JPS62214420A - System for protecting storage by backup battery - Google Patents

Abstract

PURPOSE:To prevent the decay of register data by automatically keeping a power source turned on if the voltage of a backup battery falls to a value lower than the data protection voltage of a volatile memory. CONSTITUTION:A prescribed voltage is supplied from a main power source 2 to a volatile memory 1; and when the power source is turned off, the power source is switched to a backup battery B by diodes D1 and D2 to supply power to the memory 1 automatically. A voltage detecting part 4 monitors the voltage of the battery B and lights a voltage fall display lamp L. In this case, a relay RL which holds the main power source 2 in the turning-on state and a switch circuit Tr which operates the relay RL are provided. When the voltage fall state signal is outputted from the voltage detecting part 4, power is supplied to the relay RL by the switch circuit Tr to close a contact RL-S provided in parallel with a power on/off switch S1. As the result, the function of the switch S1 is invalidated to prevent an operator from turning off the power source erroneously.

Description

[Detailed Description of the Invention] [Summary] The present invention monitors the voltage of a back amplifier battery provided for data protection in a volatile memory, and detects when the battery voltage drops below the memory retention voltage of the volatile memory. It is characterized by keeping the main power supply turned on.

[Industrial application field]

The present invention relates to an improved storage protection scheme for volatile memory.

In a data processing device or the like, important data that is constantly used, such as registered data, is stored in a volatile memory backed up by a battery and protected.

This backup battery switches to the main power supply when the power is cut off and supplies a predetermined voltage necessary for memory retention.If this voltage drops and data is lost, it must be re-registered.To prevent this, When a voltage lower than a predetermined voltage is detected, a voltage drop indicator lamp is turned on to issue a warning to the operator.

However, with the conventional method using a warning lamp, there is a possibility that appropriate processing such as canceling the power-off operation or replacing the battery may not be performed, and there is a need for a memory protection method that solves this problem.

[Conventional technology]

FIG. 3 is a block diagram of a conventional data protection unit. Volatile memory 1 is supplied with a predetermined voltage (+5V) from main power supply 2, and when the power is turned off, diodes DI, D
2 switches to backup battery B and automatically +
5).

The voltage detection unit 3 monitors the voltage E of the backup battery B, and when it detects a state below a predetermined voltage (memory retention voltage) EO necessary for memory retention in the volatile memory 1, it turns on the voltage drop indicator lamp L. lights up.

Therefore, if the voltage drop indicator lamp L is on, the operator should not disconnect the main power supply 2 and replace the backup battery B, or if it comes with a charging device, charge it and increase the voltage. After leaving it until the lowering indicator lamp L goes out, the main power source 2 is turned off.

Further, if the power-off state is longer than a predetermined time and the voltage drop indicator lamp L is lit, the main power source 2 is turned on.

In addition, in the figure, Sl is a power on/off switch of the main power supply 2.

[Problem to be Solved by the Invention 3] The conventional method described above only lights up the alarm lamp, and if the operator accidentally turns off the power when the lamp is turned on, or if the power is turned off for a long time, registered data may be lost. There was a problem that there was a possibility that it might disappear.

An object of the present invention is to provide a memory protection system that solves the above problems.

[Means for solving problems]

For the above purpose, the memory protection system using a backup battery of the present invention, as shown in the principle explanatory diagram in FIG. The device is equipped with a means (5) for keeping the main power on when the condition is detected, and when the voltage of the backup battery drops below the storage retention voltage of the volatile memory, the main power is kept on and the data is stored. It protects the memory of

[Effect]

When the voltage of the backup battery drops below a predetermined voltage, for example, a relay is operated to maintain the main power source in a power-on state.

This disables the main power on/off switch and
This prevents the operator from accidentally turning off the power, and if the battery voltage drops while the power is turned off, the power is automatically turned on.

〔Example〕

An embodiment of the present invention will be described with reference to FIG.

FIG. 2(a) is a block diagram of the data protection unit of the embodiment, and includes a relay RL for keeping the main power supply turned on.
and a switch circuit Tr for operating relay RL.

In this embodiment, the conventional voltage drop indicator lamp L is placed on standby, and the same reference numerals as in FIG. 3 represent the same objects.

The operation will be explained below.

The voltage detection unit 4 monitors the voltage of the backup battery B, and outputs a voltage drop state signal 10 when it detects a voltage lower than the storage retention voltage EO.

This voltage drop state signal 10 turns on the switch circuit Tr, makes the relay RL conductive, and closes the contact RL-S inserted in parallel to the power on/off switch S1.

As a result, the main power source 2 is maintained in the power-on state, and the function of the power on/off switch S1 is disabled.

As described above, when the voltage of the backup battery B is low, the disconnection by the power on/off switch S1 is disabled and the power on state can be maintained. When a voltage drop is detected, the main power supply 2 is automatically turned on to protect data storage.

Note that if the voltage is restored with a charging device, it can return to normal.

The present invention can be operated more effectively by providing means for validating/invalidating the holding means, and an embodiment thereof is shown in FIG.
b) Shown in the diagram representing valid/invalid means.

That is, a valid/invalid switch S2 is provided in series with the contact RL-3, and when this switch S2 is set to the open side, the contact RL-3 becomes invalid and only the alarm by the voltage drop indicator lamp L is activated.

Although the present invention automatically turns on the power in response to a voltage drop in the backup battery B, if a conventional voltage drop indicator lamp L is also used, operational effects such as battery replacement will be even greater.

〔Effect of the invention〕

Since the present invention automatically maintains the power on when the voltage of the bank-up battery drops below the data protection voltage of the volatile memory, it is extremely effective in protecting data storage.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the principle of the present invention, Fig. 2(a) is a block diagram of the data protection section of the embodiment, and Fig.
FIG. 3B is a diagram showing valid/invalid means, and FIG. 3 is a block diagram of a conventional data protection unit. In the figure, 1 is a volatile memory, 2 is a main power supply, 3.4 is a voltage detection unit, B is a backup battery, L is a voltage drop indicator lamp, Di and D2 are diodes, Sl is a power on/off switch, and S2 is a valid/invalid switch, RL is a relay, RL-3 is its contact, and Tr is a switch circuit.

Claims (1)

[Claims] A backup battery (B) is provided that supplies a predetermined voltage necessary for memory retention to the volatile memory (1), and when the main power supply (2) is cut off, the backup battery is switched to the volatile memory. A memory protection method for retaining data, comprising means (4) for monitoring the voltage of the backup battery, and maintaining the main power supply in an on state when a voltage state below the memory retention voltage is detected. A backup battery comprising means (5), characterized in that when the voltage of the backup battery drops below the memory retention voltage of the volatile memory, the main power is kept turned on to protect data storage. Memory protection method.