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:
Jul. 27, 1999
Filed:
Nov. 06, 1997
Applicant:
Inventor:
Yuji Ishikawa, Yokohama, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11C / ; G06F / ;
U.S. Cl.
CPC ...
365229 ; 365226 ; 365227 ; 365228 ;
Abstract
A change over unit 12 is controlled to become conductive only when useful data is stored in a memory 15 for storing data to be processed. Therefore, when a main power supply is shut off, a memory backup function of a backup battery 13 is operated only when useful data is stored in the memory 15, thereby preventing unnecessary backup, which results in preventing the backup battery 13 from unnecessarily discharging and realizing a reliable memory backup.