Vehicle power management system and power management method thereof

Abstract

The application discloses a vehicle power management system and a power management method thereof, and the power management method comprises the following steps: when a microcontroller receives a power-off signal, determining whether the voltage of the power-off signal is lower than a voltage threshold by the microcontroller; when the voltage of the power-off signal is lower than the voltage threshold, stopping the use of a vehicle power supply to supply power to a backup battery and starting to use the vehicle power supply to supply power to a rear-end load; starting a counter of the microcontroller; when the counting time of the counter reaches a first time threshold, stopping the use of the vehicle power supply to supply power to the rear-end load and starting to use the backup battery to supply power to the rear-end load; when the counting time reaches a second time threshold, transmitting the power-off signal to the rear-end load by the microcontroller; and when the counting time reaches a third time threshold, stopping the use of the backup battery to supply power to the rear-end load.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 420,467, filed in the United States on October 28, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a power management system and a power management method thereof, and more particularly to a power management system and a power management method applicable to vehicles. Background Technology

[0004] Currently, the power required for the operation of digital video recorders (DVRs) in vehicles and for starting the vehicle engine is provided by the vehicle's power supply. Because the computing power of digital video recorders and the power consumption of their peripheral components are relatively high, digital video recorders can only work properly when the vehicle engine is running.

[0005] Current environmental regulations require drivers to turn off the engine when a vehicle is parked on the side of the road, thus forcing the digital video recorder (DVR) to stop working. Furthermore, when drivers have installed other vehicle-mounted devices besides the DVR, this accelerates the depletion of the vehicle's power supply, often causing drivers to fail to notice insufficient power and be unable to restart the engine. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a vehicle power management system that addresses the shortcomings of existing technologies. This system is applicable to vehicle load devices and on-board power supplies, and is characterized by comprising a microcontroller, a charger, a first switching circuit, a second switching circuit, and a backup battery. The microcontroller is connected to the on-board power supply and the downstream load and includes a counter. The charger is connected to the microcontroller. The first switching circuit is connected to the charger, the microcontroller, and the on-board power supply, while the second switching circuit is connected to the microcontroller, the charger, and the downstream load. The backup battery is connected to the charger. When the microcontroller receives an ignition off signal from the on-board power supply, it determines whether the voltage of the ignition off signal is lower than a voltage threshold. When the voltage of the ignition off signal is lower than the voltage threshold, the charger stops using the on-board power supply to power the backup battery and uses the on-board power supply to power the downstream load. When the counter's counting time reaches a first time threshold, the charger stops using the on-board power supply to power the downstream load and switches to using the backup battery. When the counting time reaches a second time threshold, the microcontroller sends an ignition off signal to the downstream load. When the counting time reaches a third time threshold, the charger stops using the backup battery to power the downstream load.

[0007] Preferably, it further includes a light-emitting element connected to the microcontroller. When the microcontroller receives an ignition switch signal from the vehicle power supply, the microcontroller determines whether the voltage of the ignition switch signal is within a voltage threshold range. When the voltage of the ignition switch signal is within the voltage threshold range, the charger provides power from the vehicle power supply to the downstream load. When the voltage of the ignition switch signal is not within the voltage threshold range, the microcontroller causes the light-emitting element to emit light.

[0008] Preferably, when the voltage of the ignition switch signal is within the voltage threshold range and the backup battery is not saturated, the charger uses the vehicle power supply to power the backup battery.

[0009] Preferably, when the voltage of the switch-on signal is within the voltage threshold range, the microcontroller puts the second switching circuit into a conducting state; when the second switching circuit is in the conducting state, the microcontroller transmits the switch-on signal to the downstream load.

[0010] Preferably, when the back-end load receives the ignition switch open signal and the output voltage of the vehicle power supply is lower than a second voltage threshold, the microcontroller outputs the ignition switch closed signal to the back-end load.

[0011] Preferably, when the output power of the charger exceeds a power limit or the output current exceeds a current limit, the microcontroller puts the second switching circuit into a cut-off state.

[0012] The technical problem to be solved by the present invention is to provide a power management method for a vehicle power management system, which addresses the shortcomings of the prior art. The method includes: when a microcontroller receives an ignition switch off signal, the microcontroller determines whether the voltage of the ignition switch off signal is lower than a first voltage threshold; when the voltage of the ignition switch off signal is lower than the first voltage threshold, the use of an on-board power supply to power a backup battery is stopped, and the on-board power supply is used to power the downstream load; a counter of the microcontroller is started; when a counting time of the counter reaches a first time threshold, the use of the on-board power supply to power the downstream load is stopped, and the backup battery is used to power the downstream load instead; when the counting time reaches a second time threshold, the microcontroller transmits the ignition switch off signal to the downstream load; when the counting time reaches a third time threshold, the use of the backup battery to power the downstream load is stopped.

[0013] Preferably, it further includes monitoring an output voltage of the vehicle power supply, and when the output voltage of the vehicle power supply is lower than a second voltage threshold, the counter stops counting and stops using the vehicle power supply to power the downstream load.

[0014] Preferably, when the microcontroller receives a power switch open signal, the microcontroller determines whether the voltage of the power switch open signal is within a voltage threshold range. When the voltage of the power switch open signal is within the voltage threshold range, the microcontroller enables a power conversion component of a charger; when the voltage of the power switch open signal is not within the voltage threshold range, the microcontroller causes a light-emitting element to emit light.

[0015] Preferably, after enabling the power conversion component, it further includes determining whether the charge of a backup battery has reached a saturation state; when the charge of the backup battery has not reached a saturation state, the vehicle power supply is used to supply power to the backup battery.

[0016] Preferably, after the backup battery is powered by the vehicle power supply, the microcontroller sends the power switch signal to the back-end load.

[0017] Preferably, the method further includes determining whether an output voltage of a vehicle power supply is lower than a second voltage threshold after the ignition switch signal is transmitted to the back-end load; when the output voltage is lower than the second voltage threshold, the microcontroller outputs the ignition switch off signal to the back-end load.

[0018] One of the beneficial effects of the present invention is that the vehicle power management system and power management method provided by the present invention programmatically control the timing of the on-board power supply and the backup battery supplying power to the vehicle load equipment, as well as the timing of the ignition switch being turned off to the back-end load, so as to avoid the back-end load excessively consuming the power of the on-board power supply, thereby causing the on-board power supply to be insufficient to restart the engine that has been turned off.

[0019] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention. Attached Figure Description

[0020] Figure 1 This is a flowchart of an embodiment of the automatic diagnostic method for the vehicle power management system of the present invention.

[0021] Figure 2 This is a functional block diagram of an embodiment of the vehicle power management system of the present invention.

[0022] Figure 3 for Figure 2 A flowchart of an embodiment of a power management method for a vehicle power management system when an ignition switch is activated.

[0023] Figure 4A and Figure 4B for Figure 2A flowchart of another embodiment of the power management method for a vehicle power management system when an ignition switch event occurs.

[0024] Figure 5 for Figure 2 A flowchart of an embodiment of a power management method for a vehicle power management system when an ignition switch is turned off.

[0025] Figure 6A , Figure 6B and Figure 6C for Figure 2 A flowchart of another embodiment of the power management method for a vehicle power management system when an ignition switch is turned off. Detailed Implementation

[0026] The following specific embodiments illustrate the implementation of the "vehicle power management system and power management method" provided by the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content provided in this specification. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. Furthermore, the accompanying drawings of the present invention are for simple illustrative purposes only and are not depictions of actual dimensions; this is stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the content provided is not intended to limit the scope of protection of the present invention.

[0027] It should be understood that while terms such as "first," "second," and "third" may be used in this document to describe various components or signals, these components or signals should not be limited by these terms. These terms are primarily used to distinguish one component from another, or one signal from another. Furthermore, the term "or" as used herein should be interpreted to include, as appropriate, any combination of one or more of the related listed items.

[0028] When installing and outputting loads in a vehicle power management system, the following automatic diagnostic methods can be used to detect system anomalies and achieve energy-saving effects. Figure 1 This is a flowchart of an embodiment of the automatic diagnostic method for the vehicle power management system of the present invention. Regarding step S101, the wiring of the backup battery is connected to the microcontroller. Regarding step S103, the microcontroller and charger are initialized. Regarding step S105, the automatic diagnostic program is executed. Regarding step S107, it is determined whether the voltage of the backup battery meets the normal specifications. If it meets the normal specifications, proceed to step S109. If it does not meet the normal specifications, proceed to step S111.

[0029] Regarding step S109, the microcontroller and charger enter standby mode. Regarding step S111, the microcontroller causes the light-emitting element to illuminate. Specifically, the illumination of the light-emitting element serves as a warning that the backup battery voltage is abnormal.

[0030] Following step S109, proceed to step S113. In step S113, connect the vehicle power supply wiring to the microcontroller. In step S115, the microcontroller and charger enter standby mode. In step S117, execute the automatic diagnostic program. In step S119, determine if the vehicle power supply voltage meets normal specifications. If the vehicle power supply voltage meets normal specifications, proceed to step S121. If the vehicle power supply voltage does not meet normal specifications, proceed to step S123.

[0031] Regarding step S121, the microcontroller and charger enter standby mode. Regarding step S123, the microcontroller causes the light-emitting element to illuminate. Specifically, the illumination of the light-emitting element serves as a warning that the output voltage of the vehicle power supply is abnormal.

[0032] Following step S121, proceed to step S125. In step S125, the wiring of the downstream load is connected to the charger. In step S127, the wiring of the downstream load is connected to the microcontroller. In step S129, the microcontroller detects whether the power switch is on. If yes, proceed to step S131. If no, proceed to step S133. In step S131, the charger outputs power to the downstream load. In step S133, the microcontroller and charger enter standby mode. Following step S131, proceed to step S135. In step S135, the microcontroller determines whether the charger's output voltage or output current is abnormal. If yes, proceed to step S137. If no, proceed to step S139. In step S137, the microcontroller illuminates the light-emitting element and turns off the switch connecting the charger and the downstream load. In step S139, the charger enters normal operating mode and performs automatic system diagnostics at a fixed frequency. Following step S137, proceed to step S141. In step S141, the charger blocks the output and enters an alarm mode.

[0033] Figure 2 This is a functional block diagram of an embodiment of the vehicle power management system of the present invention. Figure 2 As shown, the vehicle power management system is applicable to an on-board power supply P and a back-end load L. The vehicle power management system includes, for example, a microcontroller 1, a charger 2, a first switching circuit 3, a second switching circuit 4, a backup battery 5, a light-emitting element 6, a first voltage detector VD1, a second voltage detector VD2, a power detector PD, and a power detector QD, but the present invention is not limited thereto.

[0034] The microcontroller 1 is connected to the vehicle power supply P, the first voltage detector VD1, the second voltage detector VD2, the power detector PD, the back-end load L, the charger 2, the first switching circuit 3, the light-emitting element 6, and the power detector QD, and the microcontroller 1 includes a counter 11.

[0035] Charger 2 is also connected to the first switching circuit 3, the second switching circuit 4, the backup battery 5, the second voltage detector VD2, and the power detector PD. The first switching circuit 3 is also connected to the vehicle power supply P and the second voltage detector VD2, while the second switching circuit 4 is also connected to charger 2, the power detector PD, and the downstream load L. The backup battery 5 is connected to the power detector QD and charger 2.

[0036] When the vehicle ignition switch, which is in the off state, is turned on, the vehicle power supply P outputs an ignition-on signal to the microcontroller 1. The microcontroller 1 then determines the voltage of the ignition-on signal via the first voltage detector VD1. Similarly, when the vehicle ignition switch, which is in the on state, is turned off, the vehicle power supply P outputs an ignition-off signal to the microcontroller 1. The microcontroller 1 then determines the voltage of the ignition-off signal via the first voltage detector VD1.

[0037] When counter 11 of microcontroller 1 is started, counter 11 begins counting. When counter 11 is turned off, counter 11 stops counting and clears the counting time.

[0038] Charger 2 includes a power conversion component, and microcontroller 1 enables or disables this component. When the power conversion component is enabled, charger 2 enters operating mode. When the power conversion component is disabled, charger 2 enters backup battery power supply mode. In backup battery power supply mode, although the vehicle's power management system has an onboard power source P connected, backup battery 5 is still used to supply power to the downstream output. At this time, charger 2 does not perform power conversion from onboard power source P to output power modulation; it only blocks the power from onboard power source P and opens the switch on the backup battery path to output power to the downstream.

[0039] When the power conversion component of charger 2 is enabled and microcontroller 1 detects via power sensor QD that the backup battery 5 is not fully charged, microcontroller 1 commands charger 2 to use the vehicle power supply P to power the downstream load L and the backup battery 5. When the power conversion component of charger 2 is enabled and microcontroller 1 detects via power sensor QD that the backup battery 5 is fully charged, microcontroller 1 commands charger 2 to use the vehicle power supply P to power the downstream load L. When the power conversion component of charger 2 is disabled and the backup battery 5 is not fully charged, microcontroller 1 commands charger 2 to stop using the vehicle power supply P to power the downstream load L and instead use the vehicle power supply P to power the backup battery 5.

[0040] The microcontroller 1 is used to control the first switching circuit 3 to be in an on or off state, and to control the second switching circuit 4 to be in an on or off state, and to drive the light-emitting element 6 to emit light. The light-emitting element 6 may include, for example, multiple light-emitting diodes of different colors, but the present invention is not limited thereto.

[0041] Figure 3 for Figure 2 A flowchart illustrating an embodiment of a power management method for a vehicle power management system when an ignition switch is activated. (See flowchart for example.) Figure 3 As shown, regarding step S301, microcontroller 1 receives a power switch open signal. Regarding step S303, microcontroller 1 determines whether the voltage of the power switch open signal is within a preset voltage threshold range. If yes, proceed to step S305. If no, proceed to step S307. Regarding step S305, microcontroller 1 enables the power conversion component of charger 2 to put charger 2 into operating mode. Regarding step S307, microcontroller 1 drives the light-emitting element 6 to a first light-emitting state. For example, when the light-emitting element 6 is in the first light-emitting state, the blue LED is constantly lit, while the green LED and red LED are in an off state.

[0042] Following step S305, proceed to step S309. In step S309, microcontroller 1 determines whether the backup battery 5 is fully charged. If yes, proceed to step S311. If no, proceed to step S313. In step S311, microcontroller 1 activates the second switching circuit 4. In step S313, microcontroller 1 commands charger 2 to supply power to the backup battery 5 using the vehicle power supply P.

[0043] Following step S311 is step S315. In step S315, microcontroller 1 commands charger 2 to use the vehicle power supply P to power the downstream load L.

[0044] Following step S313 is step S317. In step S317, the microcontroller 1 turns on the second switching circuit 4.

[0045] Following step S317, step S319 follows. In step S319, microcontroller 1 commands charger 2 to use the vehicle power supply P to power the downstream load L. Specifically, at this time, charger 2 uses the vehicle power supply P to simultaneously power both the downstream load L and the backup battery 5.

[0046] Following steps S315 and S319, step S321 follows. In step S321, microcontroller 1 outputs a power-on signal to the downstream load L.

[0047] Following step S321, step S323 follows. In step S323, the microcontroller 1 drives the light-emitting element 6 into a second emitting state. For example, when the light-emitting element 6 is in the second emitting state, the green diode is constantly lit, while the blue and red diodes are off.

[0048] Figure 4 is Figure 2 A flowchart of another embodiment of the power management method for a vehicle power management system when an ignition switch event occurs. Steps S401 to S423 in Figure 4 are the same as... Figure 3 Steps S301 to S323, the power management method in Figure 4 and Figure 3 The difference between the power management methods is that the power management method in Figure 4 further includes steps S425 to S433.

[0049] Following step S423, step S425 follows. In step S425, microcontroller 1 monitors the output power and output current of charger 2 via the power detector PD. In step S427, microcontroller 1 determines whether the output power does not exceed the power limit and whether the output current does not exceed the current limit. If the output power does not exceed the power limit and the output current does not exceed the current limit, it returns to step S425. If the output power exceeds the power limit and / or the output current exceeds the current limit, it proceeds to step S429. In step S429, microcontroller 1 puts the light-emitting element 6 into a third emitting state. For example, when the light-emitting element 6 is in the third emitting state, the red diode is constantly lit, while the blue and green diodes are off. In step S431, microcontroller 1 puts the second switching circuit 4 into a cutoff state.

[0050] Following step S423, step S433 follows. In step S433, microcontroller 1 monitors the output voltage of the vehicle power supply P via the second voltage detector VD2. In step S435, microcontroller 1 determines whether the output voltage of the vehicle power supply P is below a voltage threshold. If yes, proceed to step S437. If no, return to step S433.

[0051] Regarding step S437, the microcontroller 1 puts the light-emitting element 6 into a fourth light-emitting state. For example, when the light-emitting element 6 is in the fourth light-emitting state, the blue LED flashes, while the green LED and red LED are off.

[0052] Following step S437, step S439 follows. In step S439, microcontroller 1 outputs a power-off state to the downstream load L. In step S441, microcontroller 1 disables the power conversion components of charger 2 to put charger 2 into backup battery power mode. In step S443, microcontroller 1 shuts down the second switching circuit 4. For example, when the downstream load L is under heavy load, the output voltage of the vehicle power supply P will drop. When the output voltage of the vehicle power supply P falls below a preset voltage threshold, microcontroller 1 stops using the vehicle power supply P to power the downstream load L to prevent the power of the vehicle power supply P from being depleted by the downstream load L.

[0053] Figure 5 for Figure 2 A flowchart illustrating an embodiment of a power management method for a vehicle power management system when an ignition switch is turned off. (See flowchart for example.) Figure 5 As shown, regarding step S501, microcontroller 1 receives a power switch off signal. Regarding step S503, microcontroller 1 determines whether the voltage of the power switch off signal is lower than a voltage threshold. If yes, proceed to step S505. If no, the power management method ends. Regarding step S505, microcontroller 1 commands charger 2 to stop using the vehicle power supply P to power the backup battery 5 and to use the vehicle power supply P to power the downstream load L.

[0054] Following step S505, step S507 follows. In step S507, the counter 11 of the microcontroller 1 is started, and the output voltage of the vehicle power supply P is monitored via the second voltage detector VD2. In step S509, before the counter 11 reaches a first time threshold, the microcontroller 1 determines whether the output voltage of the vehicle power supply P is below a voltage threshold. If yes, proceed to step S511. If no, proceed to step S513.

[0055] Regarding step S511, the counter 11 of the microcontroller 1 stops counting, and the microcontroller 1 turns off the first switching circuit 3 and the second switching circuit 4. Regarding step S513, the counter 11 continues counting.

[0056] Following step S513 is step S515. In step S515, the counting time of counter 11 reaches the first time threshold.

[0057] Following step S515, step S517 follows. In step S517, microcontroller 1 disables the power conversion components of charger 2 to put charger 2 into backup battery power mode. In step S519, microcontroller 1 commands charger 2 to stop using the vehicle power supply P to power the downstream load L, and instead use the backup battery 5 to power the downstream load L. In step S521, microcontroller 1 puts the light-emitting element 6 into a fifth emitting state. For example, when the light-emitting element 6 is in the fifth emitting state, the green diode flashes, while the blue and red diodes are off.

[0058] Regarding step S523, the counting time of counter 11 reaches the second time threshold, where the second time threshold is greater than the first time threshold. Regarding step S525, microcontroller 1 outputs a power-off signal to the downstream load L and puts the light-emitting element 6 into the sixth emitting state. For example, when the light-emitting element 6 is in the sixth emitting state, the red LED flashes, while the blue and green LEDs are off.

[0059] Regarding step S527, the counting time of counter 11 reaches the third time threshold, where the third time threshold is greater than the second time threshold. Regarding step S529, microcontroller 1 puts the second switching circuit 4 into the off state and puts the light-emitting element 6 into the seventh light-emitting state. For example, when the light-emitting element 6 is in the seventh light-emitting state, the blue diode is constantly lit, the green diode is flashing, and the red diode is off. Regarding step S531, microcontroller 1 puts the first switching circuit 3 into the off state.

[0060] Furthermore, whenever a power-on event occurs during the counting period of counter 11, counter 11 of microcontroller 1 immediately stops counting and clears the accumulated counting time, and counter 11 of microcontroller 1 will not restart until the next power-off event occurs.

[0061] Figure 6 is Figure 2 A flowchart of another embodiment of the power management method for a vehicle power management system when encountering a power shut-off event. Steps S601 to S631 in Figure 6 are the same as... Figure 5 Steps S501 to S531, the power management method in Figure 6 and Figure 5 The difference between the power management methods is that the power management method in Figure 6 further includes steps S633 to S647.

[0062] Following steps S621 and S625, step S633 follows. In step S633, microcontroller 1 monitors the output power and output current of charger 2 via power detector PD. Specifically, after the counter 11 of microcontroller 1 reaches a first time threshold but before reaching a second time threshold, microcontroller 1 monitors the output power and output current of charger 2 via power detector PD. After the counter 11 of microcontroller 1 reaches a second time threshold but before reaching a third time threshold, microcontroller 1 monitors the output power and output current of charger 2 via power detector PD.

[0063] Regarding step S635, microcontroller 1 determines whether the output power does not exceed the power limit and whether the output current does not exceed the current limit. If the output power does not exceed the power limit and the output current does not exceed the current limit, it returns to step S633. If the output power exceeds the power limit and / or the output current exceeds the current limit, it proceeds to step S637. Regarding step S637, microcontroller 1 puts the second switching circuit 4 into the off state. Regarding step S639, microcontroller 1 puts the light-emitting element 6 into the eighth light-emitting state. For example, when the light-emitting element 6 is in the eighth light-emitting state, the blue diode is constantly lit, the green diode is off, and the red diode is flashing.

[0064] Following steps S621 and S625, step S641 follows. In step S641, microcontroller 1 monitors the output voltage of charger 2 via power detector PD. Specifically, after the counter 11 of microcontroller 1 reaches a first time threshold but before reaching a second time threshold, microcontroller 1 monitors the output voltage of charger 2 via power detector PD. After the counter 11 of microcontroller 1 reaches a second time threshold but before reaching a third time threshold, microcontroller 1 monitors the output voltage of charger 2 via power detector PD.

[0065] Regarding step S643, microcontroller 1 determines whether the output voltage of charger 2 is lower than the voltage threshold. If yes, proceed to step S645. If no, return to step S641. Regarding step S645, microcontroller 1 turns off the second switching circuit 4. Regarding step S647, microcontroller 1 turns off the light-emitting element 6. For example, when the light-emitting element 6 is off, the blue diode, green diode, and red diode are all off.

[0066] [Beneficial effects of the embodiments]:

[0067] One of the beneficial effects of the present invention is that the vehicle power management system and power management method provided by the present invention programmatically control the timing of the on-board power supply and the backup battery supplying power to the vehicle load equipment, as well as the timing of the power switch being turned off to the back-end load, so as to avoid the back-end load excessively consuming the power of the on-board power supply, thereby causing the on-board power supply to be insufficient to restart the engine that has been turned off.

[0068] The above-described content is merely a preferred embodiment of the present invention and is not intended to limit the scope of the claims of the present invention. Therefore, any equivalent technical changes made based on the description and drawings of the present invention are included within the scope of the claims of the present invention.

Claims

1. A vehicle power management system, applicable to a back-end load and an on-board power supply, characterized in that, The vehicle power management system includes: A microcontroller is connected to the vehicle power supply and the back-end load, and the microcontroller includes a counter; A charger is connected to the microcontroller; A first switching circuit is connected to the charger, the microcontroller, and the vehicle power supply; A second switching circuit is connected to the microcontroller, the charger, and the back-end load; and A spare battery is connected to the charger; Specifically, when the microcontroller receives an ignition switch off signal from the vehicle power supply, the microcontroller determines whether the voltage of the ignition switch off signal is lower than a first voltage threshold; When the voltage of the power off signal is lower than the first voltage threshold, the charger stops using the vehicle power supply to power the backup battery and uses the vehicle power supply to power the downstream load. When the counter reaches a first time threshold, the charger stops using the vehicle power supply to power the back-end load and switches to using the backup battery to power the back-end load. When the counting time reaches a second time threshold, the microcontroller sends the switch off signal to the back-end load; When the counting time reaches a third time threshold, the charger stops using the backup battery to power the back-end load.

2. The vehicle power management system as described in claim 1, characterized in that, It also includes a light-emitting element connected to the microcontroller. When the microcontroller receives an ignition switch signal from the vehicle power supply, the microcontroller determines whether the voltage of the ignition switch signal is within a voltage threshold range. When the voltage of the ignition switch signal is within the voltage threshold range, the charger provides power from the vehicle power supply to the downstream load. When the voltage of the ignition switch signal is not within the voltage threshold range, the microcontroller causes the light-emitting element to emit light.

3. The vehicle power management system as described in claim 2, characterized in that, When the voltage of the ignition switch signal is within the voltage threshold range and the backup battery is not saturated, the charger uses the vehicle power supply to power the backup battery.

4. The vehicle power management system as described in claim 2, characterized in that, When the voltage of the switch-on signal is within the voltage threshold range, the microcontroller puts the second switching circuit into a conducting state; when the second switching circuit is in the conducting state, the microcontroller transmits the switch-on signal to the downstream load.

5. The vehicle power management system as described in claim 4, characterized in that, When the back-end load receives the ignition switch open signal and the output voltage of the vehicle power supply is lower than a second voltage threshold, the microcontroller outputs the ignition switch closed signal to the back-end load.

6. The vehicle power management system as described in claim 1, characterized in that, When the charger's output power exceeds a power limit or its output current exceeds a current limit, the microcontroller puts the second switching circuit into a cut-off state.

7. A power management method for a vehicle power management system, characterized in that, include: When a microcontroller receives a power off signal, the microcontroller determines whether the voltage of the power off signal is lower than a first voltage threshold. When the voltage of the power switch off signal is lower than the first voltage threshold, the use of an on-board power supply to power a backup battery is stopped and the on-board power supply is used to power the downstream load. Start a counter on the microcontroller; When the counter reaches a first time threshold, the on-board power supply to the back-end load is stopped and the backup battery is used to supply power to the back-end load instead. When the counting time reaches a second time threshold, the microcontroller sends the switch off signal to the back-end load; When the counting time reaches a third time threshold, the backup battery is no longer used to power the back-end load.

8. The power management method as described in claim 7, characterized in that, It also includes monitoring an output voltage of the vehicle power supply, and when the output voltage of the vehicle power supply is lower than a second voltage threshold, the counter stops counting and stops using the vehicle power supply to power the back-end load.

9. The power management method as described in claim 7, characterized in that, It also includes that when the microcontroller receives a power switch open signal, the microcontroller determines whether the voltage of the power switch open signal is within a voltage threshold range. When the voltage of the power switch open signal is within the voltage threshold range, it enables a power conversion component of a charger; when the voltage of the power switch open signal is not within the voltage threshold range, it causes a light-emitting element to emit light.

10. The power management method as described in claim 9, characterized in that, It also includes determining whether a backup battery has reached a saturation state after enabling the power conversion component; when the backup battery has not reached a saturation state, using the vehicle power supply to power the backup battery.

11. The power management method as described in claim 10, characterized in that, It also includes the microcontroller sending the power-on signal to the back-end load after the vehicle power supply is used to power the backup battery.

12. The power management method as described in claim 11, characterized in that, It also includes determining whether an output voltage of an on-board power supply is lower than a second voltage threshold after the ignition switch signal is transmitted to the back-end load; when the output voltage is lower than the second voltage threshold, the microcontroller outputs the ignition switch off signal to the back-end load.

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