JPH0579950B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a device for detecting the lifespan of backup batteries used in integrated circuits for watches, microcomputers, and other devices.

Conventional configurations and their problems All commonly used backup battery life detection devices use a separate voltage detection circuit to detect whether the voltage of the backup battery has fallen below a predetermined value. It is simply configured to detect Therefore, although this type of device has a very simple configuration overall, it is necessary to constantly supply voltage detection current to the backup battery in order to detect the voltage of the backup battery. However, even during non-power outages, there was a problem that the backup battery was exhausted, albeit slightly.

Purpose of the Invention The present invention eliminates the above-mentioned conventional drawbacks, and provides an excellent backup battery life detection device that has a simple configuration and hardly consumes the backup battery during non-power outage or when the power is on. The purpose is to

Structure of the Invention In order to achieve the above object, the present invention provides, in addition to a first clock oscillator backed up by a backup battery at the time of a power outage or power off, a second clock oscillator that stops its operation at the time of a power outage or power off. A clock oscillator is provided, and the outputs of these oscillators are counted by separate counting circuits, and the difference is used to detect the time that the backup battery has been used, that is, the life of the backup battery. It is composed of

DESCRIPTION OF THE EMBODIMENTS The figure is a block diagram of an embodiment of the backup battery life detection device of the present invention, and in the figure a
is a power supply terminal that applies a DC voltage obtained by rectifying and smoothing the commercial power supply, 1 and 2 are diodes for backflow prevention, 3 is a battery for backup, and 4 is the voltage that appears at the connection point of diodes 1 and 2 for backflow prevention. The circuit block 5 is driven by the circuit block 4.
a first clock oscillator 6 provided within the clock oscillator 5; a counting circuit 7 for counting the output of the clock oscillator 5;
8 is a counting circuit provided in the circuit block 4 and counts the output of the second clock oscillator 7; 9 is a counting circuit 6; 10 is a count number setting means for setting a count number that is a guideline for battery life; 11 is a calculation circuit for calculating the difference between the count number of the arithmetic circuit 9 and the count number of the counting circuit 8; A comparison circuit 12 outputs a predetermined signal when the count exceeds a preset count number.

In the above embodiment, when there is no power outage, the power terminal a
A predetermined voltage is applied to the clock oscillator 5, and both the first clock oscillator 5 and the second clock oscillator 7 are in operation. Therefore, the counts of both the counting circuits 6 and 8 increase in the same way, and the output of the arithmetic circuit 9, that is, the difference between the count of the counting circuit 6 and the count of the counting circuit 8 does not change at all.

If a power failure were to occur, the first clock oscillator 5 would continue to operate using the backup battery, but the second clock oscillator 7 would stop operating at that point. Therefore, the counting circuit 6
The count number continues to increase, but the counting circuit 8
The counting number stops at the same time as a power outage, and the counting number at the time of the power outage is maintained as it is. Therefore, in this state, the difference between the output of the arithmetic circuit 9, that is, the count number of the counting circuit 6 and the count number of the counting circuit 8 gradually increases. When the power outage is removed, the second clock oscillator 7 operates again and the output of the arithmetic circuit 9 stops increasing; however, when the power outage occurs again, the output of the arithmetic circuit 9 increases and accumulates in the same way. Therefore, if the power outage is repeated several times or continues for a long time, the output of the arithmetic circuit 9 will become larger than the value set by the count setting means 10. The output of the arithmetic circuit 9 is the count number setting means 1
When the value exceeds the value set by 0, the comparison circuit 11 outputs a predetermined signal, and the alarm indicator 12 indicates that the backup battery 3
Displays the lifespan of.

In this way, according to the above embodiment, the first
In addition to the second clock oscillator, a second clock oscillator is provided that stops operating in the event of a power outage, and the outputs of these oscillators are counted by separate counting circuits, and the battery life is detected from the difference. This structure has the advantage that the backup battery is not consumed at all during non-power outages, and the life of the backup battery can be significantly extended. According to the above embodiment, the first clock oscillator uses a clock circuit that continues to operate using a backup battery even in the event of a power outage, and the second clock oscillator uses a microcomputer clock oscillator that stops operating in the event of a power outage. Since the first and second clock oscillators are the clock oscillators of standard clock circuits and microcomputers, it is not necessary to prepare separate circuits for the first and second clock oscillators. It has the advantage of simplifying the overall configuration and being inexpensive. Further, according to the above embodiment, a count number setting means 10 is separately provided, and the count number can be arbitrarily set by this means 10, so that an alarm is issued before the backup battery 3 becomes completely unusable. It is also possible to display this using the display 12, which is extremely advantageous in practice.

In the above embodiment, the arithmetic circuit 9 and the comparison circuit 1
1. There is no explanation as to where the power for the alarm indicator 12 is taken from, but if these power sources are also taken from the power terminal a, the life of the backup battery 3 can be further extended. . In addition, in the explanation of the above embodiment, it was explained how each circuit operates during a power outage and when there is no power outage, but it operates in the same way even when the power switch connected to the front stage of the power supply terminal a is turned on and off. It goes without saying that this should be done.

Effects of the Invention As is clear from the above embodiments, the present invention provides a first clock oscillator that is backed up by a backup battery at the time of a power outage or power off. A second clock oscillator that is stopped is provided, and the outputs of these oscillators are counted by separate counting circuits, and the life of the backup battery is detected based on the difference,
This has the advantage that the backup battery is hardly consumed during non-power outage or when the power is on, and the life of the backup battery as a whole is significantly extended.

Further, the setting means sets the life span of the backup battery or a value immediately before that life, and the arithmetic circuit
The display means takes out the value of the difference between the counting circuits provided in each of the second oscillators and displays it when the value of the arithmetic circuit is larger than the value of the setting means, so the user can visually check the display means. This has the advantage of being very practical, since the battery can be replaced by knowing when the backup battery is about to reach the end of its life or when it has reached its end.

Furthermore, the first clock oscillator uses a clock circuit that continues to operate using a backup battery even in the event of a power outage, and the second clock oscillator uses a microcomputer clock oscillator that stops operating in the event of a power outage. The first is the clock circuits and microcomputer clock oscillators used.
Since it is used as the second clock oscillator, there is no need to prepare separate circuits for the first and second clock oscillators, and the overall configuration can be simplified.
It has the advantage of being inexpensive.

[Brief explanation of the drawing]

The figure is a block diagram of an embodiment of the backup battery life detection device of the present invention. a... Power supply terminal, 1, 2... Backflow prevention diode, 3... Backup battery, 5, 7... Clock oscillator, 6, 8... Counting circuit, 9... Arithmetic circuit, 10... Count number Setting means, 11...comparison circuit, 12...alarm indicator.

Claims (1)

[Claims] 1. A first clock oscillator that continues to operate using a backup battery even during a power outage or power off; a second clock oscillator that stops operating during a power outage or power off; provided in each of the two clock oscillators,
a counting circuit for counting the output value of the oscillator; a calculation circuit for extracting the difference between the output values of each of the counting circuits; a setting means for setting the life of the backup battery or a value immediately before that; A lifespan detection device for a backup battery, comprising a comparison means for comparing a value of the circuit and a value of the setting means, and a display means for displaying on a display when the value of the arithmetic circuit is larger than the value of the setting means.