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:
Dec. 10, 1991
Filed:
Mar. 14, 1990
Applicant:
Inventor:
Seietsu Nara, Yokohama, JP;
Assignee:
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G06F / ;
U.S. Cl.
CPC ...
235492 ; 235487 ;
Abstract
An IC card which is substantially a portable medium incorporates data memory and control element composed of CPU. This IC card is provided with a keyboard and a display. In addition, IC card also incorporates a calender circuit which is constantly operated by internal battery, and battery checking circuit which causes resistor and Zener diode to generate a reference voltage. Battery checking circuit allows current to flow through the system constituents only when the power switch is activated for operating IC card. To implement power-saving operation of the system, semiconductor switches are installed between the internal battery and the battery checking circuit.