Matching detection method and circuit of content addressable memory cell

Abstract

The invention relates to a matching detection method and circuit of a content addressable memory cell. The matching detection method comprises the steps of: carrying out charging or charging control on a charge circuit of a first matching signal wire and a feedback control circuit of a second matching signal wire; when contents of an NOR memory cell are matched and a voltage difference exists between the matching signal wires, outputting a matching signal; and when the contents of the NOR memory cell are mismatched and no voltage difference exists between the matching signal wires, not outputting the matching signal. The matching detection method is simple and reliable, and has the advantages of reduction in additional offset voltage and offset current and further reduction in power consumption in comparison with the traditional matching detection method of the memory cell.

Description

technical field [0001] The present invention relates to a content addressable memory, in particular to a matching detection method and circuit of a content addressable memory storage unit. Background technique [0002] Content-Addressable Memory (CAM) is a content-addressable memory for specific high-speed search applications. Its working principle is: when the user provides a piece of data, CAM will traverse the entire storage space to search whether the data exists in the storage, and if so, CAM will return one or more addresses where the hit data exists. CAM is a special memory that searches the entire memory in a single operation. Therefore, in search applications, CAM is much faster than ordinary memory. The fast search feature of CAM makes CAM especially suitable for applications such as network equipment, central processing unit, and video hard codec. [0003] The storage unit structure of traditional content addressable memory is divided into NAND type storage uni...

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Problems solved by technology

[0008] From the above three traditional solutions, it can be seen that the initial discharge of the matching signal line still wastes a lot of power consumption; the use of current saving technology and positive feedback technology can reduce the charging current of the matching signal line in the state of content mismatch, but requires additional offset voltage and consume additional quiescent current in the control branch at the expense of

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