Dynamic Program Inhibit Voltage Control for Flash Memory Power Reduction
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Solution Overview
Problem
Conventional flash memory devices face challenges in reducing power consumption during programming operations without increasing the risk of reprogramming failures, as higher inhibit voltages are required to minimize failures but result in higher power consumption.
Innovation Solution
The method involves changing the program inhibit voltage applied to bit lines of memory cells that have completed programming, either by increasing it or maintaining it at different levels based on the number of cells programmed and the programming voltage, using bit line shut-off transistors and string selection transistors to control the voltage levels, thereby reducing power consumption while maintaining programming accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the program inhibit voltage is increased to reduce programming failures, then the reliability of programming is improved, but the power consumption increases
Solution Approach 1:
The patent applies dynamics by making the program inhibit voltage adjustable rather than fixed. The control logic dynamically changes the inhibit voltage level based on the programming status - using a first voltage level during initial programming loops and switching to a second voltage level when programming is complete, thereby optimizing both reliability and power consumption at different stages of the programming process
Solution Approach 2:
The patent changes the voltage parameter adaptively during programming. By monitoring programming completion status and adjusting the inhibit voltage accordingly (from first voltage level to second voltage level), the system achieves high reliability when needed while reducing power consumption when programming is complete, directly addressing the contradiction between reliability and energy use
2Manufacturing precision
If the program inhibit voltage is maintained at a high level throughout programming, then programming accuracy is improved, but power consumption increases
Solution Approach 1:
The system dynamically adjusts the inhibit voltage based on real-time programming status. During active programming loops, a first voltage level ensures programming accuracy. After programming completion is detected, the system switches to a second voltage level that reduces energy loss while maintaining sufficient accuracy, thus resolving the contradiction between precision and energy efficiency
3Use of energy by moving object
If the program inhibit voltage is lowered to reduce power consumption, then energy efficiency is improved, but the risk of reprogramming increases
Solution Approach 1:
The patent applies preliminary action by establishing a first program inhibit voltage level at the beginning of programming loops to ensure stability and prevent reprogramming. Once programming completion is confirmed, the system then switches to a second voltage level that improves energy efficiency. This sequential approach ensures reliability is maintained when needed before transitioning to energy-saving mode
Solution Approach 2:
The system dynamically transitions between two voltage levels based on programming status. The control logic monitors whether programming loops are complete and adjusts the inhibit voltage accordingly - maintaining a first level for stability during programming and switching to a second level for energy efficiency after completion, thus resolving the contradiction between energy efficiency and programming stability
Data Source
AI summary
Provided are nonvolatile memory devices and programming methods thereof. A non-volatile memory device is programmed by performing a plurality of programming loops on memory cells in a memory cell array and changing a program inhibit voltage applied to bit lines of the memory cells that have completed programming while performing the plurality of programming loops.