AU749391B2

AU749391B2 - Mobile telephone set

Info

Publication number: AU749391B2
Application number: AU23796/99A
Authority: AU
Inventors: Hidetoshi Okamura
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 1998-04-16
Filing date: 1999-04-15
Publication date: 2002-06-27
Anticipated expiration: 2019-04-15
Also published as: JPH11299114A; CN1233901A; GB2337898B; GB2337898A; AU2379699A; GB9908773D0

Description

S F Ref: 459129

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: NEC Corporation 7-1, Shiba Minato-ku Tokyo

JAPAN

Actual Inventor(s): Address for Service: Hidetoshi Okamura Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Invention Title: Mobile Telephone Set The following statement is a full description of this inventi best method of performing it known to me/us:on, including the 5845 MOBILE TELEPHONE SET CROSS REFERENCE TO RELATED APPLICATIONS The present invention claims priority from Japanese Patent Application No. 124028 filed April 16, 1998, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile telephone set including a control LSI and display means composed of, for example, two light emitting elements such as light emitting diodes (LEDs) which can emit different color lights. The control LSI controls the display means by regulating light intensity of the LEDs such that a display provided by the i" display means is variable to provide a presentation of a state of a battery according to a voltage level thereof to thereby realize a space saving of the mobile telephone set concomitantly with the requirement of compactness of the telephone set and to enable a 15 user to immediately recognize a battery voltage during a charging thereof and an available power thereof.

Description of Related Art Japanese Utility Model Application Laid-open No. Sho 59-169550 discloses a technique for displaying a battery condition such as an available power of a battery or a 20 voltage level of the battery in the course of charging by the number of lit LEDs among a plurality of LEDs or by different color lights emitted by a plurality of LEDs which emit different color lights.

In the technique disclosed in Japanese Utility Model Application Laid-open No.

Sho 59-169550, when two LEDs which emit different color lights such as red light and green light are used, these LEDs are controlled such that the red LED is lit when the battery is in the course of charging and the green LED is lit or extinguished when the charging is completed. Therefore, it is difficult for a user to easily recognize a voltage level of the battery.

Further, the available power of the battery in usual use is displayed on a LCD (liquid crystal display) by a mere switch operation by the user and, therefore, it is difficult for the user to easily recognize the level of available power of the battery since there is no indication of lights with colors.

Although Japanese Patent Application Laid-open No. Hei 06-10425 discloses a luminance regulation of LEDs by a luminance regulation signal every combination of color lights from the LEDs and Japanese Patent Application Laid-open No. Hei 06-292239 discloses a regulation of luminance/color tone of lights emitted by LEDs, these prior arts relate to the luminance regulation and the color tone regulation of the LEDs themselves and do neither disclose nor suggest a technical concept for displaying a charged voltage of the battery and/or an available power of the battery by regulating the luminance and/or color tone of the LEDs according to the charged voltage and the available power of the battery.

As such, it is difficult to easily perform a representation corresponding to the voltage level of the battery by changing a display condition of the display means composed of such as two LEDs emitting different color lights.

Further, the technique disclosed in Japanese Utility Model Application Laid-open No. Sho 59-169550 in which a number of LEDs are arranged can not cope with the requirements of space saving, reduction of size and reduction of cost. Since it is expected 20 that such requirements become more severe in the future, further reduction of the number of parts, reduction of cost and reduction of size shall be indispensable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a mobile telephone set that is constructed with a reduced number of parts.

Another object of the present invention is to provide a mobile telephone set which is capable of displaying a status of a battery corresponding to a voltage level of the battery, an available power of the battery and a required time for fully charging the battery.

Another object of the present invention is to provide a mobile telephone set which is space saving, is compact and is inexpensive.

A further object of the present invention is to provide a mobile telephone set which is capable of giving an easily recognizable information of the voltage level, the available power and the required charging time to a user.

In order to achieve the above objects, a mobile telephone set according to the present invention comprises transmitter/receiver means for transmitting and receiving a radio signal, memory means for storing various setting information including an ID information of the mobile telephone set, display means composed of a first light emitting element emitting a first color light and a second light emitting element emitting a second color light for displaying a two-color light presentation, a CPU for reading a call reception setting information stored in the memory means when a receiving signal received by the transmitter/receiver means is confirmed as having an ID information coincident with the ID information of the mobile telephone set and outputting an instruction of a call reception operation and a predetermined instruction, a charging circuit for starting a charging 15 operation of a battery and stopping the charging operation of the battery on the basis of the instructions from the CPU, and a control LSI for driving the display means to display a call reception to a user according to the setting information in response to the instruction of the call reception operation from the CPU, sending a call reception confirmation of the user to the CPU when the user confirms the call reception by the display of the display means and 20 displaying a charging state of the charging circuit and a state of the battery on the display means.

According to the mobile telephone set of the present invention, when the transmitter/receiver means receives the radio signal, the CPU determines whether an ID information contained in the receiving signal is coincident with the ID information stored in the memory means. When these ID are coincident with each other, the CPU reads in the setting information at the call reception from the memory means and instructs the control LSI to perform the call reception operation. According to the instruction of the call reception, the control LSI performs a drive control of the display means to display the call reception to the user.

When the user confirms the call reception on the display means, the control LSI gives a notice of the call reception confirmation of the user to the CPU.

During a time in which the charging circuit charges the battery, the control LSI drives the first and second light emitting elements of the display means under control of the CPU so that the charging state of the battery, the voltage level of the battery and the available power of the battery are displayed by a change of color of mixed color lights of the first and second light emitting elements, a change of light emitting conditions thereof and/or an absence or presence of lights thereof.

BRIEF DESCRIPTION OF THE DRAWINGS ~A mobile telephone set according to the present invention will be described in detail with reference to preferred embodiments shown in the accompanying drawings, in S.which: Fig. 1 is a block circuit diagram showing a whole construction of a first embodiment of a mobile telephone set according to the present invention; Fig. 2 is a block circuit diagram showing an internal construction of a control LSI of the first embodiment and a LED luminance regulation circuit which is controlled by the control LSI; Fig. 3 is a flowchart showing a call reception processing procedure in the first 20 embodiment; Fig. 4 is a flowchart showing a charging operation procedure of a charging circuit of the first embodiment; Fig. 5 is a flowchart showing a monitoring procedure for monitoring a battery voltage in the first embodiment; Fig. 6 is a flowchart showing a notice processing procedure of an available power level of a battery in the first embodiment; Fig. 7 is a graph showing a relation between a value of a voltage status register in the control LSI and a battery voltage in the first embodiment;

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Fig. 8 is a table showing a relation between the value of the voltage status register and a driving of a green LED and a red LED by a drive control circuit in the first embodiment; Fig. 9 is a graph showing a relation between a resistance value of a LED luminance regulation circuit and a luminance of the LED in the first embodiment; Fig. 10 is a graph showing a possibility of producing 5 colors on the basis of a luminance balance between a green LED and a red LED in the first embodiment; Fig. 11 is a block diagram showing a LED driving power source control circuit in a control LSI and a peripheral circuit thereof according to a second embodiment of the present invention; and °r ~Fig. 12 is a table showing a relation between the LED driving power source °o control circuit and a voltage status register in the second embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 1 is a block circuit diagram showing a whole construction of a mobile S, 15 telephone set according to a first embodiment of the present invention.

0 In Fig. 1, a radio unit 2 transmits and receives a radio signal through an antenna 1.

A base-band LSI 3 demodulates an audio signal or data which is received and modulates 0,0 ~an audio signal or data which is transmitted, drives a receiver unit 4 of the mobile telephone set, amplifies an audio signal received from a microphone 5 and performs an A/D and D/A conversions of the audio signal under control of the CPU 7. That is, the antenna 1, the radio unit 2, the base-band LSI 3, the receiver unit 4 and the microphone constitute a transmission/receiving means.

A ROM 8 stores a software for operating the CPU 7, a RAM 9 forms a region in which the CPU 7 performs a work and an EEPROM 10 as memory means stores ID information and various setting information. The ROM 8, the RAM 9 and the EEPROM are connected to the CPU 7 through a bus 7a.

Under a control of the CPU 7, a control LSI 6 performs an ON/OFF control of power sources of respective blocks, a driving of a vibrator 12 and/or an alarm phone 13 6 which produces an alarm signal at a time of a call reception, a monitoring of a manual depression of a ten key/operation key switch 11 as operation means and a control of a LED luminance regulation circuit 14 to turn on and off a green LED 15 and a red LED 16 at a call reception and to light the green LED 15 and/or the red Led 16 during a charging time of a battery of the mobile telephone set. The green LED 15 and the red LED 16 as light emitting means constitute display means for displaying a fully charged state of a battery 18 of the mobile telephone set, a charging state of the battery 18, an available power of the battery 18 and/or a charging time required to fully charge the battery 18, etc., to the user of the mobile telephone set.

10 The green LED 15 and the red LED 16 are arranged in the vicinity of a diffusion lens 17 mounted on a casing 34 of the mobile telephone set. When the LEDs emit lights, the diffusion lens 17 diffuses these lights to allow the lights to pass externally of the casing 34 as a light having a color which is a mixture of green and red.

0A charging circuit 19 is connected to one terminal of the battery 18 having the other terminal grounded and to the CPU 7 through the bus 7a. The charging circuit 19 has a plus terminal 20 and a minus terminal 21 across which a charging power source (not o shown) is to be connected. When the terminals 20 and 21 are connected across the charging power source, the charging circuit 19 controls a charging current flowing from the charging power source through the battery 18 to a constant value to fully charge the battery 18. The CPU 7 monitors an operation of the charging circuit 19 and can control a start of a charging operation thereof and a termination of the charging operation thereof.

Further, the charging circuit 19 is connected through the bus 7a to a LCD which displays a value of a voltage status register read in by the CPU 7.

Fig. 2 shows the LED luminance regulation circuit 14 in detail and shows an internal construction of the control LSI 6 related to a control of the LED luminance regulation circuit 14.

In Fig. 2, the LED luminance regulation circuit 14 includes three resistors 26, 27 and 28 having small, medium and large resistance values, arranged in parallel to each other and connected to a cathode of the green LED 15 and three resistors 23, 24 and 25 having small, medium and large resistance values, arranged in parallel to each other and connected to a cathode of the red LED 16. Anodes of the green LED 15 and the red LED 16 are connected to an LED driving power line 33 connected to the control LSI 6. An operation of the LED luminance regulation circuit 14 is controlled by an LED drive circuit 29 of the control LSI 6, which is connected to the CPU 7 through the bus 7b. The LED drive circuit 29 is composed of two groups each including three field effect transistors (FETs) which control one of the green LED 15 and the red LED 16 and a LED drive control circuit 30 for controlling driving of the field effect transistors under control of the CPU 7.

10 The control LSI 6 further includes a voltage detector circuit 31 for detecting the voltage of the battery 18 and a voltage status register 32. The voltage detector circuit 31 S• detects a voltage information of the battery 18 and sends the battery voltage information to the voltage status register 32. The CPU 7 can read out the battery voltage information from the voltage status register 32.

Now, an operation of the first embodiment constructed as mentioned above will :i be described with reference to flowcharts shown in Figs. 3 to 6.

#0oo Describing a call reception processing first with reference to the flowchart shown '•in Fig. 3, the processing is started when the mobile telephone set receives a call. In a step S1, the radio unit 2 amplifies a radio signal received by the antenna 1. The radio signal received and amplified in the step 1 is processed by the base-band LSI 3 in a step 2 and data of the processed radio signal is referenced with the ID information stored in the EEPROM 10 by the CPU 7 in a step S3.

When the ID information contained in the received radio signal is not coincident with the ID information stored in the EEPROM 10, the processing is put in a waiting state until the coincidence is confirmed. When the ID information contained in the received radio signal is coincident with the ID information stored in the EEPROM 10, the CPU 7 reads in the setting information at call reception stored in the EEPROM 10 and instructs the control LSI 6 to perform a call reception operation in a step S4.

8 The setting information at call reception in a step S5 includes a turning on and off of the red LED 16, a driving of the vibrator 12 and a driving of the alarm phone 13, etc. In a case where the setting information at call reception is to merely light the red LED 16, for example, the CPU 7 sends a signal for turning on and off a red small FET of the drive control circuit 30 connected in series to the resistor 23 having the small resistance shown in Fig. 2 to the drive control circuit 30 through the bus 7b to turn the red LED 16 on and off with a large current to thereby give a notice of a call reception to the user by transmitting high intensity red light externally of the casing 34 through the diffusion lens 17.

10 When the user confirms the call reception by the turning on and off of the red LED 16 emitting high intensity red light in a step S6 and the ten key/operation key switch :11 is depressed by the user, the control LSI 6 informs the user's depression of the key 11 to the CPU 7 in a step 57. In response to the depression of the key 11, the CPU 7 instructs the control LSI 6 to terminate the on/off operation of the red LED 16, accdrding to which the drive control circuit 30 of the control LSI 6 stops the on/off operation of the red LED 16.

:i An operation of this embodiment related to a charging of the battery will be •*go described with reference to a flowchart shown in Fig. 4, which shows the charging processing procedure by means of the battery charging circuit 19 and the display condition i processing procedure operation of this embodiment.

When the and terminals 20 and 21 are connected to the charging power source and a certain constant voltage is applied across the terminals, the charging circuit 19 gives a notice to the CPU 7 of the fact that the mobile telephone set is correctly connected to the charging power source. In response to this notice, the CPU 7 instructs the charging circuit 19 to perform a charging operation in a step S11 and the charging circuit 19 starts the charging of the battery 18.

Further, the CPU 7 controls the control LSI 6 to light the LEDs to thereby give a notice to the user of that the battery is being charged.

In detecting a full charging, the charging circuit 19 monitors a reduction of the charging current from a constant value. When the charging current becomes lower than the constant value, the charging circuit 19 gives a notice to the CPU 7 of that the battery 18 is fully charged in a step S12. In response to this notice, the CPU 7 instructs the charging circuit 19 to stop the charging operation in a step S13 and controls the drive control circuit 30 to extinguish the red LED 16 or turn on and off the green LED 15 in a step S14 to give a notice of a completion of charging, upon which the battery charging is completed to the user.

The drive control of the LEDs and a feature in a case where two LEDs emit different color lights will be described with reference to a flowchart in Fig. 5 showing a 10 monitor procedure of the battery voltage.

°The voltage of the battery 18 is always detected by the voltage detector circuit 31 shown in Fig. 2 and the detected voltage value is outputted to the voltage status register 32, as mentioned previously. The CPU 7 monitors the voltage of the battery 18 detected by the voltage detector circuit 31 in a step S21 and reads in the detected voltage value notified to the voltage status register 32 in a step S22. The voltage detector circuit 31 has a table "i showing a relation between battery voltage and voltage status register value shown in Fig.

7 and gives a notice of a voltage status register value obtained from the table to the voltage status register 32.

The CPU 7 controls the drive control circuit 30 according to a table shown in Fig.

8 which shows a relation between the voltage status register value and the driving status of the FETs of the LED drive circuit 29. That is, when the value of the voltage status register 32 read in by the CPU 7 is, for example, 000 which corresponds to the battery voltage lower than 30V, the FET corresponding to a red small terminal of the drive control circuit is turned on to display the charging state of the battery to the user by turning the red LED 16 on to emit a high intensity red light, when the value of the voltage status register 32 read in by the CPU 7 -is, for example, 010 which corresponds to the battery voltage lower than 3.6V and higher than 3.3V, the FETs corresponding to a red middle terminal and a green large terminal of the drive control circuit 30 are turned on to display the i" charging state of the battery to the user by turning the red LED 16 on to emit a middle intensity red light and turning the green LED 15 on to emit a low intensity green light.

In this manner, the CPU 7 controls the control LED 6 to light both the green and red LEDs and 16, to turn on and off the green LED 15 or to turn the green LED 15 off in a step S23.

The luminance of LED depends upon a current flowing therethrough. That is, as shown in Fig. 9 which shows a relation between the luminance of a LED and the current flowing through the LED, when the FET connected between the resistor 23 having the small resistance and the red small terminal of the LED drive circuit 29 is turned on, the LED 16 connected thereto emits red light having a high intensity and, when a FET of the °LED drive circuit 29, which is connected between the resistor such as the resistor 25 which S. has a large resistance value and the red large terminal of the drive control circuit 30 is turned on, the LED 15 connected thereto emits red light having a low intensity.

~When, in a step S24, the green LED 15 and the red LED 16 are lit simultaneously and differently colored lights therefrom are mixed by the diffusion lens 17 and pass therethrough externally of the casing 34, it is possible to produce light having 5 colors oooo according to a luminance balance between the LEDs as shown in Fig. 10. Therefore, when the battery 18 is charged from a voltage lower than 3.OV up to a value higher than 4.0V, the color of light passed through the diffusion lens 17 in a step S 25 is changed from red through orange, yellow and yellowish green to green and the user can recognizes a current battery voltage during the charging on the basis of one of these colors.

The notice of the available power of the battery to the user during a usual use of the mobile telephone set will be described with reference to a flowchart shown in Fig. 6.

In a step S31 shown in Fig. 6, when it is required to display the available power level of the battery by the user's depression of the ten key/operation key switch 11, the CPU 7 reads in the value of the voltage status register 32 to display it on the LCD 35 in a step S32. In this case, when the display by lighting the LEDs is also set, the drive control circuit 30 is controlled according to the relation between the value of the voltage status register 32 and the lighting condition of the LED drive circuit 29 shown in Fig. 8 to perform the display by the green and/or red LEDs in a step S33 and the available power level of the battery is notified to the user in a step S34. The CPU 7 controls the LEDs which are lit for the available power level notice such that they extinguish after a constant time lapses from a start of lighting thereof by counting a time from the start of lighting thereof.

As mentioned above, in the first embodiment shown in Fig. 1, the CPU 7 reads a battery voltage information by the control LSI 6 during the battery is being charged and controls the LED luminance regulation circuit 14 such that the colors of lights from the red 10 LED 16 and the green LED 15 are regulated. Therefore, it is possible to recognize the .9 battery charging state on the basis of the mixed color light emitted externally of the casing 34, which is obtained through the lit red and green LEDs and the diffusion lens 17, and to recognize the voltage level of the battery 18 including the charging state of the battery 18.

In a case where the battery voltage level is notified by the depression of the ten key/operation key switch 11, the CPU 7 reads the battery voltage information from the control LSI 6 to display the available power of the battery on the LCD 35 and controls the LED luminance regulation circuit 14 to emit a mixed color light corresponding to the level of the available power of the battery 18 including the state of the battery 18 for a constant time to thereby give a notice of the battery voltage level to the user.

Now, a second embodiment of the present invention will be described with reference to Figs. 11 and 12, in which Fig. 11 is a block diagram showing a LED driving power source control circuit 36 in the second embodiment and a peripheral circuit thereof for controlling a driving of a green LED 15 and a red LED 16, and Fig. 12 is a table showing a relation between the LED driving power source control circuit 36 and a voltage status register 32 in the second embodiment.

In the second embodiment, a CPU 7 reads a value of the voltage status register 32 and controls the power source control circuit 36 along the relation shown in Fig. 12 to light the green LED 15 and the red LED 16 to thereby display the battery state during a charging 14 I"

L

12 thereof and the available power of the battery.

That is, the power source control circuit 36 is two regulator circuits each for outputting a high voltage, a medium voltage and a low voltage for each of the green and red LEDs 15 and 16. The regulator circuits are grounded through a series circuit of the green LED 15 and a resistor 37 and a series circuit of the red LED 16 and a resistor 38.

The CPU 7 reads the value of the voltage status register 32 to control the power source control circuit 36 on the basis of the relation shown in Fig. 12 such that the voltage values to be applied to the resistors 37 and 38 are changed to change currents flowing through the green and red LEDs to thereby regulate the luminance of the green LED 10 and the luminance of the red LED 16.

According to the second embodiment, the number of resistors of the LED luminance regulation circuit 14 (Fig. 2) in the first embodiment can be reduced, resulting in the space saving in addition to the merit of the first embodiment.

According to the first embodiment or the second embodiment, the five- color display is realized by using two LEDs and, therefore, the space therefor is saved. Further, the user can recognize the current level of the battery voltage and roughly recognize a further time required to fully charge the battery by displaying the voltage level of the battery which is being charged and a currently available power of the battery with a S* plurality of colors.

As described hereinbefore, according to the present invention, the control LSI receives an instruction of call reception operation from the CPU and drives the display means capable of emitting two color lights by means of, for example, a green LED and a red LED according to the setting information stored in the memory means in such a way that the call reception and the battery status such as a charging state of the battery by means of the charging circuit and the voltage of the battery are displayed by changing the light emitting conditions of these LEDs of the display means. Therefore, it becomes possible to provide a mobile telephone set capable of displaying a call reception, a charging state of a battery, a voltage level of the battery, a currently available power of the battery and a rough time required to fully charge the battery by a plurality of color lights with using a minimum number of light emitting elements emitting different color lights.

Thus, due to the reduced number of the parts, the mobile telephone set of the present invention is space saving, has a simple construction and is inexpensive.

o *o a

Claims

1. A mobile telephone set comprising: transmitter/receiver means for transmitting and receiving a radio signal; memory means for storing various setting information including an ID information; display means for performing a two-color light presentation by means of a first light emitting element emitting a first color light and a second light emitting element emitting a second color light; a CPU for reading a call reception setting information stored in said memory °means when a receiving signal received by said transmitter/receiver means is confirmed as 10 being coincident with the ID information and outputting an instruction of a call reception operation and a predetermined instruction; charging circuit for performing a charging operation of a battery and stopping a charging operation of a battery on the basis of the instructions from said CPU; and a control LSI in response to the instruction of the call reception operation from said CPU for controlling a drive of said display means to display a call reception to a user according to the setting information, transmitting a call reception confirmation of the user S"to said CPU when the user confirms the call reception by the driving of said display means and displays a charging state of said charging circuit and a state of said battery on said display means.

2. A mobile telephone set as claimed in claim 1, further comprising a drive control circuit for controlling said display means and a diffusion lens, wherein, in order to notify a call reception to the user, said control LSI controls said drive control circuit such that said drive control circuit turns on and off only said second light emitting element of said display means to emit the second color light through said diffusion lens.

3. A mobile telephone set as claimed in claim 1, further comprising a vibrator for alarming a call reception to the user, wherein said control LSI drives said vibrator.

4. A mobile telephone set as claimed in claim 1, further comprising an alarm phone for alarming a call reception to the user, wherein said control LSI drives said alarm phone. A mobile telephone set as claimed in claim 1, wherein said control LSI notifies said CPU a confirmation of the call reception when the user depresses a ten key/operation key switch.

S.

6. A mobile telephone set as claimed in claim 1, wherein said control LSI includes a voltage detector circuit for detecting a voltage of said battery and a voltage status register for storing values corresponding to respective states of said battery, and wherein said control LSI responds to an instruction from said CPU, which corresponds to a value notified by said voltage detector circuit to said voltage status register during a time for which said battery is being charged by said charging circuit, to control said drive control circuit to drive said first and second light emitting elements to thereby display that said battery is being charged.

7. A mobile telephone set as claimed in claim 1, wherein said control LSI includes a voltage detector circuit for detecting a voltage of said battery and a voltage status register for storing values corresponding to respective states of said battery, and wherein said control LSI responds to an instruction from said CPU, which corresponds to a value notified by said voltage detector circuit to said voltage status register during a time for which said battery is being charged by said charging circuit, to control said drive control circuit to on-off drive only said first light emitting element to thereby display that said battery is being charged.

8. A mobile telephone set as claimed in claim 1, wherein said control LSI includes a voltage detector circuit for detecting a voltage of said battery and a voltage status register for storing values corresponding to respective states of said battery, and wherein said control LSI responds to an instruction from said CPU, which corresponds to a value notified by said voltage detector circuit to said voltage status register during a time for which said battery is being charged by said charging circuit, to control said drive control circuit to extinguish only said first light emitting element to thereby display that said battery is being charged.

9. A mobile telephone set as claimed in claim 1, further comprising a diffusion lens for diffusing lights emitted by said first and second light emitting elements, a LED drive control circuit for controlling said display means and a LED luminance regulation circuit for regulating light intensities of said first and second light emitting elements, wherein, when the voltage of said battery is monitored, said control LSI controls said LED drive circuit to cause said LED luminance regulation circuit to light said first and second light S. emitting elements simultaneously while changing light intensities thereof such that the battery voltage is recognized by one of five colors produced by passing the lights emitted by said first and second light emitting elements through said diffusion lens according to a balance in light intensity between said first and second light emitting elements.

A mobile telephone set as claimed in claim 1, wherein said control LSI includes a voltage status register for storing values corresponding to respective states of said battery and a liquid crystal display, and wherein said CPU reads a value of said voltage status register and displays it on said liquid crystal display to notify a level of an available power of said battery to a user.

11. A mobile telephone set as claimed in claim 1, further comprising a liquid crystal display, wherein said control LSI includes a voltage status register for storing values -17- corresponding to respective states of said battery and a drive control circuit and wherein said CPU reads a value of said voltage status register and displays it on said liquid crystal display and controls said control LSI to cause said drive control circuit to light said first and second light emitting elements such that the available power level of said battery is notified to a user.

12. A mobile telephone set as claimed in claim 1, wherein said first and second light emitting elements are connected in series with resistors, respectively and regulated in luminance by changing voltages applied to said respective resistors under control of said control LSI.

13. A mobile telephone set as claimed in claim 1, wherein said charging circuit detects a full charged state when a charging current to said battery becomes a i'oo,, constant value or less.

14. A mobile telephone set substantially as herein described with reference to Figs. 1 to 10; or Figs. 11 and 12 of the drawings. *o DATED this Thirteenth Day of April 1999 20 NEC Corporation S. Patent Attorneys for the Applicant SPRUSON FERGUSON [N:\LibLI001 54:BFD