An Efficient Low Power Sparse Clustered Network By Using Reordered Overlapped Content Addressable Memory

A reordered overlapped search mechanism for high-throughput low-energy contentaddressable memories (CAMs). Most mismatches can be found by searching a few bits of a search word. To lower power dissipation, a word circuit is often divided into two sections that are sequentially searched or even pipelined. Because of this process, most of match lines in the second section are unused. Since searching the last few bits is very fast compared to searching the rest of the bits, to increase throughput by asynchronously initiatingsecond-stage searches on the unused match lines as soon as afirststage search is complete. In our circuit implementation, eachword circuit is independently controlled by a locally generated timing signal rather than a global signal. This allows the circuits to be in the required phase for their own local operation: evaluateor precharge, instead of having to synchronize their phase to therest of the word circuits, which greatly reduces the cycle time.