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:
Oct. 03, 2000
Filed:
Sep. 10, 1999
Hiromi Nobukata, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
In a non-volatile semiconductor memory device of a flash type for recording multivalue data into memory cells, a control is made such that a word line voltage is set in accordance with a distribution state of a threshold voltage at the time of verification of data after the writing, a precharge of a bit line is controlled in accordance with data latched in a latch circuit, whether a threshold value of the memory cell exceeds a voltage applied to word line or not is detected depending on whether a current sufficiently flows in the memory cell or not, a state of the latch circuit is specified by a detection output, and when data is sufficiently written, predetermined data is set into the latch circuit. At the time of reading, a control is made so that a word line voltage is set in accordance with the distribution state of the threshold voltage, the state of the latch circuit is specified depending on whether a current sufficiently flows in the memory cell or not, and the read data is set into the latch circuit. Thus, the number of elements constructing the latch circuit is reduced.