Dual-power backup switching circuit and intelligent equipment

Abstract

The utility model discloses a dual-power-supply backup switching circuit and intelligent equipment. The dual-power-supply backup switching circuit comprises a main power supply and a standby power supply which are used for supplying power to electric equipment, the controlled end of the monostable relay is provided with a first branch circuit connected between the main power supply and the electric equipment in series and a second branch circuit connected between the standby power supply and the electric equipment in series, and the first branch circuit is switched on when the controlled end is in a power-off state; and the switching control unit is provided with a first switch connected with the main power supply and a second switch connected with the standby power supply, and the controlled end is connected between the first switch and the second switch. When the dual-power backup switching circuit is powered on and operates normally, the monostable relay is in a non-excitation state, so that a mechanical structure in the monostable relay does not need to bear continuous acting force for a long time, the action time of the monostable relay is greatly shortened, mechanical fatigue is reduced, the service life of the monostable relay is prolonged, and the reliability of the monostable relay is improved. Therefore, the stability of the dual-power backup switching circuit is improved, and the maintenance cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to power distribution technical field especially, relates to a double power backup switching circuit and intelligent equipment. BACKGROUND

[0002] In the circuit of realizing power backup using monostable relay, the relay is an important component in the control system, and its working state determines whether the whole circuit can run stably for a long time.

[0003] However, in the current double power backup switching circuit, the monostable relay is always in the excited state when the system runs normally, which makes the mechanical structure inside the monostable relay bear the continuous force for a long time, easily produces mechanical fatigue, affects the normal switching function of the monostable relay, and further affects the stability of the whole double power backup switching system, increases the frequency of after-sales maintenance and replacement, and improves the maintenance cost. UTILITY MODEL CONTENTS

[0004] The utility model provides a double power backup switching circuit and intelligent equipment for solving the problem that the relay is always in the action state in the prior art, which makes the mechanical structure inside the relay bear the continuous force for a long time, easily produces mechanical fatigue, and affects the stability of the whole circuit.

[0005] The technical scheme of the utility model is a double power backup switching circuit, which comprises a main power supply and a backup power supply for supplying power to an electric device, and further comprises:

[0006] A monostable relay, which has a first branch connected in series between the main power supply and the electric device, and a second branch connected in series between the backup power supply and the electric device, and the controlled end of the monostable relay is in an off state when the first branch is turned on;

[0007] A switching control unit, which has a first switch connected with the main power supply, and a second switch connected with the backup power supply, and the controlled end of the monostable relay is connected between the first switch and the second switch.

[0008] Further, the monostable relay further comprises:

[0009] A first common contact, a second common contact, a first normally closed contact and a second normally closed contact constituting the first branch; a first common contact, a second common contact, a first normally open contact and a second normally open contact constituting the second branch;

[0010] One end of the controlled end is connected with the output end of the switching control unit, the other end of the controlled end is grounded, the first common contact is connected with the electrical equipment, the first normally open contact is connected with the first power supply end of the backup power supply, the first normally closed contact is connected with the first power supply end of the main power supply, the second common contact is used for being connected with the master control MCU, the second normally open contact is connected with the second power supply end of the backup power supply, and the second normally closed contact is connected with the second power supply end of the main power supply.

[0011] Further, in the non-energized state, the first common contact is connected with the first normally closed contact, and the second common contact is connected with the second normally closed contact.

[0012] In the energized state, the first common contact is connected with the first normally open contact, and the second common contact is connected with the second normally open contact.

[0013] Further, the switching control unit further comprises a first resistor, a second resistor, a third resistor and a fourth resistor, and the first switch and the second switch are both triodes.

[0014] The control end of the backup power supply is connected with the first end of the first resistor and the first end of the second resistor respectively, the collector of the second switch is connected with the second end of the first resistor, the base of the second switch is connected with the second end of the second resistor, the emitter of the second switch and the collector of the first switch are respectively connected with the first end of the fourth resistor, and the second end of the fourth resistor is connected with the controlled end of the monostable relay.

[0015] The base of the first switch is connected with the second end of the third resistor, the first end of the third resistor is connected with the control end of the main power supply, and the collector of the first switch is grounded.

[0016] Further, when the monostable relay is in the non-energized state, the first switch and the second switch are both turned on.

[0017] When the monostable relay is in the energized state, the first switch is turned off, and the second switch is turned on.

[0018] Further, the first switch and the second switch are both NPN triodes.

[0019] Further, the fourth resistor is provided with a plurality of fourth resistors which are connected in series.

[0020] Further, the main power supply and the backup power supply are both AC-DC power supplies.

[0021] Further, the first resistances, the second resistances and the third resistances are provided in plurality, and the plurality of the first resistances, the plurality of the second resistances and the plurality of the third resistances are respectively arranged in series / parallel.

[0022] The utility model discloses further propose an intelligent device, the intelligent device includes above-mentioned double power backup switching circuit.

[0023] Compared with the prior art, the utility model has at least the following beneficial effects:

[0024] When the double power backup switching circuit is powered on and normally operates, the monostable relays are in non-excitation state, so that the mechanical structure inside the monostable relays does not have to bear the continuous force for a long time, the action time of the monostable relays is greatly reduced, the mechanical fatigue is reduced, the service life of the monostable relays is prolonged, the stability of the double power backup switching circuit is improved, the frequency of after-sales maintenance and replacement is reduced, and the maintenance cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the utility model belongs; the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit the utility model; the terms "include" and "have" in the specification and claims of the utility model and the above description of drawings are intended to cover the non-exclusive inclusion; the terms "first", "second" and the like in the specification and claims of the utility model or the above description of drawings are used to distinguish different objects, not to describe a specific order.

[0026] In order to more clearly illustrate the technical scheme in the embodiments of the utility model, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below; obviously, the drawings in the following description are only some embodiments of the utility model, and those skilled in the art can obtain other drawings according to these drawings without creating creative labor.

[0027] Figure 1 The module block diagram of the double power backup switching circuit provided by the utility model is shown in the figure.

[0028] Figure 2 The circuit diagram of the double power backup switching circuit provided by the utility model is shown in the figure.

[0029] Figure 3 The circuit diagram of another double power backup switching circuit provided by the utility model is shown in the figure.

[0030] Reference signs:

[0031] 10, main power supply;

[0032] 20, backup power supply;

[0033] 30, switching control unit;

[0034] 40, monostable relay;

[0035] 50, electrical equipment;

[0036] 60, master control unit. DETAILED DESCRIPTION

[0037] In order to make the technical problems, technical solutions and beneficial effects of the utility model clearer and more apparent, the utility model will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and do not limit the utility model. Therefore, one feature mentioned in the specification is used to explain one feature of one embodiment of the utility model, and it is not implied that each embodiment of the utility model must have the explained feature. In addition, it should be noted that the specification describes many features. Although certain features can be combined together to show possible system designs, these features can also be used in other combinations that are not explicitly described. Therefore, unless otherwise stated, the described combination is not intended to be limiting.

[0038] The principles and structures of the utility model will be described in detail below in combination with the drawings and embodiments.

[0039] Embodiment 1

[0040] In the existing dual power backup switching circuit, the monostable relay is always in an excited state during normal operation, which makes the mechanical structure inside the monostable relay bear continuous force for a long time, easily causing mechanical fatigue, affecting the normal switching function of the monostable relay, and further affecting the stability of the entire dual power backup switching system, increasing the frequency of after-sales maintenance and replacement, and increasing the maintenance cost.

[0041] Therefore, in order to solve the above problems, with reference to the accompanying drawings Figures 1-2 The utility model provides a dual power backup switching circuit, which comprises a main power supply 10 and a backup power supply 20 for supplying power to electrical equipment 50; and further comprises:

[0042] A monostable relay 40 has a controlled end with a first branch connected in series between the main power supply 10 and the electrical equipment 50, and a second branch connected in series between the backup power supply 20 and the electrical equipment 50, and the controlled end of the monostable relay 40 is in an off state when the first branch is turned on;

[0043] A switching control unit 30 having a first switch connected with the main power supply 10 and a second switch connected with the backup power supply 20, and the controlled end of the monostable relay 40 is connected between the first switch and the second switch.

[0044] It should be noted that when the main power supply 10 and the backup power supply 20 are both powered, the switching control unit 30 drives the monostable relay 40 to be in a non-excitation state, and the main power supply 10 supplies power to the electrical equipment 50; when the main power supply 10 is powered off, the switching control unit 30 drives the monostable relay 40 to be in an excitation state, and the backup power supply 20 supplies power to the electrical equipment 50.

[0045] And the controlled end of the monostable relay 40 in the embodiment corresponds to the coil of the monostable relay 40.

[0046] The dual power backup switching circuit further comprises a master control MCU 60 connected with the monostable relay 40 and the electrical equipment 50, and the master control MCU 60 is used to control the running state of the electrical equipment 50.

[0047] When the dual power backup switching circuit is powered on and normally running, the main power supply 10 and the backup power supply 20 are both powered, at this time the first switch and the second switch in the switching control unit 30 are both turned on, resulting in the current of the main power supply 10 and the backup power supply 20 being grounded, resulting in no current passing through the controlled end of the monostable relay 40, and thus the monostable relay 40 is in a non-excitation state, and the electrical equipment 50 is normally working by being supplied with power by the main power supply 10.

[0048] When the main power supply 10 is powered off, the first switch in the switching control unit 30 is turned off, and the second switch is turned on, resulting in the current of the backup power supply 20 being unable to be grounded, so the current of the backup power supply 20 passes through the controlled end of the monostable relay 40, resulting in the monostable relay 40 switching from a non-excitation state to an excitation state, and at this time the electrical equipment 50 is normally working by being supplied with power by the backup power supply 20; when the main power supply 10 is restored to power supply, the controlled end of the monostable relay 40 again has no current passing through, and thus the monostable relay 40 switches from an excitation state to a non-excitation state, and the electrical equipment 50 is normally working by being supplied with power by the main power supply 10.

[0049] Therefore, when the dual power backup switching circuit is powered on and normally running, the monostable relay 40 is in a non-excitation state, which can make the mechanical structure inside the monostable relay 40 not have to bear the continuous force for a long time, greatly reducing the action time of the monostable relay 40, reducing mechanical fatigue, prolonging the service life of the monostable relay 40, and thus improving the stability of the dual power backup switching circuit, reducing the frequency of after-sales maintenance and replacement, and reducing maintenance costs.

[0050] In order to ensure that the monostable relay 40 can be attracted according to whether the main power supply 10 is powered off, with reference to the accompanying drawings Figure 2 The embodiment provides a structural diagram of a monostable relay 40.

[0051] The monostable relay 40 comprises a controlled end, a first common contact, a second common contact, a first normally closed contact and a second normally closed contact which constitute the first branch circuit, and a first common contact, a second common contact, a first normally open contact and a second normally open contact which constitute the second branch circuit.

[0052] One end of the controlled end is connected with an output end of the switching control unit 30, and the other end of the controlled end is grounded; the first common contact is connected with a power supply end of the electrical equipment 50; the first normally open contact is connected with a first power supply end B_DC1 of the backup power supply 20; the first normally closed contact is connected with a first power supply end M_DC1 of the main power supply 10; the second common contact is used for being connected with a power supply end of the master control MCU 60; the second normally open contact is connected with a second power supply end B_DC2 of the backup power supply 20; and the second normally closed contact is connected with a second power supply end M_DC2 of the main power supply 10.

[0053] It should be noted that the monostable relay 40 in the embodiment is an 8-pin monostable relay, wherein a 1-pin of the monostable relay 40 is a first pin of a coil (i.e., one end of the controlled end), a 2-pin of the monostable relay 40 is a second pin of the coil (i.e., the other end of the controlled end), a 3-pin of the monostable relay 40 is the first normally closed contact, a 4-pin of the monostable relay 40 is the first common contact, a 5-pin of the monostable relay 40 is the first normally open contact, a 6-pin of the monostable relay 40 is the second normally closed contact, a 7-pin of the monostable relay 40 is the second common contact, and an 8-pin of the monostable relay 40 is the second normally open contact.

[0054] In the non-excitation state, the first common contact is connected with the first normally closed contact, and the second common contact is connected with the second normally closed contact.

[0055] In the excitation state, the first common contact is connected with the first normally open contact, and the second common contact is connected with the second normally open contact.

[0056] It should be noted that when the monostable relay 40 is in a non-energized state, the monostable relay 40 does not have any control effect on the dual power backup switching circuit, and the dual power backup switching circuit remains in a default connection state, which greatly reduces the action time of the monostable relay 40, reduces mechanical fatigue, prolongs the service life of the monostable relay 40, and improves the reliability of the entire dual power backup switching circuit. It can also reduce the frequency of after-sales maintenance and replacement, and reduce maintenance costs.

[0057] Therefore, when the main power supply 10 is powered off, the monostable relay 40 can flexibly control the state of the monostable relay 40 by whether the control end is powered on, that is, the monostable relay 40 can be quickly switched from a non-energized state to an energized state to achieve fast response.

[0058] To ensure that the switching control unit 30 can quickly switch the monostable relay 40 from a non-energized state to an energized state, with reference to the accompanying drawings, Figure 2 The embodiment provides a circuit diagram of the switching control unit 30:

[0059] The switching control unit 30 further comprises a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4; and the first switch and the second switch are both triodes, that is, the first switch in the embodiment is preferably a first triode Q1, and the second switch is preferably a second triode Q2.

[0060] The control end VDD2 of the backup power supply 20 is connected with the first end of the first resistor R1 and the first end of the second resistor R2, respectively; the collector of the second triode Q2 is connected with the second end of the first resistor R1, the base of the second triode Q2 is connected with the second end of the second resistor R2, the emitter of the second triode Q2 and the collector of the first triode Q1 are respectively connected with the first end of the fourth resistor R4, and the second end of the fourth resistor R4 is connected with the first pin of the coil of the monostable relay 40.

[0061] The base of the first triode Q1 is connected with the second end of the third resistor R3, and the first end of the third resistor R3 is connected with the control end VDD1 of the main power supply 10; and the collector of the first triode Q1 is grounded.

[0062] When the monostable relay 40 is in a non-energized state, the first triode Q1 and the second triode Q2 are both turned on.

[0063] When the monostable relay 40 is in an energized state, the first triode Q1 is turned off, and the second triode Q2 is turned on.

[0064] In this way, when the main power supply 10 is powered on, no current passes through the controlled end of the monostable relay 40, and the monostable relay 40 is in a non-energized state; when the main power supply 10 is powered off, the current of the backup power supply 20 passes through the controlled end of the monostable relay 40, and the monostable relay 40 is in an energized state.

[0065] Specifically, when the dual-power backup switching circuit is powered on and normally operates, both the main power supply 10 and the backup power supply 20 are powered on, at this time, the first triode Q1 is turned on, and the second triode Q2 is turned on, causing the current of the main power supply 10 to pass through the third resistor R3 and the first triode Q1 in turn and then be grounded; similarly, the current of the backup power supply 20 passes through the first resistor R1, the second triode Q2, and the first triode Q1 in turn and then be grounded, causing no current to pass through the controlled end of the monostable relay 40, and further causing the monostable relay 40 to be in a non-energized state, and the electrical equipment 50 is powered by the main power supply 10 to normally operate;

[0066] When the main power supply 10 is powered off, at this time, the second triode Q2 is turned on, and the first triode Q1 is turned off, the current of the main power supply 10 cannot pass through the first triode Q1 to the monostable relay 40, and the current of the backup power supply 20 passes through the first resistor R1, the second triode Q2, and the fourth resistor R4 in turn and then enters the monostable relay 40, causing the monostable relay 40 to switch from a non-energized state to an energized state, at this time, the electrical equipment 50 is powered by the backup power supply 20 to normally operate; when the main power supply 10 is powered on again, the first triode Q1 is turned on again, no current passes through the controlled end of the monostable relay 40 again, and further causing the monostable relay 40 to switch from an energized state to a non-energized state again, and the electrical equipment 50 is powered by the main power supply 10 to normally operate.

[0067] Among them, in order to control the working state of the monostable relay 40 through the second triode Q2 and the first triode Q1, the first triode Q1 and the second triode Q2 are both NPN type triodes.

[0068] Among them, the main power supply 10 and the backup power supply 20 are both AC-DC power supplies.

[0069] In this way, the main power supply 10 and the backup power supply 20 can provide reliable power support for the components or electrical equipment 50 in the dual-power backup switching circuit through efficient electric energy conversion and stable output.

[0070] Among them, the first resistor R1, the second resistor R2, and the third resistor R3 are all voltage dividing resistors. Further reducing the influence of voltage fluctuation on the dual-power backup switching circuit, improving the stability and reliability of the dual-power backup switching circuit, and also preventing the components in the dual-power backup switching circuit from being damaged by transient voltage impact.

[0071] Embodiment 2

[0072] To better limit the current flowing to the controlled end of the monostable relay 40 when the monostable relay 40 is switched to the excited state, referring to the attached Figure 3 , the fourth resistor is provided with multiple, and multiple fourth resistors are arranged in series.

[0073] In this embodiment, the fourth resistor is preferably two, namely the fourth resistor R4 and the fourth resistor R4', and the fourth resistor R4 and the fourth resistor R4' are arranged in series.

[0074] To further reduce the influence of voltage fluctuation on the dual power backup switching circuit, improve the stability and reliability of the dual power backup switching circuit, and prevent the components in the dual power backup switching circuit from being damaged by transient voltage impact, referring to the attached Figure 3 , the first resistor, the second resistor and the third resistor are each provided with multiple, and multiple first resistors, multiple second resistors and multiple third resistors are each arranged in series / parallel.

[0075] It should be noted that the first resistor in this embodiment is exemplified by two, namely the first resistor R1 and the first resistor R1', and the first resistor R1 and the first resistor R1' are arranged in series; the second resistor in this embodiment is exemplified by two, namely the second resistor R2 and the second resistor R2', and the second resistor R2 and the second resistor R2' are arranged in series; and the third resistor in this embodiment is exemplified by two, namely the third resistor R3 and the third resistor R3', and the third resistor R3 and the third resistor R3' are arranged in parallel.

[0076] Specifically, another driving control circuit provided in this embodiment is as follows:

[0077] The main power supply 10; the backup power supply 20; the first triode Q1, the second triode Q2, the first resistor R1, the first resistor R1', the second resistor R2, the second resistor R2', the third resistor R3, the third resistor R3', the fourth resistor R4 and the fourth resistor R4' constituting the switching control unit 30; the 8-pin monostable relay 40;

[0078] The control end VDD2 of the backup power supply 20 is connected with the first end of the first resistor R1 and the first end of the second resistor R2 respectively; the second end of the first resistor R1 is connected with the first end of the first resistor R1', and the second end of the second resistor R2 is connected with the first end of the second resistor R2'; the collector of the second triode Q2 is connected with the second end of the first resistor R1', the base of the second triode Q2 is connected with the second end of the second resistor R2', the emitter of the second triode Q2 and the collector of the first triode Q1 are connected with the first end of the fourth resistor R4 respectively, the second end of the fourth resistor R4 is connected with the first end of the fourth resistor R4', and the second end of the fourth resistor R4' is connected with the first pin of the coil of the monostable relay 40;

[0079] The base of the first triode Q1 is connected with the second end of the third resistor R3 and the second end of the third resistor R3' respectively, and the first end of the third resistor R3 and the first end of the third resistor R3' are connected with the control end VDD1 of the main power supply 10 respectively; the collector of the first triode Q1 and the second pin of the coil of the monostable relay 40 are grounded.

[0080] The first common contact of the monostable relay 40 is connected with the power supply end of the electric equipment 50, the first normally open contact of the monostable relay 40 is connected with the first power supply end B_DC1 of the backup power supply 20, the first normally closed contact of the monostable relay 40 is connected with the first power supply end M_DC1 of the main power supply 10, the second common contact of the monostable relay 40 is connected with the power supply end of the main control MCU 60, the second normally open contact of the monostable relay 40 is connected with the second power supply end B_DC2 of the backup power supply 20, the second normally closed contact of the monostable relay 40 is connected with the second power supply end M_DC2 of the main power supply 10, and the control end of the main control MCU 60 is connected with the input end of the electric equipment 50.

[0081] It should be noted that the first pin of the coil of the monostable relay 40 in the embodiment is equivalent to one end of the controlled end of the monostable relay 40, the second pin of the coil of the monostable relay 40 is equivalent to the other end of the controlled end of the monostable relay 40, the first triode Q1 is equivalent to the first switch, and the second triode Q2 is equivalent to the second switch.

[0082] Embodiment 3

[0083] The utility model discloses further put forward a kind of intelligent equipment, and the intelligent equipment includes the dual power backup switching circuit described above.

[0084] Therefore, when the intelligent device is powered on and normally operated, the corresponding dual power backup switching circuit is also powered on and normally operated, at this time, the monostable relay 40 is in a non-excitation state, so that the mechanical structure inside the monostable relay 40 does not have to bear the continuous force for a long time, greatly reducing the action time of the monostable relay 40, reducing mechanical fatigue, prolonging the service life of the monostable relay 40, and further improving the stability of the dual power backup switching circuit, reducing the frequency of after-sales maintenance and replacement, and reducing the maintenance cost.

[0085] Obviously, the above-described embodiments are only a part of the embodiments of the present application, rather than all the embodiments, and the preferred embodiments of the present application are given in the drawings, but do not limit the patent scope of the present application. The present application can be realized in many different forms, and conversely, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing specific embodiments, or equivalently replace some technical features. Any equivalent structure made by using the content of the present application specification and drawings, directly or indirectly applied to other related technical fields, is also within the patent protection scope of the present application.

Claims

1. A dual power backup switching circuit comprising a main power source and a backup power source for supplying power to an electrical device, characterized by, Also included are: A monostable relay having a controlled end with a first branch connected in series between the main power supply and the electrical device, and a second branch connected in series between the backup power supply and the electrical device, the controlled end of the monostable relay being in an off state when the first branch is turned on; A switching control unit having a first switch connected to the main power supply and a second switch connected to the backup power supply, the controlled end of the monostable relay being connected between the first switch and the second switch.

2. The dual supply backup switching circuit of claim 1, wherein, The monostable relay further includes: A first common contact, a second common contact, a first normally closed contact, and a second normally closed contact constituting the first branch; a first common contact, a second common contact, a first normally open contact, and a second normally open contact constituting the second branch; One end of the controlled end is connected to the output end of the switching control unit, the other end of the controlled end is grounded, the first common contact is connected to the electrical device, the first normally open contact is connected to the first power supply end of the backup power supply, the first normally closed contact is connected to the first power supply end of the main power supply, the second common contact is used to be connected to the main control MCU, the second normally open contact is connected to the second power supply end of the backup power supply, and the second normally closed contact is connected to the second power supply end of the main power supply.

3. The dual supply backup switching circuit of claim 2, wherein, The monostable relay includes a non-energized state and an energized state; The non-energized state is that the first common contact is connected to the first normally closed contact, and the second common contact is connected to the second normally closed contact; The energized state is that the first common contact is connected to the first normally open contact, and the second common contact is connected to the second normally open contact.

4. The dual supply backup switching circuit of claim 1, wherein, The switching control unit further includes a first resistor, a second resistor, a third resistor, and a fourth resistor; and the first switch and the second switch are both triodes; The control end of the backup power supply is connected to the first end of the first resistor and the first end of the second resistor, respectively; the collector of the second switch is connected to the second end of the first resistor, the base of the second switch is connected to the second end of the second resistor, the emitter of the second switch and the collector of the first switch are respectively connected to the first end of the fourth resistor, and the second end of the fourth resistor is connected to the controlled end of the monostable relay; The base of the first switch is connected to the second end of the third resistor, and the first end of the third resistor is connected to the control end of the main power supply; and the collector of the first switch is grounded.

5. The dual supply backup switching circuit of claim 4, wherein, When the monostable relay is in the non-energized state, both the first switch and the second switch are turned on; When the monostable relay is in the energized state, the first switch is turned off and the second switch is turned on.

6. The dual supply backup switching circuit of claim 4, wherein, The first switch and the second switch are both NPN triodes.

7. The dual supply backup switching circuit of claim 4, wherein, The fourth resistor is provided in multiple, and the multiple fourth resistors are connected in series.

8. The dual supply backup switching circuit of claim 4, wherein, The main power supply and the backup power supply are both AC-DC power supplies.

9. The dual supply backup switching circuit of claim 4, wherein, The first resistor, the second resistor, and the third resistor are each provided in multiple, and the multiple first resistors, the multiple second resistors, and the multiple third resistors are respectively connected in series / parallel.

10. A smart device, comprising: The intelligent device comprises the dual power backup switching circuit according to any one of claims 1-9.

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