CN107689669B

CN107689669B - Electronic device with standby power supply and charging and discharging method of standby power supply

Info

Publication number: CN107689669B
Application number: CN201610680419.5A
Authority: CN
Inventors: 张益龙
Original assignee: Join Link International Technology Co ltd
Current assignee: Join Link International Technology Co ltd
Priority date: 2016-08-03
Filing date: 2016-08-17
Publication date: 2021-06-04
Anticipated expiration: 2036-08-17
Also published as: TWI596863B; JP2018023267A; TW201806287A; CN107689669A; JP6392291B2

Abstract

An electronic device with a standby power supply and a charging and discharging method of the standby power supply are provided. The first electricity storage unit is electrically connected with the main power supply module, receives power supply of the external power supply from the main power supply module when the external power supply supplies power normally, and provides stored electric power to the electricity utilization module when the external power supply stops supplying power. The first bypass unit is connected in parallel with the first power storage unit and provides a first bypass path to limit the voltage value provided by the main power supply module to the first power storage unit. The first bypass unit is provided with a first control end which is electrically connected with an external power supply so as to selectively conduct the first bypass path according to whether the external power supply is normally powered.

Description

Electronic device with standby power supply and charging and discharging method of standby power supply

Technical Field

The present invention relates to an electronic device with a standby power supply and a charging/discharging method for the standby power supply, and more particularly, to an electronic device capable of operating with the standby power supply when an external power supply stops supplying power.

Background

Electronic devices require a power source for operation, but the current common designs cannot ensure that the electronic devices can still take good care when they lose power. Taking the driving recorder as an example, the driving recorder is used to record the driving status for the evidence of accident. The tachograph is typically powered by the vehicle. When a traffic accident or other conditions occur, which causes the power source provided by the vehicle to the driving recorder to be suddenly lost, if the driving recorder does not have a standby power supply or the electric quantity stored in the standby power supply is insufficient, the driving recorder cannot be shut down smoothly frequently, which causes the damage of the image file, even the image file at the time of the accident is not stored.

Therefore, the electronic device such as the tachograph can still maintain partial functions when the power is lost, or how to prevent the tachograph from being unable to store correct files due to the power problem becomes a practical problem that manufacturers need to solve when designing the tachograph. In other words, how to successfully complete the shutdown procedure when the electronic product loses power without warning is a problem that manufacturers can not neglect when designing products. The event recorder is installed on the client of the multi-case, but the client cannot be dispatched to the occasion at the critical moment.

Disclosure of Invention

The invention provides an electronic device with a standby power supply and a charging and discharging method of the standby power supply, so as to solve the problem that an electronic product cannot be actuated due to insufficient electric storage capacity in the prior art.

The electronic device with the standby power supply is electrically connected with an external power supply and comprises a power utilization module, a main power supply module and the standby power supply module. The main power supply module is electrically connected with an external power supply to supply power to the power utilization module. The standby power supply is provided with a first power storage unit, a second power storage unit, a first bypass unit and a second bypass unit. The first electricity storage unit is electrically connected with the main power supply module, receives power supply of the external power supply from the main power supply module when the external power supply supplies power normally, and provides stored electric power to the electricity utilization module when the external power supply stops supplying power. The first bypass unit is connected in parallel with the first power storage unit and provides a first bypass path to limit the voltage value provided by the main power supply module to the first power storage unit. The first bypass unit is provided with a first control end which is electrically connected with an external power supply so as to selectively conduct the first bypass path according to whether the external power supply is normally powered.

The charging and discharging method of the standby power supply comprises the step of supplying power of the external power supply to the power utilization module and the standby power supply module when the external power supply normally supplies power. When the standby power supply module is charged by the power supply of the external power supply, the bypass path of the standby power supply module is conducted so as to limit the voltage value supplied to the standby power supply module for charging. When the external power supply stops supplying power, the bypass path is not conducted, and the standby power supply module provides the stored power to the power utilization module.

According to the electronic device with the standby power supply and the charging and discharging method of the standby power supply disclosed by the invention, when the external power supply normally supplies power, the first bypass unit limits the voltage value provided by the main power supply module to the first power storage unit and the second power storage unit, so that the electric quantity stored in the first power storage unit and the second power storage unit can be controlled without being influenced by the equivalent resistance of the first power storage unit. When the external power source stops supplying power and the first power storage unit supplies stored power to the power utilization module, the first bypass unit is not connected in parallel with the first power storage unit, so that the power stored in the first power storage unit cannot leak electricity through the first bypass unit, and the stored power can be supplied to the power utilization module more completely.

The foregoing description of the disclosure and the following detailed description are presented to illustrate and explain the principles and spirit of the invention and to provide further explanation of the invention's scope of the claims.

Drawings

Fig. 1 is a functional block diagram of an electronic device according to an embodiment of the invention.

Fig. 2 is a functional block diagram of an electronic device according to another embodiment of the invention.

Fig. 3 is a flowchart illustrating a method for charging and discharging a backup power according to an embodiment of the invention.

Fig. 4 is a flowchart illustrating a method for charging and discharging a backup power according to another embodiment of the invention.

Description of reference numerals:

10. 30 electronic device

11. 31 main power supply module

13. 33 electric module

15. 35 stand-by power supply module

151. 351 first power storage unit

152. 352 second Power storage Unit

153. 353 first bypass unit

153a first control terminal

154a second control terminal

154. 354 second bypass unit

331 processing unit

20. 40 external power supply

DZ1 first anti-reflux unit

DZ2 second anti-reflux unit

DZ3 third prevention counterflow unit

M1 first bypass switch

M2 second bypass switch

N1 first node

N2 second node

R1 first bypass resistor

R2 second bypass resistor

R3, R4 resistance

R5 current limiting resistor

VN1 Voltage

Detailed Description

The detailed features and advantages of the present invention are described in detail in the following embodiments, which are sufficient for anyone skilled in the art to understand the technical contents of the present invention and to implement the present invention, and the related objects and advantages of the present invention can be easily understood by anyone skilled in the art from the disclosure of the present specification, the claims and the accompanying drawings. The following examples further illustrate aspects of the present invention in detail, but are not intended to limit the scope of the present invention in any way.

Referring to fig. 1, fig. 1 is a functional block diagram of an electronic device according to an embodiment of the invention. As shown in fig. 1, the electronic apparatus 10 includes a main power supply module 11, a power consumption module 13, and a backup power supply module 15. The main power module 11 is, for example, a power transmission interface, a power converter or other suitable components, the main power module 11 is electrically connected to the external power source 20 to convert the power supplied by the external power source 20 into the specification required by the power consumption module 13 and provide the converted power to the power consumption module 13, and part of the power is provided to the backup power module 15 to charge the backup power module 15.

The standby power module 15 has a first power storage unit 151, a second power storage unit 152, a first bypass unit 153, and a second bypass unit 154. The first power storage unit 151 and the main power supply module 11 are connected to the first node N1. The second power storage unit 152 and the first power storage unit 152 are connected to a second node N2. When the external power source 20 supplies power normally, the first power storage unit 151 and the second power storage unit 152 receive power from the external power source 20 from the main power module 11 and charge the external power source 20. When the external power source 20 stops supplying power, the first power storage unit 151 and the second power storage unit 152 provide the stored power to the power consumption module 13. The power utilization module 13 refers to other power utilization components in the electronic device 10, and in the case of a driving recorder, the power utilization module 13 is, for example, a processing system of the driving recorder or other suitable power utilization components.

The first bypass unit 153 is connected in parallel to the first power storage unit 151 and provides a first bypass path to limit the voltage value provided by the main power module 11 to the first power storage unit 151. The first bypass unit 153 has a first control terminal 153a, and the first control terminal 153a is electrically connected to the external power source 20 to selectively conduct the first bypass path, i.e. to conduct the first node N1 and the second node N2, according to whether the external power source 20 is normally powered. The second bypass unit 154 is connected in parallel to the second power storage unit 152 and provides a second bypass path to limit the value of the voltage supplied to the second power storage unit 152 by the main power supply module 11. The second bypass unit 154 has a second control terminal 154a, and the second control terminal 154a is electrically connected to the external power source 20 for selectively connecting the second bypass path, i.e. connecting the second node N2 and the reference potential terminal, according to whether the external power source 20 is normally powered.

In other words, when the external power source is supplying power normally, the first bypass unit 153 is electrically connected to the first node N1 and the second node N2, and the second bypass unit 154 is electrically connected to the second node N2 and the reference potential terminal, so as to limit the voltage value provided by the main power module 11 to the first power storage unit 151 and the voltage value provided by the second power storage unit 152. In practice, when the external power source 20 supplies power normally, the first and

second bypass units

153 and 154 may be configured to equally distribute the power provided by the external power source 20 to the first and second

power storage units

151 and 152, so that the first and second

power storage units

151 and 152 are charged with the same voltage value without being affected by the equivalent resistance of the first and second

power storage units

151 and 152.

When the external power source 20 stops supplying power and the first power storage unit 151 and the second power storage unit 152 supply power to the power module 13, the first bypass unit 153 is not electrically connected to the first node N1 and the second node N2, and the second bypass unit 154 is not electrically connected to the second node N2. The power stored in the first and second

power storage units

151 and 152 is supplied to the power module 13 without leakage from the first and

second bypass units

153 and 154, thereby reducing unnecessary power loss of the first and second

power storage units

151 and 152 and leakage of the first and second

power storage units

151 and 152 to the ground.

In other words, when the external power source 20 is normally powered, the power utilization module 13 of the electronic device 10 operates according to the power supplied by the external power source 20, and when the external power source 20 cannot be normally powered or even is powered off, the electronic device 10 may be powered by the standby power module 15 for a period of time, so as to enable the electronic device 10 to complete a necessary shutdown procedure. In the case of the driving recorder, the external power source 20 is, for example, a power source provided by a vehicle, and when the vehicle is powered normally, the driving recorder is powered by the vehicle, and when the vehicle stops powering, the driving recorder can be powered by the standby power module for a period of time to complete the shutdown procedure. The shutdown procedure of the driving recorder is, for example, continuous recording for 3 seconds, and the last recorded image file is closed and stored.

Next, referring to fig. 2, fig. 2 is a functional block diagram of an electronic device according to another embodiment of the invention, as shown in fig. 2, the electronic device 30 has a main power module 31, a power module 33, a standby power module 35, and a voltage dividing module 37. The main power module 31 is electrically connected to the external power source 40 to supply power to the power consumption module 33 and charge the standby power module 35. The backup power supply module 35 includes a first power storage unit 351, a second power storage unit 352, a first bypass unit 353, and a second bypass unit 354.

The first bypass unit 253 includes a first bypass resistor R1 and a first bypass switch M1 connected in series, and the first bypass resistor R1 and the first bypass switch M1 are electrically connected between the first node N1 and the second node N2. The second bypass unit 254 comprises a second bypass resistor R5 and a second bypass switch M3 connected in series, wherein the second bypass resistor R5 and the second bypass switch M3 are electrically connected between the second node N2 and the reference potential terminal. The first bypass switch M1 and the second bypass switch M2 are selectively turned on depending on whether the external power source 40 is normally powered. When the external power source 40 supplies power normally, the first bypass switch M1 and the second bypass switch M2 are turned on, the first bypass resistor R1 is electrically connected between the first node N1 and the second node N2, and the second bypass resistor R5 is electrically connected between the second node N2 and the reference potential terminal. When the external power source 40 stops supplying power, the first bypass switch M1 and the second bypass switch M2 are not turned on, the first bypass resistor R1 is not electrically connected between the first node N1 and the second node N2, and the second bypass resistor R5 is not electrically connected between the second node N2 and the reference potential terminal.

The first bypass switch M1 has a first terminal, a second terminal, and a control terminal. A first end of the first bypass switch M1 is electrically connected to the first node N1, a second end of the first bypass switch M1 is electrically connected to the second node N2, and a control end of the first bypass switch M1 is electrically connected to the voltage dividing node Nd of the voltage dividing module 37. The second bypass switch M2 has a first terminal, a second terminal, and a control terminal. The first end of the second bypass switch M2 is electrically connected to the second node N2. The second end of the second bypass switch M2 is electrically connected to the reference terminal, and the control terminal of the second bypass switch M2 is electrically connected to the voltage dividing node Nd of the voltage dividing module 37.

The voltage dividing module 37 has a resistor R3 and a resistor R4, one end of the resistor R3 is electrically connected to the external power source 40, and the other end of the resistor R3 is electrically connected to the voltage dividing node Nd. One end of the resistor R4 is electrically connected to the voltage dividing node Nd, and the other end of the resistor R4 is electrically connected to the reference voltage terminal. The voltage dividing module 37 is used for dividing the power provided by the external power source 40, so that the first bypass switch M1 and the second bypass switch M2 are selectively turned on according to the voltage of the voltage dividing node Nd.

In practice, when the external power source 40 is normally powered, the voltage difference across the first bypass resistor R1 is related to the voltage value provided by the main power module 31 to the first power storage unit 351, and the voltage difference across the second bypass resistor R2 is related to the voltage value provided by the main power module 31 to the second power storage unit 352. More specifically, the voltage value provided by the main power module 31 to the first power storage unit 351 is substantially equal to the sum of the voltage difference between the two ends of the first bypass resistor R1 and the voltage difference between the first end and the second end of the first bypass switch M1. The voltage value provided by the main power module 31 to the second power storage unit 351 is substantially equal to the sum of the voltage difference between the two terminals of the second bypass resistor R2 and the voltage difference between the first terminal and the second terminal of the second bypass switch M2.

In one embodiment, when the external power source 40 is supplying power normally, the first bypass switch M1 is turned on and the second bypass switch M2 is turned on, the first bypass resistor R1 is connected in parallel to the first power storage unit 351, and the second bypass resistor R2 is connected in parallel to the second power storage unit 352. By adjusting the resistance ratio of the first bypass resistor R1 and the second bypass resistor R2, the voltage value provided by the main power module 31 to the first power storage unit 351 and the second power storage unit 352 has a desired voltage division ratio. In practice, the ratio of the resistances of the first bypass resistor R1 and the second bypass resistor R2 is, for example, such that the first electrical storage unit 351 and the second electrical storage unit 352 have the same electrical storage capacity. In another embodiment, the ratio of the first bypass resistor R1 to the second bypass resistor R2 can make the first electrical storage unit 351 and the second electrical storage unit 352 charge with the same voltage. Those skilled in the art can design freely according to the actual requirement, and the embodiment is not limited.

When the external power source 40 stops supplying power, the first bypass switch M1 is not turned on and the second bypass switch M2 is not turned on, the first bypass resistor R1 is not connected in parallel to the first power storage unit 351, and the second bypass resistor R2 is not connected in parallel to the second power storage unit 352. The first and second

power storage units

351 and 352 can only supply power to the power-using module 23, and the power is not discharged from the first and second bypass resistors R1 and R2 by mistake.

In the present embodiment, the electronic device 30 further includes a first backflow prevention element DZ1, a second backflow prevention element DZ2, a third backflow prevention element DZ3, and a current limiting resistor R5. The first backflow prevention element DZ1 is electrically connected between the first node N1 and the power module 33. The second backflow prevention element DZ2 and the current limiting resistor R5 are connected in series between the first node N1 and the main power module 31, and the third backflow prevention element DZ3 is electrically connected between the main power module 31 and the power module 33. In practice, when the first and second

power storage units

351 and 352 are not fully charged, the power supplied from the external power source 40 charges the first and second

power storage units

351 and 352 via the main power supply 31, the second backflow prevention element DZ2, and the current limiting resistor R5. On the other hand, the power of the external power source 40 is also supplied to the power consumption module 33 through the third backflow prevention element DZ 3. When the first power storage unit 351 and the second power storage unit 352 are fully charged, the first backflow prevention element DZ1 is disposed between the first node N1 and the power module 33, so that the equivalent resistance of the path from the main power supply module 31 to the power module 33 through the first node N1 is relatively large. Therefore, the voltage output by the main power module 31 may suspend charging the first power storage unit 351 and the second power storage unit 352, so that the service life of the first power storage unit 351 and the second power storage unit 352 may be more optimized. In practice, the first backflow prevention element DZ2 and the second backflow prevention element DZ3 may also be sub-circuits formed by connecting a plurality of electronic components, and the embodiment is not limited.

In one embodiment, the power utilization module 33 includes a processing unit 331. The processing unit 331 is, for example, a central processing unit, a microprocessor or other suitable components of the electronic device 30. The processing unit 331 is electrically connected to the first node N1 for receiving a signal at the first node N1, such as a voltage VN 1. When the electronic device receives power from the external power source 40, the processing unit 331 determines the charging curves of the first power storage unit 351 and the second power storage unit 352 according to the voltage VN1 of the first node N1, and determines the capacitances of the first power storage unit 351 and the second power storage unit 352 according to the charging curves.

In more detail, whether viewed separately or integrally, the first power storage unit 351 and the second power storage unit 352 have corresponding time constants to affect the charging time and the charging rate thereof. The output voltage or charging current of the first power storage unit 351 and the second power storage unit 352 relative to time forms the charging curve. In other words, the time constants of the first power storage unit 351 and the second power storage unit 352 can be derived from the linear change of the charging curve, and the equivalent capacitance values of the first power storage unit 351 and the second power storage unit 352 can be further derived, so as to determine the wear level of the first power storage unit 351 and the second power storage unit 352. In one embodiment, when the processing unit 331 determines that the capacitance of the first power storage unit 351 and the second power storage unit 352 is lower than a predetermined threshold, the processing unit 331 may generate an alarm signal to notify the user to replace the corresponding components of the first power storage unit 351 and the second power storage unit 352.

In one embodiment, when the external power source 40 fails to supply power normally or is powered off to force the electronic device 30 to perform a shutdown procedure, the power consumption module 33 may perform a necessary shutdown procedure by supplying power from the standby power module 35, for example, after a prolonged period of time. When the processing unit 331 determines that the capacitances of the first electricity storage unit 351 and the second electricity storage unit 352 are lower than the predetermined threshold value, the processing unit 331 generates the warning signal and also notifies the electricity utilization module 33 to modify the shutdown procedure, for example, to shorten the time duration of the shutdown procedure.

Taking the driving recorder as an example, when the capacitance of the first power storage unit 351 and the second power storage unit 352 is not lower than the preset threshold value, the vehicle stops supplying power to the driving recorder, and the driving recorder can record images for 3 seconds continuously by the power supplied by the standby power module 35, and close and store the last recorded image file. When the capacitance of the first power storage unit 351 and the second power storage unit 352 is lower than the preset threshold value, the driving recorder can reduce the time for continuous recording or cancel the continuous recording, and directly close and store the last recorded image file.

On the other hand, the processing unit 331 determines the charging curves of the first power storage unit 351 and the second power storage unit 352 according to the voltage VN1 of the first node N1, and when the electronic device 30 has the first power storage unit 351 and the second power storage unit 352 shipped, the processing unit can simply detect the power storage capacities of the first power storage unit 351 and the second power storage unit 352 during the power-on or power-off process of the electronic device 30, so as to ensure the power storage capacities of the first power storage unit 351 and the second power storage unit 352 and ensure the shipment quality of the electronic device 30.

In the foregoing embodiments, for convenience of description, the embodiment having the first power storage unit, the second power storage unit, the first bypass unit and the second bypass unit is directly used for description, and in practice, a person skilled in the art may reduce the arrangement of the second power storage unit and the second bypass unit or increase the arrangement of more power storage units and bypass units according to the above-mentioned contents, and the embodiment is not limited.

To more clearly describe the charging and discharging method of the backup power source, please refer to fig. 1 and fig. 3 together, and fig. 3 is a flowchart illustrating steps of the charging and discharging method of the backup power source according to an embodiment of the invention. As shown in the figure, in step S501, the electronic device 10 supplies power from the external power source 20 to the power consumption module 13 and the standby power module 15. In step S502, when the standby power module 15 charges the external power source 20, the bypass path of the standby power module 15 is turned on to limit the voltage value provided to the standby power module 15 for charging. In step S503, it is determined whether the external power source 20 supplies power normally. When the external power supply 20 supplies power normally, it goes to step S501. When the external power source 20 stops supplying power, in step S504, the bypass path is not turned on, and the standby power module 15 supplies the stored power to the power consumption module 13.

In another embodiment, referring to fig. 1 and fig. 4 together, fig. 4 is a flowchart illustrating a method for charging and discharging a standby power according to another embodiment of the present invention. As shown in the figure, in step S601, the electronic device 10 provides the power of the external power source 20 to the power consumption module 13 and the standby power module 15. In step S602, the electronic device 10 determines a capacitance of at least one of the first power storage unit 151 and the second power storage unit 152 according to a charging curve of the at least one of the first power storage unit 151 and the second power storage unit 152. In step S604, it is determined whether the capacitance of at least one of the first electricity storage unit 151 and the second electricity storage unit 152 is lower than a threshold, and when the capacitance of at least one of the first electricity storage unit 151 and the second electricity storage unit 152 is lower than the threshold, in step S606, the electronic device 10 generates an alarm signal or reduces the extension time.

In step S603, when the standby power module 15 is charged with the power supplied from the external power source 20, the bypass paths of the standby power module 15, i.e., the first bypass path and the second bypass path provided by the first bypass unit 153 and the second bypass unit 154, are turned on to limit the voltage value provided for charging the standby power module 15. In step S605, it is determined whether the external power source 20 is supplying power normally, and when the external power source 20 is supplying power normally, the process goes to step S601. When the external power source 20 stops supplying power, in step S607, the bypass path is not turned on, and the standby power module 15 supplies the stored power to the power consumption module 13. The charging and discharging methods of the backup power supply according to the present invention are disclosed in the embodiments described above, and the description of the embodiments is not repeated here.

In summary, the present invention provides an electronic device with a standby power supply and a charging/discharging method for the standby power supply, wherein a first bypass unit and a second bypass unit are respectively connected in parallel to a first power storage unit and a second power storage unit. When the external power supply normally supplies power, the first bypass unit and the second bypass unit can limit the voltage value provided by the main power supply module to the first power storage unit and the second power storage unit, so that the electric quantity stored by the main first power storage unit and the second power storage unit can be controlled, and the influence of the equivalent resistance of the first power storage unit and the second power storage unit can be avoided. When the external power supply stops supplying power and the first power storage unit and the second power storage unit are switched to supply power to the power utilization module, the first bypass unit and the second bypass unit are not electrically connected with the first power storage unit and the second power storage unit, so that electric power stored in the first power storage unit and the second power storage unit cannot leak electricity through the first bypass unit and the second bypass unit, and the electric power stored in the first power storage unit and the second power storage unit can be supplied to the electronic device to complete a necessary shutdown program. In addition, in one embodiment, the charging curves of the first power storage unit and the second power storage unit are detected to determine the capacitance of the first power storage unit and the second power storage unit, and the electronic device may also be prompted to correct the shutdown procedure when the capacitance of the first power storage unit and the capacitance of the second power storage unit are not enough to allow the electronic device to complete a necessary shutdown procedure, so as to avoid loss caused by abnormal shutdown of the electronic device.

Although the present invention has been described with reference to the above embodiments, it is not intended to limit the invention. All changes and modifications that come within the spirit and scope of the invention are desired to be protected. With regard to the scope of protection defined by the present invention, reference should be made to the appended claims.

Claims

1. An electronic device with a standby power supply, electrically connected to an external power supply, the electronic device comprising:

an electric module;

the main power supply module is electrically connected to the external power supply to supply power to the power utilization module; and

a backup power module comprising:

the first electricity storage unit is electrically connected with the main power supply module, receives power supply of the external power supply from the main power supply module when the external power supply normally supplies power, and provides stored electric power to the electricity utilization module when the external power supply stops supplying power; and

a first bypass unit, connected in parallel to the first power storage unit, and providing a first bypass path, when the standby power module is charged with the power supplied by the external power source, the bypass path of the standby power module is turned on to limit the voltage value provided by the main power module to the first power storage unit, when the external power source stops supplying power, the bypass path is turned off, the first bypass unit has a first control end electrically connected to the external power source to selectively turn on or off the first bypass path according to whether the external power source is normally supplying power, wherein the electronic device further includes:

the second power storage unit is electrically connected with the first power storage unit, receives power supply of the external power supply from the main power supply module when the external power supply normally supplies power, and provides stored power to the power utilization module when the external power supply stops supplying power; and

the second bypass unit is connected in parallel with the second electricity storage unit and provides a second bypass path to limit the voltage value provided by the main power supply module to the second electricity storage unit, and the second bypass unit is provided with a second control end which is electrically connected with the external power supply so as to selectively conduct the second bypass path according to whether the external power supply normally supplies power or not.

2. The electronic device with a backup power supply as claimed in claim 1, wherein the first and second bypass units equally distribute the power provided by the external power supply to the first and second power storage units when the external power supply is supplying power normally.

3. The electronic device as claimed in claim 1, wherein the first bypass unit comprises a first bypass resistor and a first bypass switch, the second bypass unit comprises a second bypass resistor and a second bypass switch, the first bypass switch and the second bypass switch are selectively turned on according to whether the external power source is normally powered, wherein when the external power source is normally powered, the first bypass switch and the second bypass switch are turned on, a voltage difference across the first bypass resistor is related to a voltage value provided by the main power module to the first power storage unit, and a voltage difference across the second bypass resistor is related to a voltage value provided by the main power module to the second power storage unit.

4. The electronic device with a backup power source as claimed in claim 3, wherein the first bypass switch has a first end, a second end and the first control end, the first end of the first bypass switch is electrically connected to one end of the first power storage unit, the second end of the first bypass switch is electrically connected between the first power storage unit and the second power storage unit, the first control end of the first bypass switch is electrically connected to the main power module to receive the power from the external power source, the second bypass switch has a first end, a second end and the second control end, the first end of the second bypass switch is electrically connected between the first power storage unit and the second power storage unit, the second end of the second bypass switch is electrically connected to a reference end, the second control end of the second bypass switch is electrically connected to the main power module, to receive power from the external power source.

5. The electronic device with a backup power supply of claim 4, further comprising a voltage divider module, wherein the voltage divider module receives power from the external power supply, and the first control terminal of the first bypass switch and the second control terminal of the second bypass switch are electrically connected to a voltage dividing node of the voltage divider module.

6. The electronic device with a backup power supply as claimed in claim 1, further comprising a first anti-backflow element electrically connected between the first power storage unit and the power utilization module.

7. The electronic device with a backup power supply as claimed in claim 1, further comprising a second anti-backflow element and a current-limiting resistor electrically connected between the first power storage unit and the main power module.

8. The electronic device with a backup power supply as claimed in claim 1, wherein the power utilization module includes a processing unit, and when the electronic device receives the power from the external power supply, the processing unit determines the capacitance of the first power storage unit according to a charging curve of the first power storage unit.

9. The electronic device with a backup power supply as claimed in claim 8, wherein the processing unit generates a warning signal when the processing unit determines that the capacitance of the first power storage unit is lower than a threshold value.

10. The electronic device with a backup power source as claimed in claim 8, wherein when the electronic device executes a shutdown procedure, the power utilization module is shut down after an extended period of time, and when the processing unit determines that the capacitance of the first power storage unit is lower than a threshold value, the processing unit decreases the extended period of time.

11. A charging and discharging method of a standby power supply is suitable for an electronic device with the standby power supply, the electronic device is electrically connected with an external power supply and is provided with an electric module and a standby power supply module, and the charging and discharging method of the standby power supply comprises the following steps:

when the external power supply normally supplies power, the power supplied by the external power supply is supplied to the power utilization module and the standby power supply module;

when the standby power supply module is charged by the power supply of the external power supply, a bypass path of the standby power supply module is conducted to limit the voltage value supplied to the standby power supply module for charging; and

when the external power supply stops supplying power, the bypass path is not conducted, and the standby power supply module provides the stored power to the power utilization module, the bypass path has a first control end electrically connected to the external power source for selectively turning on or off the bypass path according to whether the external power source is supplying power normally, wherein the standby power module comprises a first power storage unit and a second power storage unit, the bypass path comprises a first bypass path corresponding to the first power storage unit and a second bypass path corresponding to the second power storage unit, the charging and discharging method of the standby power supply comprises conducting the first bypass path and the second bypass path when the first power storage unit and the second power storage unit are charged by the power supplied by the external power supply, to evenly distribute the power supplied from the external power source to the first power storage unit and the second power storage unit.

12. The method according to claim 11, further comprising determining a capacitance of at least one of the first power storage unit and the second power storage unit according to a charging curve of the at least one of the first power storage unit and the second power storage unit when the electronic device receives power from the external power source.

13. The method according to claim 12, further comprising generating an alarm signal when the capacitance of at least one of the first and second power storage units is lower than a threshold.

14. The method according to claim 12, further comprising powering off the power consuming module after an extended period of time when the electronic device executes a power-off procedure, and decreasing the extended period of time when the capacitance of the first power storage unit is lower than a threshold.