JPS61271695A - Memory device - Google Patents

Abstract

PURPOSE:To extend the service life of a backup battery and to make the backup time longer by detecting a voltage of the backup battery to use a battery voltage control means thereby controlling the supply voltage. CONSTITUTION:A voltage of the backup battery 8 is detected by a voltage detection means 1 to control the battery voltage control means 2 and when a terminal voltage of the battery 8 is high, the voltage fed to an oscillation circuit 6, a refresh circuit 5 and a dynamic RAM 4 is made low and when the terminal voltage is lowered, the voltage is made high. Thus, the current consumption is decreased, even when the voltage of the battery 8 is lowered, the backup is continued and the service life of the backup battery is extended substantially and the backup time is made longer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a memory device using a dynamic RAM.

[Conventional technology]

FIG. 2 is a block diagram showing a conventional memory device. In the figure, 3 is a power supply switching means, 4 is a dynamic RA
M (DYNAMIC RANDOM ACCESS M
5 is a refresh circuit, 6 is an oscillation circuit, and T is a CPU.

B is a battery, and 9 is a control power source.

Next, the operation will be explained. In a memory device using a dynamic RAM 4 as a memory means, when the control power supply 9 is cut off, K is switched to another power supply to retain the memory contents of the dynamic RAM 4 and rewrites the dynamic RAM 2 at regular intervals (hereinafter referred to as , called refresh).

In this case, in the conventional memory device, the power supply switching means 3 switches to the battery 8, and the battery 8 supplies power to the dynamic RAM 4, the refresh circuit 5, and the oscillation circuit 6. At this time, the oscillation circuit 8 generates a refresh timing υ, and the refresh circuit 5 refreshes the dynamic RAM J.

[Problem that the invention seeks to solve]

Since the conventional memory device is configured as described above, when the control power supply 9 is cut off and the batch IJ-8K is switched,
As shown in FIG. 3, the terminal voltage of the battery 8 is high at the beginning of discharge, and therefore the dynamic RAM 4 and other circuits consume an unnecessarily large amount of current. Since the battery 8 reaches the end of its lifespan when it is no longer able to retain the memory contents, there is a problem that the battery backup time is short.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a memory device that can reduce unnecessary current consumption during battery backup and extend battery backup time.

[Means for Solving the Problems] The memory device according to the present invention detects the voltage at one terminal of the battery with a battery voltage detection means, and when the detected voltage at one terminal of the battery is higher than the unnecessary voltage for the parts and the quads, the memory device starts supplying power to the parts and quads. The battery voltage control means controls the supply voltage to a low level, and when it becomes low, increases the power supply voltage.

[Effect]

In this invention, the backup voltage is controlled by the battery voltage detection means and the battery voltage control means,
Extend battery life by reducing current consumption.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, numerals 3 to 8 are the same as or correspond to the conventional memory device described above. 1 is a battery voltage detecting means for detecting the voltage of the battery 8; 2 is a battery voltage detecting means that, when the battery voltage detected by the battery voltage detecting means 1 is higher than the atmospheric pressure required for backup, lowers the power supply voltage and lowers the voltage required for backup; This is a battery voltage control means that controls the power supply voltage to be increased when the voltage is exceeded.

In the hair removal device configured as described above, when the control power source 9 is cut off, the power source switching means 3 switches to the battery 8 in order to maintain the stored contents of the dynamic RAM 4. At this time, the voltage at one terminal of the battery is detected by the battery voltage detection means 1, and when the voltage at one terminal of the battery is sufficiently higher than the voltage required for backup, the backup voltage is lowered by the battery voltage control means 2 to reduce current consumption. . Next, when the voltage at one terminal of the battery decreases due to consumption of the battery 8, the backup voltage is increased by the battery voltage control means 2 to continue backing up the dynamic RAM 4. Therefore, the characteristics of the voltage at one terminal of the battery are as shown in Fig. 3. When the battery 8 is initially used, the backup voltage is lower than in the case of conventional memory devices, and when the voltage at one terminal of the battery decreases due to consumption of the battery 8, the voltage at one terminal of the battery decreases. Since the battery backup voltage is increased by the battery voltage control means 2, the battery backup time is longer than that of the conventional memory device, as shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, the voltage at one terminal of the battery is detected by the battery voltage detection means, and when the detected voltage at one terminal of the battery is higher than the voltage required for backup, K lowers the power supply voltage and becomes lower. Since the power supply voltage is sometimes controlled by the battery voltage control means to increase the power supply voltage, it is possible to reduce power consumption R,t of circuits such as dynamic RAM, extend battery life, and extend backup time. effective.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a memory device according to an embodiment of the present invention, FIG. 2 is a block diagram showing a conventional memory device, and FIG. 3 is a backup time and battery terminal voltage of the present invention and a conventional memory device. It is a comparison diagram of characteristics. In the figure, 1 is a battery voltage detection means, 2 is a battery voltage control means, 3 is a power supply switching means, 4 is a dynamic RAM, and 5 is a refresh circuit. 6 is an oscillation circuit, 7 is a CPU, 8 is a battery, and 9 is a control power source. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] An oscillation circuit, a refresh circuit connected to it, and a dynamic RA controlled by this refresh circuit.
M, a battery, and a power supply switching means for switching to backup of the battery when the control power supply is turned off, the battery voltage detection means for detecting the voltage of the battery, and the battery detected by the battery voltage detection means. The battery voltage control means is provided to control the power supply voltage to be lowered when the voltage is higher than the voltage required for backup, and to increase the power supply voltage when the voltage is lower than the voltage required for backup. memory device.