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:
Jul. 04, 2000
Filed:
May. 13, 1999
Hideo Nunokawa, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A ferroelectric memory comprises a DA converter for receiving any one of 3 digital values as write data and for applying a write analog voltage corresponding to the input digital value to a electrode of a ferroelectric capacitor in order to cause the residual dielectric polarization in the ferroelectric capacitor, and an AD conversion circuit for receiving a read analog voltage obtained in accordance with the residual dielectric polarization value of the ferroelectric capacitor and for restoring the read analog voltage to the original digital value. In the ferroelectric capacitor, residual dielectric polarization corresponding to the write analog voltage occurs. The value of the residual dielectric polarization can be set to a plurality of values corresponding to the write analog voltage. Therefore, among 3 or more values of the write data, a predetermined value is stored in the ferroelectric capacitor. The AD conversion circuit receives the residual dielectric polarization value of the ferroelectric capacitor as a read analog voltage, and by restoring the read analog voltage to the original digital value, the written data can be read. Therefore, data of 3 or more values can be stored in one ferroelectric capacitor, and the stored data can be read properly.