Dynamic Sense Node Voltage for Non-Volatile Memory Sensing Accuracy
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Solution Overview
Problem
Existing non-volatile semiconductor memory devices face inaccuracies in sensing memory cells due to variations in bit line voltage and resistance, leading to inconsistent data state determination.
Innovation Solution
The technology involves charging a sense node to a voltage magnitude that accounts for the distance from the sense node to the memory cell and the bit line resistance, allowing for more accurate sensing by mitigating the impact of these variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed sense node voltage is used for sensing memory cells, then the sensing operation is simple and fast, but the sensing accuracy deteriorates due to bit line voltage and resistance variations
Solution Approach 1:
The sense node voltage is changed from a fixed value to a dynamic value that varies based on the distance to the memory cell. The voltage magnitude is adjusted according to the specific memory cell being sensed, making the sensing operation adaptive to different bit line conditions and improving accuracy without requiring complex additional circuitry.
Solution Approach 2:
The voltage parameter of the sense node is modified based on the distance to the memory cell. By changing the voltage magnitude according to position, the system compensates for bit line resistance variations and voltage drops, thereby improving sensing accuracy while maintaining a relatively simple operational framework.
2Measurement precision
If the sense node voltage is increased to overcome bit line resistance, then the sensing signal strength improves, but the voltage variations cause inconsistent sensing results across different memory cells
Solution Approach 1:
Different voltage magnitudes are applied to the sense node depending on the local condition - specifically the distance to the memory cell. Memory cells at different positions receive appropriately adjusted voltages, ensuring each sensing operation has optimal signal strength while maintaining consistency across the entire memory array.
3Measurement precision
If distance-dependent voltage compensation is implemented, then sensing accuracy improves, but the control circuit complexity increases
Solution Approach 1:
The sense node voltage is pre-adjusted based on the known distance to the memory cell before the sensing operation begins. This preliminary voltage setting compensates for expected bit line resistance effects, allowing accurate sensing without requiring complex real-time adjustments during the sensing process itself.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the accuracy of sensing memory cells by ensuring consistent bit line voltage and resistance considerations, resulting in enhanced data state determination and reduced errors.
Implementation Method 1
variations in bit line voltage and resistance
Implementation Method 2
charging a sense node to a voltage magnitude that accounts for the distance from the sense node to the memory cell and the bit line resistance
Data Source
AI summary
Technology for sensing non-volatile memory cells in which one or more sense nodes are charged to a sense voltage having a magnitude that improves sensing accuracy. One sense node may be charged to different sense voltages when sensing different memory cells at different times. Multiple sense nodes may be charged to a corresponding multiple different sense voltages when sensing different memory cells at the same time. The one or more sense nodes are allowed to discharge based on respective currents of memory cells for a pre-determined time while applying a reference voltage to the memory cells. The Vts of the selected memory cells are assessed based on respective voltages on the one or more of sense nodes after the pre-determined time. Different sensing voltages may be used based on bit line voltage, bit line resistance, distance of memory cells from the sense node, or other factors.