Computer graphics processing and selective visual display system – Display driving control circuitry – Display power source
Reexamination Certificate
1998-08-31
2001-11-06
Hjerpe, Richard (Department: 2774)
Computer graphics processing and selective visual display system
Display driving control circuitry
Display power source
C713S320000
Reexamination Certificate
active
06313832
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a remaining battery capacity display device for use in a communication device powered by a battery, and more particularly, to a remaining battery capacity display device suitable for a mobile terminal employed in a CDMA (Code Division Multiple Access)-based mobile communications network.
2. Description of the Related Art
In general, it is a matter of great concern to an operator of an apparatus powered by a battery to be informed of remaining time available for operation of the apparatus. The present invention is concerned with display of such remaining time or remaining capacity of the battery.
Conventionally, the voltage value of the battery is used in estimating remaining operating time available for operation of apparatuses of the above-mentioned type.
FIG. 11
shows an example of curves representative of current-voltage characteristics of a lithium battery exhibited at respective levels of the remaining capacity of the battery. As shown in
FIG. 11
, if the current consumption of the battery is constant, one-to-one correspondence holds between the voltage value of the battery and the remaining battery capacity. Therefore, it is possible to measure the battery voltage and then calculate the remaining battery capacity based on the measured value of the battery voltage. Further, since the current consumption is constant, it is possible to estimate remaining operating time of the device.
However, in the case of a mobile terminal powered by a battery, the passage of battery current through a transmitter, which consumes electric current more than any other component thereof, is permitted only during signal transmission, but is inhibited during standby for signal reception so as to prevent waste of remaining capacity of the battery. As a result, the battery current consumption during standby for signal reception is different from that during transmission. For that reason, in the mobile terminal, it is impossible to estimate remaining battery capacity or remaining operating time simply from a measured value of the battery voltage. Therefore, the mobile terminal employs two different methods of estimating remaining battery capacity, i.e. one used during standby for signal reception and the other used during signal transmission. For instance, the remaining battery capacity or remaining operating time is estimated such that the estimated value is smaller during signal transmission than during standby for signal reception.
In a CDMA-based mobile communications network, it is essentially required that signals transmitted from respective mobile terminals are received at the lowest possible level at each base station thereof. To this end, the base station always sends each mobile terminal a signal based on which the mobile terminal should adjust the level of a signal transmitted therefrom. Alternatively, a mobile terminal measures a reception level of a signal received from the base station, estimates an appropriate transmission level from the measured reception level, and then sends a signal to the base station at the estimated appropriate level. Therefore, the signal transmission level of the CDMA-based mobile terminal frequently changes as the terminal moves to change its position.
For the above reason, the battery current consumption by the CDMA-based mobile terminal is not constant even during transmission. Moreover, the transmission level of a signal from the terminal is required to be adjustable e.g. within a range of 20 dB to 70 dB. Therefore, the remaining battery capacity display device used in the conventional mobile terminal described above, which operates on the precondition that the battery current consumption is held constant during transmission, is not capable of displaying an exact remaining battery capacity for the CMDA-based mobile terminal.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a remaining battery capacity display device which is capable of displaying an exact remaining battery capacity even if battery current consumption varies.
To attain the above object, according to a first aspect of the present invention, there is provided a remaining battery capacity display device for use in a communication device powered by a battery. The remaining battery capacity display device according to the first aspect of the invention is characterized by comprising voltage detection means for detecting a value of voltage of the battery, current consumption calculation means for calculating a battery current consumption corresponding to a transmission output level of the communication device, remaining battery capacity calculation means for calculating a remaining battery capacity based on the value of the voltage of the battery detected by the voltage detection means and the battery current consumption calculated by the current consumption calculation means, a display device, and display control means for causing the display device to carry out display operation according to the remaining battery capacity calculated by the remaining battery capacity calculation means.
Further, to attain the above object, according to a second aspect of the invention, there is provided a remaining battery capacity display device for use in a communication device powered by a battery. The remaining battery capacity display device according to the second aspect of the invention is characterized by comprising a predetermined table that stores data of communicatable time periods over which the communication device is capable of communication, the communicatable time periods being correlated to values of voltage of the battery and transmission output levels of the communication device, respectively, voltage detection means for detecting a value of the voltage of the battery of the communication device, reading means for reading out one of the communicatable time periods corresponding to the value of the battery voltage detected by the voltage detection means and one of the transmission output levels of the communication device, with reference to the predetermined table, and display means for displaying the one of the communicatable time periods read out by the reading means.
Further, to attain the above object, according to a third aspect of the invention, there is provided a remaining battery capacity display device for use in a communication device powered by a battery. The remaining battery capacity display device according to the third aspect of the invention is characterized by comprising voltage detection means for detecting a value of voltage of the battery of the communication device, current consumption calculation means for calculating a battery current consumption corresponding to transmission output of the communication device, a predetermined table that stores data of values of remaining battery capacity of the battery, the values of the remaining battery capacity being correlated to values of the voltage of the battery of the communication device, respectively, reading means for reading out one of the values of the remaining battery capacity corresponding to the value of the battery voltage detected by the voltage detection means, with reference to the predetermined table, a display device, and display control means for causing the display device to carry out display operation based on the one of the values of the remaining battery capacity read out by the reading means.
REFERENCES:
patent: 4626765 (1986-12-01), Tanaka
patent: 5349535 (1994-09-01), Gupta
patent: 5684404 (1997-11-01), Millar
patent: 5867140 (1999-02-01), Rader
patent: 5917777 (1999-06-01), Tanigawa
patent: 5994877 (1999-11-01), Seri et al.
patent: 6005559 (1999-12-01), Miyamoto
Fujitsu Limited
Helfgott & Karas P.C.
Hjerpe Richard
Laneau Ronald
LandOfFree
Remaining battery capacity display device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Remaining battery capacity display device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Remaining battery capacity display device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2589342