The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 23, 1994
Filed:
Apr. 16, 1992
Leo A Gladstein, Boca Raton, FL (US);
Christopher D Jones, Georgetown, KY (US);
Kyriakos Leontiades, Boca Raton, FL (US);
Paritosh D Patel, Deerfield Beach, FL (US);
Paul W Petroskey, Boca Raton, FL (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A digitizer tablet computer has a host processor connected to a service processor which, in turn, is connected to a digitizer controller and to a power subsystem microcontroller. A battery supplies the primary power for operating the computer but the computer is also connectable to an external source of DC power to charge the battery and to operate the computer when it is not running on battery power. The service processor includes a battery gauge the contents of which indicate how much power is left in the battery and how much time remains at the current rate of power consumption before the power runs out. The amount of remaining power in the gauge is determined by keeping track of power consumed, power added, and power lost during off periods. The use of the second derivative of a voltage versus time discharge curve creates a point from which relative accurate estimates can be made of how much longer the computer can be operated.