Direct-current power supply input circuit and bidirectional cut-off circuit

Abstract

The utility model provides a direct current power supply input circuit and a bidirectional cut-off circuit, the bidirectional cut-off circuit can be applied to the direct current power supply input circuit, the bidirectional cut-off circuit comprises a bidirectional cut-off unit and a control unit, the bidirectional cut-off unit comprises two pairs of power tubes, and source electrodes of the two pairs of power tubes are connected in series to form a pair of jacking tubes; a first end and a second end of the bidirectional cut-off unit are connected to an input anode of the DC power supply input circuit, a third end of the bidirectional cut-off unit is connected to a first output end of the control unit, and a second output end of the control unit is connected to an input cathode of the DC power supply input circuit. A power tube in the bidirectional cut-off unit is controlled through output of the control unit so as to control connection and disconnection of the direct-current power supply input circuit and a post-stage load, and the problems that the size and cost of a relay are greatly increased when an existing circuit is applied to large current, and due to the mechanical characteristic of the relay, a contact is prone to aging after long-term use, and the reliability is poor are solved. The contact impedance is increased; and the reliability is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to a direct current power supply input circuit and a bidirectional cut-off circuit. Background Art

[0002] With the development of society, people's demand for battery-based DC power supply applications is also increasing. Batteries act as backup power supply, and need to be able to cut off the power supply to the next stage in the forward direction. At the same time, in order to prevent the battery from being reversed, it needs to be able to cut off the reverse direction to protect the battery and the circuit.

[0003] In order to meet the above application requirements, a bidirectional cut-off circuit is needed, which is connected when power is needed and disconnected when power is not needed; when the battery is connected in reverse, it can block the current to protect the battery and circuit from damage.

[0004] like Figure 1 As shown, the existing bidirectional cut-off circuit connects a high-current relay in series in the loop. When the input is reversed or the connection with the subsequent stage needs to be disconnected, it is achieved by controlling the on-off of the driving transistor Q15. However, this method will greatly increase the size and cost of the relay when used in high current applications. At the same time, due to the mechanical characteristics of the relay, the contacts are prone to aging after long-term use, the contact impedance becomes larger, and the reliability is reduced. Utility Model Content

[0005] In this regard, the present application provides a DC power supply input circuit and a bidirectional cut-off circuit to solve the problem that the existing circuit will greatly increase the size and cost of the relay when used in high current applications. At the same time, due to the mechanical characteristics of the relay, the contacts are prone to aging after long-term use, the contact impedance becomes larger, and the reliability is reduced.

[0006] To achieve the above objectives, the present application provides the following technical solutions:

[0007] In a first aspect, the present application discloses a bidirectional cut-off circuit, which is applied to a DC power supply input circuit. The bidirectional cut-off circuit comprises: a bidirectional cut-off unit and a control unit. The bidirectional cut-off unit comprises at least two pairs of power tubes. The sources of the two pairs of power tubes are connected in series to form a pair of top tubes.

[0008] The first end of the bidirectional cut-off unit and the second end of the bidirectional cut-off unit are connected to the positive input pole of the DC power supply input circuit, the third end of the bidirectional cut-off unit is connected to the first output end of the control unit, and the second output end of the control unit is connected to the negative input pole of the DC power supply input circuit.

[0009] Optionally, in the above-mentioned bidirectional cut-off circuit, the bidirectional cut-off unit includes: a first power tube, a second power tube, a third power tube, a fourth power tube, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor;

[0010] The drain of the first power tube is connected to the drain of the second power tube, the connection point serves as the first end of the bidirectional cutoff unit, the source of the first power tube is respectively connected to the source of the second power tube, the source of the third power tube, the source of the fourth power tube, one end of the first resistor, one end of the second resistor, one end of the third resistor and one end of the fourth resistor, and the connection point is connected to the signal ground;

[0011] The gate of the first power tube is respectively connected to the other end of the first resistor and one end of the fifth resistor; the gate of the second power tube is respectively connected to the other end of the second resistor and one end of the sixth resistor; the gate of the third power tube is respectively connected to the other end of the third resistor and one end of the seventh resistor; the gate of the fourth power tube is respectively connected to the other end of the fourth resistor and one end of the eighth resistor;

[0012] The other end of the fifth resistor is respectively connected to the other end of the sixth resistor, the other end of the seventh resistor and the other end of the eighth resistor, and the connection point serves as the third end of the bidirectional cutoff unit;

[0013] The drain of the third power tube is connected to the drain of the fourth power tube, and the connection point serves as the second end of the bidirectional cut-off unit.

[0014] Optionally, in the above-mentioned bidirectional cut-off circuit, the first power tube, the second power tube, the third power tube and the fourth power tube are all NMOS tubes.

[0015] Optionally, in the above-mentioned bidirectional cut-off circuit, the control unit includes: a photocoupler, a transistor, a ninth resistor and a tenth resistor;

[0016] The emitter of the photoelectric coupler serves as the first output end of the control unit; the collector of the photoelectric coupler is connected to the first power supply; the anode of the photoelectric coupler is connected to one end of the ninth resistor, and the other end of the ninth resistor is connected to the second power supply; the cathode of the photoelectric coupler is connected to the collector of the transistor, the base of the transistor is connected to one end of the tenth resistor, the emitter of the transistor serves as the second output end of the control unit, and the other end of the tenth resistor receives an on-off control signal.

[0017] The second aspect of the present application discloses a DC power supply input circuit, comprising: an anti-reverse protection unit, a sampling unit, a filtering unit, and a bidirectional cut-off circuit as described in any one of the items disclosed in the first aspect;

[0018] The anti-reverse protection unit, the sampling unit, the bidirectional cut-off circuit and the filtering unit are connected in parallel in sequence, one end of the parallel connection serves as the positive input electrode of the DC power supply input circuit, and the other end of the parallel connection serves as the negative input electrode of the DC power supply input circuit.

[0019] Optionally, in the above-mentioned DC power supply input circuit, the first end of the anti-reverse protection unit, the first end of the sampling unit, the first end of the bidirectional cut-off circuit, the second end of the bidirectional cut-off circuit, the first end of the filter unit and the second end of the filter unit are connected, and the connection point serves as one end of the parallel connection;

[0020] The second end of the anti-reverse protection unit, the third end of the anti-reverse protection unit, the second end of the sampling unit, the third end of the sampling unit, the third end of the bidirectional cutoff circuit, the third end of the filtering unit and the filtering unit are connected, and the connection point serves as the other end of the parallel connection.

[0021] Optionally, in the above-mentioned DC power supply input circuit, the anti-reverse protection unit includes: a common cathode diode, the cathode of the common cathode diode serving as the first end of the anti-reverse protection unit; the first anode and the second anode of the common cathode diode serving as the second end of the anti-reverse protection unit and the third end of the anti-reverse protection unit, respectively.

[0022] Optionally, in the above-mentioned DC power supply input circuit, the sampling unit includes: an eleventh resistor, a twelfth resistor and a first capacitor;

[0023] One end of the eleventh resistor serves as the first end of the sampling unit, and the other end of the eleventh resistor is respectively connected to one end of the twelfth resistor and one end of the first capacitor, and the connection point outputs a sampling voltage; the other end of the twelfth resistor serves as the second end of the sampling unit, and the other end of the first capacitor serves as the third end of the sampling unit.

[0024] Optionally, in the above-mentioned DC power supply input circuit, the filtering unit includes: a second capacitor and a third capacitor;

[0025] The second capacitor is connected in parallel with the third capacitor, one end of the second capacitor serves as the first end of the filtering unit, one end of the third capacitor serves as the second end of the filtering unit, the other end of the second capacitor serves as the third end of the filtering unit, and the other end of the third capacitor serves as the fourth end of the filtering unit.

[0026] Optionally, in the above-mentioned DC power supply input circuit, it further includes: an input terminal, through which the input positive electrode of the DC power supply input circuit and the input negative electrode of the DC power supply input circuit are connected to a DC power supply;

[0027] And / or, a fuse, wherein the fuse is arranged at a subsequent stage of the input terminal and is connected in series between an input positive electrode of the DC power supply input circuit and an input negative electrode of the DC power supply input circuit.

[0028] The bidirectional cut-off circuit provided in the present application can be applied to a DC power supply input circuit, comprising: a bidirectional cut-off unit and a control unit, the bidirectional cut-off unit comprising two pairs of power tubes, the sources of the two pairs of power tubes being connected in series to form a pair of top tubes; the first end and the second end of the bidirectional cut-off unit are connected to the input positive electrode of the DC power supply input circuit, the third end of the bidirectional cut-off unit is connected to the first output end of the control unit, the second output end of the control unit is connected to the input negative electrode of the DC power supply input circuit, the power tube in the bidirectional cut-off unit is controlled by the output of the control unit to realize the on-off connection between the DC power supply input circuit and the subsequent load, thereby solving the problem that the existing circuit will greatly increase the volume and cost of the relay when applied with high current, and at the same time, due to the mechanical characteristics of the relay, the contacts are prone to aging after long-term use, the contact impedance becomes larger, and the reliability is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0030] Figure 1 A circuit diagram of an existing bidirectional cut-off circuit provided in an embodiment of the present application;

[0031] Figure 2 A schematic diagram of the structure of a bidirectional cut-off circuit provided in an embodiment of the present application;

[0032] Figure 3 A circuit diagram of a bidirectional cut-off circuit provided in an embodiment of the present application;

[0033] Figure 4 A schematic diagram of the structure of a DC power supply input circuit provided in an embodiment of the present application;

[0034] Figure 5 A circuit diagram of a DC power supply input circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] The embodiment of the present application provides a bidirectional cut-off circuit to solve the problem that the existing circuit will greatly increase the size and cost of the relay when used in high current applications. At the same time, due to the mechanical characteristics of the relay, the contacts are prone to aging after long-term use, the contact impedance becomes larger, and the reliability is reduced.

[0037] See also Figure 2 The bidirectional cut-off circuit can be applied to a DC power supply input circuit, and mainly includes: a bidirectional cut-off unit 101 and a control unit 102, the bidirectional cut-off unit 101 includes at least two pairs of power tubes, and the sources of the two pairs of power tubes are connected in series to form a pair of top tubes; the first end of the bidirectional cut-off unit 101 and the second end of the bidirectional cut-off unit 101 are connected to the input positive electrode (BAT+ in the figure) of the DC power supply input circuit, the third end of the bidirectional cut-off unit 101 is connected to the first output end of the control unit 102, and the second output end of the control unit 102 is connected to the input negative electrode (BAT- in the figure) of the DC power supply input circuit.

[0038] In practical applications, the on and off of each power tube in the bidirectional cut-off unit 101 is controlled by the output voltage outputted from the first output terminal of the control unit 102; when the output voltage outputted from the first output terminal of the control unit 102 is greater than the conduction voltage of each power tube in the bidirectional cut-off unit 101, each power tube in the bidirectional cut-off unit 101 is turned on, and the DC power supply input circuit can supply power to the subsequent load; conversely, when the output voltage outputted from the first output terminal of the control unit 102 is less than the conduction voltage of each power tube in the bidirectional cut-off unit 101, each power tube in the bidirectional cut-off unit 101 is turned off, and the DC power supply input circuit cuts off the power supply to the subsequent load.

[0039] In a specific application, when the DC power supply in the DC power supply input circuit is reversed or the DC power supply does not need to be powered in standby mode, the output voltage output by the first output terminal of the control unit 102 is insufficient to control the conduction of each power tube in the bidirectional cut-off unit 101; and when the above situation does not exist and power needs to be supplied to the subsequent stage, the output voltage output by the first output terminal of the control unit 102 can control the conduction of each power tube in the bidirectional cut-off unit 101.

[0040] In some embodiments, Figure 3As shown, the bidirectional cut-off unit 101 can mainly include: a first power tube Q6, a second power tube Q9, a third power tube Q3, a fourth power tube Q4, a first resistor R30, a second resistor R39, a third resistor R24, a fourth resistor R26, a fifth resistor R35, a sixth resistor R44, a seventh resistor R25 and an eighth resistor R28.

[0041] The drain of the first power tube Q6 is connected to the drain of the second power tube Q9, and the connection point serves as the first end of the bidirectional cutoff unit 101. The source of the first power tube Q6 is respectively connected to the source of the second power tube Q9, the source of the third power tube Q3, the source of the fourth power tube Q4, one end of the first resistor R30, one end of the second resistor R39, one end of the third resistor R24, and one end of the fourth resistor R26, and the connection point is connected to the signal ground.

[0042] The gate of the first power tube Q6 is respectively connected to the other end of the first resistor R30 and one end of the fifth resistor R35; the gate of the second power tube Q9 is respectively connected to the other end of the second resistor R39 and one end of the sixth resistor R44; the gate of the third power tube Q3 is respectively connected to the other end of the third resistor R24 ​​and one end of the seventh resistor R25; the gate of the fourth power tube Q4 is respectively connected to the other end of the fourth resistor R26 and one end of the eighth resistor R28;

[0043] The other end of the fifth resistor R35 is respectively connected to the other end of the sixth resistor R44, the other end of the seventh resistor R25 and the other end of the eighth resistor R28, and the connection point serves as the third end of the bidirectional cut-off unit 101; the drain of the third power tube Q3 is connected to the drain of the fourth power tube Q4, and the connection point serves as the second end of the bidirectional cut-off unit 101.

[0044] In practical applications, the first power tube Q6 and the third power tube Q3 serve as a pair of power tubes, and the second power tube Q9 and the fourth power tube Q4 serve as another pair of power tubes; the specific types of the first power tube Q6, the second power tube Q9, the third power tube Q3 and the fourth power tube Q4 may be NMOS tubes, and further, may be NMOS tubes with very small on-resistance; of course, it is not limited to this, and can also be determined according to the application environment and user needs. This application is not limited thereto, and all are within the protection scope of this application.

[0045] For example, in some embodiments, the specific models of the first power tube Q6, the second power tube Q9, the third power tube Q3 and the fourth power tube Q4 can be SFS08R03GNF, but this is certainly not limited to this. Other existing models can also be selected depending on the application environment and user needs, all of which are within the protection scope of this application.

[0046] It should be noted that the specific voltage of the signal ground in the present application may be consistent with the voltage of the first power supply and the second power supply in the control unit 102. Exemplarily, the signal ground may be a 12V independent power supply signal ground.

[0047] It should be noted that the first resistor R30, the second resistor R39, the third resistor R24, and the fourth resistor R26 are arranged between the gate and the source of the corresponding power tube, so as to prevent the power tube from being misinterferenced. Specifically, the specific model of the first resistor R30, the second resistor R39, the third resistor R24, and the fourth resistor R26 can be 103CR, of course, it is not limited thereto, and can also be determined according to the application environment and user needs, and other existing models can also be selected, all within the protection scope of this application.

[0048] It should also be noted that the fifth resistor R35, the sixth resistor R44, the seventh resistor R25 and the eighth resistor R28, as driving resistors in the bidirectional cut-off circuit, can limit the magnitude of the driving current and adjust the switching speed of the corresponding power tube. Specifically, the specific model of the fifth resistor R35, the sixth resistor R44, the seventh resistor R25 and the eighth resistor R28 can be 221AR, of course, it is not limited to this, and can also be determined according to the application environment and user needs, and other existing models can also be selected, all within the protection scope of this application.

[0049] In some embodiments, Figure 3 As shown, the control unit 102 mainly includes: a photocoupler U8, a transistor Q15, a ninth resistor R58 and a tenth resistor R59.

[0050] The emitter of the photoelectric coupler U8 serves as the first output end of the control unit 102; the collector of the photoelectric coupler U8 is connected to the first power supply; the anode of the photoelectric coupler U8 is connected to one end of the ninth resistor R58, and the other end of the ninth resistor R58 is connected to the second power supply; the cathode of the photoelectric coupler U8 is connected to the collector of the transistor Q15, the base of the transistor Q15 is connected to one end of the tenth resistor R59, the emitter of the transistor Q15 serves as the second output end of the control unit 102, and the other end of the tenth resistor R59 receives the on-off control signal.

[0051] In practical applications, the on-off control signal can be sent by a DSP microprocessor (digital signal processor). When the on-off control signal is at a high level, the transistor Q15 is turned on, and the photocoupler U8 is driven to be turned on, and the power of the first power supply is sent to the gates of the first power tube Q6, the second power tube Q9, the third power tube Q3 and the fourth power tube Q4 in the bidirectional cut-off unit 101. The gates of the first power tube Q6, the second power tube Q9, the third power tube Q3 and the fourth power tube Q4 receive the driving voltage and are then turned on.

[0052] It should be noted that the voltage of the first power supply is generally the same as the voltage of the second power supply, and can be 12V by way of example, but is certainly not limited to this. It can also be determined in combination with the on-voltage of the first power tube Q6, the second power tube Q9, the third power tube Q3, and the fourth power tube Q4 in the bidirectional cut-off unit 101, all of which are within the protection scope of the present application.

[0053] It should be noted that, in order to achieve better protection, the second output terminal of the control unit 102 may also be connected to a power ground, ie, PGND in the figure.

[0054] For example, the specific model of the photocoupler U8 is TCLT1003, the specific model of the transistor Q15 is LMBT4401LT1G, and the specific models of the ninth resistor R58 and the tenth resistor R59 can be 472AR; of course, it is not limited to this, and can also be determined depending on the application environment and user needs, and other existing models can also be selected, all within the protection scope of this application.

[0055] In combination with the above, the present application can use NMOS tubes with very small on-resistance as power tubes, by connecting the sources of two pairs of power tubes in series to form top tubes, the source of each power tube is connected to the signal ground of an independent 12V power supply, the photocoupler U8 is connected to the driving power supply of the power tube, the drain of each power tube is outward, and the current at both ends cannot flow in opposite directions. By controlling the conduction of the photocoupler U8, the 12V power supply is sent to the gate of each power tube, and the power tube is turned on to connect the DC power supply to the subsequent stage and supply power to the subsequent load; when the DC power supply is reversed or the DC power supply is in standby mode and does not need to be powered, the photocoupler U8 is not turned on, and each power tube is disconnected from the subsequent stage.

[0056] The bidirectional cut-off circuit provided in this embodiment can be applied to a DC power supply input circuit, including: a bidirectional cut-off unit 101 and a control unit 102, the bidirectional cut-off unit 101 includes two pairs of power tubes, and the sources of the two pairs of power tubes are connected in series to form a pair of top tubes; the first end and the second end of the bidirectional cut-off unit 101 are connected to the input positive electrode of the DC power supply input circuit, the third end of the bidirectional cut-off unit 101 is connected to the first output end of the control unit 102, and the second output end of the control unit 102 is connected to the input negative electrode of the DC power supply input circuit. The power tube in the bidirectional cut-off unit 101 is controlled by the output of the control unit 102 to realize the on-off connection between the DC power supply input circuit and the subsequent load, which solves the problem that the existing circuit will greatly increase the volume and cost of the relay when applied with high current, and at the same time, due to the mechanical characteristics of the relay, the contacts are prone to aging after long-term use, the contact impedance becomes larger, and the reliability is reduced.

[0057] Based on the bidirectional cut-off circuit provided in the above embodiment, optionally, another embodiment of the present application further provides a DC power supply input circuit, see Figure 4 , the DC power supply input circuit mainly includes: an anti-reverse protection unit 202, a sampling unit 203, a filtering unit 205 and a bidirectional cut-off circuit 204 as described in any of the above embodiments;

[0058] The anti-reverse protection unit 202, the sampling unit 203, the bidirectional cut-off circuit 204 and the filtering unit 205 are connected in parallel in sequence, one end of the parallel connection is used as the positive input of the DC power supply input circuit, and the other end of the parallel connection is used as the negative input of the DC power supply input circuit.

[0059] In some embodiments, the first end of the anti-reverse protection unit 202, the first end of the sampling unit 203, the first end of the bidirectional cut-off circuit 204, the second end of the bidirectional cut-off circuit 204, the first end of the filtering unit 205 and the second end of the filtering unit 205 are connected, and the connection point serves as one end of the parallel connection; the second end of the anti-reverse protection unit 202, the third end of the anti-reverse protection unit 202, the second end of the sampling unit 203, the third end of the sampling unit 203, the third end of the bidirectional cut-off circuit 204, the third end of the filtering unit 205 and the fourth end of the filtering unit 205 are connected, and the connection point serves as the other end of the parallel connection.

[0060] In practical applications, such as Figure 5 As shown, the DC power supply input circuit may further include: an input terminal J1, and an input positive electrode of the DC power supply input circuit and an input negative electrode of the DC power supply input circuit are connected to a DC power supply through the input terminal J1. The input positive electrode of the DC power supply input circuit is connected to the positive electrode of the DC power supply through pin 2 of the input terminal J1, and the input negative electrode of the DC power supply input circuit is connected to the negative electrode of the DC power supply through pin 1 of the input terminal J1.

[0061] Specifically, the specific model of the input terminal J1 may be CON_396_2; of course, it is not limited thereto, and other existing input terminals J1 may be selected depending on the application environment and user needs. This application does not limit this, and all are within the protection scope of this application.

[0062] Combination Figure 5 The anti-reverse protection unit 202 mainly includes: a common cathode diode D14, a cathode 3 of the common cathode diode D14 serves as a first end of the anti-reverse protection unit 202; a first anode 1 and a second anode 2 of the common cathode diode D14 serve as a second end of the anti-reverse protection unit 202 and a third end of the anti-reverse protection unit 202, respectively.

[0063] It should be noted that by connecting the cathode 3 of the common cathode diode D14 to the positive input pole of the DC power supply input circuit, and connecting the first anode 1 and the second anode 2 of the common cathode diode D14 to the negative input pole of the DC power supply input circuit respectively, the reverse flow of current can be prevented, thereby protecting other circuits or devices from the influence of reverse current.

[0064] Combination Figure 5 , the sampling unit 203 may include: an eleventh resistor R36, a twelfth resistor R48 and a first capacitor C60.

[0065] Among them, one end of the eleventh resistor R36 serves as the first end of the sampling unit 203, and the other end of the eleventh resistor R36 is respectively connected to one end of the twelfth resistor R48 and one end of the first capacitor C60, and the connection point outputs the sampling voltage; the other end of the twelfth resistor R48 serves as the second end of the sampling unit 203, and the other end of the first capacitor C60 serves as the third end of the sampling unit 203.

[0066] It should be noted that the sampling unit 203 composed of the eleventh resistor R36 , the twelfth resistor R48 and the first capacitor C60 can implement sampling of the input voltage of the DC power supply input circuit.

[0067] Combination Figure 5 The filtering unit 205 mainly includes: a second capacitor C56 and a third capacitor C57.

[0068] Among them, the second capacitor C56 is connected in parallel with the third capacitor C57, one end of the second capacitor C56 serves as the first end of the filter unit 205, one end of the third capacitor C57 serves as the second end of the filter unit 205, the other end of the second capacitor C56 serves as the third end of the filter unit 205, and the other end of the third capacitor C57 serves as the fourth end of the filter unit 205.

[0069] It should be noted that, by providing the second capacitor C56 and the third capacitor C57 in the DC power supply input circuit, the distribution of voltage and current in the circuit can be adjusted, thereby improving the power supply stability of the DC power supply input circuit.

[0070] In some embodiments, see also Figure 5 The DC power supply input circuit may further include: a fuse F1, which is arranged at the rear stage of the input terminal J1 and is connected in series between the input positive electrode of the DC power supply input circuit and the input negative electrode of the DC power supply input circuit.

[0071] In practical applications, after setting the fuse F1 after the input terminal J1, when the current output by the DC power supply exceeds the limit of the fuse F1, the fuse F1 can be melted to disconnect the circuit, thereby avoiding the influence of the current exceeding the limit on the DC power supply input circuit and subsequent devices.

[0072] It should be noted that, combined with Figure 5 The bidirectional cut-off circuit 204 can be specifically arranged between the sampling unit 203 and the filtering unit 205, that is, arranged at the rear stage of the sampling unit 203 and the front stage of the filtering unit 205, and can disconnect the DC power supply input circuit from the rear stage when the DC input is reversely connected or needs to be disconnected from the rear stage.

[0073] In combination with the bidirectional cut-off circuit 204 provided in the above implementation, the first end of the bidirectional cut-off circuit 204 may be the first end of the bidirectional cut-off unit in the bidirectional cut-off circuit 204, the second end of the bidirectional cut-off circuit 204 may be the second end of the bidirectional cut-off unit in the bidirectional cut-off circuit 204, and the third end of the bidirectional cut-off circuit 204 may be the second output end of the control unit in the bidirectional cut-off circuit 204.

[0074] It should also be noted that the relevant description of the bidirectional cut-off circuit 204 can be found in the above corresponding embodiment, which will not be repeated here. The DC power supply input circuit can also be found in the prior art, which will not be repeated here.

[0075] In this embodiment, after a bidirectional cut-off circuit 204 is added to the DC power supply input circuit, the power tube in the bidirectional cut-off unit can be controlled by the output of the control unit to realize the on-off connection between the DC power supply input circuit and the subsequent load, thereby improving the application reliability of the DC power supply input circuit.

[0076] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be 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 the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

[0077] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

Claims

1. A bidirectional cut-off circuit, characterized in that: Applied to a DC power supply input circuit, the bidirectional cut-off circuit comprises: a bidirectional cut-off unit and a control unit, the bidirectional cut-off unit comprises at least two pairs of power tubes, and the sources of the two pairs of power tubes are connected in series to form top-to-top tubes; The first end of the bidirectional cut-off unit and the second end of the bidirectional cut-off unit are connected to the positive input pole of the DC power supply input circuit, the third end of the bidirectional cut-off unit is connected to the first output end of the control unit, and the second output end of the control unit is connected to the negative input pole of the DC power supply input circuit.

2. The bidirectional cutoff circuit according to claim 1, characterized in that: The bidirectional cutoff unit includes: a first power tube, a second power tube, a third power tube, a fourth power tube, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor; The drain of the first power tube is connected to the drain of the second power tube, the connection point serves as the first end of the bidirectional cutoff unit, the source of the first power tube is respectively connected to the source of the second power tube, the source of the third power tube, the source of the fourth power tube, one end of the first resistor, one end of the second resistor, one end of the third resistor and one end of the fourth resistor, and the connection point is connected to the signal ground; The gate of the first power tube is respectively connected to the other end of the first resistor and one end of the fifth resistor; the gate of the second power tube is respectively connected to the other end of the second resistor and one end of the sixth resistor; the gate of the third power tube is respectively connected to the other end of the third resistor and one end of the seventh resistor; the gate of the fourth power tube is respectively connected to the other end of the fourth resistor and one end of the eighth resistor; The other end of the fifth resistor is respectively connected to the other end of the sixth resistor, the other end of the seventh resistor and the other end of the eighth resistor, and the connection point serves as the third end of the bidirectional cutoff unit; The drain of the third power tube is connected to the drain of the fourth power tube, and the connection point serves as the second end of the bidirectional cut-off unit.

3. The bidirectional cutoff circuit according to claim 2, characterized in that: The first power tube, the second power tube, the third power tube and the fourth power tube are all NMOS tubes.

4. The bidirectional cutoff circuit according to claim 1, characterized in that: The control unit comprises: a photoelectric coupler, a triode, a ninth resistor and a tenth resistor; The emitter of the photoelectric coupler serves as the first output end of the control unit; the collector of the photoelectric coupler is connected to the first power supply; the anode of the photoelectric coupler is connected to one end of the ninth resistor, and the other end of the ninth resistor is connected to the second power supply; the cathode of the photoelectric coupler is connected to the collector of the transistor, the base of the transistor is connected to one end of the tenth resistor, the emitter of the transistor serves as the second output end of the control unit, and the other end of the tenth resistor receives an on-off control signal.

5. A DC power supply input circuit, characterized in that: include: An anti-reverse protection unit, a sampling unit, a filtering unit, and a bidirectional cut-off circuit as claimed in any one of claims 1 to 4; The anti-reverse protection unit, the sampling unit, the bidirectional cut-off circuit and the filtering unit are connected in parallel in sequence, one end of the parallel connection serves as the positive input electrode of the DC power supply input circuit, and the other end of the parallel connection serves as the negative input electrode of the DC power supply input circuit.

6. The DC power supply input circuit according to claim 5, characterized in that: The first end of the anti-reverse protection unit, the first end of the sampling unit, the first end of the bidirectional cut-off circuit, the second end of the bidirectional cut-off circuit, the first end of the filter unit and the second end of the filter unit are connected, and the connection point serves as one end of the parallel connection; The second end of the anti-reverse protection unit, the third end of the anti-reverse protection unit, the second end of the sampling unit, the third end of the sampling unit, the third end of the bidirectional cut-off circuit, the third end of the filtering unit and the fourth end of the filtering unit are connected, and the connection point serves as the other end of the parallel connection.

7. The DC power supply input circuit according to claim 6, characterized in that: The anti-reverse protection unit includes: a common cathode diode, the cathode of the common cathode diode serves as the first end of the anti-reverse protection unit; the first anode and the second anode of the common cathode diode serve as the second end and the third end of the anti-reverse protection unit respectively.

8. The DC power supply input circuit according to claim 6, characterized in that: The sampling unit comprises: an eleventh resistor, a twelfth resistor and a first capacitor; One end of the eleventh resistor serves as the first end of the sampling unit, and the other end of the eleventh resistor is respectively connected to one end of the twelfth resistor and one end of the first capacitor, and the connection point outputs a sampling voltage; the other end of the twelfth resistor serves as the second end of the sampling unit, and the other end of the first capacitor serves as the third end of the sampling unit.

9. The DC power supply input circuit according to claim 6, characterized in that: The filtering unit comprises: a second capacitor and a third capacitor; The second capacitor is connected in parallel with the third capacitor, one end of the second capacitor serves as the first end of the filtering unit, one end of the third capacitor serves as the second end of the filtering unit, the other end of the second capacitor serves as the third end of the filtering unit, and the other end of the third capacitor serves as the fourth end of the filtering unit.

10. The DC power supply input circuit according to claim 6, characterized in that: Also includes: An input terminal, through which the input positive electrode of the DC power supply input circuit and the input negative electrode of the DC power supply input circuit are connected to a DC power source; And / or, a fuse, wherein the fuse is arranged at a subsequent stage of the input terminal and is connected in series between an input positive electrode of the DC power supply input circuit and an input negative electrode of the DC power supply input circuit.

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