Memory Cell Pulse Control Using Verification Feedback
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Solution Overview
Problem
Existing methods for controlling operation pulse signals in non-volatile memory cells are prone to inefficiencies and potential damage due to variations in reference voltage, leading to program or erase failures.
Innovation Solution
A dynamic control method that adjusts pulse height and width based on the state change of the memory cell, using a bandgap reference circuit and lookup table to generate operation pulse signals, ensuring the cell reaches the target storage state efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed pulse parameters are used for programming or erasing memory cells, then the control method is simple, but program or erase failures occur due to reference voltage variations and cell state variations
Solution Approach 1:
The patent applies dynamics by transitioning from fixed pulse parameters to dynamically adjustable pulse parameters. The control circuit continuously monitors the memory cell state through verification actions and adjusts the pulse height and width in real-time based on the actual sub-state transitions, ensuring reliable programming and erasing despite voltage variations.
Solution Approach 2:
The patent implements feedback by performing verification actions between pulse applications to monitor memory cell state changes. The control circuit uses the verification results to determine whether to continue applying pulses and how to adjust subsequent pulse parameters, creating a closed-loop control system that improves program/erase reliability.
2Productivity
If higher pulse parameters are used to ensure the memory cell reaches target state, then programming efficiency improves, but cell damage increases
Solution Approach 1:
The patent uses dynamics to adapt pulse parameters to the actual needs of each memory cell. Instead of applying uniformly high pulses that cause damage, the control circuit adjusts pulse height and width dynamically based on real-time verification results, applying only the necessary amount of stress to reach the target state efficiently while minimizing cell damage.
Solution Approach 2:
The patent changes pulse parameters (height and width) based on the memory cell's actual state transitions between sub-states. The control circuit modifies these parameters dynamically during the programming or erasing process, allowing efficient progression through sub-states while avoiding excessive parameters that would cause cell damage.
3Measurement precision
If multiple verification actions are performed to ensure accurate state detection, then measurement precision improves, but operation time increases
Solution Approach 1:
The patent applies partial verification by performing verification actions at strategically chosen points during the programming or erasing process, rather than continuously. The control circuit determines when verification is sufficient to accurately detect sub-state transitions and when to proceed without additional verification, balancing measurement precision with operation time efficiency.
Data Source
AI summary
An operation pulse signal control method is provided. In a step (a), a verification action is performed to obtain a first sub-state value of a memory cell. In a step (b), a pulse of an operation pulse signal is provided to the memory cell. In a step (c), the verification action is performed to obtain a second sub-state value of the memory cell. If the second sub-state value indicates that the memory cell has not reached a target storage state, an actual difference value is defined as the second sub-state value minus the first sub-state value, a next pulse is adjusted according to the actual difference value, the first sub-state value is set to the second sub-state value, and the step (b) is performed again. If the memory cell has reached the target storage state, the next pulse is not provided.