Methods and apparatus for simultaneously charging multiple rechargeable batteries

• US 7,388,352 B2
• Filed: 09/12/2006
• Issued: 06/17/2008
• Est. Priority Date: 02/27/2004
• Status: Expired due to Term

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Research In Motion Limited (Blackberry Limited)
• Inventors: Purdy, Michael L., Bayne, Ryan Mitchell
• Primary Examiner(s): Berhane; Adolf
• Assistant Examiner(s): Berhanu; Samuel
• Application Number:
  US11/531,127
• Publication Number:
  US 20070001644A1
• Time in Patent Office: 644 Days
• Field of Search: 320/112, 320/114, 320/116, 320/138
• US Class Current: 320/138
• CPC Class Codes: H02J 2310/22 The load being a portable electronic device
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0019 using switched or multiplexed charge circuits

Abstract

A charger has two or more separate charging ports to which two or more rechargeable batteries can be coupled, respectively. Current from a single current source is allocated to the two or more separate charging ports so that the two or more rechargeable batteries will be fully charged at substantially the same time.

Claims

1. A charger comprising:

a single current source;

two or more separate charging ports;

a controller configured to determine, for each of two or more rechargeable batteries coupled respectively to the two or more ports, an amount of charge required to fully charge the respective battery based on a charge in the respective battery, and a charging current in proportion to the amount of charge required to fully charge the respective battery such that each of the two or more rechargeable batteries will reach a fully charged state at substantially the same time; and

a current allocator configured to allocate the charging currents from the single current source to the two or more ports, wherein the current allocator allocates the charging currents in proportion to the amount of charge required to fully charge each of the two or more rechargeable batteries coupled respectively to the two or more ports such that each of respectively more rechargeable batteries will reach a fully charged state at substantially the same time.

2. The charger of claim 1, further comprising:

a measurement unit to measure voltage differences at the two or more ports; and

one or more lookup tables,

wherein the controller is configured to determine from the one or more lookup tables the amount of charge required to fully charge each battery based on the measured voltage differences, a battery type of the respective battery, and an average current drain of each battery during usage.

3. The charger of claim 1, wherein a particular one of the rechargeable batteries is inside a battery-operated device and the controller is to receive a voltage of the particular rechargeable battery from the battery-operated device, the charger further comprising:

one or more lookup tables,

wherein the controller is configured to determine from the one or more lookup tables the amount of charge required to fully charge the particular battery based on the received voltage, a battery type, and an average current drain of the particular battery during usage.

4. The charger of claim 1, further comprising a measurement unit configured to measure voltage differences at the two or more ports for use in determining the charging currents.

5. The charger of claim 1, further comprising one or more lookup tables and wherein the controller is configured to determine from the one or more lookup tables the amount of charge required to fully charge each battery based on measured voltage differences at the two or more ports, a battery type of the respective battery and an average current drain of each battery during usage.

6. The charger of claim 1, wherein a particular one of the rechargeable batteries is, in use of the charger, inside a battery-operated device and the controller is configured to receive a voltage of the particular rechargeable battery from the battery-operated device for use in determining the amount of charge required to fully charge the particular battery.

7. The charger of claim 1, wherein the batteries are for a mobile electronic device.

8. The charger of claim 1, wherein the controller is configured to repeat the determination of the charging currents during charging of the rechargeable batteries and causes the current allocator to allocate the charging currents according to the newly determined charging currents.

9. The charger of claim 4, wherein the controller determines the charging currents in proportion to the measured voltage differences.

10. A method of charging two or more rechargeable batteries from a single current source by use of two or more separate charging ports, the batteries being coupled to different respective charging ports, the method comprising;

determining relative amounts of charge required to fully charge the two or more rechargeable batteries based on a charge in each of the two or more rechargeable batteries, and a charging current for each of the two or more rechargeable batteries in proportion to the amount of charge required to fully charge the respective battery such that each of the two or more rechargeable batteries will reach a fully charged state at substantially the same time; and

allocating the charging currents from the single current source to the two or more separate charging ports, wherein the charging currents are allocated in proportion to the amount of charge required to fully charge each of the two or more rechargeable batteries coupled respectively to the two or more ports such that each of the two or more rechargeable batteries will reach a fully charged state at substantially the same time.

11. The method of claim 10, wherein the steps of determining and allocating are repeated during charging of the batteries.

12. The method of claim 10, further comprising:

determining the charging current to be allocated to each charging port at least in part on an average current drain during usage of the rechargeable battery coupled to the respective charging port.

13. The method of claim 10, wherein the batteries are for a mobile electronic device.

14. The method of claim 10, wherein the step of determining includes accessing a lookup table.

15. The method of claim 10, further comprising measuring voltage differences at the two or more ports, wherein the relative amounts of charge are determined based on the measured voltage differences.

16. The method of claim 14, further comprising measuring voltage differences at the two or more ports, wherein the relative amounts of charge are determined based on measured voltage differences.

17. The method of claim 11, further comprising measuring voltage differences at the two or more ports, wherein the relative amounts of charge are determined based on the measured voltage differences.

18. The method of claim 13, further comprising measuring voltage differences at the two or more ports, wherein the relative amounts of charge are determined based on the measured voltage differences.

19. The method of claim 12, further comprising measuring voltage differences at the two or more ports, wherein the relative amounts of charge are determined based on the measured voltage differences.

20. The method of claim 11, further comprising:

determining the charging current to be allocated to each charging port at least in part on an average current drain during usage of the rechargeable battery coupled to the respective charging port.

21. The method of claim 11, wherein the step of determining includes accessing a lookup table.

22. The method of claim 12, wherein the step of determining includes accessing a lookup table.