JPH03223916A - Backup power supplies, standby power supply methods, electronic equipment, and information processing systems - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a standby power supply device that supplies power to a plurality of circuits constituting an electronic device when power from a main power source is cut off; The present invention relates to a backup power supply method, an electronic device equipped with a backup power source, and an information processing system.

[Prior Art] There is a demand for electronic devices, particularly information processing systems represented by computers, to maintain power supply even during power outages such as during power outages or when replacing batteries.

In order to achieve this, some information processing apparatuses have conventionally been provided with a backup power source in addition to a main power source that normally supplies power.

For example, some devices use a commercial power source as the main power source and a battery as a backup power source, while others use a battery as the main power source and a large-capacity capacitor as the backup power source.

These things are typically stored in backup power sources for all peripheral devices such as printers and external storage devices that make up an information processing system, and for all the multiple device component circuits that make up a specific device. Supply power until the current power is exhausted.

[Problems to be Solved by the Invention] However, in the conventional technology, power is regularly supplied from the backup power source to multiple peripheral devices and device component circuits, so the power consumption of the backup power source is large, and the backup power source is There is a problem in that the power supply time from the power supply is shortened.

The present invention has been made by paying attention to such conventional problems, and provides a backup power supply device and a backup power source that can reduce the power consumption of the backup power source and extend the power supply time from the backup power source. Its purpose is to provide power supply methods, electronic devices, and information processing systems.

[Means for Solving the Problems] To achieve the above object, the present application provides the following invention.

The invention related to an electronic device is an electronic device that includes a plurality of circuits and a backup power source that supplies power to the plurality of circuits when power from the main power source is cut off, in which a power outage of the main power source is detected. A power outage detection means to
a cutoff means capable of cutting off power supplied from the backup power source to the plurality of circuits; The present invention is characterized by comprising a cut-off instruction means for sequentially causing one of the cut-off means to cut off power based on a predetermined cut-off order or a cut-off order instructed by an operator.

In this case, the electronic device may be a single electronic device or a plurality of electronic devices, such as an information processing device that constitutes a system, such as an information processing device, a printer, a keyboard, an external storage device, etc. It may be a device. Also, l! j
The circuit described in 'lJ can be used on a circuit board of a specific electronic device as long as it is supplied with power from a sub-circuit source.
It is also possible to place the cut-off instructing means horizontally so as to instruct the cut-off means to cut off after a predetermined period of time has elapsed.

In addition, 1); Preparation to measure the voltage of the backup power supply described in ■ (11j
i'I) The source voltage measuring means is provided to cause the cutoff instructing means to cut off the cutoff means after the voltage of the standby power supply drops to a predetermined 1") leakage potential. It may also be configured to instruct.

Preferably, the electronic device is provided with a cutoff warning means for warning of power cutoff before the cutoff means cuts off power from the standby power source to the circuit.

Here, in response to the warning of power cutoff, the cutoff instruction means is configured to:
It is preferable to provide an instruction to the blocking means.

In addition, the electronic device may be provided with the following information:
Further, it is preferable to provide a display means for displaying that power from the standby power source to the circuit has been cut off.

The invention relating to a standby power supply device provides a standby power supply device equipped with a standby power supply that supplies power to a plurality of circuits constituting an electronic device when the power from the main power supply is cut off. a power outage detection means for detecting power; a cutoff means capable of cutting off power supplied from the backup power source to the plurality of circuits; A cutoff instruction means for sequentially cutting off the power to the cutoff means based on a predetermined cutoff order for the plurality of circuits of the power to be received or a cutoff room order according to an instruction from an operator. It is characterized by having the following.

The present invention is directed to a method for supplying backup power to a plurality of circuits constituting an electronic device by supplying backup power to a plurality of circuits constituting an electronic device when power from the main power source is cut off. When a power outage is detected, the power supplied from the standby power source is sequentially supplied to the plurality of circuits based on a predetermined cutoff order for the plurality of circuits or a cutoff order according to instructions from the operator. It is characterized by cutting off the power that is generated.

[Operation] When the main power supply is cut off, the power cutoff detection means detects this and the backup power supply starts supplying power to the plurality of circuits.

When a power outage of the main power supply is detected, the cutoff instruction means sequentially performs the following operations based on a predetermined cutoff order for the plurality of circuits of power supplied from the standby power supply or a cutoff order according to an instruction from the operator. Instructs the cutoff means to cut off the power.

9. Upon receiving this instruction, the cut-off means sequentially cuts off the power supplied to the circuit from the standby power source.

Therefore, the power supplied from the backup power supply to the circuits is sequentially cut off, and the power is not uniformly supplied to the plurality of circuits until the power is exhausted, thereby reducing the power consumption of the backup power supply. I can do it.

With a display means and a cutoff warning means, when the main power supply is cut off, a power cutoff is displayed, and a power cutoff warning is issued before the cutoff means cuts off power from the standby power source to the circuit. Therefore, based on this warning, the operator can take appropriate measures when the main power supply is cut off.

In addition, in the case where the operator who receives a warning from the shutdown warning means shuts off the power depending on whether or not to execute the power shutdown as instructed, the operator may refuse to shut off the power even if the warning is received while the circuit is operating. For example, the operation of the circuit can be continued.

(The following is a blank space) 10 [Examples] Various embodiments of the present invention will be described below based on FIGS. 1 to 13. Note that the same parts in the various embodiments are given the same reference numerals, and the explanation thereof will be omitted.

Figures 1 to 7 regarding the first embodiment of the information processing system
This will be explained based on the diagram.

As shown in FIG. 1, the information processing system includes an information processing device main body 4, a keyboard 7, a display 9 that displays information etc. from the main body 4 on the screen, an external storage device 23, a printer 22, The communication device 21 transmits data from the main body 4 to other devices.

The information processing device main body 4 includes a CPU, a memory 6 in which various data are stored, a main power supply circuit 5 that supplies power to each device and each circuit, and a main power supply circuit 5 that supplies power to each device and each circuit when the main power is cut off. A backup power supply 3 supplies power to each circuit, a power outage detection circuit 2 detects a power outage in the main power supply, and when a power outage in the main power supply is detected, an interrupt request signal is sent to the CPU at predetermined intervals. An interrupt timer 14 that outputs 11-, a communication device 21, a printer 22,
Cutoff switches 11, 12, 13 that can cut off power supplied to the external storage device 23, and cutoff switch 1
1, 12, and an output port 31 that outputs an operation signal to 13,
32 and 33, a power supply path 16 for supplying power from the main power supply circuit 5 to each device and each circuit, and a bus 8 for signal transmission between each device and each circuit. has been done.

The power failure detection circuit 2 includes a diode 3 as shown in FIG.
5, and a voltage detection unit 36 that measures the potential of the supplied power.
It is made up of.

The diode 3S has its anode side connected to the main power supply circuit 5.
The cathode side is connected to the positive potential side of the backup power supply 3.

The voltage detection unit 36 detects a power outage for the interrupt timer 14 when the potential of the power supplied from the main power supply circuit 5 drops to a specific value, that is, to the extent that it is determined that the main power is out of power. It is configured to output a signal 15.

12- The interrupt timer 14 determines a time period T1. after the main power supply is cut off, during which the power supplied from the backup power supply 3 to the communication device 21, printer 22, and storage device 23 is cut off. T2. T3
are set in advance, and the time until power outage T□, T2.
It is configured to output an interrupt request signal to the CPUI every time T3 is reached.

The output ports 31, 32, and 33 are composed of registers, and are normally set to Ill'', and are set to II OII when receiving a cutoff control signal from the CPUI.

The cutoff instruction means for causing the cutoff switches 11, 12, and 13 to cut off the power from the standby power source 3 includes the interrupt timer 14 and the CP
It consists of a UI, memory 6, and output ports 31, 32, and 33.

In the memory 6, the cutoff order of power supplied to the communication device 21, the printer 22, and the external storage device 23 is stored in advance. is executed by outputting a cutoff control signal to the corresponding peripheral device 21.3-22.23 via the output boat 31, 32.33 based on the cutoff order. The order is the communication device 21, the printer 22, and the external storage device 23.

As shown in FIG. 3, the cutoff switches 11, 12.13 are composed of MOS transistors, and their gates are connected to the output ports 31, 32.33.

The power failure detection means is constituted by the power failure detection circuit 2, and the cutoff means is constituted by cutoff switches 31, 32, and 33.

Further, the display 9 constituting the display means displays the power cutoff of the main power source and the cutoff of power to each peripheral device 21, 22, 23.

The backup power source 3 is a battery, and is always charged when the main power source is turned on, so that the battery capacity is maintained at full capacity.

Next, the operation of this embodiment will be explained.

14- When the power outage detection circuit 2 detects a power outage in the main power supply, it outputs a power outage detection signal 15 to the interrupt timer 14.

At this time, the power failure detection signal 15 is transmitted via the interrupt timer 14 to [
−7 CP t,J] is also output, and the display 9
As shown in FIG. 7(a), it displays that the main power supply has been cut off according to the instructions from the CPU 1.

Moreover, at this time, the backup power supply 3 has already started supplying power to each circuit and peripheral device.

The operation of the interrupt timer 14 upon receiving the power failure detection signal 15 will be explained in accordance with the order of the symbols shown in FIG.

Step 61: When the interrupt timer 14 receives the power outage detection signal, it sets the current time to the time t when the main power was cut off. Close and set.

Step 62: Set the current time t.

Step 63 1-1o, that is, compare the time from the main power cut-off to the present with the preset time T□, and if the former is greater, proceed to the next step,
If the latter is larger, go back to Stella 15 Pro 2.

Step 64: Output the first interrupt request signal to CPtJl-.

Step 65: Update the current time t.

Step 66...t-1:. and a preset time T2, and if the former is larger, the process advances to the next step, and if the latter is larger, the process returns to step 65.

Step 67: A second interrupt request signal is output to the CPUI.

Step 68: Update the current time t.

Step 69...1-1o is compared with a preset time T3, and if the former is larger, the process advances to the next step, and if the latter is larger, the process returns to step 68.

Step 70: Output a third interrupt request signal to the CPUI.

This completes the operation of the interrupt timer 14.

The operations after the interrupt request signal is output to the CPUI will be explained in the order of the symbols shown in FIG. 5. In the figure, the variable p indicates that the interrupt request signal 15 is CP.
This is a variable for counting the number of times input is made to the UI. Note that the variable p is reset to 110'' each time the main power is turned on.

Step 80...The CPU increments the value of the variable p by one and sets it to the number of times the interrupt request signal has been input.

Step 81...The CPU determines whether the value of the variable p is equal to 1, that is, whether it is the first interrupt processing request. If they are equal, the process proceeds to step 82; if not, the process proceeds to step 85.

Step 82...CPtJl outputs the cutoff control signal 10 to the output port 31 of the communication device 21, and also outputs a display signal to the display 9 indicating that the power to the communication device 21 has been cut off.

Step 83...The output port 31 consisting of registers is set from LL I II to 1, which is normally set.
10'', the gate of the cutoff switch 11 made up of a MOS transistor is set to a low level.The cutoff switch 11 is turned off, and the power to the communication device 17-21 is cut off.

Step 84: Upon receiving the display signal, the display 9 displays that the power to the communication device 21 has been cut off, as shown in FIG. 7(b).

Step 85...The CPU determines whether the value of the variable P is equal to 2, that is, whether it is the second interrupt request signal. If they are equal, the process proceeds to step 86; if not, the process proceeds to step 89.

Step 86...The CPU outputs the cutoff control signal 20 to the output port 32 of the printer 22, and also outputs a display signal to the display 9 indicating that the power to the printer 22 has been cut off.

Step 87...Similar to step 83, the cutoff switch 12 is turned off, and power to the printer 22 is cut off.

Step 88: Upon receiving the display signal, the display 9 displays that the power to the printer 22 has been cut off.

Step 89...Since the third interrupt request signal has been received, the CPU outputs the cutoff control signal 30 to the output port 33 of the external storage device 823, and also outputs the cutoff control signal 30 to the external storage device 23 to the display 9. Outputs an indication signal indicating that power has been cut off.

Step 90...Similar to step 83, the cutoff switch 13 is turned off, and power to the external storage device 23 is cut off.

Step 91: Upon receiving the display signal, the display 9 displays that the power to the external storage device 23 has been cut off.

With the above, the operation of cutting off power to the peripheral devices 21, 22, and 23 is completed, and if the main power is not turned on, the information processing device main body 4, keyboard 7, and display 9 will be operated until the power of the backup power source is exhausted. ,Operate.

Next, the operation when the main power source is turned on again while power is being supplied by the backup power source 3 will be described.

The power failure detection circuit 2 detects the CP even when the main power is turned on again.
Outputs an interrupt request signal to the UI.

In response to this, the CPUI performs the recovery process at 9. Execute. A flowchart of this process is shown in FIG.

Hereinafter, description will be made according to the symbols attached to each block.

Step 101: First, a message indicating that the main power has been turned on again is displayed on the display 9, as shown in FIG. 7(c).

Step 102: By checking the setting value of the output port 31, it is determined whether or not the communication device 21 has been cut off. If the set value is It_OIt, that is, if the power has been cut off, the process advances to step 103. If the set value is 1'1'', that is, if the power has not been cut off, step 104
Proceed to.

Step 103... Set value of output port 3 to LL
Instead of I It, the power cutoff by the cutoff switch 11 is canceled, and the communication device 21 is made to initialize. Then, as shown in FIG. 7(d), the initialization is displayed on the display 9.

Step 104: Similar to step 102, it is determined whether or not the printer 22 has been cut off.

Step 105: Similar to step 103, the power cut-off is canceled by the cut-off switch 12, the printer 22 is initialized, and the display 9 is made to indicate that the printer 22 has been initialized.

Step 106: Similar to step 102, it is determined whether or not the external storage device 23 has been powered off.

Step 107: Causes the cutoff switch 13 to release the power cutoff, and causes the display 9 to display a message to insert a system disk for initialization into the external storage device 23.

Through the above processing, the peripheral circuits whose power has been cut off are restored.

According to this embodiment, the peripheral devices 21 and 22 whose power is cut off
．． 23, the external storage device 23 is powered off last, so data can be reliably saved.

Further, since the power to the peripheral devices 21, 22, and 23 is sequentially cut off, the power consumption of the backup power source 3 can be reduced.

Information processing device body 4. Since the keyboard 7 and the display 21-9 operate until the power of the backup power source 3 is exhausted, the operator can perform some processing until the end.

In this embodiment, the order of power cut-off is predetermined, but when the main power supply is cut off, the operator is asked about the order of cut-off, and based on this order of cut-off, the order of power cut-off is determined in advance. The power may be cut off. By doing so, power to the peripheral devices 21, 22, and 23 can be cut off depending on the actual operating state of the information processing system when the main power supply is cut off.

Further, in this embodiment, the information processing device main body 4, the external storage device 23, and the display 9 are each independent, but the present invention can also be applied to a device in which these are configured integrally. May be applied.

A modification of the power failure detection circuit in this embodiment will be explained based on FIG. 8.

This modification example is a portable information processing device, so-called lap 1~
Application 22--A case where a battery 41, which is often used in a tube-shaped personal computer, etc., is used as the main power source - In this example, when the battery 41 is removed for replacement, etc., this is mechanically detected.

The power failure detection circuit 2a is provided in a battery box 40, and includes a signal output section 42 that outputs a power failure detection signal 5 when the battery 41 is removed, and contacts 43a, 43a formed at one end. A connection wire 43.43 whose end is connected to the signal output section 42, a connection switch 45 having a battery contact section 4.5a at one end and a contact 45b at the other end, and the battery 4.
The spring 46 biases the connection switch 45 in a direction in which the contact 45b of the connection switch 45 and the contacts 43a, 43a of the connection wire 4.3.4-3 come into contact when the connection switch 4.1 is removed.

A main power supply circuit and a power supply path 16 are provided inside the battery box 40, as shown in FIG.

Not drawn for simplicity.

As shown in FIG. 8(a), the battery 41 is connected to the battery box 4.
0, the contact 4.5b of the connection switch 45 and the contact 43a of the connection line 43 are separated.

23 When the battery 41 is removed, as shown in Figure 8 (1)),
The connection switch 45 biased by the spring 46 pops out, and the contact 45b of the connection switch 45 and the contact 43a of the connection line 43 come into contact.

Thereby, the signal output unit 42 outputs a power failure detection signal to the interrupt timer 14.

Next, a second embodiment of the information processing system will be described.

In this embodiment, a cutoff warning means is added to the first embodiment, which asks whether or not it is okay to cut off the power before the power to the peripheral devices 2 and 22 and 23 is cut off, and warns of the power cutoff. Additionally, the power cut-off instructing means is configured to output a cut-off control signal in accordance with an instruction from the operator who received the warning as to whether or not to execute the power cut-off.

Note that this embodiment differs from the first embodiment only in the program in the memory 6, but in terms of hardware,
There is no difference from the first embodiment. The shutdown warning means is composed of a memory 6, a CPU 1 that operates according to a program in the memory 6, and a day 4 sprayer 9.

The operation of this embodiment will be explained based on FIG. 9. Note that the description of the same operations as in flowchart 1- in FIG. 5 will be omitted.

When the CPUI receives the ]th interrupt request signal (step 81), the process proceeds to step 92.

Step 92: As shown in FIG. 10, the CPU causes the display 9 to display whether or not the power supply to the communication device 1t21 may be cut off. In response, the operator
Enter "II Y ++ or 11N" from the keyboard 7 to reply.

11N'' is input, the process returns to step 80 and the power cutoff of the communication device 2 is not executed.

When LL Y ++ is input, the process proceeds to step 82, where a cut-off control signal is output to cut off the power to the communication device 2]-.

When the CPUI receives the second interrupt request signal (step 85), the process proceeds to step 93.

Step 93 - Similar to step 92, the CPUI causes the display 9 to display whether or not it is okay to cut off the power supply 5 to the printer 22, and prompts the operator to input
Follow the responses for f Y II or “N ++.

When II N 11 is input, the process returns to step 80 and the power to the printer 22 is not cut off.

If If Y ++ is input, the process proceeds to step 86 and outputs a cut-off control signal to cut off power to the printer 22.

When the CPU 1 receives the third interrupt request signal (step 85), it proceeds to step 9/U.

Step 94...Similar to step 92, the CPUI displays on the display 9 whether or not it is okay to cut off the power supply to the external storage device 23, and the CPU
Follow II or u N u's reply.

When LL N II is input, the power cutoff process is completed and the power cutoff of the external storage device 23 is not executed.

When II Y ++ is input, the process proceeds to step 89, where a cut-off control signal is output to cut off the power to the external storage Jlk unit 23.

In this embodiment, the operator is asked whether or not the power can be cut off, and the power is cut off according to instructions from the operator, so that the power is not cut off while the peripheral devices 21, 22 and 23 are in operation. , the operation being executed is not wasted, and the system can operate efficiently when power is supplied from the standby power supply.

Next, a third embodiment of the information processing measure will be described based on FIG. 11.

In the present embodiment, in the information processing system of the first embodiment, the interrupt timer 14a is provided with an arithmetic function so that the interruption control signals 10, 20, and 30 can be directly output from the interrupt timer 14, and the display 9 LED51 instead of
, 52 and 53 constitute the display means.

Note that the cut-off instruction means consists only of the interrupt timer 1.4a. Further, this embodiment has the same configuration as the first embodiment except for the above-mentioned changes.

When the power outage detection circuit 2 detects a power outage in the main power supply, a power outage detection signal 15 is sent to the LED 51,
52, 53, and the LEDs 51, 27, 52, and 53 flash to notify the operator of the power outage of the main power source.

Then, the interrupt timer 14a transmits the cutoff control signals 10, 20, 30 to the output ports 31, 32, .
33, and output to LEDs 51 and 52.5, respectively.
Output each to 3.

Communication device 21, printer 22. Power to the external storage device 23 is sequentially cut off in accordance with cutoff control signals 1.0 and 20.30.

On the other hand, the LEDs 51, 52, and 53 also have cutoff control signals 10,
20.30, the lights flash in sequence to notify the operator of the power cutoff.

According to this embodiment, since the CPU does not intervene in the power cutoff process, when power is being supplied by the backup power source 3,
The CPUI can always execute the processing desired by the operator.

Next, regarding the fourth embodiment of the information processing system, the twelfth embodiment will be explained.
This will be explained based on the drawings and FIG. 13.

As shown in FIG. 12, this embodiment can detect a power outage of the main power source and detect the voltage of the standby power source 3 instead of the power outage detection circuit 2 and interrupt timer 14 in the first embodiment. This is provided with a detection circuit 2a that can measure at any time.

The detection circuit 2a includes a diode 37, which measures the voltage of the main power source and the voltage of the backup power source 3, and outputs a power outage detection signal 15 when the main power source is cut off, so that the voltage of the backup power source 3 increases. The voltage measurement unit 38 outputs an interrupt request signal 15a to the CPUI every time a specific voltage is reached.

As shown in FIG. 13, the voltage measurement unit 38 has VOc as the initial voltage of the standby power source 3, and VD as the peripheral device 21.22.2.
If the lowest operable voltage is 3, then VD≦v3≦v2≦
A specific voltage V with the relationship V□≦VCC, V, ,
V is set in advance.

In the various embodiments described above, the predetermined time T1゜T2
, Ta elapses, but in this embodiment, the voltage of the backup power supply 3 is set to predetermined voltages V□, V2 . Each time the voltage drops below V, an interrupt request signal 15a is output to the CPUI.

The operation after the interrupt request signal 15a is output is the same as in the various embodiments described above.

Therefore, in this embodiment as well, the peripheral devices 21 and 22
．． Since the power supplied to the power source 23 is sequentially cut off, the power consumption of the backup power source 3 can be reduced.

It is preferable to apply this embodiment to a battery whose voltage drops relatively slowly, such as a manganese battery, as the backup power source 3.

In addition, since the remaining life of such batteries can be predicted relatively accurately from the voltage drop, it is necessary to measure the relationship between voltage and remaining life in advance, as well as understand the power consumption rate of peripheral devices. Based on this relationship, when the main power is cut off, the display 9 will display, for example, "X minutes after the actual working time of the external storage device" or "Y minutes after the actual working time of the printer". You can also do this.

Although the various embodiments described above apply the present invention to information processing systems, the present invention is not limited to information processing systems, and may be applied to each circuit board that constitutes a specific electronic device. It goes without saying that the present invention can also be applied to devices that supply power from a standby power source.

[Effects of the Invention] According to the present invention, the power supply from the standby power source to each circuit is cut off in order from the circuits that are least necessary, so the power consumption of the standby power source can be reduced, and the power consumption is reduced. Supply time can be extended.

[Brief explanation of drawings]

Figures 1 to 7 show the first embodiment, where Figure 1 is an overall functional block diagram of the information processing system, Figure 2 is a functional block diagram of the power failure detection circuit, and Figure 3 is the output port. 4 is a flowchart for explaining the operation of the interrupt timer, and FIG. 5 is a flowchart 1 to 6 for explaining the system operation after the interrupt request signal is output. The figure shows flowchart 1-1 to explain the system operation when the main power is turned on again.
FIG. 7 is an explanatory diagram for explaining a display example on the display, and FIG. 8 is a functional block diagram of a modified example of the power failure detection circuit.
9 and 10 show the second implementation, FIG. 9 is a flowchart for explaining system operation,
FIG. 10 is an explanatory diagram for explaining a display example, FIG. 11 is an overall functional block diagram of the information processing system of the third embodiment, and FIGS. 12 and 13 are diagrams of the fourth embodiment. 12 is a functional block diagram of the detection circuit, and FIG. 13 is a graph showing the voltage drop state of the backup power supply. DESCRIPTION OF SYMBOLS 1...CPU, 2...Power failure detection circuit, 8...Backup power supply, 4.4a...Information processing device body, 5...Main power supply circuit, 6...Memory, 7.Keyboard, 9...Display, 14.14a...Interrupt timer, 21
- Communication device, 22... printer, 23... external storage device.

Claims (1)

[Claims] 1. In an electronic device including a plurality of circuits and a backup power source that supplies power to the plurality of circuits when power from the main power source is cut off, the main power source is disconnected. a power failure detection means for detecting a power outage; a cutoff means capable of cutting off power supplied from the backup power source to the plurality of circuits; An electronic device characterized by having a cutoff instruction means for causing the cutoff means to sequentially cut off power based on a predetermined cutoff order for the plurality of power circuits or a cutoff order based on an instruction from an operator. . 2. The electronic device according to claim 1, wherein the cutoff instructing means instructs the cutoff means to cut off after a predetermined time has elapsed. 3. A standby power supply voltage measuring means for measuring the voltage of the standby power supply is provided, and the cutoff instructing means instructs the cutoff means to cut off after the voltage of the standby power supply drops to a predetermined potential. The electronic device according to claim 1, characterized in that: 4. The electronic device according to claim 1, 2, or 3, further comprising a cutoff warning means for warning of power cutoff before the cutoff means cuts off power from the backup power source to the circuit. 5. The electronic device according to claim 4, wherein the cutoff instruction means receives the warning of power cutoff and instructs the cutoff means depending on whether or not the power cutoff is to be executed as instructed by the operator. device. 6. Claim 1, 2, 3, 4 or 5, further comprising display means for displaying that the main power source has been cut off and that power from the standby power source to the circuit has been cut off. Electronic equipment listed. 7. The electronic device according to claim 1, 2, 3, 4, 5 or 6 comprises an information processing device main body including a CPU, a printer,
An information processing system comprising an external storage device, wherein the printer and the external storage device each constitute the circuit. 8. When a power outage of the main power source is detected, the power cutoff instruction means cuts off the power supplied from the backup power source to the printer and the external storage device in that order. 8. The information processing system according to claim 7, wherein the means causes the power to be cut off. 9. In a backup power supply device equipped with a backup power source that supplies power to multiple circuits constituting an electronic device when power from the main power source is cut off, a power outage that detects a power outage of the main power source. a detection means, a cutoff means capable of cutting off the power supplied from the standby power source to the plurality of circuits, and a cutoff means capable of cutting off the power supplied from the standby power source to the plurality of circuits; A standby power supply device comprising a cutoff instruction means for sequentially causing the cutoff means to cut off power based on a predetermined cutoff order for the circuit or a cutoff order according to an instruction from an operator. 10. In a backup power supply method for supplying backup power to a plurality of circuits constituting an electronic device when power from the main power source is cut off, when a power outage of the main power source is detected, The power supplied to the plurality of circuits is sequentially cut off based on a predetermined cutoff order for the plurality of circuits of power supplied from a standby power source or a cutoff order according to an instruction from an operator. A standby power supply method.