Power management for digital devices

• US 7,808,548 B1
• Filed: 12/30/2004
• Issued: 10/05/2010
• Est. Priority Date: 04/15/2004
• Status: Active Grant

• Current Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Original Assignee: O2 Micro International Limited (O2 Micro Incorporated)
• Inventors: Popescu-Stanseti, Vlad, Du, Sterling, Lam, James, Liu, Liusheng, Denning, Bruce S.
• Primary Examiner(s): Aggarwal; Yogesh K
• Application Number:
  US11/026,801
• Time in Patent Office: 2,105 Days
• Field of Search: 348/311, 348/372, 348/374, 323/351, 455/127.1, 4553431-3436, 396301-304, 396/429, 396/277
• US Class Current: 348/372
• CPC Class Codes: H02J 1/10 Parallel operation of dc sources
• CPC Class Codes: H02J 1/14 Balancing the load in a network
• CPC Class Codes: H02M 1/008 Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators

Abstract

A method according to one embodiment includes coupling at least one power supply to a power bus comprised in a digital camera. The method of this embodiment may also include allocating power to at least one component of the digital camera by coupling at least one component to the power bus based on at least one power management priority rule. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.

Claims

1. An apparatus, comprising:

a programmable memory for storing a plurality of instructions representing a predetermined power management priority rule;

a core processor coupled to said programmable memory for monitoring an amount of power available from a plurality of power supplies and for monitoring an amount of power being supplied to a plurality of power converter components that generate power outputs, said core processor also for executing said plurality of instructions from said programmable memory;

a selector circuit coupled to said core processor for receiving monitoring information from said core processor, said selector circuit also for selecting a power supply of said plurality of power supplies according to said predetermined power management priority rule and based on said amount of power being supplied to said power converter components, and for limiting a current sunk from said power supply to a specified level; and

a control circuit coupled to said core processor for receiving monitoring information from said core processor, said control circuit also for allocating power to a power converter component of said plurality of power converter components based on said amount of power available from said power supplies.

2. The apparatus of claim 1, wherein said power supplies are selected from the group consisting of a battery power supply, an adapter power supply, an interface power supply and a coin cell power supply.

3. The apparatus of claim 1, wherein said core processor is further capable of receiving feedback information from a system load, and said predetermined power management priority rule comprises allocating power to said system load based on, at least in part, said feedback information.

4. The apparatus of claim 1, further comprising:

a battery charger circuitry capable of charging a rechargeable battery, wherein said core processor is further capable of allocating at least part of said power supply to said battery charger circuitry to charge said rechargeable battery.

5. The apparatus of claim 1, wherein said core processor is capable of managing priorities in allocating power to components of a digital camera.

6. The apparatus of claim 1, wherein said selector circuit is capable of performing “

make-before-break”

operations in the case of low battery voltage when supplying power to said system load.

7. A method, comprising:

storing a plurality of instructions representing a predetermined power management priority rule in a programmable memory;

monitoring an amount of power available from a plurality of power supplies;

monitoring an amount of power being supplied to a plurality of power converter components that generate power outputs that consume available power;

executing said plurality of instructions from said programmable memory;

selecting a power supply from said plurality of power supplies according to said predetermined power management priority rule and based on said amount of power being supplied to said power converter components;

allocating power among said power converter components based on said amount of power available from said power supplies; and

limiting a current sink from said power supply to a specified level.

8. The method of claim 7, further comprising:

receiving feedback information from a system load; and

allocating power to said system load based on, at least in part, said feedback information.

9. The method of claim 7, further comprising:

allocating at least part of said power supply to charge at least one rechargeable battery.

10. The method of claim 7, further comprising:

managing priorities in allocating power to components of a digital camera.

11. The method of claim 8, further comprising:

performing “

break-before-make”

operations in the case of high battery voltage when supplying power to said system load.

12. A camera comprising a power management processor, said power management processor comprising:

capacitor charger circuitry for charging a photoflash capacitor to enable a flash, and for generating a feedback signal;

a programmable memory for storing a plurality of instructions representing a predetermined power management priority rule;

a core processor coupled to said capacitor charger circuitry and said programmable memory for executing said plurality of instructions from said programmable memory; and

a selector circuit coupled to said core processor for selecting a power supply of a plurality of power supplies;

wherein said power management processor is operable for receiving monitoring information from said core processor and for allocating power to a power converter component of a plurality of power converter components based on an amount of voltage available from said plurality of power supplies;

said power management processor also operable for monitoring said amount of voltage available from said plurality of power supplies and for monitoring an amount of current being supplied to said plurality of power converter components that generate power outputs, for selecting a power supply of said plurality of power supplies according to said predetermined power management priority rule and based on said amount of current being supplied to said power converter components, and for limiting a current sunk from said power supply to a specified level.

13. The camera of claim 12, wherein said power supplies are selected from the group consisting of a battery power supply, an adapter power supply, an interface power supply and a coin cell power supply.

14. The camera of claim 12, wherein said power management processor is further operable for receiving feedback information from a power converter component of said plurality of power converter components, and said predetermined power management priority rule comprises allocating power to said power converter component based on, at least in part, said feedback information.

15. The camera of claim 12, further comprising:

a battery charger circuitry capable of charging a rechargeable battery, wherein said power management processor is further capable of allocating at least part of said power supply to said battery charger circuitry to charge said rechargeable battery.

16. The camera of claim 12, wherein said camera is selected from a group consisting of a still image digital camera and a video digital camera.

17. The camera of claim 12, wherein said power management processor is capable of managing priorities in allocating power to components of said camera.