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:
Mar. 22, 2005
Filed:
Sep. 12, 2003
Fumihiko Nitta, Hyogo, JP;
Shinichi Kobayashi, Hyogo, JP;
Fumihiko Nitta, Hyogo, JP;
Shinichi Kobayashi, Hyogo, JP;
Renesas Technology Corp., Tokyo, JP;
Abstract
In a flash memory, a threshold voltage of a memory transistor is decreased quickly by increasing a rising speed of a pulse voltage of an erasing pulse signal train during the first period of an erasing operation. In response to the threshold voltage of the memory transistor becoming lower than a threshold voltage of a reference transistor, the threshold voltage of the memory transistor is decreased slowly by reducing the rising speed of the pulse voltage of the erasing pulse signal train. Therefore, the erasing time can be reduced and depletion of the memory transistor can be prevented.