Memory Device Group-Based Binary Search Boundary Word Line
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Solution Overview
Problem
Conventional memory systems face inefficiencies in searching for a boundary word line during recovery operations after a sudden power-off, requiring repeated read commands and data transmission to identify the location of the boundary word line.
Innovation Solution
A memory device and system that employ a group-based binary search method to simultaneously check for and locate a boundary word line by applying a detection voltage to all word lines in a search group, minimizing the time required to find the boundary word line through the use of a control circuit that selects search groups and generates location information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a conventional binary search or linear search method is used to search for a boundary word line, then the search can be completed, but the search time is excessively long due to repeated read commands and data transmission
Solution Approach 1:
The patent divides the word lines into multiple groups and performs searching on a group level rather than individual word line level. The control circuit selects specific groups for searching and applies detection voltages to groups, which segments the search space and reduces the number of operations needed to locate the boundary word line.
Solution Approach 2:
The patent replaces the conventional mechanical/electrical read command and data transmission process with a voltage-based detection method. By applying detection voltages to groups of word lines and measuring resulting currents, the system can determine the presence and location of boundary word lines without repeated read operations, significantly reducing search time.
2Measurement precision
If repeated read commands and data transmission are performed to check each word line, then the boundary word line location can be identified, but the operation complexity and time consumption increase
Solution Approach 1:
The patent segments the word lines into groups and uses group-based searching. By determining which groups contain boundary word lines first, then narrowing down to specific word lines within those groups, the system achieves precise location identification with fewer operations compared to checking each word line individually.
Solution Approach 2:
The patent introduces detection voltages as an intermediary mechanism to indirectly detect the presence and state of word lines. Instead of directly reading each word line, the system applies detection voltages and measures resulting currents, which serve as intermediaries to infer boundary word line locations, reducing direct read operations.
3Productivity
If a group-based binary search method is used to simultaneously check multiple word lines, then the search time is reduced, but the control circuit complexity increases
Solution Approach 1:
The patent organizes word lines into groups and uses a control circuit that can selectively activate and detect specific groups. This segmentation allows the control circuit to manage complexity by handling groups as units rather than individual word lines, enabling faster parallel detection while maintaining manageable control logic.
Solution Approach 2:
The control circuit is designed to perform multiple functions: selecting groups for searching, applying detection voltages to selected groups, measuring resulting currents, and determining boundary word line locations. This multi-functionality consolidates what would otherwise require separate circuits for each operation, managing overall system complexity while enabling efficient group-based searching.
Data Source
AI summary
A memory device comprising a plurality of word lines and a plurality of bit lines, and a control circuit configured to select a search group through a group-based binary search method for a plurality of groups obtained by grouping the plurality of word lines by a set number, perform a checking operation of simultaneously checking whether a boundary word line exists among word lines of the search group and at which location among the word lines of the search group the boundary word line is located, on the basis of a search current flowing through the plurality of bit lines, in a state in which a detection voltage is applied to all word lines of the search group each time the search group is selected, generate location information when a location of the boundary word line is checked in the checking operation, and output the location information to the outside.