Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1997-06-20
2001-06-26
Wu, Daniel J. (Department: 2736)
Communications: electrical
Condition responsive indicating system
Specific condition
C702S063000, C320S118000
Reexamination Certificate
active
06252511
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a circuit and method for displaying battery charge conditions in a portable computer system, and more particularly to a real-time battery gauge display that functions independently of the operating system.
2. Description of the Related Art
Computers are often needed in mobile environments where conventional alternating current power is not available. In such conditions, rechargeable batteries cells are typically used as an alternate source of power. Many acceptable battery technologies exist or are being developed, including nickel-cadmium (NiCd), nickel-metal-hydride (NiMH), lithium ion (Li+) and lithium polymer batteries. These battery cells are capable of providing power to a portable computer system for several hours. The battery cells are incorporated in a battery pack, with the battery cells typically arranged in series fashion. The battery pack is usually recharged in either an external charger or by the power supply of the host computer system.
Despite the mobility allowed by rechargeable batteries, charge cycle life is limited. For this reason, a sensor circuit is often integrated into the battery pack to monitor the voltage of each battery cell and to provide fuel gauging capabilities. Fuel gauging is the process of determining how much useful charge remains in a battery cell or battery pack, and is typically accomplished by Coulomb counting. The sensor circuit typically monitors the battery for undervoltage, overvoltage, overcharge current, and overdischarge current, allowing the battery pack to be accurately charged and discharged.
In what are known as “intelligent” battery packs, the sensor circuit within the pack supplies battery cell information to a battery microcontroller. The microcontroller, in turn, determines whether the battery pack needs to be charged, can be discharged, or is no longer usable. This information can be communicated to the host computer system. A battery pack of this type also includes a charge switch and a discharge switch, controlled by the microcontroller, which enable or disable the charging or discharging of the battery pack according to the state of the battery cells.
In many current portable computers, charge information supplied by the battery microcontroller is converted and displayed on the computer's main video display via a software process. In general, the computer user must take affirmative action to initiate execution of the software process. Although execution of the battery gauge software can be simplified by the use of hot keys or icons, this method of displaying useful battery life suffers from an additional drawback—the portable computer must first be powered-up and the operating system initialized before the software process can be executed. Such a process can be time-consuming for a user merely wishing to ascertain the charge condition of a battery pack.
Some portable systems incorporate a lighted electronic diode (LED) or liquid crystal display (LCD) capable of providing battery charge information. These systems also suffer from practical limitations. A simple LED merely conveys whether a battery pack is capable of powering the computer system. Again, the user must reference a software battery gauge in order to effectively estimate the amount of operating time remaining before battery recharging becomes necessary.
Improved functionality and ease-of-use in the techniques for determining remaining battery life would be desirable.
SUMMARY OF THE INVENTION
Briefly, a portable computer system according to the invention incorporates an autonomous, real-time battery gauge display that is viewable when the main video display is in a closed or locked state. The battery gauge display allows a user to monitor the charge status of a battery pack when the system is powered up, when the battery is being recharged by an AC adapter, or when the portable computer is placed into a secondary operating mode. The battery gauge display functions independently of the portable computer's operating system, and the computer user need not initiate a software process in order to ascertain remaining battery life.
The disclosed embodiment of the battery gauge display is part of a multi-purpose LCD status display module connected to the system motherboard. Control signals for the LCD status display are generated by a multi-purpose microcontroller. The microcontroller receives battery status information from a battery microcontroller and is capable of controlling the LCD status display independently of the computer's operating system. Battery charge conditions are displayed from 0% to 100% in 10% increments, allowing the computer user to accurately estimate the amount of computing time sustainable by an installed battery pack. The invention is particularly useful when the portable computer system is being utilized as a stand-alone CD player or in other non-standard operating modes.
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WinBook Computer Corporation,Big Price Drop, Fall 1997, pp. 2-19.
Forlenza Dan V.
Frost Kevin R.
Memo Greg B.
Mondshine James L.
Akin Gump Strauss Hauer & Feld & LLP
Compaq Computer Corporation
Pham Toan N.
Wu Daniel J.
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