Nonvolatile Memory Write Control Voltage Stepwise Adjustment
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Solution Overview
Problem
The existing nonvolatile memory apparatuses using resistors, such as phase change RAM, require separate operations for reading and writing, leading to increased write operation time due to the need for verification read operations during data storage, which prolongs the overall write time.
Innovation Solution
A method for driving a nonvolatile memory apparatus that integrates repeated write and verification read operations, where the write control voltage is adjusted in a stepwise manner to ensure data coincidence, allowing for continuous preparation of the next write operation during verification read steps, thereby reducing the total write operation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate read and write operations are performed during write verification, then data storage reliability is improved, but write operation time increases
Solution Approach 1:
The patent merges the write operation and verification read operation into a single integrated operation. The write control voltage serves dual purposes: writing data to the memory cell and subsequently reading back the written data for verification. This combining of operations eliminates the need for separate read and write cycles, thereby reducing total operation time while maintaining verification reliability
Solution Approach 2:
The write control voltage is designed to perform multiple functions: it acts as a write voltage to program data into the memory cell, and subsequently as a read voltage to verify the stored data. This multi-functionality allows a single voltage signal to accomplish both writing and verification tasks, reducing the number of operation cycles required
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 overall write operation time by enabling simultaneous preparation for the next write operation during verification read processes, optimizing data storage efficiency in nonvolatile memory apparatuses.
Implementation Method 1
the nonvolatile memory apparatus using a resistor stores data using on phase change of a phase change material, resistance change of a variable resistor
Implementation Method 2
a phase change material such as germanium-antimony-tellurium (GST; Ge2Sb2Te5), which changes into a crystalline state or amorphous state while cooled down after being heated
Data Source
AI summary
A method for driving a nonvolatile memory apparatus includes: a data storage preparation step of setting a write control voltage to a first level of voltage; a data storage step of driving a driving transistor through the write control voltage to generate a write current, and storing an external data in a memory cell through the write current; a data detection step of varying the write control voltage by a predetermined level from a preset voltage level, and reading the data stored in the memory cell; and a data verification step of determining whether the stored data coincides with the external data or not, and repeating the data storage step and the data detection step according to a result of the determining.