JP3477975B2 - Power supply for storage device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine or a printer, or a copy management apparatus for managing the number of copies of the image forming apparatus. The present invention relates to a power supply device for a storage device used for storing device information such as the number of copies in a storage device having a nonvolatile memory or the like. 2. Description of the Related Art Conventionally, in an image forming apparatus such as the above-described electrophotographic copying machine or printer, or a copy management apparatus for managing the number of copies of the image forming apparatus, etc., the number of copies, paper size, etc. Alternatively, device information such as the total number of copies and the number of remaining copies can be stored in a storage device having a non-volatile memory such as a RAM to store the number of copies.
Management has been done. At this time, the copy management device and the like are configured to include two types of power sources, not only an external power source but also a battery backup power source, as a power source for the storage device in order to hold the storage contents of the storage device. I have. FIG. 7 shows a power supply device for the storage device.
As shown in FIG.
Is turned off, the nonvolatile memory 10 such as RAM
1 to hold the storage contents of the nonvolatile memory 101
Some power supplies have two types of power sources, such as a battery backup storage battery for supplying power to the battery and a rechargeable battery. In a copy management device or the like in which a storage device using the power supply device is built, a new storage battery or a charged rechargeable battery is manufactured as a battery backup power source 102, and the storage device is built in the storage device. In order to prevent a new storage battery or a charged rechargeable battery from being discharged between the time when the copied copy management device or the like is shipped and the time when it is actually used, a battery backup power source 102 and a non-volatile memory 101 are used. A switch 103 for preventing discharge is provided between the two, and the switch 103 for preventing discharge is turned off when the copy management apparatus or the like is shipped. Then, in the copy management device having the storage device built therein, when the user starts using the device, the discharge prevention switch 103 is turned on (O
N state), the power supply 102 for battery backup can be used. [0004] However, the above prior art has the following problems. That is, in the case of a power supply device for a storage device used in the above-mentioned conventional copy management device or the like, as shown in FIG. 7, the discharge of the battery backup power supply 102 from shipment to use is prevented. Therefore, a switch 103 for preventing discharge is provided. However, if the electrophotographic apparatus or the like is connected to the external power supply 100 while the copy management apparatus or the like is mounted on the electrophotographic apparatus or a printer, the nonvolatile memory 101 such as a CPU or a RAM that operates the storage device is energized. Therefore, even when the discharge prevention switch 103 is forgotten to be turned on (remains in the OFF state), the copy management apparatus operates normally, and copying in an electrophotographic apparatus or the like becomes possible. However, when the copy management apparatus is used with the discharge prevention switch 103 forgotten to be turned on (remaining in the OFF state), there is no problem while the external power supply 100 is on, but the external power supply 100 is turned off. Then, since the discharge prevention switch 103 is in the OFF state, power is not supplied from the battery backup power supply 102 to the nonvolatile memory 101 such as the RAM, and the data such as the number of copies stored so far stored in the memory 101 is stored. There was a problem that disappeared. The present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to provide a storage device having two types of power sources, an external power source and a battery backup power source. In a power supply device having a function of a discharge prevention switch for preventing discharge of a battery backup power supply, even when the storage device is used and the user forgets to turn on the discharge prevention switch, An object of the present invention is to provide a power supply device for a storage device that can prevent the storage contents of the storage device from being lost. That is, the present invention is directed to a storage device having an external power supply for energizing a storage device, and a backup power supply for backing up the external power supply and energizing the storage device. In the power supply device, switching means for switching the power supply to the storage device from the external power supply and the backup power supply, discharge prevention switch means for turning ON / OFF the power supply to the storage device from the backup power supply, and Control means for detecting the energization of the storage device and holding the discharge prevention switch in the conductive state even when detecting the OFF state of the energization from the external power supply to the storage device, wherein the control means It comprises a CPU connected to the device and performing a control operation, the CPU comprising:
When energized by an external power supply, a signal from the I / O port of the CPU outputs a signal in an “H” state .
The discharge prevention switch is configured to be kept conductive. In the present invention, a switching means for switching the energization from the external power supply and the backup power supply to the storage device, a discharge prevention switch for turning on / off the energization from the backup power supply to the storage device, Control means for detecting the power supply from the power supply to the storage device and maintaining the conduction state of the discharge prevention switch even when detecting the OFF state of the power supply from the external power supply to the storage device. Therefore, even when the supply of the external power is turned off, the control means detects this and keeps the conduction state of the discharge prevention switch, thereby automatically supplying power to the storage device from the backup power supply. Even if the user forgets to turn on the discharge prevention switch when using the storage device, the storage content of the storage device can be changed. It is possible to prevent the flashing of. The present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows a storage device to which a power supply device for a storage device according to an embodiment of the present invention is applied. The basic configuration of the present invention comprises an external power supply for energizing the storage device, a backup power supply for backing up the external power supply and energizing the storage device, and energizing the storage device from the external power supply and the backup power supply. Switching means for switching, a discharge prevention switch for turning on / off the power supply from the backup power supply to the storage device, and detecting the power supply from the external power supply to the storage device to supply power to the storage device from the external power supply. Even if the OFF state is detected,
A power supply device for a storage device, comprising: a control unit for maintaining a conduction state of a discharge prevention switch. As shown in FIG. 1, the power supply device for the storage device has a predetermined voltage (for example, DC) from a general external power supply 1 (commercial power supply = 100 V) via a rectifier circuit (not shown).
5V) Equipment I / F that receives supply of power that has been transformed and rectified
2, a CPU 3 that controls the operation of the entire storage device and also has a function as a control unit of the power supply device, an operation program ROM 4 storing a program for operating the CPU 3, and device information such as the number of copies. A predetermined voltage (for example, RAM 5) as a storage element for storing and a predetermined voltage as a backup power supply for backing up the external power supply 1 (for example,
DC3V), a charging circuit 7 for receiving power (for example, DC5V) from the external power supply 1 and charging the charging battery 6, an external power supply 1 and a backup power supply 6. A switching circuit 8 as switching means for switching the switching, a switching IC 9 for discharging prevention as switching means for discharging, and an OR gate 10 for detecting the energization from the external power supply 1 to the RAM 5. Switching IC 9 for preventing discharge and OR gate 10
And the RAM 5 are also operated by the rechargeable battery 6 as a backup power supply, and the switching IC for discharging prevention.
Numeral 9 is adapted to open and close according to an output signal from the OR gate 10. Also, the OR gate 10 has C
A signal from the I / O port 11 of the PU 3 and an output of the rechargeable battery 6 through the discharge prevention switching IC 9 are input. Further, the switching circuit 8 includes, for example, a diode connected to the external power supply 1 and a diode connected to the rechargeable battery 6. The higher power of the external power supply 1 and the rechargeable battery 6 is stored in the RAM 5. It is designed to be energized. In the above case, the external power supply 1 is DC5
V and the rechargeable battery 6 are set to DC3V, respectively.
5 is energized. In the above configuration, the power supply device for a storage device according to this embodiment is a power supply device for a storage device having two types of power sources, an external power source and a battery backup power source, as follows. In a device having a function of a discharge prevention switch for preventing discharge of a battery backup power source, even if the storage device is used and the user forgets to turn on the discharge prevention switch, the stored contents of the storage element Can be prevented from disappearing. That is, when the storage device having the power supply device is manufactured, as shown in FIG. 1, the external power supply 1 is not connected and the backup charge battery 6 is charged. Since the discharge prevention switching IC 9 is in the OFF state, the inputs of the OR gate 10 are both in the “L” and “L” states. Therefore, the output of the OR gate 10 is also in the “L” state as shown in FIG. 2, and the discharge prevention switching IC 9 is opened (OF).
F) state. Next, when the storage device is installed, as shown in FIG. 1, an external power source 1 such as a copy management device equipped with the storage device is connected, and the external power source 1 is connected via a device I / F 2.
When the power (DC5V) is supplied, the CPU 3
The operation starts in accordance with the program stored in advance in step S4. Then, as shown in FIG. 2, when the CPU 3 starts the operation, after a short time has elapsed since the external power supply 1 was turned on, the I / O connected to one input of the OR gate 10 is started. An “H” level signal is output from the port 11. Then, the output of the OR gate 10 also becomes “H”, the switching IC 9 for preventing discharge becomes conductive (ON), and power can be supplied from the backup power supply 6 to the RAM 5. Thereafter, even if the external power supply 1 is turned off,
Since the discharge prevention switching IC 9 is in the conductive (ON) state, the input to the OR gate 10 is “H” on the side 12 to which the backup power supply 6 is supplied, and the discharge prevention switching IC 9 is in the conductive state (ON). ON) state. As described above, when the external power supply 1 is turned on when the storage device is installed, the switching IC 9 for preventing discharge is provided.
Can be automatically turned on. Therefore, when the storage device is used, the discharge prevention switching IC 9 is automatically turned on almost at the same time when the external power supply 1 is turned on, so that power can be supplied from the backup power supply 6 to the RAM 5. Can be prevented from disappearing. The external power supply 1 and the rechargeable battery 6 are both RAM.
5, the external power supply 1 with a high voltage is connected to the RAM 5 by the switching circuit 8 as described above. In FIG. 1, if one of the inputs to the OR gate 10 is connected between the switching circuit 8 and the RAM 5, when the external power supply 1 is turned on, the input of the OR gate 10 becomes "H" immediately. Level, so I / O of CPU3
The signal from the O port 11 becomes unnecessary. FIG. 3 shows a first modification in which a manual switch for preventing discharge is used instead of a switching IC for preventing discharge as a switch means for preventing discharge. As shown in FIG. 3, a device I / F 2 which receives supply of an external power supply 1, a CPU 3 as control means,
ROM 4 for U operation program and RAM as storage element
5, a switching circuit 8 for switching between the external power supply 1 and the backup power supply 6, a discharge prevention switch 20 as switch means, a rechargeable battery 6 as a backup power supply, and a supply of charging power to the rechargeable battery 6. It comprises a charging circuit 7 and a status display LED 21. As the discharge prevention switch 20, as shown in FIG. 4, a double-pole double-throw switch (two-circuit operation with one operation knob) is used. The switching circuit 8 for switching between the external power supply 1 and the rechargeable battery 6 supplies the power for the RAM from the external power supply 1 when the apparatus power is ON and from the rechargeable battery 6 when the apparatus power is OFF. As shown in FIG. 4, one pole of the double-pole / double-throw switch 20 is connected to one end of the rechargeable battery 6, and the voltage of the rechargeable battery 6 is supplied to the RAM 5 through one pole. The two poles of the double-pole / double-throw switch 20 are connected to the signal ground, and connected to the CPU 3 together with the pull-up resistor R1.
And the input port 2 of the CPU 3
2 makes it possible to recognize "H" and "L". From the time of manufacture to the time of installation, the discharge prevention switch 20 is turned off, and the rechargeable battery 6 is disconnected from the switching circuit 8 by one pole to prevent the rechargeable battery 6 from being discharged. On the other hand, the two poles of the discharge prevention switch 20 are separated from the signal ground, and the two poles are connected by a pull-up resistor R1.
As shown in FIG. 5, the input port 22 of the PU 3 is set to “H”.
Becomes At the time of installation, the discharge prevention switch 20 is closed (ON), and the rechargeable battery 6 is connected to the circuit by one pole, so that the storage device can be backed up. on the other hand,
The two poles of the discharge prevention switch 20 are connected to the signal ground, and the input port 22 of the CPU 3 becomes “L”. That is, when the level of the input port 22 of the CPU 3 remains "H" at the same time as the setting of the rechargeable battery 6, as shown in FIG.
By using the ED 21, the user is notified that the release of the discharge prevention switch 20 is forgotten to be released, and the input of the unique information is not accepted. When the setter cannot input data, the LED 21
Recognition of forgetting to release is recognized by the display. Then, the discharge prevention switch 20 is turned on to prevent the stored contents of the RAM 5 from being lost. Modification 2 FIG. 6 shows a modification 2 using a manual discharge prevention switch instead of a discharge prevention switching IC as the discharge prevention switch means. In the configuration of the first modification, as shown in FIG. 6, a one-pole switch is used for the discharge prevention switch 20.
The detection circuit 30 detects a voltage supply from the rechargeable battery 6 in a switch closed (ON) state. The detection circuit 30 includes a switch 20 for preventing discharge.
When the battery is open (OFF), "H" is output because there is no power from the charging battery 6, and when the battery is closed (ON), "L" is output because the power is supplied from the charging battery 6. The input is such that the current consumption of the battery 6 is minimized. FIG. 5 shows a flowchart similar to that of the first modification. According to the present invention, there is provided a power supply device for a storage device having two types of power supplies, an external power supply and a battery backup power supply, comprising the above configuration and operation. In a device having a function of a discharge prevention switch for preventing a power supply from being discharged, even if the storage device is used and the user forgets to turn on the discharge prevention switch, the stored content of the storage device is lost. It is possible to provide a power supply device for a storage device which can prevent the occurrence of a power failure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a storage device to which a power supply device according to the present invention is applied. FIG. 2 is a timing chart showing an operation. FIG. 3 is a block diagram showing a first modification; FIG. 4 is a block diagram showing a main part of Modification Example 1; FIG. 5 is a flowchart showing an operation. FIG. 6 is a block diagram showing a main part of a second modification. FIG. 7 is a block diagram showing a storage device to which a conventional power supply device is applied. [Description of Signs] 1 external power supply, 3 CPU, 5 RAM, 6 rechargeable battery, 9 discharge prevention switching IC, 10 OR gate.

Claims (1)

(57) [Claim 1] A power supply device for a storage device, comprising: an external power supply for energizing the storage device; and a backup power supply for backing up the external power supply and energizing the storage device. Switching means for switching the power supply to the storage device from the external power supply and the backup power supply; discharge prevention switch means for turning ON / OFF the power supply to the storage device from the backup power supply; Control means for detecting the energization and holding the discharge prevention switch in a conductive state even when detecting an OFF state of the energization from the external power supply to the storage device, wherein the control means is connected to the storage device. A CPU for performing a control operation by
The PU is energized by an external power supply to
A power supply device for a storage device, wherein a signal from an / O port outputs a signal in an "H" state , and the discharge prevention switch is kept conductive by the signal.