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:
Aug. 24, 2004
Filed:
Jul. 03, 2002
Satoshi Shimizu, Tokyo, JP;
Mitsuhiro Tomoeda, Tokyo, JP;
Other;
Abstract
It is an object to obtain a nonvolatile semiconductor storage device and a data erasing method thereof in which a time required for a data erasing operation can be shortened. When second and succeeding erasing commands are input at a step SP a final voltage value of a batch writing pulse in a last data erasing operation is read from a storage portion ( ) at a step SP At a step SP next, a control portion ( ) sets a starting voltage value of a batch writing pulse in a present data erasing operation based on the final voltage value of the batch writing pulse in the last data erasing operation. For example, in the case in which the final voltage value of the batch writing pulse in the last data erasing operation is V =8.00 V and V =V =−6.00 V, the starting voltage value of the batch writing pulse is currently set to V =7.75 V and V =V =−5.75 V with a reduction of one step.