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. 25, 1994
Filed:
Aug. 23, 1993
Chung K Chang, Sunnyvale, CA (US);
Johnny C Chen, Cupertino, CA (US);
Michael A Van Buskirk, San Jose, CA (US);
Lee E Cleveland, Santa Clara, CA (US);
Advanced Micro Devices, Inc., Sunnyvale, CA (US);
Abstract
An improved over-erased bit correction structure is provided for performing a correction operation on over-erased memory cells in an array of flash EEPROM memory cells after erase operation so as to render high endurance. Sensing circuitry (20) is used to detect column leakage current indicative of an over-erased bit during an APDE mode of operation and for generating a logic signal representative of data stored in the memory cell. A data input buffer circuit (26) is used to compare the logic signal and a data signal representative of data programmed in the memory cell so as to generate a bit match signal. A pulse counter (30) is coupled to the data input buffer circuit for counting a plurality of programming pulses applied thereto. The data input buffer circuit selectively connects only certain ones of the columns of bit lines to the pulse counter in which the bit match signal is at a high logic level so as to program back over-erased memory cells connected to only the certain ones of the columns of bit lines.