JPS61221668A - Detecting and processing system for backup voltage - Google Patents

Abstract

PURPOSE:To perform effective processing without malfunction nor necessary operation and to improve the reliability of a system by deciding which of the voltage of a backup power source and a reference voltage is higher during a recovery from a power failure and then selecting a program. CONSTITUTION:The backup power source 24 generates a hold voltage VX for protecting the contents of a RAM 23 in a device which protects information in the RAM 23 during a power failure or when electric power is cut off. A reference voltage generator 29 generates the reference voltage Vref which is stable against temperature and corresponds to the lowest hold voltage. A decision device 30 compares the voltages VX and Vref with each other when the recovery from the power failure is made or when the power source is turned on again to decide whether the VX is higher than a voltage required to protect the contents of the RAM 23 or not. Programs for processing are switched on the basis of the state of the voltage VX i.e. according to whether the contents of the RAM 23 are protected or destroyed and necessary data in the contents of the RAM 23 are restored.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a device using a backup power source for protecting information in a semiconductor storage device used in a microcomputer or the like during a power outage or shutdown. especially,
Regarding a device that performs processing using information stored in the semiconductor storage device, it relates to a backup voltage detection processing method that determines whether the voltage of the 'rL source is high or low at the time of recovery from a power outage or when the power is turned on again, and selects a program depending on the state. .

(2) Prior Art and Problems' In general, devices that use information in semiconductor storage devices use a backup power source to protect the information in the event of a power outage or cutoff of the commercial power source.

However, the power outage or cut-off time is long and consumes the backup power supply, and the voltage of the power supply decreases, making it impossible to protect the information and resulting in destruction. Therefore, when this information is used, malfunctions occur, unnecessary processing is performed, and effective processing cannot be performed.

(3) Purpose of the Invention The present invention aims to solve this problem by:
Backup voltage detection that can determine whether the voltage of the backup power supply is higher than the holding voltage when recovering from a commercial power outage or when it is turned on again, and can select a program and perform effective processing according to the determination. The purpose is to provide a processing method.

(4) Structure of the Invention As illustrated in FIG. 1, means Ll for generating a backup voltage to protect information in a semiconductor memory device with low current consumption, means 1 for generating a reference voltage, A backup voltage detection processing method comprising means for determining whether the backup voltage is high or low between the backup voltage and the reference voltage, and means for selecting a program according to the output of the determining means.

(5) Examples of the invention Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 2 is a block diagram showing a first embodiment in which the present invention is applied to a processing device.

A read-only memory (hereinafter referred to as ROM) is used to store programs and tables for control and calculation.
n is a read/write memory (hereinafter referred to as RAM) that stores data that can be changed depending on the purpose.
This is a central processing unit (hereinafter referred to as CPU) that sequentially performs control and calculations according to the contents of 2-. Note: This is a backup power source with a battery input (see Figure 4), which will be described later, to generate a holding voltage vx to protect the contents of the RAM υ- when the commercial power supply for this device is out of power or interrupted. The output is connected to the RAM2M. The profit is the corresponding CPU
The reed is an input circuit that provides an output interface between the CPU 21 and an external circuit (device), and the reed is an input circuit that provides an input interface between the CPU 21 and the external circuit (device).
connects the CPU 21, the ROM 2u, the RAM υ-, the output circuit board and the input circuit board, respectively, and connects the address bus, data bus, control bus and DC type i
J! This is a bus consisting of power supply wiring, etc. from (not shown). The distributor is a console having a display for displaying the output from the output circuit (2) and a keyboard for inputting input to the input circuit board. A reference voltage generator is a reference voltage generator that generates a reference voltage Vref that is stable with respect to temperature and corresponds to the minimum holding voltage, and is responsible for generating a reference voltage Vref from the backup power supply C to the RAM.
This is a discriminator that compares the reference voltage VreF with the holding voltage vx which is added to the holding voltage 1 and the battery stroke occurs, and outputs an L level if the reference voltage VreF is larger than the holding voltage If the voltage vx is larger than the reference voltage Vref, an H level is output. The output of the discriminator envelope is connected to the input of the input circuitry.

FIG. 4 is a diagram showing an example of the configuration of the backup power source C of the present invention.

``Frog'' is a memory cell such as a CMOS memory in the RAM η-, and ``Frog'' is a battery such as an alkaline storage battery or an electric double layer capacitor that generates a holding voltage vx as a power supply source for the backup power supply. The voltage vx at both ends is the detection voltage.

The battery V- is connected between the voltage terminal (1) and Ov of the DC power supply via a reverse current blocking diode D1 and a charging current limiting resistor R1. D2 is a diode connected in parallel with the resistor R1 to reduce the voltage drop across the resistor R1 and supply the voltage from the battery U to the memory cell. Note that if the voltage drop across the resistor R1 is small and does not pose a problem, the diode D2 is unnecessary.

However, whether the time constants of the resistor R1 and the battery U are made sufficiently large to reduce the influence of the increase in the holding voltage vx due to charging of the battery 2 by the DC power supply, or whether the time constants of the diode D1 and the resistor R1 are It is preferable to provide a switch in between to eliminate the influence of the DC power source (I) during the discrimination period and to supply the DC power to the line battery U after the discrimination.

Normally, power is supplied to the memory cell from the power source of the voltage generator via the diode D1. If the commercial power supply is interrupted or interrupted, the DC power supply (
When the voltage (not shown) decreases, the voltage is supplied from the battery v2 to the memory cell via the diode D2. However, it is cut off by the diode D1 and no current flows through the power supply.

Referring to FIG. 3, regarding the operation of the first embodiment of the present invention,
This will be explained below.

FIG. 3(a) is a flowchart showing an overview of the operation of this embodiment, and FIG. 3(b) is an example of a flowchart showing the voltage detection processing routine n.

When the power is turned on, this program starts with the step hand and proceeds to step formation. In step 1, a voltage detection processing routine to be described later is executed, and the process proceeds to step formation. In stepping, a control routine that performs the main calculations and control of the apparatus is executed, and then the process proceeds to step and ends.

The voltage detection processing routine starts at step η2 and proceeds to step formation. In the step formation, the discrimination result on the discriminator side is inputted from the input circuit board, and the process proceeds to the step formation.

In stepping-, the reference voltage ■ is lower than the holding voltage vx.
When the resistance is small, the determination result is input as an H level, and since the contents of the memory of the RAM 2u are preserved without being destroyed, the process proceeds to step n. In step n, since the contents of the RAMn are normally saved, normal initialization (for example, initialization of the input circuit board and output circuit group) is performed, and the step is proceeded to end the voltage detection processing routine. In addition, when the reference voltage V or f is larger than the holding voltage (9) in the number of steps, the discrimination result is input as L level, and the discrimination result is not H level and the RAM f
Since the memory contents of i are destroyed, step-
Proceed to. In the step formation, at least the minimum necessary data of the contents of the RAM 21 is restored using a keyboard or the like, and after performing the same processing as step n, the step formation proceeds and the main voltage detection processing routine ends.

FIG. 5 is a block diagram showing a second embodiment in which the present invention is applied to a data logger.

In this embodiment, the same components as those in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted.

(2) is a clock for setting periodic data acquisition and for knowing the data acquisition time in the event of an abnormality, and (1) is a clock connected to the console housing, and is connected to the output circuit and input circuit board of the first embodiment. It is an input/output circuit (hereinafter referred to as Ilo) having the functions of , and ■ is a group of sensors for detecting temperature, current, power, etc. The residence is an analog-to-digital converter (hereinafter referred to as (referred to as ADC).

Notes on the CPU, ROM fl, RAM configuration, and clock 51-
Said 1105. i- and the ADC5M are respectively connected by the bus.

The operation of the second embodiment of the present invention will be described below with reference to FIG.

FIG. 6 is an example of a flowchart showing the voltage detection processing routine 32 of FIG. 3(a).

The voltage detection processing routine n starts at step number and proceeds to step number. At the step number, conversion of the ADc5H is started and the step sequence is proceeded to. In the number of steps, the ADC
The number of steps is looped until the conversion of d is completed, and when the conversion is completed, the process advances to the step number. In the step garden, the converted value move on. In step U-, conversion 1 of the ADCi
Compare IiIX with the voltage Y required to protect the contents of the RAMfi, and if Y<X, proceed to step n;
After performing the same process as step n of the first embodiment, the process proceeds to stepwise processing and the present voltage detection process routine ends. Also,
If Y≧X, the process proceeds to step correction, and after performing the same process as step n of the first embodiment, the process proceeds to step correction and ends the voltage detection processing routine.

(6) Effects of the present invention As described above, in the present invention, the holding voltage of the battery U,
Determine whether the voltage is higher than the voltage required to protect the RAM 2.2- at the time of recovery from power failure or re-powering the battery, and process when the contents of the RAM η2 are protected by the state of the holding voltage vx of the battery. and means for switching a program for processing when the contents of the RAMfl are destroyed,
Only if the contents of the RAM 22 are destroyed, the RAM 22
It is possible to restore at least necessary data among the contents of M2u, perform effective processing without malfunctions or unnecessary operations, and improve the reliability of the system.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of the present invention. FIG. 2 is a block diagram showing a first embodiment in which the present invention is applied to a processing device. FIG. 3(a) is a flowchart showing an overview of the operation of this embodiment, and FIG. 3(b) is an example of a flowchart showing the voltage detection processing routine η-. FIG. 4 is a diagram showing an example of the configuration of the backup power supply 24 of the present invention. FIG. 5 is a block diagram showing a second embodiment in which the present invention is applied to a data logger. FIG. 6 is an example of a flowchart showing the voltage detection processing routine 32 of FIG. 3(a). (Explanation of symbols)

Claims (1)

[Claims] means for generating a backup voltage to protect information in a semiconductor storage device with low voltage consumption; means for generating a reference voltage; means for determining whether the backup voltage and the reference voltage are high or low; A backup voltage detection processing method comprising means for selecting a program according to the output of the means.