JPH08328965A - Backup device for information storage device - Google Patents

Abstract

PURPOSE: To make the device compact and inexpensive without wasiting any code memory by providing a backup power source on a substrate freely attachable and detachable to a main control board and backing up memory cells on the main control board as well. CONSTITUTION: A DRAM 2 and a DRAM control circuit 3 provided with a backup control circuit are installed on a main control board 1, and a page memory and a code memory are allocated to the DRAM 2 using two DRAM chips. Besides, the DRAM control circuit 3 reads and writes data to the DRAM chips and further, even when a reference power source VCC is not prepared by power failure or the like, refresh control is continued. On the other hand, a backup battery 9 of a lower voltage than the voltage of the reference power source VCC is provided on an extended memory board 6 freely attachably and detachably connected through a connector 4 to the main control board 1 and when no power is supplied from the reference power source VCC, the backup battery 9 backs up the DRAM 2 and a DRAM 8 on the extended memory board 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backup device for an information storage device, and more particularly to a storage device provided on a main control board of the information storage device, which requires a backup, and which has an extended memory board as a main component. The present invention relates to a backup device of an information storage device that backs up together with a storage element provided in an expansion memory board by a backup power supply provided in the expansion memory board when connected to a control board.

[0002]

2. Description of the Related Art As an information storage device, a personal computer, a printer, a facsimile device and the like have been put into practical use. In the present invention, an electrophotographic plain paper facsimile device for transmitting and receiving a B4 size document is taken as an example. And explain.

Generally, a conventional electrophotographic plain paper facsimile apparatus divides the memory space of the same storage element into a page memory for storing one page of print data in a bit map form and a transmission or reception document. And a code memory for storing image data as code information.

For example, when two 1M × 4 bit DRAMs are used as the storage elements provided on the main control board, the memory space becomes 1M bytes, and the page memory has the maximum print data resolution. Since it is necessary to store fine print data of a B4 size document, about 700 Kbytes are allocated for this purpose, and the remaining about 300 Kbytes are allocated for the code memory.

This code memory can store several tens of pages of code data of an A4 size original document having a normal resolution. However, since the number of stored pages is relatively small, the code memory is generally used. Backup is not done.

However, in such a facsimile machine,
It is also known that the expansion memory board is connected to the main control board to expand the capacity of the code memory and appropriately increase the image data amount of the original document that can be stored as the entire apparatus. The number of pages that can be stored is so large that code memory needs to be backed up. Normally, in order to back up the code memory, assuming that the expansion memory board is connected to the main control board, the code memory on the expansion memory board is backed up together with the code memory on the main control board, which conventionally does not require backup. The backup device is provided on the main control board.

[0007]

In the above-mentioned facsimile machine, in order to back up the code memory, a backup device is required on the main control board. The backup device is a main power source in addition to the backup power source. It is necessary to provide a switching circuit with the backup power supply and a DC-DC converter circuit for generating a reference voltage (usually "5V") from the backup power supply, and as a result, because of an expansion memory which is originally an option. As a result, not only the facsimile apparatus itself becomes large, but also the cost of the apparatus main body rises, and it becomes impossible to meet the demand for size reduction and price reduction.

As another method for backing up the code memory, it is conceivable that a backup device is provided on the expansion memory board and only the code memory on the expansion memory board is backed up. In the same code memory provided on the control board and the expansion memory board, there are areas that are backed up and areas that are not backed up.
It is virtually impossible to manage code data in two areas in the code memory at the same time. As a result, only the code memory on the backed-up expansion memory board is used, and the code memory provided in the main control board is wasted.

The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a backup device for an information storage device which meets the demand for downsizing and cost reduction and does not waste code memory. To aim.

[0010]

In order to achieve the above object, a backup device for an information storage device according to the present invention is provided with a first storage element for holding information by backing up with a power source. And a second memory element that is detachably connected to the first substrate and that retains information by backing up with a power source and a backup for backing up the first memory element and the second memory element. An information storage device, comprising: a second substrate provided with a power source; and a main power source for supplying power to the first substrate and the second substrate, wherein the first substrate and the second substrate
A circuit for supplying electric power from the main power source to the second substrate and a circuit for backing up the first memory element and the second memory element by the backup power source when the substrate is connected, The backup power source backs up the first memory element and the second memory element when power is not supplied from the main power source.

A backup device for an information storage device according to a second aspect of the present invention is the backup device for an information storage device according to the first aspect, wherein the second substrate is in a non-connection state with the first substrate, A circuit for backing up the second memory element from a backup power supply is not formed, and no current flows from the backup power supply.

[0012]

In the backup device of the information storage device of the present invention, the first substrate is provided with the first storage element, the first storage element holds information by backing up with a power source, and the second substrate is the first storage element. 2 storage elements and a backup power source are provided and detachably connected to the first substrate,
The memory element holds information by backing up with a power source, the backup power source backs up the first memory element and the second memory element, and the main power source supplies power to the first substrate and the second substrate. And a circuit for supplying electric power from the main power source to the second substrate when the first substrate and the second substrate are connected and the backup power source, and the first memory element and the first memory element. Two
A circuit for backing up the storage element is formed, and when power is not supplied from the main power supply, the backup power supply backs up the first storage element and the second storage element.

In the backup device of the information storage device of the present invention, the second substrate does not form a circuit for backing up the second storage element from the backup power supply when the second substrate is not connected to the first substrate, No current flows from the backup power supply.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A backup device for an information storage device according to the present invention will be described in detail below with reference to the drawings based on an embodiment in which it is applied to an electrophotographic facsimile machine.

FIG. 1 is a circuit diagram showing a memory configuration of a backup device for an information storage device according to the present invention.

The facsimile machine is controlled by a central control unit (hereinafter referred to as "CPU", not shown) provided on the main control board 1, and the CPU has a ROM for storing a control program and a control. It has a plurality of necessary flag areas and is composed of a RAM or the like for temporarily storing data and the like.

The main control board 1 has a DR including a DRAM 2 having a storage capacity of 1 Mbyte and a backup control circuit.
An AM control circuit 3 is provided. DRAM2 is 1M
It uses 2 x 4bit DRAM chips, and the page memory is about 700M in 1Mbyte of memory space.
K bytes are allocated, and the remaining about 300 K bytes are allocated to the code memory.

The DRAM control circuit 3 is a circuit for performing data read / write / refresh control for the DRAM chip and a circuit for continuously performing refresh control even when a reference power supply VCC, which will be described later, is not created due to a power failure or the like. It is configured.

A memory bus 5 is connected to the DRAM 2, the DRAM control circuit 3 and the connector 4, and control signals such as addresses and data and strobe signals such as RAS, CAS, WE and OE are connected via the memory bus 5. Come and go.

The main control board 1 is provided with a reference power supply VCC created from a main power supply (not shown) for supplying power.
And the power supply ground GND are given through the power supply line, and the reference power supply VCC and the power supply ground GND are
It is connected to the connector 4. Further, the anode of the Schottky diode D1 is connected to the reference power supply VCC, and the cathode of the Schottky diode D1 becomes the reference power supply VBU1. Also, the Schottky diode D1
The cathode of the Schottky diode D2 is connected to the cathode of, and the anode of the Schottky diode D2 is connected to the connector 4.

The reference power source VBU1 is V of the DRAM chip.
DRAM connected to the DD terminal and the DRAM control circuit 3
Power is supplied to the chip and the DRAM control circuit 3, and the power supply ground GND is the GND terminal of the DRAM chip and the DR.
Connected to the AM control circuit 3, and further to the DRAM control circuit 3
A reference power supply VCC is connected to the.

The expansion memory board 6 is detachably connected to the main control board 1 via the connector 4, and the reference power supply VCC and the power supply ground GND are applied to the power supply line of the expansion memory board 6. The reference power supply VCC is
The anode of the Schottky diode D3 is connected, and the cathode of the Schottky diode D3 has a DC-
It is connected to the IN terminal of the DC converter 7, and the OUT terminal of the DC-DC converter 7 becomes the reference power supply VBU2,
A predetermined voltage is output.

VDD terminals of two DRAM chips constituting the DRAM 8 are connected to the reference power source VBU2, and D
Supplies power to the RAM chip. Further, the GND terminal of the DRAM chip is connected to the power supply ground GND. D
The RAM 8 is a 1M × 4 bit D like the DRAM 2.
Two RAM chips are used, and the entire 1 Mbyte memory space is allocated to the code memory. However,
The DRAM 8 is not limited to 1 Mbytes, and the storage capacity is appropriately expanded or reduced as necessary.
Further, the DRAM 8 is connected to the memory bus 5 via the connector 4, and control signals and strobe signals are exchanged between them.

Further, the reference power supply VBU2 is connected to the cathode of the Schottky diode D2 via the connector 4. Further, the reference power source VBU2 is a capacitor C1.
And the other end of the capacitor C1 is connected to the power supply ground GND.

The reference power supply VCC is supplied to the expansion memory board 6 via the connector 4. Then, the reference power source VC
C is connected to the resistor R1, and the other end of the resistor R1 is connected to the anode of the Schottky diode D4. The cathode of the Schottky diode D4 is connected to the positive electrode of the backup battery 9, and the negative electrode of the backup battery 9 is connected to the power supply ground GND. Backup battery 9
Is a rechargeable secondary battery such as a lithium battery, and the voltage of the backup battery 9 is lower than the voltage of the reference power supply VCC and is usually charged to about 3V.

The positive electrode of the backup battery 9 is connected to the anode of the Schottky diode D5 via the connector 4 and the short circuit formed in the main control board 1, and the cathode of the Schottky diode D5 is connected to the anode of the Schottky diode D5. , DC-DC converter 7 is connected to the IN terminal.

Next, the operation of the backup device for the information storage device according to the present invention constructed as described above will be described. The main control board 1 and the extended memory board 6 are connected to each other when they are not connected. Description will be made separately for each state.

1) Not connected: By turning on the main power source, the reference power source V is supplied to the main control board 1.
When CC and the power supply ground GND are supplied, the reference power supply VCC is connected to the anode of the Schottky diode D1, so that the cathode of the Schottky diode D1 becomes the reference power supply VBU1 and a predetermined voltage is generated. The voltage of the reference power supply VBU1 is the reference power supply VCC.
The voltage is lower than the voltage of 1 by the voltage drop in the Schottky diode D1. As a result, a predetermined voltage is applied to the DRAM 2 and the DRAM control circuit 3, so that a normal operation regarding data storage is started according to an instruction from the CPU, and the DRAM 2 stores data.

Next, in this state, the reference power source V
When CC and power ground GND are not supplied, D
Since a predetermined voltage is not applied to the RAM 2 and the DRAM control circuit 3, the data stored in the DRAM 2 is
Disappear.

Further, since the expansion memory board 6 is not connected to the main control board 1, the reference power supply VCC and the power supply ground GND are not supplied. Further, the positive electrode of the backup battery 9 is the Schottky diode D4.
Since it is connected only to the cathode of, the current does not flow and the backup battery 9 deteriorates in this state,
It does not reduce the battery life.

2) Connected state: When the main control board 1 and the expansion memory board 6 are connected and the main power supply is turned on, various signal lines and power supply lines are connected via the connector 4 as described above. Connected.

The voltage of the reference power supply VCC is applied to the anode of the Schottky diode D3, and the positive voltage of the backup battery 9 is applied to the anode of the Schottky diode D5. Since it is higher than the voltage of the positive electrode of the backup battery 9, a voltage lower than the voltage of the reference power supply VCC by the voltage drop of the Schottky diode D3 is applied to the IN terminal of the DC-DC converter 7.

A current flows from the reference power source VCC to the backup battery 9 via the resistor R1 and the Schottky diode D4, and the backup battery 9 is charged.

The OUT terminal of the DC-DC converter 7 is
It becomes the reference power supply VBU2, and a predetermined voltage slightly lower than the reference power supply VCC is output from the reference power supply VBU2.
The reference power source VBU2 is connected to the anode of the Schottky diode D2, but since the voltage of the reference power source VCC is higher than the voltage of the reference power source VBU2, the reference power source VBU2.
The voltage of BU1 becomes lower than the voltage of the reference power supply VCC by the amount of voltage drop in the Schottky diode D1, and no current flows from the reference power supply VBU2 to the DRAM2.

The reference power supply VBU2 is connected to the VDD terminal of the DRAM chip of the DRAM8 to supply power to the DRAM chip, and the power supply ground GND is connected to the GND terminal of the DRAM chip.
In accordance with a PU instruction, a normal operation for data storage is started, and a control signal and a strobe signal are sent back and forth via the memory bus 5 to store data. In addition, DRAM2
Since the voltage of the reference power supply VBU1 is applied to the DRAM control circuit 3 and the DRAM control circuit 3, the normal operation for data storage is started in accordance with the instruction of the CPU, as in the DRAM 8.
AM2 stores data.

Next, a description will be given of a case where the reference power supply VCC and the power supply ground GND are no longer supplied from the main power supply to the main control board 1 and the extension memory board 6 due to a power failure or the like in this state.

When the reference power supply VCC and the power supply ground GND are not supplied, the reference power supply VCC is in an electrically open state, and the power supply ground GND is connected to the backup battery 9 via the connector 4 by the power supply line. Therefore, the potential becomes the same as the negative electrode potential of the backup battery 9.

The positive electrode of the backup battery 9 is the connector 4
Via a short circuit formed on the main control board 1 to the anode of the Schottky diode D5, and the cathode of the Schottky diode D5 is DC-
Since it is connected to the IN terminal of the DC converter 7, from the moment when the voltage of the reference power supply VCC becomes lower than the voltage of the backup battery 9, the IN terminal of the DC-DC converter 7 becomes lower than the voltage of the backup battery 9. A lower voltage is applied as much as the voltage drop occurs at the Schottky diode D5.

The DC-DC converter 7 boosts the voltage applied to the IN terminal of the DC-DC converter 7 in its internal circuit, and the OUT terminal of the DC-DC converter 7 is the reference power source supplied from the main power source. The reference power supply VBU2 has a predetermined voltage slightly lower than VCC. Reference power supply V
BU2 is connected to the anode of the Schottky diode D2 via the connector 4, and the cathode of the Schottky diode D2 has a reference power supply VBU2 from the moment the voltage of the reference power supply VCC becomes lower than the voltage of the reference power supply VBU2. A voltage lower than the voltage of 1 by a voltage drop in the Schottky diode D2 is generated, and the cathode of the Schottky diode D2 serves as the reference power supply VBU1.

The reference power source VBU1 is the DRA of the DRAM2.
It is connected to the VDD terminal of the M chip and the DRAM control circuit 3, and supplies power to the DRAM chip and the DRAM control circuit 3. The power ground GND is the GND of the DRAM chip
Since it is connected to the D terminal and the DRAM control circuit 3,
The DRAM control circuit 3 can perform control necessary for holding the data stored in the DRAM 2.

Similarly, the reference power source VBU2 is DR
DR connected to VDD terminal of DRAM chip of AM8
Power is supplied to the AM chip, and the power supply ground GND is D
Since it is connected to the GND terminal of the RAM chip, DR
The AM control circuit 3 can perform control necessary for holding the data stored in the DRAM 8 via the connector 4.

[0042]

As described above, the backup device for the information storage device of the present invention is optional.
Since the substrate is provided with a backup power supply for backing up the first memory element and the second memory element, it is possible to meet the demand for downsizing and cost reduction, and further, with the backup power source on the second substrate, Not only the second storage element but also the first storage element on the first substrate is backed up, so that a backup apparatus for the information storage apparatus that does not waste the first storage element originally included in the information storage apparatus is provided. It becomes possible.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a memory configuration of a backup device for an information storage device according to the present invention.

[Explanation of symbols]

 1 Main Control Board 2 DRAM 3 DRAM Control Circuit 4 Connector 5 Memory Bus 6 Extended Memory Board 7 DC-DC Converter 8 DRAM 9 Backup Battery

Claims (2)

[Claims] 1. A first substrate provided with a first memory element for holding information by backing up with a power source; and a first substrate removably connected to the first substrate for holding information by backing up with a power source. A second substrate provided with a backup power supply for backing up the two storage elements and the first storage element and the second storage element; and a main power supply for supplying power to the first substrate and the second substrate. An information storage device comprising: a circuit for supplying power from the main power supply to the second substrate when the first substrate and the second substrate are connected; A circuit for backing up the second storage element is formed, and when power is not supplied from the main power supply, the backup power supply is the first storage element. Backing up the fine said second storage element, the backup device of the information storage device according to claim. 2. The backup device for an information storage device according to claim 1, wherein the second substrate is a circuit for backing up the second memory element from the backup power source when the second substrate is not connected to the first substrate. And a current does not flow from the backup power supply, the backup device for the information storage device.