Apple Inc.

Nils E Mattisson

Jeffrey G Koller

Thomas Charles Greening

P Jeffrey Ungar

Binu K Mathew

William C Athas

A system for tracking the capacity of a battery in a portable electronic device is described. While the portable electronic device remains plugged in to a power adapter, the system estimates the capacity of the battery by performing the following operations. The system measures a first open-circuit voltage for the battery while the battery rests at a first state of charge. Next, the system causes the battery to transition to a second state of charge. While the battery transitions to the second state of charge, the system integrates a current through the battery to determine a net change in charge for the battery. Next, the system measures a second open-circuit voltage for the battery while the battery rests at the second state of charge. Finally, the system estimates a capacity for the battery based on the first open-circuit voltage, the second open-circuit voltage and the net change in charge. This capacity measurement is repeated and the multiple results are fit to a line. The slope of fitted line is then used to estimate how the true battery capacity has faded since last measured using traditional methods that require the battery to be rested at a low state of charge.

Tracking fading battery capacity in a plugged-in portable electronic device

The disclosed embodiments provide a system that facilitates driving a display in a computer system. During operation, the system receives an input video stream from a graphics source, wherein the input video stream comprises a sequence of video frames. Next, the system directs the input video stream through a set of two or more memory buffers including a front buffer and a back buffer to produce an output video stream, which is used to drive the display. While directing the input video stream through the set of memory buffers, the system writes a video frame from the input video stream into the back buffer, and concurrently drives the output video stream from a preceding video frame in the front buffer. When the writing of the video frame completes, the system switches buffers so that the back buffer becomes the front buffer, which drives the output video stream, and the front buffer becomes either a spare buffer or the back buffer, which receives a subsequent frame from the input video stream.

Switching video streams for a display without a visible interruption

The disclosed embodiments provide a system that manages use of a battery in a portable electronic device. During operation, the system obtains a voltage of the battery and a state-of-charge of the battery and calculates an effective C-rate of the battery using the voltage and the state-of-charge. Next, the system uses the effective C-rate to estimate an inaccessible capacity of the battery. Finally, the system manages use of the battery with the portable electronic device based on the inaccessible capacity.

Using effective C-rates to determine inaccessible capacities of batteries

Some embodiments of the present invention provide a system that accurately and reliably updates a full charge capacity of a battery. During operation, the system charges the battery from an initial state to a rest point prior to reaching a fully charged state. The system then interrupts the charging process to allow the battery to relax to a resting voltage. Next, the system measures the resting voltage. The system then resumes the charging process toward the fully charged state. The system subsequently estimates the capacity of the battery based on the measured resting voltage and one or more other parameters.

Method and apparatus for determining a capacity of a battery

Some embodiments of the present invention provide a system that estimates a state of charge for a battery. During operation, while the battery is relaxing toward a fully rested state, the system determines if a modified state of charge of the battery is substantially consistent with a predetermined decay pattern. If so, the system estimates the state of charge of the battery as a value of the modified state of charge determined at the time when the consistency is observed. Otherwise, the system continues monitoring the modified state of charge of the battery. In one embodiment, the predetermined decay pattern is a single exponential decay. After estimating the state of charge of the battery, the system may determine an uncertainty of the estimated state of charge. More specifically, the system can estimate the uncertainty as substantially equal to a fraction of the difference between the value of the modified state of charge and the value of the voltage-based state of charge at the time when the consistency is observed.

Estimating state of charge (SOC) and uncertainty from relaxing voltage measurements in a battery

A system and method for configuring the display of a virtual workspace on multiple monitors connected to a single computing device based on images/frames captured by multiple cameras is described. A monitor orientation controller analyzes the frames to detect motion/movement within the captured scene and a corresponding centroid of the detected motion. The monitor orientation controller determines the positions of the monitors relative to each other based on the calculated centroids. Based on the relative determined positions of the monitors, the monitor orientation controller adjusts how the virtual workspace is displayed on the monitors. Other embodiments are also described.

Automatic configuration of the logical orientation of multiple monitors based on captured images

A system for tracking the capacity of a battery in a portable electronic device is described. While plugged in-to a power adapter, the system measures a first open-circuit voltage for the battery while the battery rests at a first state of charge. Next, the system causes the battery to transition to a second state of charge. During the transition, the system integrates a current through the battery to determine a net change in charge. Next, the system measures a second open-circuit voltage while the battery rests at the second state of charge. Finally, the system estimates a capacity for the battery based on the first and second open-circuit voltages and the net change in charge. This capacity measurement is repeated and the multiple results are fitted to a line. The slope of fitted line is used to estimate how the battery capacity has faded since last measured using traditional techniques.

The disclosed embodiments provide a system that facilitates driving a display in a computer system. During operation, the system receives an input video stream from a graphics source. The system directs the input video stream through a front memory buffer and a back memory buffer to produce an output video stream. While directing the input video stream through the set of memory buffers, the system writes a video frame from the input video stream into the back buffer, and concurrently drives the output video stream from a preceding video frame in the front buffer. When the writing of the video frame completes, the system switches buffers so that the back buffer becomes the front buffer, which drives the output video stream, and the front buffer becomes either a spare buffer or the back buffer, which receives a subsequent frame from the input video stream.

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San Francisco, CA, United States of America

Nils E Mattisson