Systems and methods for determining and managing the power remaining in a handheld electronic device

• US 7,921,309 B1
• Filed: 06/14/2007
• Issued: 04/05/2011
• Est. Priority Date: 05/21/2007
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Isbister, David J., Vaccaro, Nicholas J., Williams, Marshall
• Primary Examiner(s): Lee; Thomas
• Assistant Examiner(s): Rehman; Mohammed H
• Application Number:
  US11/763,339
• Time in Patent Office: 1,391 Days
• Field of Search: 713/300
• US Class Current: 713/300
• CPC Class Codes: G06F 1/325 Power saving in peripheral device
• CPC Class Codes: G06F 16/31 Indexing; Data structures therefor; Storage structures
• CPC Class Codes: G06F 21/109 by using specially-adapted hardware at the client
• CPC Class Codes: G06Q 20/1235 with control of digital rights management [DRM]
• CPC Class Codes: G06Q 30/00 Commerce
• CPC Class Codes: H04L 63/10 for controlling access to devices or network resources
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04L 67/60 Scheduling or organising the servicing of application requests, e.g. requests for application data transmissions using the analysis and optimisation of the required network resources admission control or resource allocation H04L47/70

Abstract

Portable user devices, such as electronic book reader devices, may have a limited power supply. Power management techniques, such as current sensing, dynamic voltage measurement, and/or power state control may be used to manage power usage of such user devices.

Claims

1. A method comprising:

measuring a battery voltage for a battery associated with an electronic device;

determining a current drawn by components of the electronic device;

determining a series resistance value for the electronic device; and

utilizing the values for battery voltage, current drawn by the components, and the series resistance to display the power remaining in the battery on a display of the electronic device, wherein the power remaining in the battery (V_{BATT REAL}) is determined by performing the following calculation;

V_{BATT REAL}=V_{BATT MEASURED}+(I_compensated×

R_series),

where V_{BATT MEASURED} is the measured battery voltage, I_compensated is the current drawn by the components, and R_series is the series resistance.

2. A method as recited in claim 1, wherein the calculation is performed using software.

3. A method as recited in claim 1, further comprising sending the power remaining in the battery to a power management module that determines to which components within the electronic device to send power.

4. An apparatus comprising:

a module for sensing a battery voltage and for converting the voltage signal from analog to digital form;

a module to adjust the voltage signal to prevent the voltage signal from falling below a threshold value to determine an adjusted battery voltage (V_{BATT REAL}) utilizing the following equation;

V_{BATT REAL}=V_{BATT MEASURED}+(I_compensated×

R_series); and

a module to display the adjusted battery voltage (V_{BATT REAL}) on a display of the apparatus.

5. An apparatus as recited in claim 4, wherein if the voltage signal falls below the threshold value, one or more components are disabled.

6. An apparatus as recited in claim 4, wherein if the voltage signal falls below the threshold value, one or more software programs are disabled.

7. An apparatus as recited in claim 4, wherein if the voltage signal falls below the threshold value, one or more hardware components are disabled.

8. An apparatus as recited in claim 4, wherein the module that adjusts the voltage signal is a power management module that smoothes a voltage-time curve to avoid voltage spikes.

9. A method comprising:

measuring battery voltage (V_{BATT MEASURED}) of a battery associated with an electronic device;

determining a value for the current (I_compensated) drawn by components of the device;

determining a series resistance value (R_series) associated with the battery;

determining an adjusted battery voltage (V_{BATT REAL}) utilizing the following equation;

V_{BATT REAL}=V_{BATT MEASURED}+(I_compensated×

R_series); and

displaying the adjusted battery voltage (V_{BATT REAL}) on a display of the electronic device.

10. The method of claim 9, wherein I_compensated is determined using an error value calculated by inputting a known signal across a resistor and determining a difference between the known signal multiplied by a predetermined gain value and an amplified signal.