Palm, Incorporated

Palmsource Inc.

Nicholas Twyman

Scott R Johnson

Francis James Canova, Jr

Eric Michael Lunsford

Steven C Lemke

Neal A Osborn

Neal A Osborne

Ronald Marianetti, Ii

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.

Software-based voltage detection to reserve device power upon shutdown

Embodiments of the invention provide for operating a handheld computer with multiple time-out periods in a manner that is more efficient and effective for conserving power than previous systems. In an embodiment, the handheld computer implements one or more additional time-out periods by identifying an occurrence of an event that requires the handheld computer to be in the high power state to perform a specific function. An event may include a function such as sounding an alarm, although other events are also encompassed by embodiments of this invention. When an event is identified, the power state of the handheld computer prior to identifying the event is recalled. The handheld computer then implements a time-out period based on its previous power state. In one embodiment, if the handheld computer was in a low-power state prior to the event occurring, the time-out period is shortened.

Portable computer with differentiated time-out feature

Methods and apparatus are described for providing a time-based warning indicating that the energy capacity of a primary energy source of a battery-powered computer has discharged to a low level, and using residual energy of the primary energy source to perform at least one pre-cutoff function. The time-based warning ensures that the warning is provided in a timely manner by overcoming problems caused by analog to digital converter voltage measurement accuracy limitations and flat battery operating voltage versus discharge curves. The primary energy source can be a rechargeable battery, which can also be the sole energy source for the computer. The battery provides power to operate the computer until the battery voltage discharges to the cutoff voltage. The methods and apparatus provide advantages because they reserve the residual energy in the battery to perform at least one pre-cutoff function within a first duration before the battery discharges to the cutoff voltage. For example, the residual energy can be used to retain data stored in the computer between opportunities to charge the battery. Some embodiments of the invention include hardware resources coupled with the processor to lock out power and application activation when the rechargeable battery has discharged to a predetermined hardware lockout voltage. The value of the hardware lockout voltage can be based on the battery retaining a residual energy sufficient for performing the corresponding pre-cutoff function within an amount of time that is expected to enable the user to perform the function.

Method and apparatus for using residual energy in a battery-powered computer

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San Francisco, CA, United States of America

Nicholas Twyman