Dual-mode fuel gauge for display in battery-powered equipment

• US 6,191,557 B1
• Filed: 11/05/1999
• Issued: 02/20/2001
• Est. Priority Date: 11/05/1999
• Status: Expired due to Term

• Current Assignee: GE Medical Systems Information Technologies Incorporated (General Electric Company)
• Original Assignee: GE Marquette Medical Systems, Inc. (General Electric Company)
• Inventors: Gray, James M., Schieble, David L.
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US09/435,164
• Time in Patent Office: 473 Days
• Field of Search: 320/132, 320/162, 320/34, 320/136, 324/427, 324/432, 324/433, 702/63, 600/513
• US Class Current: 320/132
• CPC Class Codes: G01R 31/3646 for indicating electrical conditions or variables, e.g. visual or audible indicators
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H01M 10/488 Cells or batteries combined with indicating means for external visualization of the condition, e.g. by change of colour or of light density
• CPC Class Codes: H01M 50/247 specially adapted for portable devices, e.g. mobile phones, computers, hand tools or pacemakers
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method and an apparatus for informing a system user of the remaining battery terminal voltage as the battery approaches the fully discharged condition. One horizontal fuel gauge icon for each battery is displayed on the host system display panel. The fuel gauge is displayed as two overlapping rectangles which are left justified. The first layer is a solid outline, always the same width, representing the full charge capacity of the battery. The second layer is a filled-in rectangle representing the present (actual) charge capacity as a percentage of the full charge capacity in a charge depletion mode and representing the battery terminal voltage in a voltage mode. The fuel gauging switches from the charge depletion mode to the voltage mode is response to detection of a battery terminal voltage threshold greater than a shutdown voltage threshold.

Claims

1. An apparatus comprising:

a smart battery comprising a battery and memory for storing a first value representing a current charge capacity and a second value representing a terminal voltage of said battery;

a display panel; and

a processor for controlling said display panel to display a gauge comprising an indicator representing said first value in a charge depletion mode or an indicator representing said second value in a voltage mode,

wherein said processor comprises means for switching from said charge depletion mode to said voltage mode when said terminal voltage reaches a predetermined threshold.

2. The apparatus as recited in claim 1, wherein said indicator comprises a filled-in rectangle.

3. The apparatus as recited in claim 2, wherein said filled-in rectangle has a width equal to a number of pixels roughly proportional to said terminal voltage.

4. The apparatus as recited in claim 1, further comprising means for interrogating said smart battery and means for acquiring one or both of said first and second values in response to said interrogation.

5. An apparatus comprising:

a smart battery comprising a battery having a terminal voltage and a current charge capacity, means for acquiring a first value representing the current charge capacity of said battery, and means for acquiring a second value representing the terminal voltage of said battery;

a display panel; and

a processor for controlling said display panel to display a gauge comprising an indicator representing said first value in a charge depletion mode or an indicator representing said second value in a voltage mode,

wherein said processor comprises means for switching from said charge depletion mode to said voltage mode when said terminal voltage reaches a predetermined threshold.

6. An apparatus comprising:

a smart battery having a current charge capacity and a terminal voltage;

a display panel; and

a computer programmed to perform the steps of controlling said display panel to display a gauge comprising an indicator representing said current charge capacity of said smart battery in a charge depletion mode or an indicator representing said terminal voltage of said smart battery in a voltage mode, and switching from said charge depletion mode to said voltage mode when said terminal voltage reaches a predetermined threshold.

7. The apparatus as recited in claim 6, wherein said computer is further programmed to perform the steps of interrogating said smart battery to obtain said terminal voltage and said current charge capacity.

8. The apparatus as recited in claim 6, wherein said indicator comprises a filled-in rectangle.

9. The apparatus as recited in claim 8, wherein said filled-in rectangle has a width equal to a number of pixels roughly proportional to said terminal voltage.

10. A patient monitor incorporating an apparatus as recited in claim 6.

11. A method of displaying a gauge representing the state of a battery, comprising the steps of:

calculating electronic data representing a gauge comprising an indicator representing a current charge capacity of the battery in a charge depletion mode or an indicator representing a terminal voltage of the battery in a voltage mode;

displaying said electronic data on a display panel; and

switching from said charge depletion mode to said voltage mode when said terminal voltage reaches a predetermined threshold.

12. The method as recited in claim 11, further comprising the steps of interrogating the battery to obtain said terminal voltage and said current charge capacity.

13. A method of displaying a gauge representing the state of a battery, comprising the steps of:

calculating electronic data representing a gauge comprising an indicator representing a current charge capacity of the battery in a charge depletion mode or an indicator representing a terminal voltage of the battery in a voltage mode;

displaying said electronic data on a display panel; and

scaling a portion of the width of said gauge to a difference between a predetermined voltage threshold and a predetermined shutdown voltage.

14. An apparatus comprising:

a smart battery having a current charge capacity and a terminal voltage;

a display panel; and

a computer programmed to perform the steps of controlling said display panel to display a gauge comprising an indicator representing said current charge capacity of said smart battery in a charge depletion mode or an indicator representing said terminal voltage of said smart battery in a voltage mode, and scaling a portion of the width of said gauge to a difference between a predetermined voltage threshold and a predetermined shutdown voltage.