Memory Device Read Voltage Control for Program Step Determination
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Solution Overview
Problem
Existing memory devices face inefficiencies in determining the program step of memory cells, which prolongs the time required to read data, especially when determining the program step based on the number of off cells.
Innovation Solution
A memory device and method that utilize a second read voltage to count off cells and then switch to a first read voltage based on the number of off cells, allowing for improved read speed by determining the program step efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the program step is determined based on the number of off cells using a second read voltage, then the data read accuracy is improved, but the read operation time is prolonged
Solution Approach 1:
The system performs a preliminary read operation using a second read voltage to count off cells and determine the program step before executing the actual data read. This preliminary action enables the system to select the optimal read voltage (first or second) in advance, avoiding unnecessary time consumption during the actual read operation.
Solution Approach 2:
The read voltage controller dynamically selects between the first read voltage and the second read voltage based on the determined program step. When the program step is determined to be the first program step, the first read voltage is used; otherwise, the second read voltage is used. This dynamic adaptation optimizes the read operation time while maintaining accuracy.
2Ease of operation
If a single read voltage is used for all memory cells, then the read operation is simplified, but the read speed is reduced due to inefficient program step determination
Solution Approach 1:
Different read voltages are applied to different groups of memory cells based on their program step status. The first read voltage is applied to memory cells that completed the first program step, while the second read voltage is applied to memory cells that completed the second program step. This local differentiation optimizes read speed without significantly complicating the overall operation.
Solution Approach 2:
The system changes the read voltage parameter based on the determined program step. By adjusting the read voltage from the first read voltage to the second read voltage (or vice versa) according to the program step status, the system achieves faster read operations while maintaining operational manageability through automated voltage selection.
3Measurement precision
If the number of off cells is counted to determine the program step, then the data read accuracy is improved, but the device complexity increases
Solution Approach 1:
The memory device performs self-diagnosis by automatically counting the number of off cells during the read operation to determine the program step. The read voltage controller uses this self-generated information to select the appropriate read voltage without requiring external intervention or complex control mechanisms from the host system.
Solution Approach 2:
The system implements feedback by using the off cell count information to adjust the read voltage selection. The read voltage controller receives feedback about the program step status and accordingly selects between the first and second read voltages, creating a closed-loop control mechanism that improves accuracy while keeping the complexity manageable through automated feedback processing.
Data Source
AI summary
The present technology relates to an electronic device. A memory device according to the present technology includes a plurality of memory cells connected to a word line, an operation controller configured to apply a first or a second read voltage to the word line and to obtain data that is stored in the plurality of memory cells through bit lines that are respectively connected to the plurality of memory cells, and a read voltage controller configured to control the operation controller to read the data that is stored in the plurality of memory cells by using the second read voltage, and to read the data that is stored in the plurality of memory cells by using the first read voltage according to the number of off cells that are counted based on the data that is read by using the second read voltage, in response to a read command.