JP2000081469A - Battery remaining check device - Google Patents

Abstract

(57) [Summary] [Object] To obtain a device capable of more accurately determining the remaining amounts of a plurality of types of batteries. A CPU recognizes a type of a battery by an ON / OFF state of a battery changeover switch,
Depending on the type of battery, load application time (time when the battery is connected to the load resistor), recovery time (time when the battery is not connected to the load resistor), number of activations (number of times to check the remaining amount repeatedly), The voltage value for determining the remaining amount is extracted from the EEPROM 60. The CPU 10 connects the batteries to the load resistors 21 and 22 for a load time set for each type of battery and discharges the battery, compares the voltage value at this time with a voltage value for remaining capacity determination, and The remaining amount is determined. In this determination, when it is determined that the remaining amount of the battery is “no”, the same discharge is repeatedly performed using the set maximum number of activation times as an upper limit until the determination is made that the remaining amount of the battery is no longer “no”.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery remaining amount checking device capable of accurately determining the remaining amount of different types of batteries (batteries).

[0002]

2. Description of the Related Art In recent cameras, a motor performs not only focusing but also film winding. For this reason, the remaining battery level is automatically checked (when the power is turned on) before using the camera so that troubles such as failure of shooting due to running out of battery do not occur.

However, in the conventional battery remaining amount checking device, the purpose is to check one type of battery, so that the load application time, the recovery time, and the number of times of activation of the battery are unique to the battery. It was set as fixed. For this reason, different types of batteries could not be checked.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a battery remaining amount checking device capable of determining the remaining amounts of a plurality of types of batteries more accurately based on the above problem awareness.

[0005]

SUMMARY OF THE INVENTION The present invention provides a battery detecting means for detecting a type of a battery to be subjected to a remaining amount check, and a battery detected by the battery detecting means.
Load applying means for applying a load corresponding to the type of battery, voltage detecting means for detecting the voltage of the battery when the load is applied by the load applying means, and type and voltage of the battery detected by the battery detecting means And a remaining amount determining unit for determining a remaining amount of the battery according to a voltage level detected by the detecting unit. According to this battery remaining amount checking device, a load corresponding to the detected battery type is applied, and the remaining battery amount is determined according to the detected battery type and the detected voltage level.
The remaining amounts of different types of batteries can be accurately determined.

The load applying means includes, for example, a pulse generating means for generating a pulse corresponding to a set load time and a recovery time according to the type of the battery detected by the detecting means, and a pulse generating means based on the pulse from the pulse generating means. Switching means for connecting the battery to the load resistor. According to this configuration, it is possible to apply an optimum load according to the type of the battery, and it is possible to accurately check the remaining amount of the battery.

Further, according to this configuration, it is possible to promote the activation of the battery as well as to check the remaining amount of the battery.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The battery remaining amount checking device according to the present invention operates when a release button is half-pressed for the first time after a main switch of a camera is turned on. In addition, in order to be able to check the remaining power appropriately according to the type of battery,
Load application time (time when the battery is connected to the load resistor (discharge time)), recovery time (time when the battery is not connected to the load resistor), activation according to the type of battery to be checked The number of times (the number of times the remaining amount check (load application and remaining amount check) is repeated) is changed. Therefore, the battery is connected to the load resistor for a load time set for each type of battery and discharged, and the remaining battery level is measured based on the voltage value at this time. In this measurement, when it is determined that the remaining battery level is “no”, the battery level is determined to be “no” with the set number of activation times as an upper limit.
The same discharge is repeatedly performed until it is not judged that the discharge is completed.

FIG. 1 is a block diagram showing a schematic configuration of a battery remaining amount checking device according to an embodiment of the present invention. The CPU 10 shown in FIG. 1 generally controls the operation of the camera, but in the present invention, a load applying means for applying a load to the battery (specifically, connecting a load resistor), and a remaining amount of the battery. Judgment ("Normal" when the remaining amount is enough, or "Warning" when the remaining amount is running low
Function as a remaining amount determining means and a pulse generating means for determining whether there is no remaining amount and the camera cannot be operated.

The A / D conversion circuit 12 provided in the CPU 10 converts the terminal voltage of one load resistor 22 provided in the battery check circuit 20 into a digital value. The remaining battery level is determined based on the digital value. The A / D conversion circuit 12 and the CPU 10 function as voltage detection means.

The battery check circuit 20 is a circuit for discharging the battery switched by the battery selector switch 50 via two load resistors 21 and 22 connected in series, and functions as a load applying means. The battery check circuit 20 includes a switching transistor 24 functioning as a switching means.
Is provided, and this switching transistor 24 is
The ON / OFF operation is performed according to the pulses output from the CPU 10 corresponding to the desired load time and the desired recovery time. While the switching transistor 24 is ON, one of the batteries (batteries) switched by the battery selection switch 50 is connected to the above-described two load resistors 21 and 22, so that the two load resistors 21, 2
2, a current flows. The above-described A / D conversion circuit 12 converts the voltage between both ends of one load resistor 22 of the two load resistors 21 and 22 from an analog value to a digital value, and based on the digital value, the CPU 10 Determine the state of charge of the battery.

A predetermined constant voltage is always supplied to the CPU 10 via a voltage regulator 30. Note that the CPU 1
0 operates even if a voltage equal to or higher than a predetermined voltage is supplied from the voltage regulator 30 even if it is determined that the battery is not present.

The oscillator 40 generates a clock pulse for operating the CPU 10. The CPU 10 creates (measures) time with an internal timer based on the clock pulse, and generates a pulse to be given to the switching transistor 24 and a pulse necessary for the A / D conversion circuit 12 to perform a conversion operation. Therefore, the oscillator 40 and the CPU 10 function as pulse generating means.

The battery selection switch 50 is a switch for selecting a battery mounted on the camera. In this example, when switching to the “1” side, the lithium battery LB
However, when it is switched to the “2” side, the AA alkaline batteries AB are detected as the batteries to be checked for the remaining battery level. This battery selection switch 50 is connected to the CP
Battery switch 5 connected to U10
It is configured to move in conjunction with 1. In the present embodiment, the battery changeover switch 51 is manually switched, and the battery selection switch 50 is switched mechanically in conjunction with the battery changeover switch 51. As batteries, AA alkaline batteries are 1.5V x 4 (6
V) or a lithium battery of 3 V × 2 (6 V) can be used alternatively. In this embodiment, the camera uses AA
Four alkaline batteries and two lithium batteries can be loaded. The battery selection switch 50 switches to connection with the loaded battery when one type of battery is loaded, and connects to the type of battery switched by the battery switch 51 when both batteries are loaded. It can be configured to replace.

The EEPROM 60 stores various data (load application time, recovery time,
(Data related to the number of times of activation). A main switch 62 is a main power switch of the camera, and a photometric switch 64 is a switch that operates a photometric IC (including a sensor) 66 to perform photometry, and causes the CPU 10 to calculate an aperture value and a shutter speed for proper exposure. The release switch 70 is a switch that causes the CPU 10 to operate the aperture control circuit 68 based on the calculated aperture value to adjust the aperture, operate the shutter control circuit 72 at the calculated shutter speed, and release the shutter at an appropriate speed. is there.

Next, the operation of the apparatus of the present invention will be described with reference to the operation flowchart of FIG. When the main switch 62 of the camera is turned on, the CPU 10 itself and the CPU 1
Initialization processing for resetting all circuits connected to 0 is performed (S1).

When the release button is first half-pressed (the photometric switch 64 is turned on), a battery check process for determining the remaining amount of the battery is performed (S2,
S3). This battery check will be described later in detail. If it is determined that there is a remaining amount as a result of the battery check, the CPU 10 operates the photometric IC 66 to perform photometry (S4), and calculates an appropriate aperture value and a shutter speed according to the photometric result (S5). . Next, the distance to the subject is measured, and AF (autofocus) processing is performed according to the result (S6, S7). As a result, if focus is achieved, the release button is pressed halfway (photometric switch 64).
Is turned on (S8, S9), and the exposure processing is performed on condition that the release button is fully pressed (the release switch 70 is turned on), that is, the CPU 10 controls the aperture control circuit 68 so that an appropriate exposure amount is obtained. The aperture is operated, and the shutter is operated by the shutter control circuit 72 to release the shutter at a predetermined shutter speed (S10, S11).

FIG. 3 is a subroutine flowchart of the battery check process (S3) in the flowchart of FIG. The CPU 10 determines whether the battery changeover switch 51 is ON or OFF. If it is ON, the battery selection switch 50 linked with the battery changeover switch 51 has been switched to the “2” side. AA written in advance
(Alkaline dry cell) for the counter (bc loop
counter, and if it is OFF, it has been switched to the "1" side, so the number of CR2 (lithium battery) times is set in the counter (S21-S2).
3).

The number of times for AA or CR2 is
This is the number of times the battery check (remaining amount check) is repeatedly performed to activate the battery. In the present embodiment, the number of times for AA is set to 50 times, and the number of times for CR2 is set to 2 times. The reason why the number of times is changed according to the type of the battery is that the battery characteristics are completely different between the AA alkaline battery and the lithium battery.

That is, when an alkaline battery is left unused for a long time, the initial output voltage tends to greatly decrease regardless of the remaining amount. Conversely, as shown in c), the output voltage increases (specifically, 0.1 V to 0.5 V per battery).
V). In addition, activation is
This means discharging the battery whose output voltage has dropped to increase the output voltage.

Therefore, in the alkaline battery, the number of times is set to 50 times so that the effect of the activation can be sufficiently obtained. On the other hand, the number of times of the lithium battery is set to two, since there is almost no decrease in the initial output voltage due to non-use unlike the alkaline battery.

Next, the CPU 10 determines whether or not the value of this counter is 0. If not, the CPU 10 subtracts 1 from the value of the counter (S24, S25), and the A / D conversion circuit 12 The voltage value of the battery is indirectly detected from the A / D converted voltage of the load resistor 22 (S2).
6). The detected voltage value of the battery is temporarily stored in the RAM in the CPU 10, and this voltage value is stored in the EEPROM 6.
It is compared with a voltage value written to 0 according to the type of battery.

FIG. 6 is a graph showing an example of the relationship between the used capacity and the voltage value of four series (AA) alkaline batteries and two series lithium batteries. According to this graph, it can be seen that the lithium battery has a characteristic that the voltage decreases gradually while the remaining capacity is large, but the voltage decreases rapidly when the remaining capacity decreases. Therefore, in order to safely use a battery having such characteristics, in the present embodiment, a voltage larger than 4.2 V is determined to be “normal”, that is, a state in which the remaining capacity of the battery is sufficient, A voltage of 4.2 V or lower and a voltage higher than 4.0 V are regarded as a "warning", that is, a state in which the remaining amount is gradually reduced, and a voltage of 4.0 V or lower is determined as "not available".
That is, it is determined that the camera is in a state in which the remaining amount has run out and the camera cannot function.

On the other hand, the voltage of an alkaline battery gradually decreases with use until the remaining capacity is exhausted, and there is no sharp drop unlike a lithium battery. 3.8V or less, 3.6V
A voltage higher than this is determined as “warning” and a voltage of 3.6 V or less is determined as “absent”. The reason for setting a higher voltage value such as “warning” for a lithium battery is that the camera suddenly becomes inoperable before it is judged as “warning” because the voltage drop when the battery is exhausted is sudden. This is to prevent the voltage from dropping.

These voltage values are stored in the EEPROM 60, and the CPU 10 compares the voltage values detected by the A / D converter 12 with these voltage values according to the type of the battery to determine the state of the remaining amount. A determination is made (S27).

The determination of the remaining amount by the CPU 10 is "no",
That is, when it is determined that the battery is in a locked state in which the remaining amount is low and the camera cannot be operated, the value of the counter is further reduced by 1 to activate the battery again.

Such activation is performed even if the result of the first remaining amount check determines that the remaining amount is “no”, and then the activation is repeated to reduce the battery voltage value to “warning”. Alternatively, the voltage may recover to a voltage value that is determined to be “normal”.

The above activation is repeated until the remaining amount is determined to be "warning" or "normal" by the CPU 10 up to the maximum number of times set in the counter (S
28; Y, S24). In addition, if the camera is left unused for a long time, the metal pieces of the battery holder may be oxidized and a film may be formed, but when this film is formed, it is detected by the resistance of the film. There is a possibility that the apparent battery voltage is reduced, and the remaining capacity is erroneously determined to be “no” even though the remaining capacity is sufficient. When the activation is repeated several times, a large current flows, so that an effect that this film is destroyed and it can be returned to a normal state can also be obtained.

FIG. 4 is a flowchart showing the battery A / D conversion process in the subroutine flowchart of FIG. The CPU 10 determines whether the battery switch 51 is ON or OFF,
If so, AA written in advance in the EEPROM 60
The load time and the recovery time for the CR2 (for lithium) are set if they are OFF (S31 to S33).

The load time is a time during which the CPU 10 applies a voltage to the switching transistor 24 to connect a battery (AA or lithium) to the load resistors 21 and 22 and discharge the battery. The recovery time is defined as CP
This is the time when U10 turns off the switching transistor 24 to disconnect the battery from the load resistors 21 and 22. Therefore, the switching transistor 24
Is given a pulse determined by the load time and the recovery time.

In this embodiment, in the case of a lithium battery,
As shown in FIG. 7 (A), both the load time and the recovery time are 3
msec (millisecond). On the other hand, in the case of AA batteries, both the load time and the recovery time are set to 5 msec, as shown in FIG.

Next, the CPU 10 energizes the load resistors 21 and 22 for the set load time, detects the voltage of the load resistors during that period as a digital value by the A / D converter 12, and detects this as a RAM value. (S34 to S34)
36). Then, the current supply to the load resistors 21 and 22 is stopped for the recovery time, and the A / D conversion process of the battery is terminated (S37, S38).

FIG. 5 is a flowchart showing the process of setting the battery state in the subroutine flowchart of FIG. The CPU 10 determines whether the battery switch 51 is ON or OFF,
If so, AA written in advance in the EEPROM 60
Data for judging the remaining amount for battery, that is, a voltage value for judging “normal”, “warning”, and “none”, while if OFF, the remaining amount for CR2 (for lithium) is set. A voltage value for determination is set (S41 to S43).

These voltage values are described above. In the case of a lithium battery, “normal” is a voltage larger than 4.2 V,
"Warning" is a voltage less than 4.2V, greater than 4.0V,
“None” is a voltage of 4.0 V or less, and in the case of AA alkaline batteries, “Normal” is a voltage greater than 3.8 V, “Warning” is a voltage of 3.8 V or less, a voltage greater than 3.6 V, "Not present" is a voltage of 3.6 V or less.

The CPU 10 compares the voltage value detected by the A / D converter 12 with the set voltage,
If the detected voltage value is higher than the "warning" level,
It is determined that the remaining amount is “normal” (S44,
S45) If it is at the "warning" level, it is determined to be a "warning" in which the remaining amount is short (S46, S4).
7) If it does not reach the "warning" level, the remaining amount is determined to be "none" (S48).

As described above, in the battery remaining amount checking device according to the present invention, the type of the battery is determined by the ON / OFF state of the battery changeover switch, and the load time, the recovery time, and the activation time according to the type of the battery are determined. The remaining amount of the battery is determined based on the number of times and the determination voltage of the remaining amount.

In the above-described embodiment, the timing of the remaining amount check is performed when the release button is first half-pressed. However, regardless of this timing, when the main switch is turned on, the film is replaced. Arbitrary timing can be set at times. Also, load time,
Needless to say, the recovery time, the number of times of activation, and the voltage for determining the remaining amount may be set differently from the above example according to the battery. In addition, although the case where two types of batteries are checked for the remaining amount is shown, the present invention can be applied to the case where there are three or more types of batteries.

Although the embodiment shown in FIG. 1 has been described as a configuration in which both an alkaline battery and a lithium battery can be simultaneously loaded into a camera, the present invention provides a battery pack that can be detachably mounted on a camera body. It may be formed according to. In the case of this embodiment, for example, when a battery pack loaded with an alkaline battery is mounted on the camera body, the battery changeover switch 5 is provided by an alkaline battery identification member provided on the battery pack, for example, a nail.
1 may be turned on (see FIG. 8), and the battery changeover switch 51 may be turned off (see FIG. 9) when a battery pack loaded with a lithium battery is mounted on the camera body. In the illustrated embodiment, two types of batteries, ie, an alkaline battery and a lithium battery, can be loaded and can be switched / detected. However, the present invention enables loading of three or more types of batteries and the types of batteries loaded. It is needless to say that the battery can be switched / detected depending on the battery type, and the battery check process can be executed according to the type of battery.

[0039]

According to the present invention, a load corresponding to the detected battery type is applied, and the remaining amount of the battery is determined according to the detected battery type and the detected voltage level. Therefore, the remaining amounts of the different types of batteries can be accurately determined. In addition, by applying a load to the battery based on the pulse corresponding to the load time and the recovery time set in accordance with the detected battery type, it is possible to provide an optimal load according to the battery type, thereby achieving accurate Battery level can be checked. Further, when it is determined that the remaining battery level is “no”, the maximum number of times set according to the battery type is set as an upper limit, and the battery type is repeatedly determined until the remaining battery level is not determined to be “no”. By appropriately applying the load, the activation of the battery can be promoted as well as the remaining amount of the battery is checked.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a battery remaining amount checking device according to the present invention.

FIG. 2 is a main flowchart showing the operation of the battery remaining amount checking device according to the present invention.

FIG. 3 is a subroutine flowchart of a battery check process in the main flowchart of FIG. 2;

FIG. 4 is a flowchart showing a battery A / D conversion process in the subroutine flowchart of FIG. 3;

FIG. 5 is a flowchart showing a battery state setting process in the subroutine flowchart of FIG. 3;

FIG. 6 is a graph showing the used capacity-voltage characteristics of an AA alkaline battery and a lithium battery.

FIG. 7 is a diagram illustrating the load time and recovery time of a lithium battery and an AA alkaline battery, and the effect of activating the AA alkaline battery.

FIG. 8 shows a schematic configuration of an embodiment in which a battery remaining amount checking device according to the present invention is applied to a camera in which a battery pack containing a lithium battery or an AA alkaline battery is detachable, when an alkaline battery is mounted. It is a block diagram shown in a state.

FIG. 9 is a block diagram showing a schematic configuration of the embodiment shown in FIG. 8 when a lithium battery is mounted.

[Explanation of symbols]

 Reference Signs List 10 CPU 12 A / D converter 20 Battery check circuit, 50 Battery detection switch 51 Battery changeover switch 60 EEPROM 64 Photometry switch 70 Release switch

Claims (8)

[Claims] 1. A battery detecting means for detecting a type of a battery to be checked for a remaining amount, and a load corresponding to the type of the battery detected by the battery detecting means is applied to the battery to be checked for a remaining amount. Load applying means, voltage detecting means for detecting a voltage of the battery when a load is applied by the load applying means, type of battery detected by the battery detecting means, and voltage detected by the voltage detecting means. And a remaining amount determination unit for determining the remaining amount of the battery according to the voltage. 2. A battery remaining amount checking device for a device capable of attaching and detaching a battery pack formed according to the type of a battery, wherein the battery detection detects a type of a battery loaded in the mounted battery pack. Load means for applying a load corresponding to the battery detected by the battery detection means to a battery loaded in the battery pack, the load being preset according to the type of battery; and Voltage detecting means for detecting a voltage of the battery when a load is applied by the applying means; and a voltage of the battery in accordance with the type of the battery detected by the battery detecting means and the voltage detected by the voltage detecting means. And a remaining amount determining unit for determining a remaining amount. The remaining amount checking device. 3. A load generating means for generating a pulse corresponding to a load time and a recovery time set in accordance with a type of a battery, a pulse generating means for generating a pulse corresponding to a load time and a recovery time in accordance with a type of the battery detected by the battery detecting means. Switching means for connecting the battery to a load resistor based on a pulse corresponding to the load time output from the pulse generating means, and disconnecting the battery from the load resistor based on a pulse corresponding to the recovery time. 3. The device for checking the remaining amount of a battery according to claim 1, further comprising: 4. When the remaining amount determining unit determines that the remaining amount of the battery is “no”, the pulse generating unit determines the maximum number of times set according to the type of the battery detected by the battery detecting unit. Until the remaining amount of the battery is not determined to be `` absent '' as an upper limit, the process of applying the load according to the type of the battery by the load applying unit and detecting the voltage at that time by the voltage detecting unit is repeated, 4. The battery remaining amount checking device according to claim 3, wherein the application of the load and the voltage check are stopped when it is not determined that the remaining amount of the battery is "no" before the maximum number is reached. 5. The voltage detecting means detects a voltage of the load resistor when the switching means connects the battery to the load resistor, and the remaining amount determining means determines the voltage based on the detected voltage. 5. The apparatus according to claim 4, wherein the remaining battery level is determined. 6. When the remaining amount determining unit determines that the remaining amount of the battery is “no”, the pulse generating unit determines the maximum number of times set according to the type of the battery detected by the battery detecting unit. Until the remaining amount of the battery is determined to be "no" with the upper limit set, the load applying means outputs a pulse corresponding to the load time and a pulse corresponding to the recovery time according to the type of the battery and corresponds to the load time. The process of detecting a voltage by the voltage detecting means is repeated while outputting a pulse to be output. When the remaining amount of the battery is not determined to be “no” before the maximum number of times is reached, the load applying means and the voltage detecting 6. The apparatus according to claim 3, wherein the operation of the means is stopped. 7. The apparatus according to claim 1, wherein said battery remaining amount checking device is mounted on a camera, and said remaining amount determining means executes a remaining amount determining process when a power switch of said camera is turned on. 7. The battery remaining amount checking device according to any one of claims 1 to 6. 8. The battery remaining amount checking device is mounted on a camera, and when a switch for operating a photometric device of the camera is turned on, the remaining amount determining means executes a remaining amount determining process. The battery remaining amount checking device according to any one of claims 1 to 7.