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:
Dec. 31, 2002
Filed:
Oct. 11, 2001
Frederick A. Perner, Palo Alto, CA (US);
Andrew L. Van Brocklin, Corvallis, OR (US);
Peter J. Fricke, Corvallis, OR (US);
James R. Eaton, Jr., Palo Alto, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A sense amplifier is provided for reading data in a multiple-state memory cell of a resistive memory array in response to a read voltage applied across the sensed memory cell, including a differential amplifier having first and second input nodes. A sense circuit determines the current in the memory cell with the read voltage applied thereto and applies a sense current representative of the memory cell current to the first input node of the differential amplifier. A reference circuit has first and second resistive elements for applying a reference current to the second input node of the differential amplifier to provide a reference value against which to compare the sense current to determine the state of the memory cell. The first resistive element has a resistance representative of a first state of the memory cell, and the second resistive element has a resistance representative of a second state of the memory cell. A voltage source for applying the read voltage across the first and second resistive elements to generate a reference current by averaging the currents through the first and second resistive elements. A first translator transistor applies the sense current to the first node of the differential amplifier. A second translator transistor applies the reference current to the second node of the differential amplifier. A comparator circuit is used to compare the signals at the first and second input nodes of the differential amplifier to provide an output indicative of the state of the sensed memory cell.