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:
Mar. 14, 2006
Filed:
Feb. 07, 2005
Shoichiro Kawashima, Kawasaki, JP;
Toru Endo, Kawasaki, JP;
Tomohisa Hirayama, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A bit line is connected, via a first pMOS transistor, to a first node whose potential is set at a prescribed negative voltage in advance. The gate voltage of the first pMOS transistor is set at a constant voltage that is slightly lower than its threshold voltage. During a read operation, a current that flows into the bit line from a memory cell in accordance with a residual dielectric polarization value of a ferroelectric capacitor always leaks to the first node, whereby the potential of the first node increases. The logical value of data stored in the memory cell is judged on the basis of a voltage increase at the first node. Since no control circuit for keeping the potential of the first node at the ground potential during a read operation is necessary, the layout size and the power consumption of a ferroelectric memory can be decreased.