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:
Sep. 28, 1999
Filed:
Aug. 26, 1997
Chin-Hsi Lin, Hsinchu, TW;
Shi-Charng Ai, Taipei, TW;
Chien-Sing Lee, Taipei, TW;
Ful-Long Ni, Hsinchu, TW;
Mam-Tsung Wang, Hsinchu, TW;
Chin-Yi Huang, Hsinchu, TW;
Macronix International Co., Ltd., Hsinchu, TW;
Abstract
The present invention provides a method and an apparatus for programming a selected call within a virtual ground EPROM array cell without disturbing adjacent array cells. The electrical disturbance of data stored in adjacent cells is limited in a number of ways: (1) a column connection circuit is provided for selectively coupling together adjacent pairs of even-odd or odd-even column lines so that source and drain terminals of adjacent memory cells are electrically coupled together, thereby preventing the data stored within the adjacent cells from being disturbed; (2) a current limiter circuit is provided for lowering a potential on a terminal of the selected cell at a controlled rate during programming so that voltages on terminals of the selected cell do not disturb data stored on adjacent memory cells; (3) the order in which programming signals are applied to terminals of the selected cell are controlled in such a way as to reduce the disturbance of data on adjacent cells; and (4) high wordline and data line voltages are applied to the selected cell in two steps, first to an intermediate voltage, and then to a high voltage. This reduces the disturbance to adjacent cells and improves programming.