Content-Addressable Memory Pre-Search for Search Bit-Line Power Reduction
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Solution Overview
Problem
Existing content-addressable memory technologies fail to effectively reduce power consumption caused by charging and discharging the search bit-lines, despite efforts to manage power consumption related to match lines.
Innovation Solution
The implementation of a content-addressable memory system comprising a pre-search content-addressable memory array, a control circuit, and a main search content-addressable memory array, where the pre-search array performs a first data search to adjust match line levels, generating detection and enable signals to determine whether the main search array should perform a second data search.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the main search content-addressable memory array performs a second data search without conditional control, then the data search completeness is maintained, but the power consumption increases due to unnecessary charging and discharging of search bit-lines
Solution Approach 1:
The pre-search content-addressable memory array performs a preliminary first data search before the main search array executes the second data search. This preliminary search evaluates data using a first hash function and generates a detection signal that determines whether the main search should proceed, thereby avoiding unnecessary full searches and reducing power consumption while maintaining search completeness for matching data
2Loss of energy
If the pre-search content-addressable memory array performs a first data search with hash function evaluation, then the power consumption is reduced by avoiding unnecessary main searches, but the device complexity increases due to additional control circuits and detection mechanisms
Solution Approach 1:
The content-addressable memory search function is segmented into two independent arrays: a pre-search array that performs initial data evaluation using a first hash function, and a main search array that performs the complete search using a second hash function. The pre-search array includes separate components for hash evaluation, detection signal generation, and control signal output, dividing the complex search control functionality into manageable segments that reduce overall system complexity
3Loss of energy
If the main search array is selectively enabled based on detection signals, then the power consumption from search bit-lines is reduced, but the search time increases due to the additional pre-search step
Solution Approach 1:
The search process is structured as a periodic two-phase action: the pre-search array first performs a quick evaluation phase using a first hash function to generate detection signals, and only when these signals indicate potential matches does the main search array execute the complete search phase using a second hash function. This periodic evaluation-completion cycle reduces overall search time by avoiding full searches for non-matching data while maintaining completeness for matching data
Data Source
AI summary
A content-addressable memory includes a pre-search content-addressable memory array, a control circuit, and a main search content-addressable memory array. The pre-search content-addressable memory array is configured to perform a first data search to selectively adjust levels of a plurality of match lines in the pre-search content-addressable memory array. The control circuit is configured to generate a detection signal according to the levels of the plurality of match lines after the first data search is performed, and to generate an enable signal according to the detection signal. The main search content-addressable memory array is configured to selectively perform a second data search according to the enable signal.