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:
Aug. 06, 1991
Filed:
Nov. 19, 1990
Cornelis D Hartgring, Dublin, IE;
Tiemen Poorter, Heerlen, NL;
U.S. Philips Corp., New York, NY (US);
Abstract
A memory cell is read by first charging a pair of bit lines to given positive potentials and then raising the potential of a cell access line to render access transistors conductive. The cell supply voltage is sufficient to cause substantial hot-electron stress in the n-channel transistors of the cell if it were applied directly across their source-drain paths while they were conductive. However, a limit is imposed on the maximum positive potentials which are applied to the bit lines from the exterior, and on the minimum ratio of the sizes of the cell n-channel amplifier transistors to the sizes of the access transistors, taking into account the threshold voltages of the amplifier transistors, and as a result substantial hot-electron stress does not occur. Substantial hot-electron stress is also prevented during a write operation by arranging that this is effectively preceded by a read operation.