US Patent 7995380 Negative differential resistance pull up element for DRAM

Patent 7995380 was granted and assigned to Synopsys on August, 2011 by the United States Patent and Trademark Office.

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Is a

Patent

Patent attributes

Current Assignee

Synopsys

Patent Jurisdiction

United States Patent and Trademark Office

Patent Number

7995380

Patent Inventor Names

Tsu-Jae King Liu0

Date of Patent

August 9, 2011

Patent Application Number

12250463

Date Filed

October 13, 2008

Patent Primary Examiner

‌

Tuan T Nguyen

Patent abstract

A memory cell includes a pull-up element that exhibits a refresh behavior that is dependent on the data value stored in the memory cell. The pull-up element is an NDR FET connected between a high voltage source and a storage node of the memory cell. The NDR FET receives a pulsed gate bias signal, wherein each pulse turns on the NDR FET when a logic HIGH value is stored at the storage node, and further wherein each pulse does not turn on the NDR FET when a logic LOW value is stored at the storage node. In this fashion a DRAM cell (and device) can be operated without a separate refresh cycle.