Memory Cell Sensing Using Boost Voltage
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Solution Overview
Problem
Existing flash memory devices require complex and power-consuming circuitry to generate negative sensing voltages for determining the state of memory cells with negative threshold voltages, which increases device size and decreases performance.
Innovation Solution
The use of a boost voltage to pre-charge and float a data line associated with a selected memory cell, allowing the state to be determined by sensing the discharge of the data line without applying a negative sensing voltage, thereby enabling the detection of memory cells with negative threshold voltages using only positive voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If negative sensing voltage is applied to sense memory cells with negative threshold voltages, then the state of memory cells can be determined, but complex circuitry (negative voltage pump and isolated devices) is required which increases device size and power consumption
Solution Approach 1:
Instead of applying negative voltage to the control gate to sense negative threshold voltage cells, the patent inverts the approach by applying positive boost voltage to the data line. This causes current to flow from the data line through the memory cell to the source line, enabling sensing of negative threshold voltage cells using only positive voltages on the control gate, thereby eliminating the need for negative voltage generation circuitry
Solution Approach 2:
The patent introduces a boost circuit as an intermediary component that generates the positive boost voltage applied to the data line. This intermediary mechanism enables the sensing of negative threshold voltage cells without requiring direct negative voltage application, thus avoiding the complexity of negative voltage pumps while still achieving the desired sensing capability
2Measurement precision
If negative sensing voltage is applied to sense memory cells with negative threshold voltages, then the state of memory cells can be determined, but power consumption increases
Solution Approach 1:
The patent inverts the conventional sensing approach by applying positive boost voltage to the data line instead of negative voltage to the control gate. This allows sensing of negative threshold voltage cells through current flow from the boosted data line through the cell to the source line, eliminating power consumption associated with negative voltage generation while maintaining sensing accuracy
3Measurement precision
If complex circuitry is added to generate negative sensing voltage, then memory cells with negative threshold voltages can be sensed, but device size increases
Solution Approach 1:
The patent eliminates the need for complex negative voltage generation circuitry by inverting the sensing approach: applying positive boost voltage to the data line causes current to flow through memory cells with negative threshold voltages to the source line. This approach achieves sensing of negative threshold voltage cells without requiring additional space for negative voltage pumps or isolated devices, thereby reducing device size
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 reduces the size and power consumption of memory devices while enabling the sensing of a wider range of threshold voltages, including those with greater negative magnitudes, thereby increasing performance and expanding the programming window.
Implementation Method 1
pre-charging and/or floating a data line associated with a selected memory cell, boosting the pre-charged and/or floating data line
Data Source
AI summary
The present disclosure includes devices, methods, and systems including memory cell sensing using a boost voltage. One or more embodiments include pre-charging and/or floating a data line associated with a selected memory cell, boosting the pre-charged and/or floating data line, and determining a state of the selected memory cell based on a sensed discharge of the data line after boosting the data line.