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. 16, 1996
Filed:
Dec. 23, 1993
Shouichi Kawamura, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
The objects of the present invention are to enhance the operating speed by improving the access speed to a redundant memory, and also to enable a redundant address to be written into an electrically programmable memory device, which stores the redundant address, even for a semiconductor memory designed to operate with a low-voltage, single power supply. In a semiconductor memory according to a first aspect of the invention, an address detection circuit, which determines whether the access is for a replaced element, is constructed with a gate circuit that can be set either to such a state as to enable one of two complementary input signals for output or to a high impedance state, and a signal line, onto which a signal to inhibit the selection of normal memory cells is output upon detection of an address signal for redundancy, is directly controlled by an output of a redundancy memory circuit which stores the state of the redundancy function. Furthermore, in a semiconductor memory according to a second aspect of the invention, the write voltage for writing an address into a redundancy nonvolatile semiconductor memory is supplied from outside the semiconductor memory.