JPH06201804A - Detecting device for low voltage - Google Patents

Abstract

PURPOSE:To provide a detecting device of a low voltage capable of accurately detecting a low voltage of a cell even when the cell is the one like an air cell having a discharge characteristic of continuing a flat voltage for a comparatively long time in a low loading condition. CONSTITUTION:The detecting device comprises a heavy load applying means 15, e.g. a resister of heavy load, which applies periodically a heavy load to a cell, e.g. an air-zinc cell 9 and a heavy load applying condition voltage detecting means 11, e.g. a voltage detector. A low voltage judging means 2, e.g. CPU judges whether or not the voltage decrease lower than a reference voltage. Thereby, even when the cell is the one having a discharge characteristic of continuing a flat voltage for a comparatively long time in a low loading condition, it is possible to accurately detect a consumption condition thereof so that a cell-exchanging time is adequately noticed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used to detect a low voltage state of a battery incorporated in various electronic devices, to know the exhausted state of the battery, and to judge when to replace the battery. The present invention relates to a low voltage detection device for a battery, and particularly to a low voltage detection device when a heavy load is applied to the output voltage of the battery.

[0002]

2. Description of the Related Art In a conventional general low voltage detection device provided in an electronic device in which a battery is incorporated, a power switch of the electronic device is turned on to supply electric power from the battery to various devices in the electronic device. Then, when the heavy load is applied to the battery, the voltage detection is stopped. Then, the power switch of the electronic device is turned off, and the battery voltage is regularly monitored with the load applied to the battery being a light load, and the battery voltage becomes lower than the reference voltage in this light load condition. In this case, the battery consumption status is determined by the speaker or LED based on the detection signal from the low voltage detection device.
A notification device such as the above is used for notification, or a warning is issued to prompt battery replacement.

A low voltage detecting device for detecting the voltage of a battery in such a light load state is an electronic device incorporating a battery having a discharge characteristic such that the output voltage gradually decreases with the passage of time like a manganese battery or an alkaline battery. When applied to a device, it was possible to know the consumed state of the battery relatively accurately and to notify the necessity of battery replacement at an appropriate time.

[0004]

However, an electronic device such as a small portable radio receiver such as a pager of a paging system, which is a type of mobile communication system for which demand has recently been increasing, has an excellent discharge at a light load. In many cases, an air zinc battery exhibiting characteristics (hereinafter referred to as an air battery) is incorporated, but the conventional low voltage detection device cannot accurately detect the exhaustion state of the air battery.
That is, in the air battery, for example, activated carbon is used as an anode, amalgamated zinc (Zn) is used as a cathode, and caustic soda (Na) is used.
(OH) solution or ammonium chloride solution (NH ₄ Cl) as electrolyte, and oxygen (O ₂ ) in the air taken in from the air holes
Has a structure that generates an electromotive force (about 1.35 V) by reacting with, and the voltage drop at the beginning is large, but after that (from the beginning of discharge to the end of discharge), in a light load state for a relatively long time (continuous use). Although it shows a discharge characteristic in a flat state for about 400 hours (see FIG. 3), if the voltage drop is simply detected as in the conventional case, the accurate consumption state of the air battery and the battery replacement time can be known. There was a problem that I could not.

Therefore, the present invention has been made in order to solve the above-mentioned problems, and it is a battery such as an air battery which exhibits a discharge characteristic in a flat state for a relatively long time in a light load state. An object of the present invention is to provide a low-voltage detection device capable of accurately detecting a low-voltage state of a battery so that an accurate battery consumption state and an accurate battery replacement time can be grasped.

[0006]

The means of the present invention are as follows. That is, in order to solve the above problems, the low voltage detection device according to the invention of claim 1 is a low voltage determination device for determining whether or not the voltage of a battery incorporated in an electronic device is lower than a reference voltage. In a low voltage detection device including means, a heavy load applying means for periodically applying a heavy load to the battery, and a heavy load state voltage for detecting a battery voltage in a state in which a heavy load is applied by the heavy load applying means. The low voltage detecting device according to the invention of claim 2 is provided with a detecting means, wherein the electronic device is provided with a power supply startup frequency counting means for counting the number of power supply startup times of the electronic device. When the count by the counting means exceeds a predetermined number, a heavy load is periodically applied to the battery by the heavy load adding means, and a heavy load is applied by the heavy load state voltage detecting means. In the low voltage detection device according to the invention of claim 3, the battery is installed in the electronic device, and the battery is installed in the electronic device. A battery mounting time measuring means for measuring the elapsed time is provided, and when the measuring time by the battery mounting time measuring means exceeds a predetermined time, a heavy load is periodically applied to the battery by the heavy load adding means. The low voltage detection device according to claim 4, wherein the heavy load state voltage detection means is configured to detect a battery voltage in a state in which a heavy load is applied. A battery temperature measuring means for measuring the temperature of the battery; and a reference voltage changing means for changing the reference voltage based on a signal from the battery temperature measuring means. Low-voltage detection device according to the above on the basis of the determination result of the low-voltage determining means is characterized by comprising a battery drain state informing means for informing a consumption state of the battery.

[0007]

According to the low voltage detection device of the first aspect of the present invention, the heavy load applying means (for example, control of the CPU) energizes the battery (for example, air battery) incorporated in the electronic device. / A heavy load is periodically applied by a resistor that is switched to a non-energized state, and a heavy load state voltage detection means (for example, a voltage detector) detects the battery voltage in the state where the heavy load is applied, By determining whether or not the battery voltage is lower than the reference voltage by the voltage determining means (for example, CPU), it is possible to grasp an accurate consumption state even for a battery which causes a rapid voltage drop during heavy load, It becomes possible to know the exact battery replacement time.

Further, as described in claim 2, the number of times the power source of the electronic device is turned on (for example, the number of times the power switch is turned on) is counted by the power source startup number counting means (for example, an electronic counter). Then, when the count number exceeds a predetermined number, by starting the detection of the battery voltage in the above-mentioned heavy load state, it is a waste of adding a heavy load in the state where the battery voltage has sufficiently reached the reference voltage. Can be omitted. That is, it becomes possible to start monitoring the battery voltage when the battery has been consumed to some extent.

Further, as described in claim 3, by the battery mounting time measuring means (for example, an electronic timer),
By measuring the time since the battery was incorporated in the electronic device, and when the measured time has passed a predetermined time (for example, 500 hours), by starting the detection of the battery voltage in the above-mentioned heavy load state, Monitoring the battery voltage when the power of the electronic device is not turned on for a long period of time (that is, when the electronic device is not used for a long period of time) and the battery is depleted to some extent due to long-term spontaneous discharge. It is possible to start. Further, for example, whether the number of times the power source has been turned on exceeds a predetermined number or whether the number of times the battery has been turned on exceeds a predetermined time by using the power source startup number counting means and the battery mounting time measuring means according to claim 2 together. It is also possible to start the detection of the battery voltage in the heavy load state when either of the conditions is satisfied, and it is possible to start the voltage monitoring at a more accurate time.

Further, as described in claim 4, the temperature of the battery incorporated in the electronic device is measured by the battery temperature measuring means (for example, a temperature sensor using a thermistor), and the battery temperature measuring means is used. By changing the reference voltage by a reference voltage changing unit (for example, a ROM storing numerical data of discharge characteristics corresponding to a battery temperature connected to the CPU) based on the signal of
It is possible to detect a low voltage in accordance with the change in discharge characteristics due to the temperature of the battery, and it is possible to more accurately know the consumption state of the battery.

Furthermore, as described in claim 5, based on the judgment of the low voltage judging means, a battery consumption state notifying means (for example, a speaker for notifying the battery consumption state by voice, an LED for visually notifying, etc.). ), The user of the electronic device can replace the battery or the like at an appropriate time.

[0012]

EXAMPLES Examples will be described below with reference to FIGS. 1 is a circuit diagram showing a schematic circuit configuration of a low voltage detection device according to the present invention, and FIG. 2 is a flowchart showing a processing procedure of the low voltage detection device according to the present invention.
3 to 7 are graphs showing discharge characteristics and load recovery characteristics of zinc-air batteries (air batteries) at various temperatures.

In FIG. 1, reference numeral 1 denotes the entire low voltage detection circuit arranged in the main body of a pager P which is a kind of electronic equipment, and 2 denotes a heavy load applying means, a heavy load state voltage detecting means, and a reference. A CPU (Centra) that controls voltage changing means, etc.
l Processing Unit). The CPU 2 includes a temperature sensor 3 that uses a thermistor that constitutes a battery temperature measuring means, an electronic timer 4 that constitutes a battery mounting time measuring means, a speaker 5 and an LED 6 that constitute a battery consumption state notifying means, An electronic counter 7 which constitutes a power-up frequency counting means, and a battery temperature (-10 ° C, 0
ROM (Read Only Memory) that stores four-stage discharge characteristics (° C, 25 ° C, 60 ° C) as a table of numerical data
8 are connected to each other. The temperature sensor 3 is arranged in contact with or close to a battery described later so that the temperature of the battery can be detected.

Reference numeral 9 is an air zinc battery for supplying electric power to various devices (not shown) of the pager P. The air battery 9 is, for example, a button-type primary battery using oxygen (O ₂ ) in the air as a depolarizer, for example, porous activated carbon thinly coated with paraffin is used as an anode, and a cathode is amalgamated. Using zinc (Zn), caustic soda (NaOH) solution or ammonium chloride solution (NH ₄ Cl) as an electrolyte, and reacting with oxygen (O ₂ ) in the air taken in from the air holes, an electromotive force (about 1 It has a structure for generating 0.35 V) and has a discharge characteristic as shown in FIG. 3 at a temperature (Ta) of 25 ° C. under a light load. That is, the battery voltage of the air battery 9 in a light load state such as when the power switch of the pager P is in the off state or when the pager P is in the reception standby state is as shown by the characteristic curve K in FIG. (Discharge rate)
The stable discharge of the terminal voltage of 1.35 V is possible until the voltage reaches about 97%.

The air battery 9 is housed so as to come into contact with an electrical contact of a battery chamber (not shown) of the pager P after the seal of the air hole is removed and the electromotive force is generated.
The air battery 9 is connected to the CPU 2 via a wire connected to an electric contact. A protection diode 10 is connected to the negative electrode side of the air battery 9,
It prevents the reverse current from flowing into U.

Further, in parallel with the air battery 9, a voltage detector 11 also serving as a heavy load state voltage detecting means and a low voltage determining means, and an effect of the voltage fluctuation of the air battery 9 on the CPU 2 are alleviated, An electric double layer capacitor for keeping the power supply voltage (V _DD , Vss) constant is connected. The voltage detector 11 is connected to the CPU 2 via a control line 13 to send a voltage detection signal to the CPU 2 or the CPU 2
Receive control signals from. In addition, the voltage detector 11 is
It has a built-in register that temporarily stores the reference voltage for low voltage determination. For example, the temperature detected by the temperature sensor 3 is 25 ° C.
Criteria of 1.00 volt in case of 60 ° C., 1.15 volt in case of 60 ° C., 0.78 volt in case of 0 ° C., 0.65 volt in case of −10 ° C. The voltage is stored as numerical data. If the voltage detector 11 determines that the battery voltage exceeds the reference voltage, it continues to detect the battery voltage periodically, and if it determines that the battery voltage is below the reference voltage, the control line The low voltage detection signal is sent to the CPU 2 via
Is transmitted to the user, and the user is informed of the exhausted state of the battery by the sound from the speaker 5, the lighting of the LED 6, and the like.

Further, the switching transistor 14
Is connected in parallel with the collector terminal and the emitter terminal of the air battery 9, and the collector terminal of the switching transistor 14 is a heavy load resistor for applying a predetermined virtual heavy load to the air battery 9. 15 is connected. Further, the base terminal of the switching transistor 14 is connected to the CPU 2 via the bias resistor 16 so that the switching transistor 14 is turned on / off based on a control signal from the CPU 2. The resistance value of the heavy load resistor 15 is, for example, 30Ω (power consumption of about 4 so that it becomes equal to the load when the pager P receives a transmission radio wave and performs a calling operation).
It is set to 8 mW). This heavy load resistor 1
The discharge characteristic when a virtual heavy load is applied to the air battery 9 by 5 is as shown by the curve G ′ in FIG. 4, and this curve G ′ shows when the pager P is actually in the calling operation state. Since it is approximately similar to the curve G of FIG. 3 showing the discharge characteristics, if the battery voltage under the condition that a virtual heavy load is applied is detected by the heavy load resistor 15, the air battery 9 normally drives the pager P. It is possible to accurately grasp whether or not it has a battery voltage that can be caused (that is, whether or not the air battery is in a low voltage state due to exhaustion). If a variable resistor that can be controlled manually or by the CPU 2 is used as the heavy load resistor 15, the size of the heavy load applied to the air battery 9 can be changed appropriately.

Further, based on a temperature detection signal input from the temperature sensor 3 to the CPU 2, numerical data of discharge characteristics corresponding to the battery temperature is read from the ROM 8 into the CPU 2, and voltage detection is performed based on the numerical data. Bowl 11
A control signal for selecting and designating a reference voltage value for low voltage determination, which is temporarily stored in a register therein, is transmitted to the voltage detector 11 via the control line 13. Accordingly, the reference voltage for determining the battery exhaustion state can be changed according to the change in the discharge characteristic due to the temperature change of the air battery 9, and even when the usage environment of the electronic device such as the pager P is different, Accurate low voltage detection can always be performed.

The electronic timer 4 counts the frequency output from a frequency-divided crystal oscillator (not shown) or the like, and detects the presence or absence of a battery in the battery chamber that houses the air battery 9, for example. A switch or the like is provided, and the time from the time when the air battery 9 is incorporated into the pager P is measured in conjunction with the switch and output to the CPU 2. CPU
In the case of No. 2, the reference time (for example, 500 hours) stored in a predetermined area in the ROM 8 is compared with the time measured by the timer 4, and when it is determined that the reference time is not exceeded, When the timer 4 continues measurement as it is and it is determined that the reference time has been exceeded, a control signal is periodically (for example, every 10 hours) output to the switching transistor 14 and the voltage detector 11, and the air battery A heavy load is applied to 9 and the battery voltage under the heavy load is detected. And the voltage detector 1
The reference voltage corresponding to the predetermined temperature (for example, the battery temperature is 25
In the case of ° C, 1.00 volt) and the detected battery voltage are compared and determined in the voltage detector 11, and when it is determined that the battery voltage exceeds the reference voltage, the battery voltage is detected. When it is determined that the battery voltage is lower than the reference voltage (that is, the air battery 9 is in the low voltage state), the low voltage detection signal is sent to the CPU 2 via the control line 13 when the operation is continued periodically. Then, the CPU 2 outputs a control signal to the speaker 5 and the LED 6 based on the low voltage detection signal to indicate that the built-in air battery 9 is in a low voltage state due to exhaustion or that the battery needs to be replaced. The user is notified by voice from the speaker 5, lighting of the LED 6, or the like.

On the other hand, the counter 7 connected to the CPU 2
Counts the number of times the power switch (not shown) of the pager P is turned on and off (that is, the number of times the power of the pager P is turned on) and outputs it to the CPU 2. CPU2 is
The reference number (for example, 50 times) stored in a predetermined area of the ROM 8 is compared and determined with the count value of the counter 7, and when it is determined that the count value does not exceed the reference number, the counting by the counter 7 is continued. If it is determined that the count value exceeds the reference number of times, the switching transistor 1
4 and the voltage detector 11 are periodically output (for example, every 10 hours) to apply a heavy load to the air battery 9 and to detect the battery voltage under the heavy load. Then, as described above, when it is determined that the battery voltage exceeds the reference voltage, the detection of the battery voltage is periodically continued, and when it is determined that the battery voltage is lower than the reference voltage, the control line 13 is set. Low voltage detection signal via C
It sends to PU2, and the sound from speaker 5 and LED6
The user is notified of the exhausted state of the battery by, for example, lighting.

Further, the CPU 2 monitors the time measured by the timer 4 and the count by the counter 7 to determine whether the measurement time exceeds the reference time or the count value exceeds the reference number of times. By detecting the battery voltage when a heavy load is applied when the load is satisfied, for example, when the pager P is not used for a long time, the heavy load is caused by exceeding the reference time of the measurement time. In this state, the battery voltage detection is started, and conversely, even if the reference time is not exceeded, the voltage detection is started when the number of power-ups exceeds the reference number.
It is possible to start the voltage detection of the battery at an appropriate time according to various usage conditions of. In this embodiment, the battery voltage is detected while applying a heavy load to the air battery 9, but instead, a heavy load is applied to the air battery 9 for a certain period of time to release the heavy load. After a certain time (for example,
The so-called return voltage after 3 seconds (see the characteristic curve F in FIGS. 3, 5 to 7) may be detected by the voltage detector 11. However, it is needless to say that it is necessary to appropriately change the above-mentioned reference voltage in order to accurately detect the low voltage state of the air battery 9 from this return voltage.

The above is the configuration of an embodiment of the low voltage detecting device according to the present invention, and its operation will be described with reference to the flowchart of FIG. Here, in order to simplify the description, the case where a new air battery 9 is incorporated in the pager P will be described.

First, the air cell 9 is housed in the battery chamber of the pager P in a state in which the air holes of the air cell 9 are removed and an electromotive force is generated. At this time, the battery detection switch provided in the battery chamber is turned on, and the timer 7 starts measuring the elapsed time from the battery installation based on the signal from the switch. When using the pager P in which the air battery 9 is incorporated, the power switch is operated in the ON state, and the counter 7 is incremented by 1 each time the power switch is operated. In addition, the temperature sensor 3 allows the air battery 9 in the battery chamber.
Is measured and the measurement signal is transmitted to the CPU 2.

Regarding the detection of the low voltage of the air battery 9, the processing by program control as shown in the flowchart of FIG. 2 is performed. First, in step S1, it is determined whether the time measured by the timer 4 is an eccentric time (for example, 500 hours) or more. Then, when it is determined that the measurement time is less than the reference time, the process returns to 1 and the above process is repeatedly performed until the reference number of times or more or the reference time or more.

When it is determined in step S2 that the measurement time exceeds the reference time, the process proceeds to step S3, and the process of turning on the heavy load of the air battery 9 is executed. That is, a control signal is input from the CPU 2 to the base terminal of the switching transistor 14, the switching transistor 14 is turned on, and the heavy load resistor 1 connected to the collector terminal of the switching transistor 14 is turned on.
A virtual heavy load is applied to the air battery 9 by 5.
On the other hand, if it is determined in step S1 that the count value of the counter 7 is greater than or equal to the reference number of times, step S1.
The routine proceeds to step S3 without executing 2, and the processing of turning on the application of the heavy load to the air battery 9 is executed as described above.

Subsequently, in step S4, the battery voltage in a state where the virtual heavy load is applied to the air battery 9 is detected, and the battery voltage is a reference voltage (for example, when the battery temperature is 25 ° C.). Is greater than or equal to the reference voltage of 1.00 volt). When it is determined that the voltage is not higher than the reference voltage, the process proceeds to step S5, and the low voltage warning is given by the speaker 5 or the LED 6, and then the process ends. For the low voltage warning, specifically, audio data (digital data) stored in a predetermined area of the ROM 8 is converted into audio data (analog data) by a D / A converter (not shown), and the speaker 5 outputs the audio data. For example, by sending a message such as "DENTIGA GAMOUS YOU MAYU. Aurally or visually informs that the replacement time of is approaching. Further, when it is determined in step S4 that the battery voltage is equal to or higher than the reference voltage, the process proceeds to the next step S6, and the process of turning off the heavy load to the air battery 9 is executed, and at the same time, step S7. The timer 4 for a preset time (for example, a timer for 10 hours) is started at. Next, in step S8, it is monitored whether or not the time is up, and when the time is up, the process returns to step S3.
The processes after step S3 are executed again.

Therefore, when any one of the condition that the count value of the counter 7 exceeds the reference number of times or the measurement time of the timer 4 exceeds the reference time, a heavy load is applied. Since the battery voltage is detected, if the pager P is not used for a long time, the battery voltage detection in a heavy load state is started by exceeding the reference time of the measurement time, and vice versa. Even if it does not exceed the limit, the above voltage detection is started when the number of times the power is turned on exceeds the reference number. Therefore, according to various usage conditions of the pager P, the voltage detection of the battery should be started at an appropriate time. You can Further, by performing the above-described processing, when the air battery 9 is still new and has a capacity that sufficiently satisfies the reference voltage (that is, when the battery is installed in the pager P shortly after, When the pager P is used infrequently and the power switch is turned on a small number of times), it is possible to eliminate the waste of adding a virtual heavy load by the heavy load resistor 15.

In the present embodiment, the temperature sensor 3 is provided to measure the temperature of the air battery 9, and the reference voltage for determining the low voltage is appropriately set according to the change in the discharge characteristic of the battery due to the temperature change. A case has been described in which the timer 4 for measuring the elapsed time from the mounting of the battery and the counter 7 for counting the number of power-ups are provided side by side, but the invention is not limited to this. Each device can be selected according to the cost and grade of the electronic device, and the combination thereof can be freely selected. Therefore, for example, when an electronic device such as a pager is to be provided at low cost, the temperature sensor, the timer, and the counter are not provided, and the air battery is simply provided with a heavy load resistor at predetermined intervals. Even if the battery voltage is detected by applying a heavy load, it is possible to substantially achieve the purpose of notifying the exhaustion of the air battery. In addition, although a case has been described with the present embodiment where low voltage detection is performed in a pager applied to a paging system, which is a type of mobile communication system, the present invention is not limited to this, and the present invention is applied to various electronic devices incorporating a battery. It is possible. Furthermore, in the present embodiment, the case where an air zinc battery (air battery) is incorporated has been described, but the present invention is not limited to this, and stable discharge characteristics are exhibited at a light load, but a sharp decrease in the discharge characteristic is exhibited at a heavy load. A battery having various characteristics can effectively exhibit its function.

In the present embodiment, the virtual heavy load is applied to the air battery 9 by the on / off control of the switching transistor 14. However, the present invention is not limited to this, and other switching elements (for example, thyristor) are used. ) And the like may be used. Further, in the above embodiment, the case where the voltage detector 11 makes a comparison judgment between the battery voltage and the reference voltage has been described.
U2 or the like may be used, and the voltage detector 1
You may make it use an A / D converter for 1. Further, by providing the reference voltage in multiple stages, it is possible to more accurately know the battery consumption state and the like. Furthermore, in this embodiment,
Although the number of times the pager P is turned on is measured, the number of times the speaker 5 of the pager P is driven (that is, the number of times the pager P is called) may be counted instead.

[0030]

As described above, according to the low voltage detecting device of the present invention, a heavy load applying means (for example, an air battery) for a battery (for example, an air battery) incorporated in an electronic device is provided.
A heavy load is periodically added by a heavy load resistor that can be switched between energized / de-energized by the control of the CPU,
The heavy load state voltage detection means (for example, voltage detector) detects the battery voltage in the state where the heavy load is applied, and the low voltage determination means (for example, CPU) determines whether or not the battery voltage is lower than the reference voltage. By determining whether
Even if the battery shows a flat discharge characteristic for a relatively long time in a light load state, it is possible to grasp the exact consumption state and to know the exact battery replacement time. is there.

Further, the number of times the power is turned on (for example, the number of times the power switch is turned on) of the electronic device is counted by the power-up number counting means (for example, an electronic counter), and the counted number is a predetermined number. If it exceeds, by detecting the battery voltage in the heavy load state described above, it is possible to eliminate the waste of adding a heavy load in a state where the battery voltage has sufficiently reached the reference voltage. That is,
There is also an effect that it is possible to start monitoring the battery voltage when it can be estimated that the battery has been consumed to some extent.

Further, a battery mounting time measuring means (for example,
An electronic timer) measures the time after the battery is incorporated in the electronic device, and when the measured time exceeds a predetermined time (for example, 500 hours), the battery voltage of the above-mentioned heavy load state is measured. By starting the detection, the power of the electronic device was not turned on for a long period of time (that is, when the electronic device was not used for a long period of time), and the battery was exhausted to some extent due to long-term spontaneous discharge. At the time point, it is possible to start monitoring the battery voltage. In addition, by using both the power-up frequency counting means and the battery mounting time measuring means, either the power-up frequency exceeds a predetermined number or the battery mounting time exceeds a predetermined time. If the detection of the battery voltage in the heavy load state is started at the time point, it becomes possible to start monitoring the battery voltage at a more accurate time.

The battery temperature measuring means (for example, a temperature sensor using a thermistor) measures the temperature of the battery incorporated in the electronic equipment, and the reference voltage is changed based on the signal from the battery temperature measuring means. Means (eg CP
By changing the reference voltage with the ROM that stores the numerical data of the discharge characteristics corresponding to the battery temperature connected to U and its CPU, it is possible to detect a low voltage that matches the change in the discharge characteristics due to the temperature of the battery. Therefore, there is also an effect that it becomes possible to know the battery consumption state and the like more accurately.

Further, based on the judgment of the low voltage judging means, a battery consumption state notifying means (for example, a speaker for notifying the battery consumption state by voice or an LED for visually notifying).
By notifying the exhausted state of the battery with (1) or the like, there is also an effect that the user of the electronic device can replace the battery at an appropriate time.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a schematic circuit configuration of a low voltage detection device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing procedure relating to low voltage detection of the low voltage detection device according to the embodiment of the present invention.

FIG. 3 is a graph showing discharge characteristics (25 ° C.) of an air battery.

FIG. 4 is a graph showing discharge characteristics (25 ° C.) when a virtual heavy load is applied to an air battery.

FIG. 5 is a graph showing discharge characteristics (60 ° C.) of an air battery.

FIG. 6 is a graph showing discharge characteristics (0 ° C.) of an air battery.

FIG. 7 is a graph showing discharge characteristics (-10 ° C.) of an air battery.

[Explanation of symbols]

P pager (electronic device) 1 low voltage detection circuit 2 CPU (Central Processing Unit) 3 temperature sensor (battery temperature measuring means) 4 timer (battery mounting time measuring means) 5 speaker (battery consumption state notification means) 6 LED (battery consumption) Status notification means 7 Counter (power supply startup frequency counting means) 8 ROM (Read Only Memory) 9 Air zinc battery (battery) 10 Protection diode 11 Voltage detector (heavy load state voltage detection means, low voltage determination means) 12 Electricity Double layer capacitor 13 Control line 14 Switching transistor 15 Heavy load resistor (heavy load applying means) 16 Bias resistor

Claims (5)

[Claims] 1. A low voltage detection device comprising low voltage determination means for detecting the voltage of a battery incorporated in an electronic device and determining whether or not the battery voltage is lower than a reference voltage. On the other hand, a heavy load applying means for periodically applying a heavy load, and a heavy load state voltage detecting means for detecting a battery voltage in a state in which the heavy load is applied by the heavy load applying means, are provided. Voltage detection device. 2. A power supply startup frequency counting means for counting the power supply startup frequency of the electronic device is provided in the electronic device,
When the count by the counting means reaches a predetermined number or more, the heavy load adding means periodically applies a heavy load to the battery, and the heavy load state voltage detecting means applies a heavy load to the battery voltage. The low voltage detection device according to claim 1, wherein the low voltage detection device is configured to detect 3. An electronic device is provided with a battery mounting time measuring means for measuring an elapsed time after the battery is incorporated in the electronic device, and a measuring time by the battery mounting time measuring means is a predetermined time or more. When it becomes, a heavy load is periodically applied to the battery by the heavy load adding means,
The low voltage detection device according to claim 1 or 2, wherein the heavy load state voltage detection means is configured to detect a battery voltage in a state where a heavy load is applied. 4. A battery temperature measuring means for measuring the temperature of the battery and a reference voltage changing means for changing the reference voltage based on a signal from the battery temperature measuring means are provided in the electronic device. The low-voltage detection device according to claim 1, wherein the low-voltage detection device is characterized. 5. The battery exhaustion state informing unit for informing the exhaustion state of the battery based on the determination result of the low voltage determining unit, according to any one of claims 1 to 4.
The low-voltage detector described in.