METHOD AND APPARATUS FOR POWER MANAGEMENT IN AN ELECTRONIC DEVICE

• US 20100014848A1
• Filed: 09/29/2009
• Published: 01/21/2010
• Est. Priority Date: 08/10/2006
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: GUTHRIE, Martin, BOOK, Christopher, WINGER, Lyall
• Granted Patent: US 7,970,272 B2
• Time in Patent Office: Days
• US Class Current: 396/205
• CPC Class Codes: G03B 7/26 Power supplies; Circuitry or arrangement to switch on the power source; Circuitry to check the power source voltage

Abstract

An electronic device and method for power management in an electronic device is provided. In an embodiment, the electronic device includes the functionality of a personal digital assistant, wireless email paging and a camera with a flash that is operated via self-contained power supply in the form of a battery. The device also includes a supervisor circuit which causes the device to enter sleep mode, or disables the device, or certain features of the device, if the battery level falls below a certain threshold. A method in accordance with an embodiment performs, in response to a request to fire the flash, a pre-flash test which is selected so as to not trip the supervisor circuit. The battery level is examined before the pre-flash test and examined as a consequence of performing the pre-flash test, if a change in the battery level as so examined meets certain criterion, then the full flash is not permitted to proceed. If the battery level does not meet the criterion, the full flash is permitted to proceed.

Claims

1. A method of power management in an electronic device having a supervisor circuit for disabling all or a portion of functions of said device if a first level of power to said device falls below a predefined threshold, said method comprising:

receiving a request for a function to be performed by said electronic device;

determining a second level of power to said device;

performing a pre-function test;

said pre-function test based on said function and selected to consume fewer power resources than said function and also selected to not to fall below said predefined threshold;

determining a third level of power to said device as a consequence of performing said pre-function test; and

,

if a difference between said second level of power and said third level of power meets a predefined criterion, preventing said device from performing said function and otherwise permitting said device to perform said function.

2. The method of claim 1 wherein said function is a camera flash.

3. The method of claim 2 wherein said flash is activated according to said function for a period of about eighty milliseconds and draws power of about one ampere;

and wherein said flash is activated according to said pre-function test for a period of about two milliseconds and draws power of about one ampere.

4. The method of claim 1 wherein, in conjunction with preventing said device from performing said function, generating an output signal from said device indicating that there is insufficient power to perform said function.

5. The method of claims 1 wherein said power is provided via a rechargeable battery housed within said electronic device.

6. The method of claim 5 wherein at least one of said first level of power, said second level of power or said third level of power is measured using one or more of battery voltage, battery amperage, battery equivalent series resistance, and battery temperature.

7. The method of claim 1 further comprising measuring a plurality of additional levels of power throughout the performance of said pre-function test.

8. The method of claim 7 wherein said predefined criterion is based on changes within said additional levels of power.

9. The method claim 1 further comprising the step of, after preventing said device from performing said function, permitting said device to perform an alternative function that consumes less power than said function.

10. The method of claim 9 wherein said function is a camera flash used at full power and said alternative function is said camera flash used at less than full power.

11. The method of claim 9 wherein the alternative function is chosen to consume another level of power that is greater than said predetermined threshold and differs from said predetermined threshold by a value that approaches zero.

12. An electronic device comprising:

a power supply;

a supervisor circuit connected to said power supply for disabling all or a portion of functions of said electronic device if a first level of power from said power supply falls below a predefined threshold;

a processor connected to said power supply and said supervisor circuit;

said processor configured to receive a request via an input device for a function to be performed by said electronic device;

an output device connected to said power supply, said processor, and said supervisor circuit, said output device configured to perform a function that draws power from said power supply;

said processor configured to measure a second level of power from said power supply and then perform a pre-function test;

said pre-function test based on said function and selected to consume fewer power resources than said function and also selected to not to fall below said predefined threshold;

said processor further configured to determine a third level of power drawn from said power supply as a consequence of performing said pre-function test; and

,

said processor further configured to, if a difference between said second level of power and said third level of power meets a predefined criterion, prevent said output device from performing said function and otherwise permitting said output device to perform said function.

13. The electronic device of claim 12 wherein said output device is a camera flash.

14. The electronic device of claim 13 wherein said flash is activated according to said function for a period of about eighty milliseconds and draws power of about one ampere;

and wherein said flash is activated according to said pre-function test for a period of about two milliseconds and draws power of about one ampere.

15. The electronic device of claim 12 wherein, in conjunction with preventing said device from performing said function, generating an output signal from said electronic device indicating that there is insufficient power to perform said function.

16. The electronic device of claim 12 wherein said power is provided via a rechargeable battery housed within said electronic device.

17. The electronic device of claim 12 wherein at least one of said first level of power, said second level of power or said third level of power is measured using one or more of battery voltage, battery amperage, battery equivalent series resistance, and battery temperature.

18. The electronic device claim 12 wherein said processor is configured to measure a plurality of additional power levels throughout the performance of said pre-function test.

19. The electronic device of claim 18 wherein said predefined criterion is based on changes within said additional levels of power.

20. The electronic device claim 12 wherein said processor is further configured to, after preventing said electronic device from performing said function, permitting said output device to perform an alternative function that consumes less power than said function.

21. The electronic device of claim 20 wherein said function is a camera flash used at full power and said alternative function is said camera flash used at less than full power.

22. The electronic device of claim 21 wherein the alternative function is chosen to consume another level of power that is greater than said predetermined threshold and differs from said predetermined threshold by a value that approaches zero.

23. An electronic device comprising:

a power supply;

a supervisor circuit connected to said power supply for disabling all or a portion of functions of said electronic device if a first level of power from said power supply falls below a predefined threshold,

a radio, said supervisor circuit configured to disable said radio when said power supply falls below about 3.4 Volts for at least about five milliseconds;

a processor connected to said power supply and said supervisor circuit;

said processor configured to receive a request via an input device for a function to be performed by said electronic device;

an output device connected to said power supply, said processor, and said supervisor circuit, said output device configured to perform a function that draws power from said power supply;

said processor being configured to perform the steps of;

performing a pre-function test;

said pre-function test based on said function and selected to consume less power than said function and also selected to not cause the first level of power to fall below said predefined threshold;

determining a second level of power to said device as a consequence of performing said pre-function test; and

,

if said second level of power meets at least one predefined criterion, preventing said device from performing said function or otherwise permitting said device to perform said function.

24. The electronic device of claim 23 wherein said output device is a camera flash.

25. The electronic device of claim 24 wherein said processor is configured to activate said flash according to said function for a period of about eighty milliseconds and draws current of about one ampere;

and wherein said processor is configured to activate said flash according to said pre-function test for a period of about two milliseconds and draws current of about one ampere.