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:
Sep. 08, 1992
Filed:
Nov. 20, 1990
Yasuo Torimaru, Nara, JP;
Kouji Inoue, Osaka, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A field memory self-refresh system includes a dynamic random access memory (RAM) having memory cells arranged in a matrix of rows and columns. A row decoder is designated so that the data stored in the memory cells of a row corresponding to the designated row decoder are read out. Subsequently, a row address for refreshing the memory cell array is automatically generated by a refresh address counter which is located in the dynamic RAM, whereby the memory cells on the row of the memory cell array are refreshed without any external refresh control unit. The refresh system includes a refresh RAS signal generating circuit responsive to the output of a column counter. A multiplexer selects the output of a refresh address counter, a plurality of times, between activation of successive rows in response to the refresh RAS signal. Accordingly, it is possible to perform a self-refresh operation in a shortened refresh period.