Software-based voltage detection to reserve device power upon shutdown

• US 6,571,343 B1
• Filed: 02/16/2000
• Issued: 05/27/2003
• Est. Priority Date: 05/28/1999
• Status: Expired

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Palmsource Incorporated (Access Company Limited)
• Inventors: Twyman, Nicholas, Canova, Francis J., Osborne, Neal A., Johnson, Scott R., Lunsford, Eric M.
• Primary Examiner(s): AUVE, GLENN ALLEN
• Application Number:
  US09/505,446
• Time in Patent Office: 1,196 Days
• Field of Search: 713/320, 713/322, 713/323, 713/324, 713/340, 714/22, 714/24
• US Class Current: 713/340
• CPC Class Codes: G06F 1/28 Supervision thereof, e.g. detecting power-supply failure by out of limits supervision

Abstract

Methods and apparatus are provided for reserving power in a handheld computer by inducing a sleep mode when the energy supply of the handheld computer reaches a predetermined low level. A software is provided which operates a sleep mode when a device of the handheld computer detects a predetermined low battery voltage. A processor operates the software to place the handheld computer in a low energy-consuming shutdown state in which an interrupt controller operates to mask those interrupt signals thus providing an user with the impression that the device has entered an unresponsive sleep mode. In maintaining the sleep mode, the processor operates such that all input signals that request the handheld computer to power up remain active but so long as the battery voltage remains below a predetermined voltage the interrupt signals to power up selected applications and devices are masked. A method for returning the handheld computer to its normal operational mode once the energy supply has been replenished, is also provided.

Claims

1. A method for managing power in a handheld computer, the handheld computer having a sleep mode setting and comprising a battery, at least one input device for turning the handheld computer on, and at least one device for detecting a battery power level, the method comprising:

receiving an input signal to turn the handheld computer on;

determining whether the handheld computer is in the sleep mode;

accessing the device for detecting the battery power level if the handheld computer is in the sleep mode;

responsive to detecting the battery power level, comparing the detected battery power level to a first predetermined power level that is selected from a group of power levels consisting of (i) a power level that occurs on or about one week prior to the handheld computer losing data stored in a memory of the handheld computer, (ii) a power level that is based on measuring an ambient temperature of the handheld computer, and (iii) a power level that is based on about 3.71 volts; and

maintaining the handheld computer in the sleep mode if the detected battery power level is less than the first predetermined power level.

2. The method of claim 1, wherein accessing the device for detecting the battery power level is carried out by an analog-to-digital converter device.

3. The method of claim 1, wherein maintaining the sleep mode comprises:

receiving an input signal for turning on power in the handheld computer;

responding to the input signal by determining whether the handheld computer is in a sleep mode; and

responsive to determining that the handheld computer is in a sleep mode, masking interrupt signals for powering one or more applications and devices of the handheld computer.

4. The method of claim 3, wherein;

masking interrupt signals for powering the one or more applications and devices of the handheld computer includes masking interrupt signals for powering one or more applications and devices which provide a feedback to the user that the handheld computer is operational.

5. The method of claim 4, wherein masking interrupt signals for powering the one or more applications and devices which provide a feedback to the user that the handheld computer is operational includes masking interrupt signals for powering a display device.

6. The method of claim 4, wherein masking interrupt signals for powering the one or more applications and devices which provide a feedback to the user that the handheld computer is operational includes masking interrupt signals for powering a communications device.

7. A method for managing power in a handheld computer having a sleep mode setting, the handheld computer comprising a battery, at least one input device for turning the handheld computer on, and at least one device for detecting a battery power level, the method comprising:

replenishing the primary energy source;

receiving an input signal to turn the handheld computer on;

determining whether the handheld computer is in the sleep mode;

accessing the device for detecting the battery power level if the handheld computer is in the sleep mode;

responsive to detecting the battery power level, comparing the detected battery power level to a first predetermined power level;

comparing the detected battery power level to a second predetermined power level if the detected battery power level is greater than the first predetermined power level; and

exiting the sleep mode when the detected battery power level is greater than the second predetermined power level.

8. The method of claim 7, wherein the battery of the handheld computer is a rechargeable battery, replenishing the primary energy source comprising:

recharging the rechargeable battery.

9. The method of claim 7, wherein the battery of the handheld computer is a non-rechargeable battery, replenishing the primary energy source comprising:

replacing the non-rechargeable battery.

10. The method of claim 7, wherein the exiting the sleep mode occurs when the detected battery power level is greater than a second predetermined voltage of on or about 0.10 volts higher than the first predetermined voltage.

11. The method of claim 7, wherein the exiting the sleep mode occurs when the detected battery power level is greater than a second predetermined voltage of on or about 3.81 volts.

12. An apparatus for reserving power in a handheld computer, the handheld computer having a sleep mode setting, a battery as a primary energy source, at least one input device for turning on power, and at least one device for detecting a battery power level, the handheld computer including a subsystem, wherein the subsystem comprises a processor coupled to a interrupt controller and a memory controller, the interrupt controller coupled to a memory, the memory including a sleep mode software and a residual energy manager module, and wherein the subsystem is coupled to the device for detecting a battery power level, the apparatus comprising:

responsive to receiving an input signal to turn device power on, means for accessing the sleep mode setting;

responsive to determining that the handheld computer is in the sleep mode, means for accessing the device for detecting the battery power level; and

responsive to the detected battery power level, means for maintaining the sleep mode or exiting the sleep mode;

responsive to detecting a battery power level, means comparing the detected battery power level to a first predetermined power level; and

responsive to determining the detected battery power level is less than the first predetermined power level, means for maintaining the handheld computer in the sleep mode;

wherein the first predetermined power level is set at a level which provides on or about seven days of a normal usage of the handheld computer prior to the handheld computer losing data stored in a memory of the handheld computer.

13. The apparatus of claim 12, wherein:

the device for detecting the battery power level includes an analog-to-digital converter.

14. The apparatus of claim 12, further comprising:

responsive to receiving an input signal for turning on power in the handheld computer, means for determining whether the handheld computer is in a sleep mode; and

responsive to determining that the handheld computer is in a sleep mode, means for operating the interrupt controller to mask interrupt signals for powering one or more applications and devices of the handheld computer.

15. The apparatus of claim 14, wherein the one or more applications and devices of the handheld computer includes an application or device which provides a feedback to the user that the handheld computer is operational.

16. The apparatus of claim 15, wherein the one or more applications and devices of the handheld computer includes a display device.

17. The apparatus of claim 15, wherein the one or more applications and devices of the handheld computer includes a communications device.

18. An apparatus for reserving power in a handheld computer, the handheld computer having a sleep mode setting, a battery as a primary energy source, at least one input device for turning on power, and at least one device for detecting a battery power level, the handheld computer including a subsystem, wherein the subsystem comprises a processor coupled to a interrupt controller and a memory controller, the interrupt controller coupled to a memory, the memory including a sleep mode software and a residual energy manager module, and wherein the subsystem is coupled to the device for detecting a battery power level, the apparatus comprising:

responsive to receiving an input signal to turn device power on, means for accessing the sleep mode setting;

responsive to determining that the handheld computer is in the sleep mode, means for accessing the device for detecting the battery power level; and

responsive to the detected battery power level, means for maintaining the sleep mode or exiting the sleep mode;

responsive to detecting a battery power level, means comparing the detected battery power level to a first predetermined power level; and

responsive to determining the detected battery power level is less than the first predetermined power level, means for maintaining the handheld computer in the sleep mode;

a thermal sensor; and

means for setting the first predetermined power level based on the thermal sensor detecting an ambient temperature of the handheld computer.

19. The apparatus of claim 18, wherein:

the device for detecting the battery power level includes an analog-to-digital converter.

20. The apparatus of claim 18, further comprising:

responsive to receiving an input signal for turning on power in the handheld computer, means for determining whether the handheld computer is in a sleep mode; and

responsive to determining that the handheld computer is in a sleep mode, means for operating the interrupt controller to mask interrupt signals for powering one or more applications and devices of the handheld computer.

21. The apparatus of claim 20, wherein the one or more applications and devices of the handheld computer includes an application or device which provides a feedback to the user that the handheld computer is operational.

22. The apparatus of claim 21, wherein the one or more applications and devices of the handheld computer includes a display device.

23. The apparatus of claim 21, wherein the one or more applications and devices of the handheld computer includes a communications device.

24. An apparatus for reserving power in a handheld computer, the handheld computer having a sleep mode setting, a battery as a primary energy source, at least one input device for turning on power, and at least one device for detecting a battery power level, the handheld computer including a subsystem, wherein the subsystem comprises a processor coupled to a interrupt controller and a memory controller, the interrupt controller coupled to a memory, the memory including a sleep mode software and a residual energy manager module, and wherein the subsystem is coupled to the device for detecting a battery power level, the apparatus comprising:

responsive to receiving an input signal to turn device power on, means for accessing the sleep mode setting;

responsive to determining that the handheld computer is in the sleep mode, means for accessing the device for detecting the battery power level; and

responsive to the detected battery power level, means for maintaining the sleep mode or exiting the sleep mode;

responsive to detecting a battery power level, means comparing the detected battery power level to a first predetermined power level; and

responsive to determining the detected battery power level is less than the first predetermined power level, means for maintaining the handheld computer in the sleep mode;

wherein the first predetermined power level is on or about 3.71 volts.

25. The apparatus of claim 24, wherein:

the device for detecting the battery power level includes an analog-to-digital converter.

26. The apparatus of claim 24, further comprising:

responsive to receiving an input signal for turning on power in the handheld computer, means for determining whether the handheld computer is in a sleep mode; and

responsive to determining that the handheld computer is in sleep mode, means for operating the interrupt controller to mask interrupt signals for powering one or more applications and devices of the handheld computer.

27. The apparatus of claim 26, wherein the one or more applications and devices of the handheld computer includes an application or device which provides a feedback to the user that the handheld computer is operational.

28. The apparatus of claim 27, wherein the one or more applications and devices of the handheld computer includes a display device.

29. The apparatus of claim 27, wherein the one or more applications and devices of the handheld computer includes a communications device.