Portable telephone with built-in charger

Details Portable telephone with built-in charger Portable telephone with built-in charger

1997-07-28

2001-06-12

Maung, Nay (Department: 2681)

Telecommunications

Transmitter and receiver at same station

Radiotelephone equipment detail

C455S572000, C320S127000

Reexamination Certificate

active

06246890

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a portable telephone with a built-in charger for use as a public communication apparatus.
A recent portable telephone uses a lithium battery or the like as a power source. In use of the portable telephone, the battery is discharged so that the discharged battery needs to be charged again. Recharge of the battery has been carried out by a charger provided separately from the portable telephone.
FIG. 3
shows the configuration of such a conventional portable telephone. In
FIG. 3
, the reference numeral
31
represents a portable telephone. A lithium-ion battery pack
33
is charged by a charger
32
. A user makes the charger
32
carry out its charging operation while monitoring the respective terminal voltages of the portable telephone
31
and the lithium-ion battery pack
33
by a voltage detector
37
and controlling the charger
38
by a charge controller
39
. At that time, the charge-restart is carried out when the terminal voltage of the lithium-ion battery pack
33
becomes lower than a charge-restart threshold voltage. One and the same table of the charge-restart threshold voltage is always used because the respective operation states of a calling circuit
34
, a keyboard with backlight
35
, a radio transceiver
36
, etc. of the portable telephone
31
cannot be discriminated.
Since the charge-restart was thus carried out in the charger for the conventional portable telephone on the basis of a constant charge-restart threshold voltage regardless of the operation states of various sections, a problem was caused so that a lost of capacity of the battery after charge was generated when the load of the portable telephone was large, for example, when a charge-discharge-charge cycle was extremely short because of a terminal voltage drop at the time of speaking or backlight lighting.
SUMMARY OF THE INVENTION
The present invention is to solve the foregoing conventional problem, and it is an object of the invention to provide a portable telephone with a built-in charger, in which a battery can be always charged fully in any load condition of the portable telephone.
In order to attain the foregoing object, according to the present invention, a charging circuit is built-in a portable telephone. A charge-restart timer, and a charge-restart threshold voltage, and/or a charge-restart time are selected in accordance with the use-state of the portable telephone and the battery; and a terminal voltage, and/or a discharge time are monitored to make it possible to carry out proper charge/discharge control in accordance with the use-state of the portable telephone.
According to the present invention, provided is a portable telephone using a chargeable battery as a power source, comprising a charging circuit for charging said battery with an external power supply, a voltage detector for detecting a terminal voltage of said battery, a memory having charge-restart threshold voltages and/or charge-restart times stored therein in advance correspondingly to various use-states of said telephone, and a controller for monitoring the use-state of said telephone, selecting an optimum one of the charge-restart threshold voltages and/or an optimum one of the charge-restart times corresponding to the use-state at that time, and carrying out timing control to recharge said battery. Since the charge of the battery is started in accordance with the present use-state of the portable telephone, the battery can be always charged fully, and the loss of the battery capacity due to discharge can be reduced.


REFERENCES:
patent: 4266178 (1981-05-01), Asakawa
patent: 4622507 (1986-11-01), Persen
patent: 5148043 (1992-09-01), Hirata et al.
patent: 5182509 (1993-01-01), Simmonds
patent: 5304915 (1994-04-01), Sanpei et al.
patent: 5519302 (1996-05-01), Mino et al.
patent: 5547775 (1996-08-01), Eguchi et al.
patent: 5648712 (1997-07-01), Hahn
patent: 5686815 (1997-11-01), Reipur et al.
patent: 5747189 (1998-05-01), Perkins
patent: 5847541 (1998-12-01), Hahn

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