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:
Jan. 01, 1991
Filed:
Nov. 27, 1989
Takeo Tatematsu, Yokohama, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A semiconductor memory device carrying out a self-refresh operation in response to a refresh request signal. The device includes a memory cell array formed on a chip; a plurality of pseudo memory cells distributed and arranged on the chip, each having the same constitution as the memory cells in the memory cell array; a first circuit for monitoring the capacitor voltage in the pseudo memory cells; and a second circuit for generating the refresh request signal and charging each capacitor in the pseudo memory cells. When the potential of at least one of the capacitors in the pseudo cells falls below a predetermined level, the refresh request signal is generated, thereby enabling the device to lengthen a refresh interval as desired and to decrease power dissipation, while facilitating work requiring any adjustment.