JPH04156236A - Battery backup circuit for memory - Google Patents

Abstract

PURPOSE:To easily and surely perform battery exchange without destroying the content of a memory by exchanging the first battery after the power supply to the memory is stabilized by connecting the second battery or a substitute DC power supply to a connector after the system power supply is turned off at the time of performing the battery exchange. CONSTITUTION:At the time of exchanging the first battery 4a, the second battery having a sufficient capacity is connected to a connector so as to stabilize the power supply to a data holding memory 1 after system power supply is turned off. After the power supply to the memory 1 is stabilized, the first battery 4a is removed and a new battery 4b having a sufficient capacity is mounted in place of the old battery 4a. When the second battery 5 is disconnected front the connector 3, the battery exchange is completed. Therefore, the battery exchange can be performed easily and surely without destroying the data in the memory.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to battery backup of memory, and more specifically, when the battery capacity for retaining memory data is exhausted, it is possible to restore the battery without losing the retained data. The present invention relates to a battery backup circuit for memory that can be replaced.

2. Description of the Related Art In recent years, it has become increasingly necessary for information processing equipment to retain data set by an operator or data set by a host even when the power is turned off. The capacity of such data varies depending on each information processing device, but it can be as small as several tens of bytes and as large as several tens of kilobytes.

Lithium batteries are usually used as batteries for battery backup circuits of such memories. Although this lithium battery cannot be recharged with a rechargeable battery, it is inexpensive and safe (recently, products that can be recharged with a lithium battery have been commercialized, but they are still expensive).

In recent years, the amount of memory data that must be held by batteries has increased, and the battery capacity required to hold data in memory has also increased. In addition, as the quality and reliability of information processing equipment improves, the lifespan of individual products is becoming longer and longer. Situations have arisen in which the battery must be replaced.In addition to these cases, there are also cases where the battery is rapidly depleted due to an unexpected accident and the battery must be replaced.

Hereinafter, a method for replacing a exhausted battery in a conventional memory battery backup circuit will be described.

FIG. 2 is a block diagram showing a battery pull-up circuit of a conventional memory.
It consists of a switching means 2 for switching between the system power source and the power source from the battery, a transistor 4, a resistor 6, and a diode 7.

When power is being supplied from the system, the switching means 2 is turned on and power to the memory 1 is supplied from the system side. At this time, the system power supply is +6v, for example.
Since the battery 4 normally has a voltage of about +3V, the diode 7 becomes a reverse negative voltage and becomes non-conductive. In this way, the diode 7 functions to block charging current to the battery 4 when the system power is turned on. This is because lithium batteries do not have a charging function.

If the system power is cut off, switching means 2
is turned off, and the voltage of the battery 4 is supplied to the memory 1. At this time, the resistor 6: -i (plays the role of limiting resistance for the current from the notebook). In this figure 2, when the capacity of the battery 4 decreases and the battery 4 must be replaced, the system power If the battery 4 is turned off, the battery 4 is removed, and a new battery is inserted, the power that should be supplied to the memory 1 will run out midway through, and there is a risk that the data in the memory 1 will be destroyed.

Problems to be Solved by the Invention In the conventional configuration described above, in order to replace the battery without destroying memory data, the data in memory 1 must be used by another system while the system power is on. The data must be read out, stored in another memory means, and then the battery must be replaced and the previously read memory data must be written into the memory 1 again.

Alternatively, the battery 4 must be replaced while the system power is on, but in this case, if the system power is suddenly cut off for some reason, the data in the memory 1 may be lost.

One way to solve this problem is to keep battery 4 at 2
It is possible to have multiple batteries in parallel, but it would require multiple batteries at all times, and it would be difficult to keep track of which battery is depleted.
■It is difficult to check, running costs are high, and portable devices increase volume and weight, so it is not a good idea.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and provide a memory backup circuit that reliably protects data in the memory and allows easy battery replacement.

Means for Solving the Problems In order to achieve the above object, the present invention provides a system in which a memory is connected in series between a system power supply and a power supply terminal of the memory, and when the system power is supplied to the memory. a switching means that is turned on and turned off when the system power supply is cut off; and a first switch that is always connected in a conductive direction to the diode through a diode and a resistor in series between the power terminal and the ground terminal of the memory. battery and
The first terminal is connected to the positive terminal side of the first battery, and the second terminal is connected to the negative terminal side of the first battery, and the first terminal is connected to the negative terminal side of the first battery, and the second terminal is connected to the negative terminal side of the first battery. and a connector for connecting a battery or an alternative DC power source such that the first terminal side becomes the positive terminal, and for removing the second battery or the alternative DC power source after replacing the first battery. The structure is as follows.

According to the above-described configuration, the present invention connects the battery or an alternative DC power source to the connector of the cylinder 2 after turning off the system power when replacing the battery to keep the power supplied to the memory stable, and then By replacing the first battery, the battery can be easily and reliably replaced without destroying the contents of the memory.

Embodiment FIG. 1 is a block diagram showing a memory backup circuit according to an embodiment of the present invention, which includes a memory 1 for holding data, a switching means 2 for switching power from the system power supply, First battery 41
L1 second connector 3 for connecting C connector 5,
a resistor 6 that limits the discharge current of the first battery 4a;
Diode 7 for blocking charging current to the battery
It consists of

In this embodiment consisting of the above-mentioned components, the operation of a battery replacement method when the first battery 4 is exhausted and the battery capacity is reduced will be described.

Whether the capacity of the first battery 4IL has decreased is determined by the first
It can be detected by monitoring whether the voltage of the battery has fallen below the memory retention voltage (not shown).

In FIG. 1, when replacing the first patch 1J41L, first turn off the system power, connect the second battery 6 with sufficient capacity to the connector 3, and then replace the data retention memory 1.
Stabilize the power supply to. The battery connection method at this time is to connect the positive terminal side of the second socket 6 to the connector 3.
Connect the negative terminal to the first terminal 3m of the connector 3', and connect the negative terminal to the second terminal 3m of the connector 3'.
The first battery 4 and the second battery 6 are connected in parallel to each other.As described in the conventional example, when the system power is off, the switching means 2 is turned off, and power to the memory 1 is supplied by the first and second batteries 41L16 connected in parallel.Next, the exhausted first battery 4a is removed. 2
The second battery 5 supplies power to the memory, and even if the first battery 4a is removed, the power supplied to the memory 1 remains stable. Here's a new capacity-enough bunch! J41
) (not shown) is attached to the part where the first battery 41L was removed. Finally, the second battery 6 is removed from the connector 3 to complete the battery replacement. At this point, the power supply for memory 1 is powered by the newly replaced first batch 1J.
Powered by 4b.

As described above, according to this embodiment, a connector 3 for battery replacement is provided, and a spare battery is connected to the connector while a worn-out battery is replaced, thereby providing a temporary power supply source to the memory. , battery replacement can be easily and reliably performed without destroying data in the memory.

Note that the second battery does not have to be a battery and may be a stabilized alternative DC power source.

Although the specific configuration of the switching means 2 was not mentioned in this embodiment, this switching means uses switching elements such as transistors and diodes to gradually reduce the voltage when turning off the supply from the system power supply. All you need is a function to do this, and it can be configured easily.

Note that the memory 1 may be removed from the main body, and in that case, this switching means may be located on the main body side or on the memory side.

Effects of the Invention The present invention provides a connector for connecting a battery for temporary power supply to the memory or an alternative DC power source when replacing the battery, thereby destroying the data held in the memory that is backed up by the battery. Without,
It is possible to realize an excellent 9-memory backup circuit that allows the battery to be easily and reliably replaced, and that also has the effect of reducing regular volume and weight, and lowering running costs.

[Brief explanation of the drawing]

Figure 1 shows one 5i! of the present invention! FIG. 2 is a block diagram of a battery backup circuit of a memory according to an embodiment. FIG. 2 is a block diagram of a battery backup circuit of a conventional memory. 1.--Memory, 2.--Switching means,
3... Connector, 3a... First terminal,
3b...Second terminal, 41L, 4b...
・First battery, 6...-Second battery, 6
...Resistor, 7...Diode. Name of agent: Patent attorney Akira Kaji and 2 others 3-
Connector 3a---I I n1 child 3b-1142H14 child 4---$16 battery 5---It 2a battery

Claims (1)

[Claims] A memory battery backup circuit capable of retaining data stored in the memory using battery power even when the system power supply is cut off, the circuit being connected between the memory and the system power supply and the power supply terminal of the memory. a switching means that is connected in series to the memory and turns on when system power is supplied to the memory and turns off when the system power is cut off; and a diode and a resistor between the power supply terminal and the ground terminal of the memory. a first battery that is always connected in a conductive direction to the diode in series; its first terminal is connected to the positive terminal of the first battery; and its second terminal is connected to the negative terminal of the first battery. a second battery or an alternative DC power source is connected in advance so that the first terminal side becomes the positive terminal when the first battery is removed for replacement;
and a connector for removing the second battery or alternative DC power source after battery replacement.