DE4041696C1 - Charge state monitor for power source of electronic timepiece - has output voltage measurer connected to counter for lower and upper thresholds - Google Patents

Abstract

A circuit, for monitoring the state of charge of a battery source for clocks/watches which run independently of mains supply measures the output voltage of the source (Ua) via a metering module (1). A pulse generator (4), driving a counter (2), provides a timed interval of 24 hours during which the voltage (Ua) must be continuously below a threshold value before a warning signal unit (7) is activated. A second counter (6) triggers a signal unit (7) after 10 days as long term confirmation of battery exhaustion. Warning signals may be optical or acoustic. USE/ADVANTAGE - Prevents spurious triggering of first warning signal caused by transient voltage drops, e.g. stepping motor jamming. Gives user several days forewarning before battery is in totally unserviceable state. Applicable to either analogue or digital display.

Description

The invention relates to a device for monitoring the loading State of batteries and accumulators of off-grid Electronic clocks according to the preamble of claim 1.

Network-independent, i.e. battery or accumulator-operated Electronic watches are well known today, both in the form of so-called small watches, which means above all a bracelet clocks, as well as in the form of so-called clocks, that is, before all wall, table and alarm clocks. For example, is out the Braun program overview, autumn 1990, page 29 the quarzge controlled Braun alarm clock AB 30 known as an energy source either with an operating voltage of 1.5 volts the so-called "mignon cell" or with a corresponding Ak accumulator is operated, the latter mostly being Nickel-cadmium accumulators deals with a voltage of 1.2 volts have a capacity of about 500 mAh.

A disadvantage of all such watches is the fact that their users far beyond the state of charge of their energy source going to be left in the dark. With an average The lifespan of between 1 and 3 years is announced Exhaustion of such energy sources only by the fact that ent neither the clock is running, in the case of alarm clocks that is from a piezoelek Acoustic signal emitted trical converter garbled abge will give or even fail, or from an often existing Device for electrical lighting of the time display only a dull or no light is emitted anymore. In all of these Cases, it may already be too late for the user of the watch to procure new batteries immediately, for the sake of their not in stock even without aging should be kept.  

To make matters worse, the exhaustion of energy accompanying voltage drop for different types of Energy sources run very differently. This is how it goes Voltage drop in batteries of relatively high capacity, as in for example, mercury, silver or lithium batteries for a long time very flat and only accelerates towards the end of their le Life drastically. Conventional medium capacity batteries show, on the other hand, a significantly larger voltage drop on, but fall out at the end of their lifespan output voltage not so drastically.

As a result of these conditions, unexpected occurrences occur again and again drive interruptions of the watch, which is particularly the case with alarm clocks watches can have unpleasant consequences.

To avoid such uncertainties are for electronic Watches have already been proposed with various means the end of the life of the energy source can be monitored, and which may emit a warning signal.

So in US-PS 40 24 415 is also in an electronic Watch usable circuit described, the at least one pair of MOS transistors, which are connected so that at least one of these transistors in its conductive state is offset when the output voltage of the energy source is below a definable threshold drops. As a result of this by means of a complementary MOS inverter case signaling display element activated. Disadvantageous this method of monitoring the state of charge of the energy source it is that the display directly shows all voltage fluctuations of the Energy source follows. So all faults that lead to an Un exceeding the threshold value of the output voltage are connected to address the display, on the other hand, by a, with  a load rise associated with a rise in the output voltage the display is deleted when the threshold is exceeded. For example, when displaying an upright, analog display the clock can be when the second hand is against the heavy moved upward by force, the indicator light up while it again when the second hand moves on its way down goes out.

Another solution is described in CH 6 07 603 G (A3). A Quartz movement controlled by an electromagnetically driven The second hand of the watch, that at normal Output voltage of the energy source switched on every second becomes. If the output voltage falls below a certain threshold value, the second hand will be spaced by two Seconds incremented by two seconds at a time.

Finally, EP 02 03 330 B1 is a battery-operated one known electronic watch, which is also an electromagnetic driven stepping mechanism. Advance switching on the step switch, which are not executed by this, are fed to a counter and increase its counter reading. A warning signal is issued when a certain counter reading is reached set. A disadvantage of this indirect method of determination of the state of charge of the energy source is that an error in the on drove the watch, be it electrical or mechanical, also leads to the delivery of the warning signal, although the Energy source are still in a sufficient state of charge can. Another disadvantage of this known method is in that for fundamental reasons it is hardly used for digital displays de clocks can be used. Because it is hardly possible to a comparable to the advancement of a second hand indirect way to determine whether the driver circuit of a Di gital ad works properly or whether it is due to exhaustion the energy source to a barely perceptible display  ge or even to the failure of the digital information to be displayed tion is coming.

Accordingly, the invention has for its object a direction according to the preamble of claim 1 to improve that this firstly has a lower drawer state of the energy source when its output voltage falls permanently below a predefinable threshold value and at others without changing their structure, even with digital displays Clocks can be used.

This task is for a device according to the preamble of Claim 1 by the characterizing features of this Pa claim resolved.

The device according to the invention has the advantage that it directly measures the output voltage of the energy source without immediately when it first drops below the predefinable threshold Give warning signal. This will cause the watch to malfunction, caused, for example, by a malfunction of the stepping mechanism or the driver circuit of a digital display and not through an excessive drop in the output voltage of the energy source caused for the user of the watch not falsely connected with the warning signal "battery discharged". To this In this way, the user can start the watch when the time stops means of pointing, be it pointers or a digital display, clearly recognize whether a dead battery or a defect in the pointer drive or the driver circuit of the digital display for an inhibited or even stationary time display. By on the other hand, the use of the counter does not become the same Any undershoot of the predefinable threshold value of the output voltage answered with a warning signal, since there is only a The voltage undershoot that often started the meter leads to the issuance of the warning signal.  

If the device is further developed according to claim 2, the result is the advantage that longer-term, but again temporary Undershoot of the threshold value of the output voltage of the Energy source can occur without being mistakenly the same a warning signal is given. Such temporary sub A step switch, for example, can interfere caused by a speck of dust, which after some Switching steps can be grated again and thus is ineffective again.

The embodiment of the device according to claim 3 enables it, the device itself and the warning signal delivery device to be installed separately on the clockwork. This is the half of an advantage because, for example, alarm clocks already have one Have signal delivery device that the warning signal delivery replace direction and also indicated by the device can be controlled. This makes it possible to set alarm clocks on relatively simple way to complete the device, what a Cost-effective expansion of the variety of types in large series manufacture manufactured alarm clocks means.

If the device is further developed according to claim 4, the result is the advantage for the user of the watch that he with increasing Er creation of the state of charge of the energy source and finally another, different warning signal ver gets averaged. So the user of the watch after the appearance of the Warning signal still enough time to procure a new one Plan for an energy source because he can count on the Do not stop operating your watch very soon becomes.

Warning signals according to claim 5 and 6 offer the advantage that they clearly differ from each other for the user of the watch  the one, so that there can be no doubt as to which of the two discharge states the energy source is actually located finds.

One chooses if the threshold value is continuously fallen below the output voltage for the duration of the warning signal nals and for the period of time until the warning signal modulates or on further warning signal is sent, periods of time according to claim 7, this results reasonably for the practical operation of the watch periods of time that are available to its users for one Change the energy source. That already gives way The 24-hour warning signal is sufficient for the user early warning that a change of energy source is on stands without there being a risk that the watch will be out of loading drive is set. First of all, the user refrains from doing so Replacing the energy source, it will be ten days later occurring modulated or indicated by the further warning signal shows that there is now even a risk that the clock will soon "stop.

Finally, if the device is developed according to claim 8, this eliminates the need for the user of the watch when changing the energy giequelle a manual reset of the two counters, which the Ease of use of the watch increases and no false guess can come, the newly used energy source is also be already unloaded.

An exemplary embodiment of the invention is described below the only figure showing a block diagram.

According to the figure, the output voltage U _{a of} a clock, not shown, energy source B (battery or battery) is continuously fed to a voltage detection device 1 . In the event that the measured value of the output voltage U _{a is} below a predeterminable threshold value, the counting input 2 a of a counter 2 is supplied by the voltage detection device 1 with a signal. In the opposite case, that is, when the output voltage U _{a of} the energy source B is equal to or greater than the threshold value, a signal is fed from the voltage detection device 1 to a reset device 3 via its input 3 a. The output of the reset device 3 is connected to a second input 2 b of the counter 2 .

The counter 2 also has a third input 2 c, which is connected to the output of a clock generator 4 .

This arrangement works as follows: A clock generator 4 , clock signals supplied via the third input 2 c of the counter 2 continuously releases the counter input 2 a of the counter 2 and blocks it thereon again. If the output voltage U _{a is} below the threshold when counter input 2 a is enabled, the counter reading of counter 2 is increased by one unit. The initial state of the counter 2 before it is connected to its voltage supply, that is to say before the energy source B is inserted into the clock, is “zero”. If the counter 2 has a non-zero counter reading and it reaches or exceeds the output voltage U _a when the counter input 2 a is released, the counter reading of the counter 2 is reset to "zero".

If the counter 2 reaches its overflow when the output voltage U _{a is} below the threshold value, it outputs an overflow signal S ₁ via its output, which is fed to the input 5 a of a state memory 5 , which is periodically released and blocked by the clock generator 4 in the same way as the counter input 2 a of the counter 2 . The state memory 5 has a first output 5 b and a second output 5 c, wherein the first output 5 b to a first input 7a of a warning signal from display device 7 and the second output 5 c connected to the counting input of a further counter 6 whose output is connected to the second input 7 b of the warning signal delivery device 7 .

The counter 2 downstream part of the device placed in the block diagram represents operates as follows: Once with enabled input 5 a of the state memory 5 therein, the overflow signal S ₁ is applied, the state memory 5 are via its first output 5 b a trigger signal S ₂ from which the Warning signal delivery device 7 is fed via its first input 7 a, whereupon the latter emits a warning signal. This can be an acoustic warning signal or, in order to protect energy source B, only a periodic optical warning signal.

At the second output 5 c of the state memory 5 there is periodically an output signal S ₃ , likewise determined by the clock generator 5 , at the occurrence of which the counter reading 5 of the further counter 6 is always increased by one unit until it overflows. Also, the further counter 6 , when it is not connected to its voltage supply, that is, when the energy source is not used in the clock or is completely exhausted, the initial reading of the counter reading "zero". If, on the other hand, the counter reading of the further counter 6 still overflows when the counter reading of the counter 2 has already overflowed, the further counter 6 outputs a further trigger signal S ₄ to the second input 7 b of the warning signal output device 7 . The further trigger signal S _{4 has the} effect that either the warning signal is modulated by the warning signal delivery device 7 or that an additional warning signal is emitted by this. In spite of the relatively high energy requirement in comparison to an optical warning signal, it may be appropriate to use an acoustic warning signal in order to illustrate to the user the urgency of replacing the energy source B.

The respective counter reading after the exceeding of the counter 2 and the further counter 6 overflows and the clock frequency of the clock generator 4 may be adjusted, for example, one another so that at a permanent shortfall of the threshold value of the output voltage U _a of the counter 2 after 24 hours and the further counter Reached their overflow state 6 more ten days later.

Claims (8)

1. Device for monitoring the state of charge of the elec trical energy source (B) of a mains-independent electronic clock, the state of charge being monitored by measuring the output voltage (U _a ) of the energy source (B), characterized in that the output voltage (Ua) is continuously measured by a voltage detection device ( 1 ), which in turn is connected to a counter ( 2 ), the counter input ( 2 a) of which is periodically released and blocked again by a clock generator ( 4 ) and whose counter reading - starting from a definable initial reading - in each case it is increased by one when the counting input ( 2 a) enables the measured value of the output voltage (U _a ) to be below a predefinable threshold value and that when the counter reading of the counter ( 2 ) overflows, the watch emits a warning signal. 2. Apparatus according to claim 1, characterized in that the voltage detection device ( 1 ) is also connected to a reset device ( 3 ) which - as long as the counter reading of the counter ( 2 ) has not yet reached its overflow - when the output voltage ( U _a ) when the counter input ( 2 a) is enabled, the threshold value is reached or exceeded, the counter reading of the counter ( 2 ) is reset to the initial state. 3. Apparatus according to claim 1 or 2, characterized in that the counter ( 2 ) emits an overflow signal (S ₁ ) upon overflow of its counter reading at the input ( 5 a) of a state memory ( 5 ), after its occurrence from a first output (5 b) of the state memory (5) a first input (7 a) a warning signal output means (7) Auslösesig nal (S ₂₎ is fed, whereupon means of the warning signal emitter (7), the warning signal is output itself. 4. The device according to claim 3, characterized in that the input ( 5 a) of the state memory ( 5 ) by the clock ( 4 ) at the same times as the input ( 2 a) of the counter ( 2 ) is periodically either released or blocked That the state memory ( 5 ) has a second output ( 5 c), whose periodic output signal (S ₃ ), which is also determined by the clock generator ( 4 ), is fed to the counter input of a further counter ( 6 ), which has its counter reading, starting from one Definable initial state, always increased by one unit when the overflow signal (S ₁ ) is present at the enabled input ( 5 a) of the state memory ( 5 ) and that the further counter ( 6 ) after its overflow to a second input ( 7 b) the warning signal delivery device ( 7 ) emits a further trigger signal (S ₄ ), whereupon the latter either modulates the warning signal or emits another, different, warning signal. 5. The device according to claim 4, characterized, that the warning signal from an intermittent optical Signal exists and that its modulation takes place by that its frequency, its pulse repetition frequency or its Intensity changed, preferably increased. 6. The device according to claim 4, characterized, that the warning signal from an optical and the further warning signal consists of an acoustic signal.   7. The device according to claim 4, characterized in that the period within which the clock ( 4 ) releases the counting input ( 2 a) of the counter ( 2 ) and the input ( 5 a) of the state memory ( 5 ) and blocks again and the number of counts, which lead to an overflow of the counter ( 2 ) and the further counter ( 6 ), are matched to one another so that if the threshold value of the output voltage (U _a ) of the energy source (B) continues to fall below the warning signal after 24 hours and that its modulation or the transmission of the further warning signal occurs after another ten days. 8. The device according to claim 4, characterized in that both the counter ( 2 ) and the further counter ( 6 ) are supplied by the electrical energy source (B) to be monitored with their operating voltage, that this operating voltage below the threshold value of the output voltage ( U _a ) of the electrical energy source (B) and that both counters ( 2 , 6 ) have the counter reading "0" as the initial reading when there is no operating voltage.