Tohoku University

Nec Corporation

Shoun Matsunaga

Takahiro Hanyu

Tadahiko Sugibayashi

Hideo Ohno

Noboru Sakimura

Ryusuke Nebashi

Naoya Onizawa

Vincent Gaudet

A semiconductor storage deviceincludes: an input controller (); and a content-addressable memory block () connected to the input controller (). Each word circuit () of the content-addressable memory block () includes: a k-bit 1st-stage sub word () connected to search line 1 (SL1) of the input controller (); and an (n-k)-bit 2nd-stage sub word () connected to search line 2 (SL2) of the input controller (). The k-bit 1st-stage sub word () and the (n-k)-bit 2nd-stage sub word () are separated by a segmentation circuit (). When the 1st-stage sub word outputs a match signal, the match result is stored in the segmentation circuit (), and a plurality of local match circuits within the 2nd-stage sub word () are operated.

Semiconductor storage device

Provided is a nonvolatile content addressable memory. Each word circuit includes a plurality of segments having an order relation. Each of the segments includes one or more memory cells. Each of the memory cells includes a nonvolatile storage element. Each of the segments includes a power switch for turning on/off a power of a memory cell of the segment. During stand-by, all the power switches are turned off, and, in search operation, the power switch is turned on as necessary for each of the segments.

Nonvolatile content addressable memory and method for operating same

Growing community of inventors

Sendai, Japan

Shoun Matsunaga