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. 19, 2010
Filed:
Dec. 27, 2007
Masaki Okuda, Kawasaki, JP;
Atsushi Fujii, Kawasaki, JP;
Masaki Okuda, Kawasaki, JP;
Atsushi Fujii, Kawasaki, JP;
Fujitsu Microelectronics Limited, Tokyo, JP;
Abstract
A semiconductor memory has a memory cell array having dynamic memory cells. An access control circuit accesses the memory cells in response to an access command which is supplied externally. A refresh control circuit generates, during a test mode, a test refresh request signal in synchronization with the access command so as to execute a refresh operation of the memory cells when a refresh mask signal is at an invalid level. Also, the refresh control circuit prohibits generation of the test refresh request signal when the refresh mask signal is at a valid level. The test refresh request signal is generated or prohibited from being generated according to the level of the refresh mask signal. Thus, only a refresh operation needed for a test can be executed, and hence test efficiency can be improved.