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:
Feb. 23, 1999
Filed:
May. 28, 1993
Takumi Nasu, Tsuchiura, JP;
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
Objective: To make it possible to easily increase the integration level and increase the memory capacity of a semiconductor memory device by using a single redundant decoder to completely repair defects at one or two neighboring addresses. Structure: The redundant circuit of the present invention comprises the following: an address code conversion circuit (2) which converts address signals, inputted in binary code, into gray code; a decoder (3) which outputs a coincidence signal after determining whether the addresses set in advance coincide or do not coincide with the gray code outputted from the aforementioned address code conversion circuit; a first driver (DR2) which drives a first redundant line which is connected to a redundant memory cell designed to supplement memory cells in which defects have occurred; and a second driver (DR1) which drives a second redundant line. Either the first driver or the second driver (DR1 or DR2), which respectively drive the first and second redundant lines, is selected according to the coincidence signal outputted from the aforementioned decoder (3), the least significant bit in the aforementioned binary code address signal, and the corresponding complemented signal. Defects at one or two neighboring addresses are thus repaired using a single decoder.