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. 02, 2005
Filed:
Apr. 07, 2004
Shoichi Masui, Kawasaki, JP;
Shoichi Masui, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
Memory cells each include a latch having storage nodes of data, and ferroelectric capacitors connected to the storage nodes at one ends, respectively, and to a plate line at the other ends. An operation control circuit performs volatile and nonvolatile write operations. A plate driver sets the plate line at a predetermined voltage so that a voltage exceeding a coercive voltage is applied between electrodes of the ferroelectric capacitor connected to either one end of the latch during the volatile write operation. Here, the latch retains the write data. It is therefore possible to dispense with a circuit generating a voltage lower than or equal to the coercive voltage and a circuit for switching voltages. This also eliminates the need for power supply line of the voltage lower than or equal to the coercive voltage, making the wiring area unnecessary. Consequently, the ferroelectric memory can be reduced in chip size.