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:
Jul. 04, 1995
Filed:
Oct. 13, 1993
Matsushita Electronics Corporation, Osaka, JP;
Abstract
In an EEPROM, source electrodes S of memory cell transistors MT1 to MTn are grounded, via transistors MG1 to MGn. The source electrodes S are separated from each other so as to maintain the source electrode S of each of the memory cell transistors MT1 to MTn at an open state, even when a leak path is formed by the memory cell transistor MTi in the written state (low threshold voltage). In the EEPROM, an EPROM circuit in which the write operation can be continuously performed without the erase operation can be obtained. Further, an EEPROM circuit having the nonerasable region (the region which functions as the EPROM) and the erasable region (the region which functions as the EEPROM) can be also provided.