voltage of the potential detection terminal of the second voltage dividing module; Wherein, the comparison result of the first voltage and the second voltage before the power supply is disconnected is opposite to the comparison result after the power supply is disconnected; The isolation unit includes a diode, the anode of the diode serves as the power input terminal of the isolation unit, and the cathode of the diode serves as the power output terminal of the isolation unit; The first energy storage module includes a first capacitor, a positive electrode of the first capacitor is used to connect to a power source, and a negative electrode of the first capacitor is grounded.

2. The DC power failure detection circuit according to claim 1, characterized in that: The comparison unit is a comparator or a controller.

3. The DC power failure detection circuit according to claim 2, characterized in that: When the comparison unit is a comparator, the positive end of the comparator is connected to the potential detection end of the first voltage divider module, the reverse end of the comparator is connected to the potential detection end of the second voltage divider module, and the first energy storage module is also used to be connected in parallel with an external load; When the power supply is normally powered, the first voltage of the potential detection end of the first voltage dividing module is greater than the second voltage of the potential detection end of the second voltage dividing module; The first voltage is determined according to the following formula: U1=U*R U1 / R 11 , U1 represents the first voltage, U represents the voltage of the power supply, R U1 represents the resistance between the potential detection terminal of the first voltage divider module and the ground, R 11 Represents the total resistance of the first voltage divider module; The second voltage is determined according to the following formula: U2=(UU g )*R U2 / R 22 , U2 represents the second voltage, R U2 represents the resistance between the potential detection terminal of the second voltage divider module and the ground, R 22 Represents the total resistance of the second voltage divider module; U g represents the voltage across the isolation unit; A discharge time ratio of a first discharge time of the first discharge unit to a second discharge time of the second discharge unit is less than 1; The discharge time ratio is determined according to the following formula: k represents the discharge time ratio, R f represents the equivalent resistance of the external load, C1 represents the equivalent capacitance of the first energy storage module, and C2 represents the equivalent capacitance of the second energy storage module.

4. The DC power failure detection circuit according to claim 2, characterized in that: When the comparison unit is a comparator, the reverse end of the comparator is connected to the potential detection end of the first voltage divider module, the forward end of the comparator is connected to the potential detection end of the second voltage divider module, and the first energy storage module is also used to be connected in parallel with an external load; When the power supply is normally supplied, the first voltage of the potential detection end of the first voltage dividing module is less than the second voltage of the potential detection end of the second voltage dividing module; The first voltage is determined according to the following formula: U1=U*R U1 / R 11 , U1 represents the first voltage, U represents the voltage of the power supply, R U1 represents the resistance between the potential detection terminal of the first voltage divider module and the ground, R 11 Represents the total resistance of the first voltage divider module; The second voltage is determined according to the following formula: U2=(UU g )*R U2 / R 22 , U2 represents the second voltage, R U2 represents the resistance between the potential detection terminal of the second voltage divider module and the ground, R 22 Represents the total resistance of the second voltage divider module; U g represents the voltage across the isolation unit; A discharge time ratio of a first discharge time of the first discharge unit to a second discharge time of the second discharge unit is greater than 1; The discharge time ratio is determined according to the following formula: k represents the discharge time ratio, R f represents the equivalent resistance of the external load, C1 represents the equivalent capacitance of the first energy storage module, and C2 represents the equivalent capacitance of the second energy storage module.

5. The DC power failure detection circuit according to claim 1, characterized in that: The first voltage divider module includes a first resistor and a second resistor, one end of the first resistor is connected to the positive electrode of the first capacitor, the other end of the first resistor serves as the potential detection end of the first voltage divider module and is connected to one end of the second resistor, and the other end of the second resistor is grounded.

6. The DC power failure detection circuit according to claim 1, characterized in that: The second energy storage module includes a second capacitor, a positive electrode of the second capacitor is connected to the power output end of the isolation unit, and a negative electrode of the second capacitor is grounded.

7. The DC power failure detection circuit according to claim 6, characterized in that: The second voltage divider module includes a third resistor and a fourth resistor, one end of the third resistor is connected to the positive electrode of the second capacitor, the other end of the third resistor serves as the potential detection end of the second voltage divider module and is connected to one end of the fourth resistor, and the other end of the fourth resistor is grounded.

8. A DC power failure detection device, characterized in that: The device comprises the DC power failure detection circuit according to any one of claims 1 to 7.

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