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, 2009
Filed:
Dec. 01, 2006
Hiroshi Mawatari, Kawasaki, JP;
Norito Hibino, Kawasaki, JP;
Naoto Emi, Kawasaki, JP;
Fujitsu Microelectronics Limited, Tokyo, JP;
Abstract
Nonvolatile evaluation memory cells are programmed to be a plurality of different values in advance, respectively. An internal voltage generating circuit can change the value of an internal voltage according to adjusting signals. To make the internal voltage close to its expected value, a voltage adjusting circuit outputs adjusting signals in accordance with cell currents that flow through the evaluation memory cells, respectively, in a read operation on the evaluation memory cells. As a result, the interval voltage that is shifted from its expected value due to variations in manufacturing conditions can automatically be set to the expected value by using the adjusting signals. Since an internal circuit operates on a correct internal voltage, operation margins can be increased. The yield of a nonvolatile semiconductor memory can thus be increased.