Two-wire multi-rate battery charger

• US 6,034,504 A
• Filed: 06/10/1998
• Issued: 03/07/2000
• Est. Priority Date: 06/10/1998
• Status: Expired due to Term

• Current Assignee: Unwired Planet LLC (JP Morgan Chase & Co)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Holcomb, Henry
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US09/095,190
• Time in Patent Office: 636 Days
• Field of Search: 320/106, 320/110, 320/125, 320/128, 320/132, 320/134, 320/136, 320/160
• US Class Current: 320/110
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries

Abstract

A battery charger includes a first portion of a charging circuit with first and second terminals, a detector for detecting a selected signal sequence in the charging circuit, and a regulator for switching from a first output level to a second output level in the charging circuit in response to the detector detecting the selected signal sequence. A communication unit has a port for a rechargeable battery and includes a second portion of the charging circuit through the battery port with third and fourth terminals connectable with the first and second terminals and fifth and sixth terminals connectable to terminals of a rechargeable battery when in the port. The communication unit also has a switch in the second portion of the charging circuit controlled by a processor, with the processor adapted to control the switch according to the selected signal sequence when a battery is in the port which requires the second output level. The regulator may also open the circuit first portion responsive to a selected condition such as excess current or a fault in the charging circuit. This uses a method of charging a mobile communication unit battery by connecting the terminals to close the charging circuit with a battery therein, detecting the presence of a selected condition (the presence of such condition causing a switch in the circuit second portion to be automatically thrown according to a selected sequence), and selecting a second output level for the external current source in response to the switch being thrown according to the selected sequence.

Claims

1. A communication unit and external power source, comprising:

an external power source including

a first portion of a power circuit with first and second terminals,

a first detector for detecting a selected signal sequence in said power circuit, and

a regulator for switching from a first output level to a second output level in said power circuit in response to said first detector detecting said selected signal sequence; and

a communication unit including

a second portion of the power circuit having third and fourth terminals connectable with said first and second terminals,

a second detector for detecting a selected condition in which the second output level is appropriate in the power circuit,

a switch in said second portion of the power circuit, and

a processor adapted to control said switch according to said selected signal sequence in response to said second detector detecting said selected condition.

2. The communication unit and external power source of claim 1, wherein said selected condition is a rechargeable battery in the second portion of the power circuit which may be safely charged by the second output level in the power circuit.

3. The communication unit and external power source of claim 1, wherein said selected condition is the communication unit transmitting a signal.

4. The communication unit and external power source of claim 1, wherein said regulator defaults said power circuit to said first power level until said selected signal sequence is detected.

5. The communication unit and external power source of claim 1, wherein said regulator switches said first portion of the power circuit to a third output level responsive to a second selected condition.

6. The communication unit and external power source of claim 5, wherein said second selected condition is excess current in the power circuit and said third output level is less than said first and second output levels.

7. The communication unit and external power source of claim 5, wherein said second selected condition is a current level indicative of a fault in the power circuit and said third output level is less than said first and second output levels.

8. A battery charger and communication unit, comprising:

a charger including

a first portion of a charging circuit with first and second terminals,

a detector for detecting a selected signal sequence in said charging circuit, and

a regulator for switching from a first output level to a second output level in said charging circuit in response to said detector detecting said selected signal sequence; and

a communication unit with a port for a rechargeable battery, said unit including

a second portion of the charging circuit through the battery port including

third and fourth terminals connectable with said first and second terminals, and

fifth and sixth terminals connectable to terminals of a rechargeable battery when in said port, and

a switch in said second portion of said charging circuit controlled by a processor, said processor adapted to control said switch according to said selected signal sequence when a battery is in the port which requires said second output level.

9. The battery charger and communication unit of claim 8, wherein said detector comprises:

a voltage detector detecting the presence of a voltage drop over a resistor in the first portion of the charging circuit; and

a detector circuit detecting whether said voltage drop occurs in a sequence equal to said selected signal sequence.

10. The battery charger and communication unit of claim 8, wherein said regulator changes the first portion of said charging circuit to a third output level responsive to a selected condition in said charging circuit.

11. The battery charger and communication unit of claim 10, wherein said selected condition is excess current in the charging circuit and said third output level is less than said first and second output levels.

12. The battery charger and communication unit of claim 10, wherein said selected condition is a current level indicative of a fault in the charging circuit and said third output level is less than said first and second output levels.

13. The battery charger and communication unit of claim 8, wherein said regulator defaults said charging circuit to said first power level at initial connection of said first and second terminals to said third and fourth terminals and of said fifth and sixth terminals to battery terminals.

14. The battery charger and communication unit of claim 13, wherein said regulator maintains said second power level in said charging circuit after said detector detects the selected signal sequence in said charging circuit.

15. A method of supplying power to a mobile communication unit battery, comprising the steps of:

connecting two terminals of a first portion of a charging circuit of an external current source with two terminals of a second portion of a charging circuit in the communication unit having a battery therein, said external current source having a first output level and a selectable second output level;

detecting the presence of a selected condition;

automatically throwing a switch in the charging circuit second portion according to a selected sequence if the selected condition is present; and

selecting said second output level for said external current source in response to said switch being thrown according to said selected sequence.

16. The method of claim 15, wherein said selected condition is transmission by the mobile communication unit.

17. The method of claim 15, wherein said selected condition is a battery chargeable with the second output level.