Use-adaptive fuel gauging for battery powered electronic devices

• US 20030069704A1
• Filed: 10/09/2001
• Published: 04/10/2003
• Est. Priority Date: 10/09/2001
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Bean, Heather N.
• Granted Patent: US 7,107,160 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 31/3646 for indicating electrical conditions or variables, e.g. visual or audible indicators
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm

Abstract

A method and a battery powered electronic device incorporate use-adaptive fuel gauging. The use-adaptive fuel gauging adapts a fuel gauge algorithm to an average use model for the device. The adaptation accounts for the effects that variations in average use by a user of the device have on a total available energy or charge capacity of a battery. Accordingly, use-adaptivity can improve the fuel gauging accuracy by improving an estimate of the total energy available. The method and device optionally account for different battery chemistries yielding further increases in fuel gauging accuracy compared to conventional fuel gauging approaches.

Claims

1. A method of fuel gauging in an electronic device having a battery, the method comprising:

adapting the fuel gauging in the device to a use model, wherein the use model comprises how the device is actually used by a user.

2. The method of claim 1, wherein the use model further comprises historical data of a total net energy extracted from each battery used in the device by the user.

3. The method of claim 1, wherein the step of adapting the fuel gauging comprises:

monitoring a net energy extracted from the battery as a function of time during use of the device by the user;

updating an estimated total available battery energy, wherein the estimated total available battery energy is derived from the net energy extracted; and

adapting the fuel gauging to the updated estimated total available battery energy.

4. The method of claim 3, further comprising checking a charge level of the battery prior to the step of monitoring each time the battery is replaced.

5. The method of claim 4, wherein the step of checking battery charge level comprises:

measuring the charge level of the battery; and

comparing the measured charge level to an expected charge level range.

6. The method of claim 5, wherein the step of checking battery charge level further comprises detecting a battery replacement event prior to the step of measuring the charge level of the battery.

7. The method of claim 5, wherein the step of checking battery charge level determines whether the battery is fully charged, and in the step of comparing, the expected charge level range is the range for a fully charged battery.

8. The method of claim 7, wherein only when a fully charged battery is determined, are the steps of monitoring, updating and adapting performed.

9. The method of claim 3, wherein the step of monitoring comprises:

determining the net energy extracted from the battery; and

recording in a memory of the device a value representing the determined net extracted energy.

10. The method of claim 3, wherein the net energy extracted from the battery is monitored until a cut-off point is reached in a discharge cycle of the battery.

11. The method of claim 8, wherein the net energy extracted from the battery is determined directly by measuring a net energy flowing out of the battery.

12. The method of claim 8, wherein the net energy extracted from the battery is determined indirectly by keeping track of the operations performed by the device and using known energy consumption characteristics associated with each of the device operations.

13. The method of claim 8, optionally further comprising periodically measuring a battery voltage during device operation, and recording the measured voltage in memory of the device.

14. The method of claim 3, wherein the step of updating an estimated total available energy from the battery comprises computing an average of a previous estimated total available energy and a total of the net energy extracted from a most recently installed battery.

15. The method of claim 3, wherein the step of updating an estimated total available energy from the battery comprises computing a moving average of a value for a total of the net energy extracted from a most recently installed battery and a value for a total of the net energy extracted for one or more previously installed batteries.

16. The method of claim 1, further comprising:

monitoring a net energy extracted from the battery during use of the device by the user; and

updating an estimated total available battery energy, the estimated total available battery energy being derived from the net energy extracted,

wherein the updated estimated total available battery energy represents the use model.

17. The method of claim 16, wherein the fuel gauging is adapted to the updated estimated total available battery energy by subtracting the net energy extracted from the updated estimated energy to generate a fuel gauge reading.

18. The method of claim 17, wherein the fuel gauging is adapted in parallel with the step of monitoring, such that the fuel gauging is adapted to an existing estimated total available battery energy from a previous step of updating.

19. The method of claim 1, further comprising:

determining a battery chemistry for the battery; and

further adapting the fuel gauging to the determined battery chemistry.

20. The method of claim 19, wherein a rechargeable battery chemistry is distinguished from a non-rechargeable battery chemistry.

21. An electronic device with use-adaptive fuel gauging, the electronic device using a battery for power, the electronic device comprising:

a battery monitor that measures a characteristic of the battery;

a controller that receives the measured battery characteristic from the battery monitor;

a memory that provides temporary data storage for the controller;

a user interface that displays results produced by the controller; and

a fuel gauge algorithm stored in the memory as a computer program,

wherein the computer program comprises instructions that, when executed by the controller, check the charge level of a newly installed battery, monitor a net energy extracted from the battery, update an estimated total available energy, and adapt the fuel gauging to the estimated total available energy.

22. The electronic device of claim 21, wherein the computer program further comprises instructions that optionally determine battery chemistry, and wherein the fuel gauging is further adapted to the determined battery chemistry.

23. The electronic device of claim 21, wherein the computer program is stored in the memory as either firmware or software.

24. The electronic device of claim 21, wherein the computer program is incorporated into logic circuitry of the electronic device.

25. The electronic device of claim 21, wherein the electronic device is a digital camera that further comprises an optical subsystem that is controlled by the controller.

26. An electronic device with use-adaptive fuel gauging, the electronic device using a battery for power, the electronic device comprising:

a battery monitor that measures a characteristic of the battery;

a controller that receives the measured battery characteristic from the battery monitor;

a memory that provides temporary data storage for the controller;

a user interface that displays results produced by the controller; and

a fuel gauge algorithm stored in the memory as a computer program,

wherein the computer program comprises instructions that, when executed by the controller, adapt the fuel gauging in the device to a use model, wherein the use model comprises how the device is actually used by a user.