JP2002250758A - Display device for battery residual power - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device, for a battery residual power, in which the precise battery residual power in each operating mode is displayed by a small memory capacity. SOLUTION: A threshold value corresponding to a consumption current in each operating mode is calculated by using a threshold value (by a second storage means 52) which discriminates a consumption current (by a first storage means 51) in each operating mode from the battery residual power in an operating mode as a reference. Thereby, the battery residual power in each operating mode is displayed.

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 display device and a battery remaining amount displaying method for a portable electronic device operated by a battery.

[0002]

2. Description of the Related Art A conventional battery remaining amount display device is disclosed, for example, in Japanese Patent Application Laid-Open No. 7-282857. FIG.
1 is a block diagram of a conventional battery remaining amount display device. Figure 1
In 1, 1 is a battery, 2 is a voltage detecting unit for detecting the voltage of the battery, 3 is a load, 4 is a microcomputer, 5 is an RO
Reference numerals M and 6 denote a remaining battery level display unit for displaying the remaining battery level output from the microcomputer 4. The microcomputer 4 has an input / output unit 41, an operation mode detection unit 42 for detecting an operation mode of the battery remaining amount display device, and a remaining amount determination unit 44 for determining the remaining amount of the battery 1. The ROM 5 stores a threshold value of the remaining battery level according to the operation mode of each operation mode.

The threshold value will be described with reference to FIGS. FIG. 3 is a view showing the discharge characteristics and the remaining amount display of the battery in the recording mode and the flash charging mode of the battery remaining amount display device. The vertical axis shows the output voltage of the battery, and the horizontal axis shows the discharge time. It is preferable that the battery remaining amount display unit 6 displays a battery remaining amount according to a usable time of the battery. If t = 0 when the battery is fully charged and t = T3 when the device stops operating, set T1T50% × T3 and T2 ≒ 90% × T3. from t = 0
FULL between T1, HALF between T1 and T2, EM between T2 and T3
After PTY, T3, the remaining battery level is displayed in four stages, such as the operation of this device is stopped (the remaining amount is not displayed) (the mode that does not display the remaining amount is also included in one stage).

The output voltage of a battery changes according to the operation mode due to the internal resistance of the battery. V1, V2, and V3 are battery voltages at times T1, T2, and T3 in the discharge characteristics of the battery in the recording mode, and are thresholds for determining the remaining battery level in the recording mode. Similarly, V12, V22, and V32 are the battery voltages at times T1, T2, and T3 in the discharge characteristics of the battery in the strobe charging mode, and are threshold values for determining the remaining amount of the battery in the strobe charging mode. The thresholds V1 and V12 are the voltage when the remaining battery power reaches 50%, the thresholds V2 and V22 are the voltage when the remaining battery power reaches 10%, and the thresholds V3 and V32 are the devices. Shows the cut-off voltage at which the operation of FIG.

FIG. 4 is a diagram showing an example of current consumption in a typical operation mode of a digital still camera at a certain voltage and a change in output voltage of the battery when the digital still camera is operated with the same battery. The vertical axis indicates the output voltage of the battery, and the horizontal axis indicates the operation mode. When an ideal battery is used, the battery voltage does not depend on the current consumption (depending on the operation mode). However, since an actual battery has an internal resistance r, the output voltage changes according to the current consumption. In the case of a digital still camera, there are operation modes such as an initialization mode, a strobe charging mode, a recording mode, and a reproduction mode, and furthermore, there are more operation modes depending on conditions such as ON / OFF of a liquid crystal. Since power consumption differs in each operation mode, the battery voltage also changes according to the operation mode.

If the remaining battery level is displayed with the same threshold value in all the operation modes, the user cannot know the usage time of the remaining battery. For example, if the remaining battery level is displayed using the thresholds V1, V2, and V3 in the flash charging mode in FIG. 3, the remaining battery level becomes HALF immediately after full charge (t = 0), Despite the remaining battery, the device stops operating and no longer displays the remaining battery level. Therefore, the remaining battery level display device displays the remaining battery level using an optimum threshold value for each operation mode. FIG.
Is obtained by adding a threshold value to FIG. V1, V2, and V3 indicate the threshold values of the recording mode, which is the reference operation mode, and V11, V21, and V31 are the threshold values of the initialization mode, V12, and V2.
2, V32 is the strobe charge mode threshold, V13, V23, V3
3 indicates a threshold value of the reproduction mode. The threshold values in these operation modes are stored in the ROM 5. One example is shown in FIG.

In FIG. 11, the voltage of a battery 1 is detected by a voltage detector 2 and input to a microcomputer 4. The input / output unit 41 inputs a detection signal of the voltage detection unit 2. The operation mode detection unit 42 detects a current operation mode of a device including the battery remaining amount display device. Remaining amount determination unit 44
Reads the remaining battery level threshold corresponding to the current operation mode from the ROM 5 storing the remaining battery level threshold corresponding to each operation mode, and determines the remaining battery level based on the threshold. . The determined remaining battery level is output to the remaining battery level display unit 6. The battery level indicator 6 is a microcomputer 4
The remaining battery level is displayed based on the remaining battery level signal output from.

For example, it is assumed that the operation mode of the device is the reproduction mode and the detected voltage of the battery 1 is VB. V13
If <VB, it indicates that the battery level is "FULL".
If V23 <VB ≦ V13, it is displayed that the remaining battery level is “HALF”. If V33 <VB ≤ V23, the battery level is "EMPTY"
Is displayed. If VB ≦ V33, the operation of the device is stopped and the remaining amount is not displayed. As described above, since all the threshold values in each operation mode are stored, the remaining battery level can be accurately predicted even when the operation mode of the device changes.

[0009]

In the above conventional battery remaining amount display device, when there are n different operation modes and m threshold values, the threshold value of (n × m) batteries is determined. Must be stored, which causes an increase in storage capacity. The present invention solves the above problem, and in each operation mode having different current consumption,
Battery level display that displays the battery level accurately for each operation mode with a small storage capacity by calculating and correcting using the threshold value of one reference operation mode and the current consumption of each operation mode It is intended to provide a device.

In a device in which the load of the battery is a constant voltage power supply and a circuit to which the output voltage of the constant voltage power supply is supplied, the current consumption increases as the voltage decreases. In the conventional battery remaining amount display device, the accuracy of the battery remaining amount display is not high because the battery remaining amount display is not performed in consideration of a change in current consumption due to a decrease in battery voltage. The present invention solves the above-described problem, and provides a battery remaining amount display device that can accurately display a battery remaining amount by calculating an increase in current consumption due to a decrease in battery voltage. The purpose is to:

[0011]

In order to solve the above problems, the present invention has the following arrangement. The invention according to claim 1 of the present invention includes a voltage detection unit that detects a voltage of a battery, an operation mode detection unit that detects an operation mode of a device using the battery, and a plurality of operation modes of the device. A first storage unit for storing current consumption, a second storage unit for storing a threshold value for determining a remaining battery level in a reference operation mode, and an operation mode detected by the operation mode detection unit Based on the current consumption, the current consumption corresponding to the reference operation mode, and the threshold value corresponding to the reference operation mode, the operation mode corresponds to the operation mode detected by the operation mode detection unit. A calculating unit that calculates the corrected threshold value; a remaining amount determining unit that determines the remaining battery amount based on the corrected threshold value; and a battery remaining amount that is displayed based on a determination signal of the remaining amount determining unit. Battery level display A battery remaining display apparatus, comprising a.

According to a third aspect of the present invention, there is provided a voltage detecting step for detecting a voltage of a battery, an operating mode detecting step for detecting an operating mode of an apparatus using the battery, and the operating mode detecting step. The operation mode detected in the operation mode detection step based on the current consumption corresponding to the detected operation mode, the current consumption corresponding to the reference operation mode, and the threshold value corresponding to the reference operation mode A calculating step of calculating a corrected threshold value corresponding to, and a remaining amount determining step of determining a remaining battery level based on the corrected threshold value,
A remaining battery level display step of displaying a remaining battery level based on the determination signal generated in the remaining level determination step. The use of the corrected threshold value of the present invention has an effect that the remaining battery level can be accurately displayed for each operation mode using data stored in a small storage area.

According to a second aspect of the present invention, the current consumption stored in the first storage unit is a current value at a constant reference voltage, and the arithmetic unit is configured to detect the current value by the voltage detection unit. And the reference voltage and the consumption current corresponding to the operation mode detected by the operation mode detection unit, and calculate the consumption current at the voltage detected by the voltage detection unit. Correction corresponding to the operation mode detected by the operation mode detection unit based on the current consumption, the current consumption corresponding to the reference operation mode, and the threshold value corresponding to the reference operation mode The battery level display device according to claim 1, wherein the calculated threshold value is calculated.

According to a fourth aspect of the present invention, in the calculating step, the voltage detected in the voltage detecting step, a reference voltage, and the reference voltage corresponding to the operation mode detected in the operation mode detecting step. The current consumption at the voltage detected in the voltage detection step is calculated based on the current consumption in the above, the current consumption as a result of the calculation, the current consumption at the reference voltage in the reference operation mode, and The corrected threshold value corresponding to the operation mode detected in the operation mode detection step is calculated based on the threshold value corresponding to the reference operation mode. This is a method for displaying the remaining battery level.

For example, if most of the load is a constant voltage power supply composed of a DC / DC converter and a circuit supplied with power by the constant voltage power supply, the current consumption changes according to the voltage. The conventional battery remaining amount display in which the current consumption is a fixed value for each operation mode is not sufficiently accurate. The present invention is characterized in that when the voltage of the battery decreases, the calculation is also performed for the increase in the current consumption of the device, and accurate for each operation code over a wide range from the beginning of the battery to immediately before the end of the battery. It has the effect of being able to display the remaining battery power.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; << Embodiment 1 >> The battery remaining amount display device of Embodiment 1 will be described with reference to FIGS. The battery remaining amount display device according to the first embodiment is mounted on a digital still camera. Figure 1
1 is a block diagram of a battery remaining amount display device according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a battery, 2 denotes a voltage detecting unit for detecting the voltage of the battery, 3 denotes a load, 4 denotes a microcomputer, 5 denotes a ROM, and 6 denotes a battery remaining amount which indicates the remaining battery power output from the microcomputer 4. It is a quantity display section. The microcomputer 4 includes an input / output unit 41, an operation mode detection unit 42 for detecting an operation mode of the battery remaining amount display device, an arithmetic unit 43 for correcting a threshold for determining the battery remaining amount, and the battery 1
It has a remaining amount determination unit 44 for determining the remaining amount of.

The ROM 5 has a first storage unit 51 and a second storage unit 52. The first storage unit 51 stores the current consumption of each operation mode, and the second storage unit 52 stores a threshold value for determining the remaining battery level in the reference operation mode. The reference operation mode is arbitrary, but is a recording mode in the first embodiment. In the first embodiment, the first storage unit 51 and the second storage unit 52 are ROMs, but the first storage unit 51 and the second storage unit 52 are arbitrary nonvolatile memories (for example, EEPROM). May be.

FIG. 6 is a flowchart of the battery remaining amount display device according to the first embodiment of the present invention. In FIG. 6, first, in step 101, the voltage of the battery 1 connected to the device is detected by the voltage detection unit 2, and is input to the microcomputer 4. The input / output unit 41 inputs a detection signal of the voltage detection unit 2. Next, in step 102, the operation mode detection unit 42
Detects the current operation mode of the device including the remaining battery level display device. Since the microcomputer 4 controls the entire digital still camera, the operation mode detection unit 42 can detect the operation mode of the digital still camera. In step 103, the threshold value of the detected operation mode is calculated from the threshold value of the reference operation mode (see FIG. 7 for details). In step 104, the remaining battery level is determined by comparing the corrected threshold value with the voltage of the battery 1 in the remaining capacity determining section 44 (see FIG. 8 for details). Finally step 10
In 5, the remaining battery level is displayed on the remaining battery level display section 6 based on the remaining battery level signal output from the microcomputer 4.

Hereinafter, the processing of the arithmetic unit 43 will be described. FIG.
5 is a flowchart of a threshold value correction calculation executed by a calculation unit 43 of the battery remaining amount display device according to the first embodiment of the present invention. i is the current consumption of the reference operation mode, i1 is the current consumption of the detected operation mode, V1, V2, V3 are the threshold values of the reference operation mode, V is the correction amount of the threshold value, and r is the battery 1
, V1x, V2x, and V3x indicate the corrected threshold values. In the flowchart of FIG.
Step 103 of the flowchart of FIG. In step 103, the corrected threshold values V1x, V2x, V3x are calculated by an arithmetic expression based on the consumed currents i, i1, and the threshold values V1, V2, V3.

In FIG. 7, first, in step 301, the detected current consumption i1 of the operation mode and the current consumption i of the reference operation mode are read from the first storage unit 51. Next, at step 302, the threshold values V1, V2, V3 of the reference operation mode are read from the second storage unit 52. Based on these, in step 303, a threshold correction amount V for correcting the threshold is calculated. Formula is V
= R (i1-i). The internal resistance r of the battery 1 is included in the calculation formula. Further, in step 304, threshold values V1x, V2x, V3x in the detected operation mode are calculated. The corrected thresholds are V1x = V1-V, V2x = V2-V, V3x = V3-V
It is. According to the present invention, if the threshold values V1, V2, V3 of the reference operation modes and the current consumption i1 in each operation mode are stored, the threshold values of each operation mode do not need to be stored. Can be calculated.

FIG. 8 is a flowchart showing how the remaining battery level determining unit 44 of the battery remaining power display device according to the first embodiment of the present invention determines the remaining battery power. Vy indicates the battery voltage detected by the voltage detection unit 2. In FIG. 8, first, in step 201, it is determined whether or not the battery voltage Vy is larger than the corrected threshold value (50%) V1x. If it is larger than the threshold value (50%) V1x, the process proceeds to step 204. In step 204, the battery level is output to the battery level indicator 6 to indicate that the battery level is "FULL". In step 201, the battery voltage Vy is adjusted to the corrected threshold value (50
%) If less than or equal to V1x, go to step 202. In step 202, it is determined whether or not the battery voltage Vy is larger than the corrected threshold value (10%) V2x. Threshold (10
%) If it is larger than V2x, the process proceeds to step 205. In step 205, the battery level is output to the battery level display section 6 and the battery level is set to “H”.
ALF "is displayed.

In step 202, if the battery voltage Vy is smaller than or equal to the corrected threshold value (10%) V2x, the process proceeds to step 203. In step 203, it is determined whether or not the battery voltage Vy is larger than the corrected threshold value (0%) V3x.
If it is larger than the threshold value (0%) V3x, the process proceeds to step 206. In step 206, the battery level is output to the battery level indicator 6 to indicate that the battery level is "EMPTY". In step 203, when the battery voltage Vy is smaller than or equal to the corrected threshold value (0%) V3x, the process proceeds to step 207. Step 20
At 7, the operation of the device is stopped and the remaining battery level is not displayed on the remaining battery level display section 6.

FIG. 9 shows an example of the threshold current and the current consumption stored in the ROM 5 of the battery level display device according to the first embodiment of the present invention. Conventionally, as shown in FIG. 12, all the threshold values in each operation mode must be stored.
In other words, the number of information becomes (number of remaining amount display stages −1) × the number of operation modes, and in this example, 12 pieces of information had to be stored. According to the present invention, if the threshold value of the reference operation mode and the current consumption in each operation mode are stored as shown in FIG. 9, the threshold value of each operation mode can be calculated without storing. Since it is possible, the number of information is (the number of remaining amount display steps −1) + the number of operation modes. In this example, it is sufficient to store seven pieces of information.

Here, four levels of remaining amount display are performed as an example, but the number of threshold values may be further increased to increase the resolution of the remaining amount display. Further, an actual digital still camera has more operation modes depending on settings such as ON / OFF of a liquid crystal. The remaining battery level display device of the present invention has a greater memory reduction effect as the number of operation modes and the number of operation modes are larger.

<< Embodiment 2 >> Referring to FIGS. 2 and 10, a battery remaining amount display device according to Embodiment 2 will be described. The battery remaining amount display device according to the second embodiment is mounted on a digital still camera. FIG. 2 is a block diagram of a battery remaining amount display device according to a second embodiment of the present invention. In FIG. 2, reference numeral 1 denotes a battery, 2 denotes a voltage detecting unit for detecting the voltage of the battery, 3 denotes a load, 4 denotes a microcomputer, 5 denotes a ROM, and 6 denotes a battery remaining amount which indicates the remaining battery power output from the microcomputer 4. It is a quantity display section. The load 3 has a constant voltage power supply 31 and a circuit 32. The microcomputer 4 includes an input / output unit 41, an operation mode detection unit 42 that detects an operation mode of the battery remaining amount display device, and a calculation unit 4 that calculates current consumption and corrects a threshold value for determining the remaining battery amount.
5. It has a remaining amount determining unit 44 for determining the remaining amount of the battery 1.

The ROM 5 has a first storage unit 51 and a second storage unit 52. The first storage unit 51 stores the current consumption at the reference voltage V0 in each operation mode, and the second storage unit 52 stores a threshold value for determining the remaining battery level in the reference operation mode. The reference operation mode is arbitrary, but is a recording mode in the second embodiment. Example 1
The same blocks as those in FIG. 1 are denoted by the same reference numerals.
The battery remaining amount display device according to the second embodiment is different from the battery remaining amount according to the first embodiment in that the load 3 is the constant voltage power supply 31 and the like and that a calculation unit 45 is provided instead of the calculation unit 43. The constant voltage power supply 31 is a DC / DC converter. The load 3 consumes constant power regardless of the value of the power supply voltage.

The voltage of the battery 1 connected to the device is detected by the voltage detector 2 and is input to the microcomputer 4. The input / output unit 41 inputs a detection signal of the voltage detection unit 2. Next, the operation mode detection unit 42 detects the current operation mode of the device including the battery remaining amount display device. Since the microcomputer 4 controls the entire digital still camera, the operation mode detection unit 42 can detect the operation mode of the digital still camera. Arithmetic unit 45
Then, the current consumption at the detected voltage is calculated, and the threshold value of the detected operation mode is calculated (for details, see FIG. 1).
0). Then, the remaining battery level determination unit 44 determines the remaining battery level.
(See Fig. 8 for details). Finally, based on the signal of the remaining battery level output from the microcomputer 4, the remaining battery level display section 6 displays the remaining battery level.

Like the battery remaining amount display device of the first embodiment, the battery remaining amount display device of the second embodiment executes the flowchart of FIG. Hereinafter, the processing (step 103) of the calculation unit 45 will be described. FIG. 10 is a flowchart of the threshold value calculation unit executed by the calculation unit 45 of the battery remaining amount display device according to the second embodiment of the present invention. V0 is a constant voltage, Vy is the voltage of the detected battery 1, i1 is the current consumption at the constant voltage V0 in the detected operation mode, and i2 is the voltage detected in the detected operation mode.
Current consumption in Vy, V1, V2, and V3 are threshold values of a reference operation mode, V is a correction amount of the threshold value, r is an internal resistance of the battery 1, V1x, V2x, and V3x are corrected threshold values. Is shown. In step 103, the corrected threshold values V1x, V2x, V3x are calculated based on the current consumptions i, i1, and the threshold values V1, V2, V3 by an arithmetic expression.
Is calculated.

Referring to FIG. 10, first, in step 401, the current consumption i1 at the reference voltage V0 in the detected operation mode.
The current consumption i at the reference voltage V0 in the reference operation mode is read from the first storage unit 51. Next, at step 402, the threshold values V1, V2,
V3 is read from the second storage unit 52. Based on these, in step 403, a correction amount V of the threshold value at the detected voltage Vy for correcting the threshold value is calculated. The DC / DC converter (constant voltage power supply 31) consumes constant power regardless of the value of the power supply voltage. Therefore, the correction amount V of the threshold is obtained by the calculation formula V = r · V0 / Vy (i1−i). The values of the internal resistance r of the battery 1 and the reference voltage V0 are included in the calculation formula. Further, in step 404, threshold values V1x, V2x, V3x in the detected operation mode are calculated.
The corrected threshold values are V1x = V1-V, V2x = V2-V, V3x = V3
−V.

According to the present invention, the battery remaining amount display device of the second embodiment has the threshold V1 corrected at the detected voltage Vy.
x, V2x, and V3x indicate the battery level. In the above embodiment, the battery remaining amount display device is mounted on a digital still camera, but is not limited to this, and can be mounted on any device that has a plurality of operation modes and runs on batteries.

[0031]

According to the present invention, by using the corrected threshold value, it is possible to realize a battery remaining amount display device having a smaller storage capacity than a conventional battery remaining amount display device. ADVANTAGE OF THE INVENTION According to this invention, the effect of being able to implement | achieve more accurate battery remaining amount display compared with the conventional battery remaining amount display device is acquired by correct | amending with respect to the increase of the consumption current by the battery voltage fall.

[Brief description of the drawings]

FIG. 1 is a block diagram of a battery remaining amount display device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a battery remaining amount display device according to a second embodiment of the present invention;

FIG. 3 is a diagram showing a discharge characteristic of a battery in a recording mode and a strobe charging mode and a remaining amount display of a battery remaining amount display device.

FIG. 4 is a diagram illustrating an example of a consumption current in a typical operation mode of the digital still camera at a certain voltage, and a change in an output voltage of the battery when the digital still camera is operated with the same battery.

FIG. 5 shows current consumption in a typical operation mode of a digital still camera at a certain voltage, output voltage of a battery in each operation mode when the digital still camera is operated with the same battery, and battery in each operation mode. Diagram showing an example of a threshold for determining the remaining amount

FIG. 6 is a flowchart of a battery remaining amount display device according to the first and second embodiments of the present invention.

FIG. 7 is a flowchart of a calculation unit of the battery remaining amount display device according to the first embodiment of the present invention.

FIG. 8 is a flowchart for determining the remaining battery level of the remaining battery level display device according to the first and second embodiments of the present invention.

FIG. 9 is a diagram illustrating an example of threshold values and current consumption stored in a ROM 5 of the battery remaining amount display devices according to the first and second embodiments of the present invention.

FIG. 10 is a flowchart of a calculation unit of the battery remaining amount display device according to the second embodiment of the present invention.

FIG. 11 is a block diagram of a conventional battery remaining amount display device.

FIG. 12 is a diagram showing an example of a threshold value stored in a ROM 5 of a conventional battery remaining amount display device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 battery 2 voltage detection unit 3 load 4 microcomputer 5 ROM 6 battery remaining amount display unit 31 constant voltage power supply 32 circuit 41 input / output unit 42 operation mode detection unit 43, 45 calculation unit 44 remaining amount determination unit 51 first storage Unit 52 Second Storage Unit

Claims (4)

[Claims] 1. A voltage detector for detecting a voltage of a battery, an operation mode detector for detecting an operation mode of a device using the battery, and a first memory for storing current consumption of each of a plurality of operation modes of the device. A second storage unit that stores a threshold value for determining a remaining battery level in a reference operation mode; a current consumption corresponding to an operation mode detected by the operation mode detection unit; Based on the current consumption corresponding to the operation mode to be, and the threshold value corresponding to the reference operation mode, the corrected threshold value corresponding to the operation mode detected by the operation mode detection unit, A calculating unit for calculating, a remaining amount determining unit for determining a remaining battery amount based on the corrected threshold value, and a remaining battery amount displaying unit for displaying a remaining battery amount based on a determination signal of the remaining amount determining unit. Having Battery remaining display apparatus according to claim. 2. The method according to claim 2, wherein the current consumption stored in the first storage unit is a current value at a constant reference voltage, and the calculation unit includes: a voltage detected by the voltage detection unit; the reference voltage; Based on the current consumption corresponding to the operation mode detected by the operation mode detection unit, the current consumption at the voltage detected by the voltage detection unit is calculated, and the calculated current consumption and the reference operation mode Calculating a corrected threshold value corresponding to the operation mode detected by the operation mode detection unit, based on the current consumption corresponding to the operation mode and the threshold value corresponding to the reference operation mode. The battery remaining amount display device according to claim 1, wherein: 3. A voltage detecting step of detecting a voltage of a battery, an operating mode detecting step of detecting an operating mode of a device using the battery, and a current consumption corresponding to the operating mode detected in the operating mode detecting step. Based on a current consumption corresponding to a reference operation mode and a threshold value corresponding to the reference operation mode, a corrected threshold value corresponding to the operation mode detected in the operation mode detection step. A calculating step for calculating; a remaining capacity determining step for determining a remaining battery capacity based on the corrected threshold value; and a remaining battery capacity display for displaying the remaining battery capacity based on the determination signal generated in the remaining capacity determining step. A method for displaying a remaining battery level, comprising: 4. In the calculating step, based on a voltage detected in the voltage detecting step, a reference voltage, and a current consumption at the reference voltage corresponding to the operation mode detected in the operation mode detecting step. The current consumption at the voltage detected in the voltage detection step is calculated, the current consumption as a result of the calculation, the current consumption at the reference voltage in the reference operation mode, and the current consumption corresponding to the reference operation mode. The method according to claim 3, wherein a corrected threshold value corresponding to the operation mode detected in the operation mode detection step is calculated based on the threshold value.