JPH09257889A - Battery remaining capacity detector and portable telephone using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect the remaining capacity of a battery without influence of the load state. SOLUTION: The using state of the telephone is detected (ST11). A load current in a speaking state increases as compared with that in a waiting state, and a battery voltage is lowered by its internal resistance. In the case of the speaking state, a correction value is added as VC to the battery voltage. On the other hand, at the time of no speaking state, the correction value is set to 0, and the battery state remains as it is (ST12 to ST14). The voltage value after the correction is detected (ST15), reference values Va, Vb, Vc corresponding to no speaking state are read from a ROM 30 (ST16). The voltage value after the correction is compared with the reference value to obtain the remaining information (compared result) of the battery (ST17). The display responsive to the remaining information is conducted on a liquid crystal display unit (ST18). In the speaking state for increasing the load current, the correction value is added to the battery voltage to be corrected. Thus, the remaining information which excludes the influence of the load state of the battery can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery level detector and a mobile phone having the same. More specifically, the present invention relates to a battery remaining amount detector capable of accurately detecting the battery remaining amount by changing the correction value of the battery voltage based on the load state of the battery, and a mobile phone having the same. .

[0002]

2. Description of the Related Art FIG. 9 shows a battery level detecting circuit used in a headphone stereo or the like.

The negative terminal of the battery 101 is grounded and the positive terminal thereof is grounded via the load 102. Also, the battery 1
A resistor 10 for voltage division is provided between the positive electrode terminal of 01 and the ground.
A series circuit of 3,104 is connected. And resistor 1
The connection point P of 03, 104 is the comparator 105, 106, 10
7 non-inverting input terminal.

Between the positive terminal of the battery 101 and the ground, a series circuit of a resistor 108 and a Zener diode (constant voltage diode) 109, a series circuit of a resistor 110 and a Zener diode 111, and a resistor 112.
And a series circuit of the Zener diode 113 are connected in parallel.

The connection point of the resistor 108 and the diode 109 is connected to the inverting input terminal of the comparator 105, and the connection point of the resistor 110 and the diode 111 is connected to the comparator 106.
Of the resistor 112 and the diode 113 are connected to the inverting input terminal of the comparator 107. The output terminals of the comparators 105, 106 and 107 are respectively connected to the light emitting diodes 114, 115 and 1
It is grounded through 16.

Here, the diodes 109, 111, 11
The Zener voltage (breakdown voltage) of 3 is the battery voltage V
It is set to be equal to the voltage obtained at the connection point P when B is Va, Vb, Vc (Va>Vb> Vc). Each of the comparators 105, 106 and 107 outputs a high level “H” signal when the input voltage at the non-inverting input terminal is higher than the input voltage at the inverting input terminal, and outputs a low level “H” otherwise. The L signal is output.

In the above structure, the battery voltage VB is Va
When larger (VB> Va), the comparators 105 and 10
6, 107 outputs a high level “H” signal. Therefore, the light emitting diodes 114, 115, 116
Current flows through the light emitting diodes 114, 115,
All 116 are in a light emitting state. Also, the battery voltage VB is V
When a or less and greater than Vb (Va ≧ VB> V
b), a low level “L” signal is output from the comparator 105, and a high level “H” is output from the comparators 106 and 107.
Signal is output. Therefore, the light emitting diode 114
Current does not flow to the light emitting diodes 115 and 116, and a current flows only to the light emitting diodes 115 and 116. Therefore, the light emitting diode 114 is in a non-light emitting state, and the light emitting diodes 115 and 116 are in a light emitting state.

Further, the battery voltage VB is Vb or less, and V
When it is larger than c (Vb ≧ VB> Vc), the comparator 10
A low level “L” signal is output from 5, 106,
A high level “H” signal is output from the comparator 107. Therefore, no current flows through the light emitting diodes 114 and 115, and only a current flows through the light emitting diode 116.
Therefore, the light emitting diodes 114 and 115 are in a non-light emitting state, and the light emitting diode 116 is in a light emitting state. Also,
When the battery voltage VB is equal to or lower than Vc (Vc ≧ VB), the comparators 105, 106 and 107 output low level “L” signals. Therefore, the light emitting diode 114,
No current flows through 115, 116, and all the light emitting diodes 114, 115, 116 are in a non-light emitting state.

[0009]

In the headphone stereo, the load current becomes large when the operation is started (when the motor is started). In this case, the battery voltage VB greatly decreases due to the internal resistance of the battery 101, and even if there is still a sufficient remaining amount, the remaining amount is detected as small, and the light emitting diodes 114, 115,
The number of light emission of 116 decreases.

For example, as shown in FIG. 10, the battery voltage when there is no load is E, the internal resistance R _{S of} the battery 101, and the load 102.
Let _{RL be} the resistance of R and load current be I, then VB = EI
It becomes R _S. From this, it is understood that the battery voltage VB decreases as the load current I increases.

By the way, in a mobile phone, the load current changes greatly depending on the usage condition. For example, the load current during a call is much larger than the load current during a standby. Therefore, if the battery residual amount detection circuit as shown in FIG. 9 is applied to such a mobile phone, the residual battery amount cannot be correctly detected when the load current is large such as during a call.

Therefore, an object of the present invention is to make it possible to accurately detect the remaining battery level.

[0013]

SUMMARY OF THE INVENTION A battery remaining amount detecting circuit according to the present invention comprises voltage correcting means for correcting and outputting a battery voltage, and voltage value detecting means for detecting an output voltage value of the voltage correcting means. A state detecting means for detecting a load state of the battery, a comparing means for comparing the voltage value detected by the voltage value detecting means with a reference value to obtain remaining battery level information, and a state detecting means for detecting Correction value changing means for changing the correction value in the voltage correcting means based on the load state of the battery.

The mobile phone according to the present invention uses a battery as a power source and has a battery remaining amount detecting circuit for detecting the remaining amount of the battery. Then, the battery remaining amount detection circuit, voltage correction means for correcting and outputting the voltage of the battery,
The voltage value detecting means for detecting the output voltage value of the voltage correcting means, the state detecting means for detecting the load state of the battery, and the voltage value detected by the voltage value detecting means are compared with a reference value to determine the battery level. The comparison means for obtaining the remaining amount information and the correction value changing means for changing the correction value in the voltage correcting means based on the load state of the battery detected by the state detecting means are provided.

The state detecting means detects the load state of the battery. For example, when a battery is used in a mobile phone, the load state of the battery corresponds to the usage state of the mobile phone such as a call state and a standby state. Further, the voltage correction means corrects the battery voltage. In this case, the voltage of the battery changes depending on the load state due to the internal resistance of the battery, and therefore is changed based on the load state of the battery. The output voltage value of the voltage correction means is detected by the voltage value detection means. Then, the comparison means compares the voltage value detected by the voltage value detection means with the reference value. As a result, the remaining amount information (comparison result) of the battery in which the influence of the load state of the battery is excluded can be obtained from the comparison means.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a simplified portable telephone (PHS: Personal) as a first embodiment.
Handyphone System) 10.

The telephone 10 includes a microcomputer 11 for controlling the entire system (hereinafter referred to as "microcomputer"), a transmitting / receiving antenna 12, and the antenna 1.
2 is down-converted to a π / 4 shift QPSK (Quadrature Phase Shim).
ft Keying) signal, a radio section 13 for up-converting a π / 4 shift QPSK signal output from a digital modulation / demodulation section described later to obtain a transmission signal of a predetermined frequency, and an output from the radio section 13 The π / 4-shifted QPSK signal is demodulated to obtain received data, and TDMA (Time Division Multiple Acces
s) a digital modulation / demodulation unit 14 for modulating transmission data output from the processing unit to obtain a π / 4 QPSK signal.

Further, the telephone set 10 selects the data of the preset downlink slot from the received data (time-division multiplexed data of a plurality of slots) output from the digital modulation / demodulation unit 14 and separates it into control data and compressed voice data. At the same time, it has a TDMA processing unit 15 that multiplexes compressed audio data output from an audio codec unit, which will be described later, and control data output from the microcomputer 11 into a preset upstream slot.

Further, the telephone 10 has a TDMA processing unit 15
The received audio signal is obtained by performing a decoding process (including an error correction process) on the output compressed audio data, and a compression encoding process (including an error correction code addition process) is performed on the transmission audio signal. ) To obtain compressed audio data, and an audio codec 16
It has a speaker (receiver) 17 to which a received audio signal is supplied, and a microphone (speaker) 18 for supplying a transmission audio signal to the audio codec section 16.

The telephone 10 has a voice codec section 1
6, the DTMF (Dual Tone) obtained as the received voice signal
Multiple frequency) signal is converted into key data corresponding to special input keys of “*” and “#” and numeric keys of “0” to “9”, and supplied to the microcomputer 11.
The key data corresponding to the special input keys of “*” and “#” and the numeric keys of “0” to “9” output from DT
A DTMF modulator / demodulator 19 which converts the MF signal into an MF signal and supplies the MF signal to the audio codec 16 as a transmission audio signal;
A conversion format storage unit 20 for converting key data output from the F modem unit 19 into character data. The conversion format storage unit 20 is connected to the microcomputer 11.

Further, the telephone set 10 records the received voice signal obtained by the voice codec section 16 in the absence recording mode, and records the received voice signal and the prerecorded response message (voice signal) by the key described later. A voice recording / playback section 21 for reproduction by operating the input section or control of the microcomputer 11, a vibration generation section 22 for vibrating the telephone body under control of the microcomputer 11 when a call is received when the vibration mode is set, and a vibration mode. When there is no setting, the microcomputer 11
And a ringing tone output unit 23 that outputs a ringing tone under the control of. Here, the audio recording / reproducing unit 21 has a semiconductor memory as a recording medium for audio signals. Voice recording part 2
Although the operation of 1 is controlled by the microcomputer 11, the audio recording / reproducing unit 21 supplies the microcomputer 11 with a signal indicating the operation state of the audio recording / reproducing unit 21.

Further, the telephone 10 gives an instruction to make a call,
To enter a call key for answering an incoming call, a call end key for ending a call, a function key for entering the phonebook registration mode, setting an answering machine mode or vibration mode, a telephone number, etc. It has a key input unit 24 in which ten keys, special input keys, keys for operating recording and reproduction of the voice recording / playback unit 21, and the like are arranged. Key input unit 2
Reference numeral 4 is connected to the microcomputer 11, and the microcomputer 11 monitors the key operation of the key input unit 24.

Further, the telephone set 10 has a nonvolatile memory 25 for storing telephone directory data, redial data, text message data transmitted from the other party, mode setting information, and the like, a system state, Liquid crystal display (LCD: LiquidCr) for displaying the telephone number of the other party when making a call and the text message sent from the other party
ystal display) 26. This liquid crystal display 2
6 is driven by an LCD driver 27 controlled by the microcomputer 11.

The telephone 10 has a battery 2 as a power source.
The microcomputer 11 converts the voltage VB of 8 into a digital signal.
And an A / D (analog-to-digital) converter 29 supplied to the. In the microcomputer 11, as will be described later, the A / D converter 29 is turned on at the time of power-on and at every constant time thereafter.
The voltage value of the battery 28 is detected from the output data of the CPU, and this voltage value and the ROM (Read Only) built in the microcomputer 11 are detected.
Memory) 30 is compared with a reference value stored in memory 30 to obtain remaining amount information of battery 28.

2 and 3 show the appearance of the telephone 10, and parts corresponding to those in FIG. 1 are designated by the same reference numerals.

The antenna 12 is provided at the upper end of the telephone body 40.
Is arranged. Further, a sound passage hole 41 for guiding sound from the built-in speaker to the outside is formed above the main body 40, and the liquid crystal display 26 is disposed below the sound passage hole 41. further,
The microphone 18 is arranged below the main body 40. Also,
A call key 42, a function key 43, and an end call key 44 are arranged side by side in the center of the main body 40 and below the liquid crystal display 26. The end call key 44 turns on / off when pressed.
Off key.

Further, below the keys 42 to 44, left, right, up and down cursor movement keys 45, a registration key 46 for registering telephone directory data, a clear key 47 for clearing input data, a ten key 48, and special input. Keys 49, 50
Is arranged. Here, the "↑" key that constitutes the cursor movement key 45 also serves as a key for starting the search of redial data or phone book data, and the "↓" key shifts to the character sending mode during a call and the received character is received. Also serves as a key for checking data.

Further, the main body 40 is provided with a key protection lid 51 which is constructed so as to be openable and closable around the arrangement portion of the microphone 18 as a fulcrum. When the key protection lid 51 is closed, the keys 45 to 50 are covered. Therefore, the keys 45-5
Operation 0 must be performed with the key protection cover 51 opened. FIG. 2 shows a state in which the key protection cover 51 is removed.

On the side surface of the main body 40, the voice recording / reproducing section 2
Recording key 5 for operating recording and playback of 1 (see FIG. 1)
2 and a reproduction key 53, and a volume adjustment key 54 for adjusting the volume. The volume adjustment key 54 is
The configuration is such that the volume increases when the side is pressed, and decreases when the side is pressed.

Next, the operation of the telephone 10 shown in FIG. 1 will be described.

Since the control channel is out of synchronization when the power is turned on, the control channel transmitted from the base station is received to establish the control channel. Then, after the control channel is established, the location registration of being in the area of the base station is performed. This location registration is done using the call channel. After the location registration is completed, it returns to the control channel reception state and enters the standby state.

Further, the key input section 24 (numerical keypad 48, etc.)
Enter the telephone number of the other party by using the key operation of or call key 4 after searching the redial data or phone book data.
When 2 is operated, first, telephone number data or the like is supplied as control data from the microcomputer 11 to the TDMA processing unit 15 and transmitted to the base station through the control channel. As a result, the line connection with the other party is established, and a call is made possible.

Here, the call is performed using the call channel, but during the line connection processing, the control channel is used to transmit the communication frequency and slot position data of the call channel from the base station as control data to perform the TDMA processing. It is supplied from the unit 15 to the microcomputer 11. The microcomputer 11
The radio section 13 is controlled based on the communication frequency data so that the transmission / reception frequency matches the communication frequency of the communication channel, and the slot selected by the TDMA processing section 15 is set based on the slot position data. Therefore, the call is made using the call channel notified from the base station.

Further, when the base station transmits call data as control data using the control channel and the call data is supplied from the TDMA processing section 15 to the microcomputer 11 to detect an incoming call, the microcomputer 11 issues a ring tone. The output unit 23 is controlled to output a ringing tone, or the microcomputer 11 controls the vibration generator 22 to vibrate the telephone body 40.

With this calling operation being performed,
When the call key 42 is operated and there is a response, the microcomputer 11
Response data is more control data than the TDMA processing unit 15.
And transmitted on the control channel to the base station. As a result, the line connection with the other party is established, and a call is made possible. Also in this case, the communication is performed using the communication channel notified from the base station.

In the call state, the compressed voice data transmitted through the call channel is output from the TDMA processing section 15. The compressed audio data is supplied to the audio codec 16 and subjected to a decoding process, and then converted into an analog signal. Then, the received audio signal output from the audio codec section 16 is supplied to the speaker 17 and the speaker 1
7 outputs a sound.

The transmission voice signal output from the microphone 18 is supplied to the voice codec section 16 and converted into a digital signal, which is then compression-encoded to form compressed voice data. Then, the audio codec section 16
The output compressed audio data is supplied to the TDMA processing unit 15 and transmitted to the other party through a communication channel.

In this case, "↓" of the cursor movement key 45
By operating the keys, ten keys 48 and special input keys 4
The character data can be transmitted using 9, 50. In this case, the DTMF signal corresponding to the operated key is DT
The audio codec section 16 is output from the MF modulation / demodulation section 19.
Is supplied as a transmission audio signal.

Further, as described above, the calling data is TDM.
When an incoming call is supplied from the A processing unit 15 to the microcomputer 11 and an incoming call is detected, when the answering machine mode is set, a ringing tone is output only for a predetermined time, and the telephone is automatically answered to be in a call ready state. . Then, after a response message to the effect that the received voice signal is recorded is transmitted to the calling side, the recording of the received voice signal is started by the voice recording / reproducing unit 21.

Also, when the character message data by the DTMF signal is sent from the other party during the absence recording or during the call, the key data output from the DTMF modulator / demodulator 19 is stored in the conversion format under the control of the microcomputer 11. It is converted to character data by referring to the section 20, and the character data is written in the character message area of the non-volatile memory 25. When the character data is written in the non-volatile memory 25 as described above, the character message based on the character data is displayed on the liquid crystal display 26 and confirmed by long-pressing the “↑” key of the cursor movement key 45. It becomes possible.

Further, the microcomputer 11 performs a battery remaining amount detecting process according to the flowchart of FIG. 4 at the time of power-on and at every constant time thereafter.

First, in step ST1, the A / D converter 2
The voltage value of the battery 28 is detected based on the output data of 9. Next, in step ST2, the usage state of the telephone 10 is detected. Then, in step ST3, it is determined whether the telephone call state or another state (for example, a standby state).

When it is determined in step ST3 that the call is in progress, the reference values Vac, Vbc and Vcc (Vac>Vbc> Vcc) in the call state are read from the ROM 30 in step ST4. On the other hand, when it is determined in step ST3 that the call is not in progress, the reference values Va, Vb, Vc (Va>Vb> when the call is not in progress are read from the ROM 30 in step ST5.
Vc) is read.

As described above, the load current in the call state becomes larger than that in the standby state, and the battery voltage VB decreases due to the internal resistance R _S. Therefore, as shown in FIG. 5, the reference values Vac, Vbc, Vcc are obtained. Are reference values Va,
It is set to a value smaller than Vb and Vc by the correction value VC. The curve a shows the relationship between the battery voltage and the time in the call state, and the curve b shows the relationship between the battery voltage and the time in the standby state.

Returning to FIG. 4, next, in step ST6,
The voltage value is compared with the reference value to obtain the remaining amount information (comparison result) of the battery 28. Then, in step ST7, a display is displayed on the liquid crystal display 26 in accordance with the remaining amount information. FIG. 6 shows a display example of the liquid crystal display 26. The electric field strength is displayed on the display portion Pa, the display portion Pb indicates whether or not the mobile terminal is within the range of a public base station or a self-employed base station, and the display portion Pc indicates whether or not the vibration mode is set by mail ( Whether or not there is received character data) is displayed.

Then, the remaining battery level is displayed by the three bars d1, d2, d3 arranged on the display portion Pd.
For example, when the battery level is sufficient, VB> Va (Va
c), and all the bars d1 to d3 are displayed in black.
In addition, when the battery level decreases, Va (Vac) ≧ VB> Vb
When it becomes (Vbc), the bars d1 and d2 are displayed in black. Furthermore, the remaining battery level decreases, and Vb (Vbc) ≧ VB>
When it becomes Vc (Vcc), only the bar d1 is displayed in black. And when the battery level is almost exhausted, V
Since c (Vcc) ≧ VB, none of the bars d1 to d3 is displayed in black.

As described above, in the first embodiment,
The reference value that is compared with the voltage value of the battery 28 to obtain the remaining amount information is changed to be smaller by the correction value VC in the call state in which the load current is larger than in the other states. Therefore, the microcomputer 11 can obtain the remaining amount information (comparison result) excluding the influence of the load state of the battery 28, and can accurately detect the remaining amount of the battery.

In the first embodiment, the reference values Va and V are stored in the ROM 30 built in the microcomputer 11.
Although b, Vc and reference values Vac, Vbc, Vcc are stored, the reference values Va, Vb, Vc and the correction value V are shown.
C may be stored and the reference values Vac, Vbc, Vcc may be calculated and obtained. Similarly, the reference values Vac, Vbc,
Vcc and the correction value VC are stored and the reference values Va, Vb,
Vc may be calculated and obtained.

FIG. 7 shows a simplified mobile phone 60 as a second embodiment. In FIG. 7, FIG.
The same reference numerals are given to the portions corresponding to and the detailed description will be omitted.

The telephone 60 is a D / A (digital-converter) which converts the correction value e output from the microcomputer 11 into an analog signal.
to-analog) converter 61 and D / to the voltage VB of the battery 28
It has an adder 62 that adds and corrects the correction value e output from the A converter 61 and supplies the corrected battery voltage VBC to the A / D converter 29. Further, the ROM 30 incorporated in the microcomputer 11 stores the reference values Va, Vb, Vc corresponding to the time when the call is not in progress, and the correction value VC data read and used in the call (see FIG. 5).

Then, the microcomputer 11 detects the corrected voltage value of the battery 28 from the output data of the A / D converter 29 at the time of power-on and at regular intervals thereafter, and stores this voltage value and the ROM 30 in the ROM 30. Compared with the reference value,
Information on the remaining amount of the battery 28 is obtained. Other configurations and operations in the second embodiment are similar to those in the above-described first embodiment.

In the second embodiment, the microcomputer 11
Performs battery remaining amount detection processing according to the flowchart of FIG. 8 at the time of power-on and at fixed time intervals thereafter.

First, in step ST11, the usage state of the telephone 10 is detected. Then, in step ST12, it is determined whether the telephone call state or another state (for example, a standby state).

As described above, the load current in the call state becomes larger than that in the standby state, and the battery voltage VB decreases due to the internal resistance R _S. Therefore, step ST1
When it is determined that the call is in progress in step 2, step ST1
At 3, the correction value VC is read out from the ROM 30 as the correction value e and output. As a result, in the adder 62, the correction value VC is added to the voltage VB of the battery 28, and the corrected battery voltage V
BC is obtained. On the other hand, when it is determined in step ST12 that the communication is not in progress, 0 is output as the correction value e in step ST14. In this case, the corrected battery voltage VBC obtained from the adder 62 becomes the voltage VB itself.

Next, in step ST15, the corrected voltage value of the battery 28 is detected based on the output data of the A / D converter 29. Next, in step ST16, the reference values Va, Vb, V corresponding to the case when the call is not in progress are read from the ROM 30.
Read c. Then, in step ST17, the voltage value and the reference value are compared to obtain the remaining amount information (comparison result) of the battery 28.

Then, in step ST18, a display corresponding to the remaining amount information is displayed on the display portion Pd (see FIG. 6) of the liquid crystal display 26. For example, when the battery level is sufficient, VBC>
It becomes Va, and all the bars d1 to d3 are displayed in black.
Further, when the battery level decreases and Va ≧ VBC> Vb, the bars d1 and d2 are displayed in black. When the remaining battery level further decreases and Vb ≧ VBC> Vc, only the bar d1 is displayed in black. Then, when the remaining battery level is almost exhausted, Vc ≧ VBC, and the bar d1 to
None of d3 is displayed in black.

As described above, in the second embodiment,
The correction value e is added to the battery voltage VB by the adder 62. In the call state in which the load current becomes large, the battery voltage V
The correction value VC is added to B to correct the battery voltage VB. Therefore, the microcomputer 11 can obtain the remaining amount information (comparison result) excluding the influence of the load state of the battery 28, and can accurately detect the remaining amount of the battery as in the first embodiment. it can.

In the second embodiment, the adder 62 adds the correction value e to the battery voltage VB in an analog manner. However, for example, the correction value e is added digitally in the microcomputer 11. Good.

Further, in the second embodiment, RO
The reference values Va, Vb, Vc stored in the M30 correspond to when the call state is not in use, but the ROM 30 stores the reference values Vac, Vbc, Vcc (see FIG. 5) corresponding to the call state. If so, the adder 62 is replaced with a subtracter, and the microcomputer 11 outputs 0 as the correction value e when in the call state, and outputs the correction value VC as the correction value e from the ROM 30 when not in the call state. You can do it.

Further, in the above-described embodiment, the telephone 10 is used as the use state, but is divided into the call state and other states. However, the reference value and the correction value are divided into more states with different load states. May be changed.

Further, in the above-mentioned embodiments, the battery remaining amount detecting circuit according to the present invention is applied to the simple type portable telephone, but the load state (load current) changes greatly depending on the use state. It is suitable for use in portable electronic devices.

Further, in the above-described embodiment, the user is informed of the battery remaining amount by visually displaying the battery remaining amount on the liquid crystal display 26 based on the battery 28 remaining amount information. The remaining battery level may be audibly notified by voice or the like.

[0063]

According to the present invention, the correction value of the battery voltage is changed based on the load state of the battery, and the remaining amount information excluding the influence of the load state of the battery can be obtained.
Therefore, the remaining battery level can be detected accurately. Therefore, it is suitable to be applied to a portable electronic device such as a telephone whose load condition changes greatly depending on the use condition.

[Brief description of drawings]

FIG. 1 is a block diagram showing a simplified mobile phone according to a first embodiment.

FIG. 2 is a front view showing the simplified mobile phone (with a key protection cover removed).

FIG. 3 is a side view showing a simplified mobile phone.

FIG. 4 is a flowchart showing a battery remaining amount detection process according to the first embodiment.

FIG. 5 is a diagram for explaining a change in reference voltage.

FIG. 6 is a diagram showing a display example of a liquid crystal display.

FIG. 7 is a block diagram showing a simplified mobile phone as a mobile phone according to a second embodiment.

FIG. 8 is a flowchart showing a battery remaining amount detection process according to the second embodiment.

FIG. 9 is a connection diagram showing a conventional battery remaining amount detection circuit.

FIG. 10 is a diagram for explaining a battery voltage when there is an internal resistance.

[Explanation of symbols]

 10,60 Simple mobile phone 11 Microcomputer 12 Transmission / reception antenna 13 Radio part 14 Digital modulation / demodulation part 15 TDMA processing part 16 Voice codec part 17 Speaker (receiver) 18 Microphone (speaker) 19 DTMF modulation / demodulation part 20 Conversion format storage Part 21 Voice recording / playback part 22 Vibration generation part 23 Ring tone output part 24 Key input part 25 Non-volatile memory 26 Liquid crystal display 28 Battery 29 A / D converter 30 ROM 61 D / A converter 62 Adder

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshito Takeshima 1-2-111 Ikenota, Taito-ku, Tokyo Aiwa Co., Ltd. (72) Inventor Ryoji Terada 1-2-11 Ikenota, Taito-ku, Tokyo Aiwa Inside the corporation

Claims (7)

[Claims] 1. A voltage correcting means for correcting and outputting a voltage of a battery, a voltage value detecting means for detecting an output voltage value of the voltage correcting means, a state detecting means for detecting a load state of the battery, Comparing means for comparing the voltage value detected by the voltage value detecting means with a reference value to obtain remaining battery level information, and voltage correcting means based on the load state of the battery detected by the state detecting means. And a correction value changing means for changing the correction value in 1. 2. The battery remaining amount detection circuit according to claim 1, further comprising a memory unit that stores data for changing the correction value by the correction value changing unit. 3. The battery remaining amount detection according to claim 1, further comprising a remaining amount notifying unit for notifying the remaining amount of the battery based on the remaining amount information of the battery obtained from the comparing unit. circuit. 4. The battery remaining amount detecting circuit according to claim 3, wherein the remaining amount notifying means auditorily notifies the remaining amount of the battery. 5. The battery remaining amount detecting circuit according to claim 3, wherein the remaining amount notifying unit visually notifies the remaining amount of the battery. 6. A mobile phone using a battery as a power source, which has a battery remaining amount detection circuit for detecting the remaining amount of the battery, and the battery remaining amount detection circuit corrects and outputs the voltage of the battery. Voltage correction means, voltage value detection means for detecting the output voltage value of the voltage correction means, state detection means for detecting the load state of the battery, and the voltage value detected by the voltage value detection means as a reference value. And a correction value changing means for changing the correction value in the voltage correcting means based on the load state of the battery detected by the state detecting means. A mobile phone characterized by. 7. The mobile phone according to claim 6, further comprising a remaining amount notifying unit for notifying the remaining amount of the battery based on the remaining amount information of the battery obtained from the comparing unit.