Charging system of mobile telephone

• US 6,377,826 B1
• Filed: 03/26/1999
• Issued: 04/23/2002
• Est. Priority Date: 03/27/1998
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Kaneko, Yasuhiro
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US09/276,937
• Time in Patent Office: 1,124 Days
• Field of Search: 455/566, 455/550, 455/571, 455/572, 455/573, 455/574, 455/575, 455/90, 455/343
• US Class Current: 455/573
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02J 7/342 The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging with circuits for polarity protection H02J7/0034
• CPC Class Codes: H04B 1/3883 Arrangements for mounting batteries or battery chargers

Abstract

A charging system of a mobile telephone in which the current of lighting for the mobile telephone does not influence the control of charging of a charger using a car battery is provided. The mobile telephone provides an external connecting terminal connecting to the charger using a car battery and a battery connecting terminal connecting to a secondary battery. At the external connecting terminal of the mobile telephone, a power supply terminal for lighting is provided, the power supply to a lighting circuit of the mobile telephone is connected to either the secondary battery or the power supply terminal for lighting by a change-over switch controlled by a controller. The charger using a car battery provides a power supply for lighting besides a charging circuit. At the time when the mobile telephone is connected to the charger using a car battery, the power supply for lighting in the charger using a car battery is connected to the power supply terminal for lighting of the mobile telephone. The controller monitors the signal from a car battery mode detecting terminal, at the time when the controller detects the connection between the charger using a car battery and the mobile telephone, the controller directs the change-over switch to change the switch to the power supply terminal for lighting.

Claims

1. A charging system of a mobile telephone in which the mobile telephone provides a lighting circuit for lighting a display and an operating section, and a secondary battery that is charged by a charger, wherein, said mobile telephone, comprising:

a power supply terminal for lighting;

a change-over switch which connects either said power supply terminal for lighting or a battery connecting terminal to said lighting circuit; and

a controller which changes said change-over switch to said power supply terminal for lighting by detecting that the mobile telephone is connected to said charger;

wherein, said charger, comprising;

a charging circuit providing a control means which implements charging with a predetermined charging current until the charged voltage of said secondary battery reaches to a predetermined charged voltage, and makes the charging current decrease with time passing by making the charged voltage a predetermined constant value after the charged voltage reached said predetermined voltage value, and controls to finish charging by detecting that said charging current reached the predetermined value; and

a power supply for lighting which is provided as a separate line from the said charging circuit and is connected to said power supply terminal for lighting and supplies the current to said lighting circuit during the time that said charging circuit is charging said secondary battery.

2. A charging system of a mobile telephone in accordance with claim 1, wherein:

said charger is a charger using a car battery.

3. A charging system of a mobile telephone in accordance with claim 2, wherein, said mobile telephone comprising:

a car battery mode detecting terminal and

said controller controls said change-over switch by receiving a signal from said car battery mode detecting terminal.

4. A charger for charging a secondary battery of a mobile telephone of the type which includes a lighting circuit for lighting a display and an operating section, comprising:

a charging circuit having a controller for

a) charging said secondary battery with a first charging current until a predetermined charged voltage of said secondary battery is reached,

b) charging said secondary battery with a second charging current after reaching said predetermined charged voltage, said second charging current decreasing with time relative to said first charging current and

c) terminating charging with said second charging current upon detecting that said second charging current reaches a predetermined value; and

a power supply for said lighting a line separate from said charging circuit and is connectable to a power supply terminal provided at said mobile telephone, said power supply being provided to supply current through said power supply terminal to said lighting circuit during the time that said charging circuit is charging said secondary battery.

5. A charger in accordance with claim 4, wherein: