Charger for charging a rechargeable battery

• US 5,343,136 A
• Filed: 05/02/1991
• Issued: 08/30/1994
• Est. Priority Date: 01/31/1989
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Ito, Koichi, Yamaguchi, Shuji
• Primary Examiner(s): Hickey, R. J.
• Application Number:
  US07/696,275
• Time in Patent Office: 1,216 Days
• Field of Search: 320/2, 320/3, 320/56, 455/89, 379/61, 379/63, 307/151
• US Class Current: 320/103
• CPC Class Codes: H01M 10/00 Secondary cells; Manufacture thereof
• CPC Class Codes: H01M 10/46 Accumulators structurally combined with charging apparatus circuits for charging H02J7/00
• CPC Class Codes: H01M 6/5033 used as charging means for another battery
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A cordless telephone system in which a battery of a mobile unit can be charged with use of a cordless charger. The charger, which is provided separately from a base unit, has a chargeable battery which is larger in current capacity than the battery within the mobile unit. When the mobile unit is mounted on the charger, the battery of the mobile unit is charged with the battery of the charger. So long as the charge level of the battery within the charger is sufficiently high, the battery of the mobile unit is charged with the battery of the charger and without use of a commercial AC power source.

Claims

1. An electronic apparatus, comprising:

a mobile electronic device having a first rechargeable battery;

a charger detachable from and connectable to said mobile electronic device for charging said first rechargeable battery of the charger, said charger including;

a plug connectable to an alternating current power source,

means coupled to the plug for converting alternating current power to direct current power,

a second rechargeable battery coupled to said converting means for holding said direct current power therein, and

output terminal means coupled to said converting means and said second rechargeable battery for providing said direct current power to charge the first rechargeable battery of the mobile electronic device;

diode means in said mobile electronic device and coupled between said first and second rechargeable batteries for preventing a reverse current from the first rechargeable battery to the second rechargeable battery when the mobile electronic device is connected to the output terminal means of the charger,

wherein said converting means charges both the first rechargeable battery of the mobile electronic device and the second rechargeable battery of the charger during the time when the plug of the charger is connected to the alternating current power source and the mobile electronic device is connected to the output terminal means of the charger, and wherein the second rechargeable battery of the charger charges the first rechargeable battery of the mobile electronic device during the time when the plug of the charger is disconnected from the alternating current power source and the mobile electronic device is connected to the output terminal means of the charger;

means coupled to said output terminal means for detecting whether a voltage at the output terminal means is below a predetermined value; and

means in the mobile electronic device and coupled to said detecting means for indicating a detection result to the user of the mobile electronic device.

2. A charger for use in a hand-carried mobile unit of a radio communication apparatus wherein the mobile unit includes a first rechargeable battery as a power source therefor and is detachable from and connectable to the charger, the charger supplying electricity to the first rechargeable battery when the charger is connected to the mobile unit, the charger comprising:

converting means for converting alternating current power to direct current power;

a second rechargeable battery connected to said converting means and charged by direct current supplied from said converting means;

first connecting means for detachably connecting the converting means to a commercial AC power source;

second connecting means for detachably connecting said second rechargeable battery to said first rechargeable battery of the mobile unit, wherein;

in a first state in which said converting means is connected to the commercial AC power source through said first connecting means and said second rechargeable battery is not connected to said first rechargeable battery, said second rechargeable battery is charged by direct current supplied from said converting means,

in a second state in which said converting means is connected to the commercial AC power source through said first connecting means and said second rechargeable battery is connected to said first rechargeable battery through said second connecting means, said first rechargeable battery as well as said second rechargeable battery are charged by direct current supplied from said converting means, and

in a third state in which said converting means is not connected to the commercial AC power source and said second rechargeable battery is connected to said first rechargeable battery through said second connecting means, said first rechargeable battery is charged said second rechargeable battery;

means connected to said second rechargeable battery, for detecting a voltage of said second rechargeable battery; and

means for transmitting an output of said detecting means to the mobile unit when the mobile unit is connected to the charger,

wherein a charged state of said second rechargeable battery is indicated at the mobile unit based upon the output of said detecting means which is transmitted by said transmitting means.

3. A radio communication apparatus comprising:

a hand-carried mobile unit operable by a first rechargeable battery and including means for preventing reverse flow of a charging current for said first rechargeable battery; and

a charger detachable from and connectable to said mobile unit, for supplying electricity to said first rechargeable battery when said charger is connected to said mobile unit, of the charger, wherein said charger comprises;

converting means for converting alternating current power to direct current power;

a second rechargeable battery connected to said converting means and charged by direct current supplied from said converting means;

first connecting means for detachably connecting the converting means to a commercial AC power source;

second connecting means for detachably connecting said second rechargeable battery to said first rechargeable battery of said mobile unit;

means connected to said second rechargeable battery, for detecting a voltage of said second rechargeable battery; and

means for transmitting an output of said detecting means to said mobile unit when said mobile unit is connected to said charger, and

wherein said mobile unit further comprises;

means for indicating a charged state of said second rechargeable battery based upon the output of said detecting means which is transmitted by said transmitting means, wherein;

in a first state in which said converting means is connected to the commercial AC power source through said means and said second rechargeable battery is not connected to said first rechargeable battery, said second rechargeable battery is charged by direct current supplied from said converting means,

in a second state in which said converting means is connected to the commercial AC power source through said first connecting means and said second rechargeable battery is connected to said first rechargeable battery through said second connecting means, said first rechargeable battery is charged direct current supplied from said converting means via said reverse flow preventing means while said second rechargeable battery is charged direct current supplied from said converting means, and

in a third state in which said converting means is not connected to the commercial AC power source and said second rechargeable battery is connected to said first rechargeable battery through said second connecting means, said first rechargeable battery is charge by said second rechargeable battery via said reverse flow preventing means,

whereby said first rechargeable battery of said mobile unit can be charged even when said charger is not connected to the commercial AC power source.

4. A radio communication apparatus comprising:

a hand-carried mobile unit operable by a first rechargeable battery and including means for preventing reverse flow of a charging current for said first rechargeable battery; and

a charger detachable from and connectable to said mobile unit, for supplying electricity to said first rechargeable battery when said charger is connected to said mobile unit, of the charger, wherein said charger comprises;

converting means for converting alternating current power to direct current power;

a second rechargeable battery connected to said converting means and charged by direct current supplied from said converting means;

first connecting means for detachably connecting the converting means to a commercial AC power source;

second connecting means for detachably connecting said second rechargeable battery to said first rechargeable battery of said mobile unit;

first detecting means connected to said second rechargeable battery, for detecting a voltage of said second rechargeable battery; and

means for transmitting an output of said first detecting means to said mobile unit when said mobile unit is connected to said charger, and

wherein said mobile unit further comprises;

second detecting means connected to said first rechargeable battery, for detecting a voltage of said first rechargeable battery;

third detecting means for detecting whether said charger is connected to said mobile unit; and

means for indicating a charged state of said first rechargeable battery based upon the output of said second detecting means when said third detecting means detects that said charger is not connected to said mobile unit, and indicating a charged state of said second rechargeable battery based upon the output of said first detecting means which is transmitted by said transmitting means when said charger is connected to said mobile unit,

wherein;

in a first state in which said converting means is connected to the commercial AC power source through said first connecting means and said second rechargeable battery is not connected to said first rechargeable battery, said second rechargeable battery is charged by direct current supplied from said converting means,

in a second state in which said converting means is connected to the commercial AC power source through said first connecting means and said second rechargeable battery is connected to said first rechargeable battery through said second connecting mean, said first rechargeable battery is charged direct current supplied from said converting means via said reverse flow preventing means while said second rechargeable battery is charged by direct current supplied from said converting means, and

in a third state in which said converting means is not connected to the commercial AC power source and said second rechargeable battery is connected to said first rechargeable battery through said second connecting means, said first rechargeable battery is charged by said second rechargeable battery via said reverse flow preventing means,

whereby said first rechargeable battery of said mobile unit can be charged even when said charger is not connected to the commercial AC power source.