Ground Selection Line Voltage Timing for Faster NAND Read Recovery
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Solution Overview
Problem
The pre pulse operation in nonvolatile memory devices consumes time and power, necessitating a recovery operation to return to the pre-pulse state, which is inefficient and energy-intensive.
Innovation Solution
A method for adjusting the pre pulse recovery operation by controlling the voltage of ground selection lines in a nonvolatile memory device, including applying different voltages to selected ground selection lines at specific times during the word line setup period to optimize the recovery process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre pulse operation is performed to prevent hot carrier injection, then reliability is improved, but time consumption and power consumption increase
Solution Approach 1:
The ground selection lines are divided into multiple groups based on process characteristics (first process characteristic and second process characteristic). Different voltage levels are applied to different groups at different times during the recovery period, allowing parallel and differentiated recovery operations that reduce overall recovery time while maintaining reliability
Solution Approach 2:
The patent dynamically adjusts the recovery operation by applying different voltage levels (first voltage and second voltage) to different ground selection line groups at different time intervals. This dynamic approach optimizes the recovery process by adapting to varying process characteristics rather than using a fixed uniform recovery protocol
2Reliability
If a pre pulse operation is performed to prevent hot carrier injection, then reliability is improved, but power consumption increases
Solution Approach 1:
By segmenting ground selection lines into groups with different process characteristics and applying voltages differentially, the system reduces unnecessary power consumption in groups that recover faster, while ensuring adequate recovery for slower groups, thereby reducing overall power consumption while maintaining reliability
Solution Approach 2:
The patent changes the voltage parameter dynamically during the recovery operation. By applying a first voltage to first ground selection lines and a second voltage to second ground selection lines at different times, the system optimizes power consumption by matching voltage levels to actual recovery needs of different process characteristics
Data Source
AI summary
Provided is an operating method of a nonvolatile memory device. The operating method includes receiving a read command, increasing a voltage applied to a plurality of unselected ground selection lines from an off voltage to an on voltage during a word line setup period, applying a first voltage to a first selected ground selection line corresponding to a first process characteristic, until a first time in the word line setup period, applying a second voltage to the first selected ground selection line after the first time in the word line setup period, applying the first voltage to a second selected ground selection line corresponding to a second process characteristic, until a second time earlier than the first time in the word line setup period, and applying the second voltage to the second selected ground selection line after the second time in the word line setup period.