Dual-power supply backup circuit, backup method, and vehicle

Abstract

The present invention relates to the field of power management of vehicles. A dual-power supply backup circuit of the present invention comprises a first power supply, a second power supply, a first load, and a second load. An output end of the first power supply is connected to the first load by means of a first one-way conduction element, and an output end of the second power supply is connected to the second load by means of a second one-way conduction element. The dual-power supply backup circuit further comprises a first switching circuit and a second switching circuit. When it is detected that an output voltage of the second power supply is lower than a preset threshold, the first switching circuit is controlled to be switched on, so that the first power supply supplies power to the second load by means of the first switching circuit; and when it is detected that an output voltage of the first power supply is lower than the preset threshold, the second switching circuit is controlled to be switched on, so that the second power supply supplies power to the first load by means of the second switching circuit. The circuit of the present invention is simple, costs are low, and mutual backup between power supplies is achieved.

Description

Dual power supply backup circuit, backup method and vehicle

[0001] This application claims priority to Chinese patent application No. 202311769609.0, filed on December 20, 2023, entitled “A dual-power supply backup circuit, backup method and vehicle”. The entire contents of the above Chinese patent application are incorporated into this application by reference. Technical Field

[0002] The present invention relates to the field of power management of vehicles, and specifically provides a dual-power backup circuit, a backup method and a vehicle. Background Art

[0003] With the development of electric vehicles, motor controllers are widely used, and the power supply method of motor control is also receiving more and more attention, especially when using permanent magnet synchronous motors. When the vehicle is driving, when the small battery KL30 is lost, the permanent magnet motor is in power generation mode and charges the bus capacitor. When the bus voltage is too high, it will damage the controller. The existing circuit structure is expensive because it is suitable for high-voltage devices. It is necessary to develop a simple and low-cost circuit structure to achieve mutual power backup. Summary of the Invention

[0004] In order to overcome the above-mentioned defects, the present invention proposes a dual-power backup circuit, a backup method and a vehicle. The circuit structure of the present invention is simple and the cost is low.

[0005] In a first aspect, the present invention provides a dual-power supply backup circuit, comprising a first power supply, a second power supply, a first load, and a second load, wherein the output end of the first power supply is connected to the first load through a first unidirectional conduction element, and the output end of the second power supply is connected to the second load through a second unidirectional conduction element, and further comprising a first switching circuit and a second switching circuit, wherein, when it is detected that the output voltage of the second power supply is lower than a preset threshold, the first switching circuit is controlled to be turned on so that the first power supply supplies power to the second load through the first switching circuit, and when it is detected that the output voltage of the first power supply is lower than the preset threshold, the second switching circuit is controlled to be turned on so that the second power supply supplies power to the first load through the second switching circuit.

[0006] In one technical solution of the above circuit, the forward conducting end of the first unidirectional conducting element is connected to the output end of the first power supply, and the reverse blocking end of the first unidirectional conducting element is connected to the first load; the forward conducting end of the second unidirectional conducting element is connected to the output end of the second power supply, and the reverse blocking end of the second unidirectional conducting element is connected to the second load.

[0007] In one technical solution of the above circuit, the circuit includes a first detection circuit and a second detection circuit, the first switching circuit includes a first switching element and a third unidirectional conducting element, wherein the first detection circuit is connected to the output terminal of the second power supply for obtaining the output voltage of the second power supply, the first end of the first switching element is connected to the first detection circuit, the second end of the first switching element is connected to the reverse blocking end of the first unidirectional conducting element, the third end of the first switching element is connected to the forward blocking end of the third unidirectional conducting element, the reverse blocking end of the third unidirectional conducting element is connected to the reverse blocking end of the second unidirectional conducting element, and the first end of the second unidirectional conducting element is connected to the output terminal of the first power supply;

[0008] The second switching circuit includes a second switching element and a fourth unidirectional conducting element, wherein the second detection circuit is connected to the output end of the first power supply for obtaining the output voltage of the first power supply, the first end of the second switching element is connected to the second detection circuit, the second end of the second switching element is connected to the reverse cut-off end of the second unidirectional conducting element, the forward cut-off end of the second unidirectional conducting element is connected to the second power supply, the third end of the second switching element is connected to the forward cut-off end of the fourth unidirectional conducting element, the reverse cut-off end of the fourth unidirectional conducting element is connected to the reverse cut-off end of the first unidirectional conducting element, and the forward cut-off end of the first unidirectional conducting element is connected to the first power supply.

[0009] In a technical solution of the above circuit, the first switching element and the second switching element are efuse, MOS tube, IGBT tube or triode; the first unidirectional conducting element, the second unidirectional conducting element, the third unidirectional conducting element and the fourth unidirectional conducting element are diodes.

[0010] In one technical solution of the above circuit, the first switching element is a MOS transistor, the input end of the first switching element is connected to the cathode of the first unidirectional conducting element, the output end of the first switching element is connected to the anode of the third unidirectional conducting element, the control end of the first switching element receives a control signal to change the operating state of the first switching element, and the cathode of the third unidirectional conducting element is connected to the cathode of the second unidirectional conducting element;

[0011] The second switching element is a MOS tube, the input end of the second switching element is connected to the cathode of the second unidirectional conducting element, the output end of the second switching element is connected to the anode of the fourth unidirectional conducting element, the control end of the second switching element receives a control signal to change the working state of the second switching element, and the cathode of the fourth unidirectional conducting element is connected to the cathode of the first unidirectional conducting element.

[0012] In one technical solution of the above circuit, the first load includes a first DC-DC converter and a first driver, wherein the first DC-DC converter is used to receive a first voltage signal output by a first power supply and convert the first voltage signal into a second voltage signal, and the first driver is used to receive the second voltage signal, an input end of the first DC-DC converter is connected to the reverse cutoff end of the first unidirectional conducting element, and an output end of the first DC-DC converter is connected to the first driver;

[0013] The second load includes a second DC-DC converter and a second driver, wherein the second DC-DC converter is used to receive a third voltage signal output by the second power supply and convert the third voltage signal into a fourth voltage signal, and the second driver is used to receive the fourth voltage signal. The input end of the second DC-DC converter is connected to the reverse cut-off end of the second unidirectional conducting element, and the output end of the second DC-DC converter is connected to the second driver.

[0014] In a technical solution of the above circuit, the first DC-DC converter and the second DC-DC converter are single-ended flyback DC-DC converters.

[0015] In a technical solution of the above circuit, the first power supply and the second power supply are respectively a DC-DC power supply and an auxiliary power supply or respectively an auxiliary power supply and a DC-DC power supply.

[0016] In a second aspect, the present invention provides a backup method for a backup circuit of a dual power supply, comprising: when it is detected that the output voltage of the second power supply is lower than a preset threshold, controlling a first switching circuit to be turned on so that the first power supply supplies power to a second load through the first switching circuit;

[0017] When it is detected that the output voltage of the first power supply is lower than a preset threshold, the second switching circuit is controlled to be turned on, so that the second power supply supplies power to the first load through the second switching circuit.

[0018] In one technical solution of the above method, when it is detected that the output voltage of the second power supply is lower than a preset threshold, controlling the first switching circuit to be turned on so that the first power supply supplies power to the second load through the first switching circuit further includes:

[0019] Control the first power supply to supply power to the first load through the conductive first unidirectional conductive element;

[0020] When it is detected that the output voltage of the first power supply is lower than a preset threshold, controlling the second switching circuit to be turned on so that the second power supply supplies power to the first load through the second switching circuit further includes:

[0021] The second power supply is controlled to supply power to the second load through the conductive second unidirectional conducting element.

[0022] In a third aspect, the present invention provides a vehicle comprising the circuit according to the first aspect.

[0023] The above one or more technical solutions of the present invention have at least one or more of the following beneficial effects:

[0024] In the technical solution implementing the present invention, a unidirectional conducting element and a switching element are connected in series to form two switching circuits, including a first switching circuit and a second switching circuit. When a power failure is detected in one power source, power is switched to the other power source. The present invention has a simple circuit structure and low cost, and achieves dual power backup. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The disclosure of the present invention will be more easily understood with reference to the accompanying drawings. Those skilled in the art will readily appreciate that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Furthermore, similar numbers in the drawings represent similar components, wherein:

[0026] FIG1 is a schematic diagram of the main components of a dual power backup circuit according to an embodiment of the present invention;

[0027] FIG2 is a schematic diagram of the main components of a dual power backup circuit according to an embodiment of the present invention;

[0028] FIG3 is a schematic diagram of the main components of a comparative circuit according to the present invention;

[0029] FIG4 is a schematic diagram of the main flow of a backup method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] Some embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0031] As shown in Figure 1, the present invention provides a dual-power backup circuit, including a first power supply V1, a second power supply V2, a first load R1, and a second load R2, wherein the output end of the first power supply V1 is connected to the first load R1 through a first unidirectional conducting element D1, and the output end of the second power supply V2 is connected to the second load R2 through a second unidirectional conducting element D2. The circuit also includes a first switching circuit and a second switching circuit, wherein when it is detected that the output voltage of the second power supply V2 is lower than a preset threshold, the first switching circuit is controlled to be turned on so that the first power supply V1 supplies power to the second load R2 through the first switching circuit; when it is detected that the output voltage of the first power supply V1 is lower than the preset threshold, the second switching circuit is controlled to be turned on so that the second power supply V2 supplies power to the first load R1 through the second switching circuit.

[0032] In one embodiment, the forward conducting end of the first unidirectional conducting element D1 is connected to the output end of the first power supply V1, and the reverse blocking end of the first unidirectional conducting element D1 is connected to the first load R1; the forward conducting end of the second unidirectional conducting element D2 is connected to the output end of the second power supply V2, and the reverse blocking end of the second unidirectional conducting element D2 is connected to the second load R2.

[0033] The present invention provides two switching circuits, including a first switching circuit and a second switching circuit, for switching to another power supply to realize power supply when a failure of one power supply is detected.

[0034] The first power supply V1 and the second power supply V2 can back up each other. When one power supply fails, the corresponding switching circuit is started to maintain power supply.

[0035] Under normal operation, the first power supply V1 supplies power to the first load R1, and the second power supply V2 supplies power to the second load R2. The first switching circuit monitors the output voltage of the second power supply V2 in real time, and the second switching circuit monitors the output voltage of the first power supply V1 in real time. If the first switching circuit detects an abnormal output voltage of the second power supply V2, i.e., the output voltage of the second power supply V2 is below a preset threshold, such as a power failure, indicating that the second power supply V2 is unable to properly supply power to the second load R2. In this case, the second load R2 lacks a power source. The first switching circuit is then controlled to conduct. Once the first switching circuit is established, the first power supply V1, which is in a normal state, supplies power to the second load R2 through the first switching circuit. In this way, the first power supply V1 maintains normal power supply to the first load R1 through the normal operation of the path and the first unidirectional conducting element D1. Furthermore, the first power supply V1 supplies power to the second load R2 through the conducting first switching circuit. Thus, even though the second power supply V2 is unable to supply power to the second load R2 due to a power failure, the first power supply V1 can still serve as a backup power source to provide power to the second load R2. Similarly, when it is detected that the first power supply V1 has lost power, it means that the first power supply V1 cannot normally supply power to the first load R1. At this time, the first load R1 has no power source, so the second switching circuit is controlled to be turned on. After the second switching circuit becomes a path, the second power supply V2 in a normal state is used to supply power to the first load R1 through the path of the second switching circuit. In this way, the second power supply V2 maintains normal power supply to the second load R2 through the normally operating path and the second unidirectional conducting element D2. In addition, the second power supply V2 supplies power to the first load R1 through the conductive second switching circuit. In this way, although the second power supply V2 loses power and cannot supply power to the first load R1, the second power supply V2 can be used as a backup power supply to supplement the power supply to the second power supply V2.

[0036] In one embodiment, the circuit includes a first detection circuit and a second detection circuit, the first switching circuit includes a first switching element T1 and a third unidirectional conducting element D3, wherein the first detection circuit is connected to the output end of the second power supply for obtaining the output voltage of the second power supply V2, the first end of the first switching element T1 is connected to the first detection circuit, the second end of the first switching element T1 is connected to the reverse cut-off end of the first unidirectional conducting element D1, the third end of the first switching element T1 is connected to the forward cut-off end of the third unidirectional conducting element D3, the reverse cut-off end of the third unidirectional conducting element D1 is connected to the reverse cut-off end of the second unidirectional conducting element D2, and the first end of the second unidirectional conducting element D2 is connected to the output end of the first power supply V1;

[0037] The second switching circuit includes a second switch element T2 and a fourth unidirectional conducting element D4, wherein the second detection circuit is connected to the output end of the first power supply V1 for obtaining the output voltage of the first power supply V1, the first end of the second switch element T2 is connected to the second detection circuit, the second end of the second switch element T2 is connected to the reverse cut-off end of the second unidirectional conducting element D2, the forward cut-off end of the second unidirectional conducting element D2 is connected to the second power supply V2, the third end of the second switch element T2 is connected to the forward cut-off end of the fourth unidirectional conducting element D4, the reverse cut-off end of the fourth unidirectional conducting element D4 is connected to the reverse cut-off end of the first unidirectional conducting element D1, and the forward cut-off end of the first unidirectional conducting element D1 is connected to the first power supply V1.

[0038] Still referring to FIG. 1 , after the first switching circuit is turned on, the first switch element T1 is closed, and the current flows to: the first power supply V1 , the first switch element T1 , the third unidirectional conducting element D3 , and the second load R2 .

[0039] After the second switching circuit is turned on, the first switch element T1 is closed, and the current flows to: the second power supply V2, the second switch element T2, the fourth unidirectional conducting element D4, and the first load R1.

[0040] In one embodiment, the first switching element is an efuse, a MOS tube, an IGBT tube or a triode. The efuse is an electronic fuse.

[0041] In one application scenario, the first switching element is efuse, and two ends of the first switching element efuse are respectively connected to the reverse cutoff end of the first unidirectional conducting element D1 and the forward conducting end of the third unidirectional conducting element D3.

[0042] In one embodiment, the second switching element is an efuse, a MOS tube, an IGBT tube or a triode.

[0043] In one application scenario, the second switch element is an efuse, and two ends of the second switch element efuse2 are respectively connected to the reverse blocking end of the second unidirectional conducting element D2 and the forward conducting end of the fourth unidirectional conducting element D4.

[0044] The first unidirectional conducting element, the second unidirectional conducting element, the third unidirectional conducting element, and the fourth unidirectional conducting element are diodes.

[0045] The forward conducting end of the unidirectional conducting element is the anode of the diode, and the reverse blocking end of the unidirectional conducting element is the cathode of the diode.

[0046] In one embodiment, the first switching element is a MOS transistor, the input end of the first switching element T1 is connected to the cathode of the first unidirectional conducting element (first diode) D1, the output end of the first switching element T1 is connected to the anode of the third unidirectional conducting element (third diode) D3, the control end of the first switching element T1 receives a control signal to change the working state of the first switching element T1, and the cathode of the third unidirectional conducting element is connected to the cathode of the second unidirectional conducting element.

[0047] In one embodiment, a protection diode is connected in parallel to the MOS transistor corresponding to the first switching element T1. The drain of the MOS transistor is connected to the cathode of the protection diode, and the source of the MOS transistor is connected to the anode of the protection diode. The protection diode can direct excessive voltage or reverse voltage to ground or normal output, thereby protecting the MOS transistor from electrostatic breakdown. In addition, the protection diode can effectively improve the recovery time of the MOS transistor.

[0048] In one embodiment, the second switch element T2 is a MOS transistor, the input end of the second switch element T2 is connected to the cathode of the second unidirectional conducting element (second diode) D2, the output end of the second switch element T2 is connected to the anode of the fourth unidirectional conducting element (fourth diode) D4, the control end of the second switch element T2 receives a control signal to change the working state of the second switch element T2, and the cathode of the fourth unidirectional conducting element is connected to the cathode of the first unidirectional conducting element.

[0049] In one embodiment, the MOS transistor corresponding to the second switch element T2 is connected in parallel with a protection diode, the drain of the MOS transistor is connected to the cathode of the protection diode, the source of the MOS transistor is connected to the anode of the protection diode, and the drain of the MOS transistor is connected to the cathode of the protection diode.

[0050] In one embodiment, referring to FIG2 , the first load includes a first DC-DC converter and a first driver, wherein the first DC-DC converter is configured to receive a first voltage signal output by a first power supply V1 and convert the first voltage signal into a second voltage signal, and the first driver is configured to receive the second voltage signal. An input end of the first DC-DC converter is connected to a reverse cutoff end of a first unidirectional conducting element D1, and an output end of the first DC-DC converter is connected to the first driver.

[0051] The second load includes a second DC-DC converter and a second driver, wherein the second DC-DC converter is used to receive a third voltage signal output by the second power supply V2 and convert the third voltage signal into a fourth voltage signal, and the second driver is used to receive the fourth voltage signal. The input end of the second DC-DC converter is connected to the reverse cut-off end of the second unidirectional conducting element D2, and the output end of the second DC-DC converter is connected to the second driver.

[0052] In one embodiment, the first driver and the second driver are used to power the IGBT.

[0053] In one embodiment, the output end of the first driver is connected to the third switching element T3, the fourth switching element T4, and the fifth switching element T5, and the first driver is used to supply power to the third switching element T3, the fourth switching element T4, and the fifth switching element T5 respectively.

[0054] The output end of the second driver is connected to the sixth switching element T6, the seventh switching element T7 and the eighth switching element T8, and the second driver is used to supply power to the sixth switching element T6, the seventh switching element T7 and the eighth switching element T8 respectively.

[0055] In one embodiment, the third to eighth switching elements T3 to T8 are all IGBTs. A capacitor C1 is connected between the input end of the third switching element T3 and the output end of the sixth switching element T6. The output end of the third switching element T3 and the input end of the sixth switching element T6 are commonly connected to the first phase line of the motor. The common connection point is shown in A in FIG2 . The input end of the fourth switching element T4 is connected to the input end of the third switching element T3. The output end of the fourth switching element T4 and the input end of the seventh switching element T7 are commonly connected to the second phase line of the motor. The common connection point is shown in B in FIG2 . The input end of the fifth switching element T5 is connected to the input end of the fourth switching element T4. The output end of the fifth switching element T5 is connected to the input end of the eighth switching element T8 and are commonly connected to the third phase line of the motor. The output end of the eighth switching element T8 is connected to the output end of the seventh switching element T7. The common connection point is shown in C in FIG2 . The control ends of the fourth to eighth switching elements T4 to T8 each receive a control signal to change their operating state. In this embodiment, the third switching element T3 to the fifth switching element T5 are three upper-bridge IGBTs, and the sixth switching element T6 to the eighth switching element T8 are three lower-bridge IGBTs.

[0056] In one embodiment, the first DC-DC converter is a single-ended flyback DC-DC converter; and the second DC-DC converter is a single-ended flyback DC-DC converter.

[0057] In one embodiment, the first power supply and the second power supply are respectively a DC-DC power supply and an auxiliary power supply or respectively an auxiliary power supply and a DC-DC power supply.

[0058] In one embodiment, the auxiliary power source is a battery. In one application scenario, it can specifically be a KL30 battery.

[0059] This invention utilizes the voltage signal transformation function of the DC-DC converter. After drawing power from a DC-DC power supply and an auxiliary power supply, such as a small KL30 battery, it supplies power to three upper-bridge IGBTs and three lower-bridge IGBTs via two flyback circuits. The DC-DC power supply and the auxiliary power supply provide mutual backup, jointly implementing the vehicle's ASC (Active Stability Control) function.

[0060] In one application scenario, the present invention uses two simple unidirectional EFUSE1 (first switching element T1) and EFUSE2 (second switching element T2) with diodes D3 and D4 connected in series, respectively. When the DC-DC (first power supply V1) output 12V power failure is detected, the switch of EFUSE2 is closed, and KL30 (first power supply V2) supplies power to flyback1 through EFUSE2 and D4. When the output 12V of KL30 is detected to be power failure, the switch of EFUSE1 is closed, and the DC-DC IN supplies power to flyback2 through Efuse1 and D3, thereby achieving mutual backup of the two power supplies. This circuit structure is simple and low-cost.

[0061] Comparative Example 1

[0062] Referring to Figure 3 , the circuit in this comparative example is as follows: power is supplied from the busbar through a high-voltage flyback to the three upper-bridge IGBTs, while power is supplied to the three lower-bridge IGBTs via a low-voltage flyback after drawing power from the KL30. If the KL30 is lost during driving, hardware triggers the closure of the upper three transistors (the three upper-bridge IGBTs) to discharge the motor's energy. The use of high-voltage flyback necessitates the use of high-voltage components, which results in relatively high costs.

[0063] By comparing the embodiment of the present invention with the technical solution of Comparative Example 1, it can be seen that the present invention can achieve mutual power backup with a simpler structural circuit and lower cost.

[0064] The present invention also provides a backup method for a dual power backup circuit, referring to FIG4 , comprising:

[0065] S10, when it is detected that the output voltage of the second power supply V2 is lower than the preset threshold, the first switching circuit is controlled to be turned on, so that the first power supply V1 supplies power to the second load R2 through the first switching circuit;

[0066] S20 , when it is detected that the output voltage of the first power supply V1 is lower than a preset threshold, the second switching circuit is controlled to be turned on, so that the second power supply V2 supplies power to the first load R1 through the second switching circuit.

[0067] The step S20, wherein when it is detected that the output voltage of the second power supply V2 is lower than a preset threshold, controlling the first switching circuit to be turned on so that the first power supply V1 supplies power to the second load R2 through the first switching circuit, further includes:

[0068] Control the first power supply V1 to supply power to the first load R1 through the conductive first unidirectional conducting element D1;

[0069] The step S20, in which, when it is detected that the output voltage of the first power supply V1 is lower than a preset threshold, the second switching circuit is controlled to be turned on so that the second power supply V2 supplies power to the second load R2 through the second switching circuit, further includes:

[0070] The second power source V2 is controlled to supply power to the second load R2 through the conductive second unidirectional conducting element D2.

[0071] In the present invention, when the first switching circuit detects that the output voltage of the second power supply V2 is lower than a preset threshold, indicating that the second power supply V2 cannot normally supply power to the second load R2, the first switching circuit is controlled to be turned on, so that the first power supply V1 maintains normal power supply to the first load R1 through a normally operating path. In addition, the first power supply V1 supplies power to the second load R2 through the turned-on first switching circuit, so that the first power supply V1 can serve as a backup power supply to provide power to the second load R2.

[0072] When it is detected that the first power supply V1 cannot normally supply power to the first load R1, the second switching circuit is controlled to be turned on. After the second switching circuit becomes a path, the second power supply V2 supplies power to the first load R1 through the path of the second switching circuit. In this way, the second power supply V2 maintains normal power supply to the second load R2 through the normally operating path. In addition, the second power supply V2 supplies power to the first load R1 through the conducted second switching circuit.

[0073] In this way, in the entire circuit, both the first load R1 and the second load R2 can meet the power supply requirements. When one power supply fails, the other power supply can be backed up by switching the circuit to supply power to the load corresponding to the failed power supply.

[0074] The present invention also provides a vehicle equipped with the circuit described above.

[0075] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A dual power backup circuit, comprising a first power supply, a second power supply, a first load and a second load, wherein: The output end of the first power supply is connected to the first load through a first unidirectional conduction element, and the output end of the second power supply is connected to the second load through a second unidirectional conduction element. It is characterized in that it also includes a first switching circuit and a second switching circuit, wherein when it is detected that the output voltage of the second power supply is lower than a preset threshold, the first switching circuit is controlled to be turned on, so that the first power supply supplies power to the second load through the first switching circuit; when it is detected that the output voltage of the first power supply is lower than the preset threshold, the second switching circuit is controlled to be turned on, so that the second power supply supplies power to the first load through the second switching circuit.

2. The circuit according to claim 1, characterized in that: The forward conducting end of the first unidirectional conducting element is connected to the output end of the first power supply, and the reverse blocking end of the first unidirectional conducting element is connected to the first load; the forward conducting end of the second unidirectional conducting element is connected to the output end of the second power supply, and the reverse blocking end of the second unidirectional conducting element is connected to the second load.

3. The circuit according to claim 1 or 2, characterized in that: The circuit includes a first detection circuit and a second detection circuit, the first switching circuit includes a first switch element and a third unidirectional conducting element, wherein the first detection circuit is connected to the output end of the second power supply to obtain the output voltage of the second power supply, the first end of the first switch element is connected to the first detection circuit, the second end of the first switch element is connected to the reverse cut-off end of the first unidirectional conducting element, the third end of the first switch element is connected to the forward conduction end of the third unidirectional conducting element, the reverse cut-off end of the third unidirectional conducting element is connected to the reverse cut-off end of the second unidirectional conducting element, and the first end of the second unidirectional conducting element is connected to the output end of the first power supply; The second switching circuit includes a second switch element and a fourth unidirectional conducting element, wherein the second detection circuit is connected to the output end of the first power supply for obtaining the output voltage of the first power supply, the first end of the second switch element is connected to the second detection circuit, the second end of the second switch element is connected to the reverse cut-off end of the second unidirectional conducting element, the forward conduction end of the second unidirectional conducting element is connected to the second power supply, the third end of the second switch element is connected to the forward conduction end of the fourth unidirectional conducting element, the reverse cut-off end of the fourth unidirectional conducting element is connected to the reverse cut-off end of the first unidirectional conducting element, and the forward conduction end of the first unidirectional conducting element is connected to the first power supply.

4. The circuit according to claim 3, characterized in that The first switch element and the second switch element are efuse, MOS tube, IGBT tube or triode; the first unidirectional conductive element, the second unidirectional conductive element, the third unidirectional conductive element and the fourth unidirectional conductive element are diodes.

5. The circuit according to claim 4, characterized in that The first switch element is a MOS tube, the input end of the first switch element is connected to the cathode of the first unidirectional conductive element, the output end of the first switch element is connected to the anode of the third unidirectional conductive element, the control end of the first switch element receives a control signal to change the working state of the first switch element, and the cathode of the third unidirectional conductive element is connected to the cathode of the second unidirectional conductive element; The second switch element is a MOS tube, the input end of the second switch element is connected to the cathode of the second unidirectional conductive element, the output end of the second switch element is connected to the anode of the fourth unidirectional conductive element, the control end of the second switch element receives a control signal to change the working state of the second switch element, and the cathode of the fourth unidirectional conductive element is connected to the cathode of the first unidirectional conductive element.

6. The circuit according to claim 1, characterized in that The first load includes a first DC-DC converter and a first driver, wherein the first DC-DC converter is used to receive a first voltage signal output by a first power supply and convert the first voltage signal into a second voltage signal, the first driver is used to receive the second voltage signal, the input end of the first DC-DC converter is connected to the reverse cut-off end of the first unidirectional conducting element, and the output end of the first DC-DC converter is connected to the first driver; The second load includes a second DC-DC converter and a second driver, wherein the second DC-DC converter is used to receive a third voltage signal output by a second power supply and convert the third voltage signal into a fourth voltage signal, the second driver is used to receive the fourth voltage signal, the input end of the second DC-DC converter is connected to the reverse cutoff end of the second unidirectional conducting element, and the output end of the second DC-DC converter is connected to the second driver.

7. The circuit according to claim 6, characterized in that The first DC-DC converter and the second DC-DC converter are single-ended flyback DC-DC converters.

8. The circuit according to claim 1, characterized in that The first power supply and the second power supply are respectively a DC-DC power supply and an auxiliary power supply or respectively an auxiliary power supply and a DC-DC power supply.

9. A backup method for a dual power backup circuit, characterized in that: include: When it is detected that the output voltage of the second power supply is lower than a preset threshold, the first switching circuit is controlled to be turned on, so that the first power supply supplies power to the second load through the first switching circuit; When it is detected that the output voltage of the first power supply is lower than a preset threshold, the second switching circuit is controlled to be turned on, so that the second power supply supplies power to the first load through the second switching circuit.

10. The method according to claim 9, characterized in that When it is detected that the output voltage of the second power supply is lower than a preset threshold, controlling the first switching circuit to be turned on so that the first power supply supplies power to the second load through the first switching circuit also includes: Control the first power supply to supply power to the first load through the first unidirectional conductive element; When it is detected that the output voltage of the first power supply is lower than a preset threshold, controlling the second switching circuit to be turned on so that the second power supply supplies power to the first load through the second switching circuit also includes: The second power supply is controlled to supply power to the second load through the conductive second unidirectional conducting element.

11. A vehicle, characterized in that: A circuit comprising the circuit according to any one of claims 1 to 10.

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