Variable Resistance Memory Write Driver External Voltage
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Solution Overview
Problem
Non-volatile memory devices using phase change materials face inefficiencies in write performance, particularly requiring longer times to write set data compared to reset data due to the need for precise temperature control and limited current drive capability of internal voltage generators.
Innovation Solution
A non-volatile memory device design that includes a memory cell array, a first voltage generator, a second voltage generator, a write driver supplied with an external voltage for improved write performance, and decoders for selecting memory cells, where the write driver is driven directly by an external voltage to enhance write speed and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an internal voltage generator is used to drive the write driver, then the device structure remains simple, but the write speed is limited and write performance is slow
Solution Approach 1:
The patent extracts the voltage generation function from the memory device itself by providing an external voltage generator. The external voltage generator supplies voltage to the write driver, separating the voltage generation function from the memory cell array. This extraction resolves the contradiction by enabling faster write speeds through external voltage supply while keeping the core memory structure relatively simple.
Solution Approach 2:
The patent introduces an external voltage generator as an intermediary component between the power source and the write driver. This intermediary provides the necessary high voltage for fast writing without requiring complex internal voltage multiplication circuits, thus improving write speed while maintaining structural simplicity.
2Productivity
If a set pulse is applied to heat the phase change material to crystallization temperature, then set data can be written, but the writing time is five times longer than reset writing time
Solution Approach 1:
The patent changes the voltage parameter by applying different voltage levels for set and reset operations. The external voltage generator enables application of higher voltage pulses that can rapidly heat the phase change material to crystallization temperature, reducing the time required for set writing compared to conventional methods where set writing took five times longer than reset writing.
Solution Approach 2:
The patent employs periodic pulsed voltage application to the phase change material. By using short, high-intensity voltage pulses from the external voltage generator, the material is rapidly heated and cooled in controlled cycles, enabling both set and reset operations to complete in similar time frames, thus improving overall write efficiency.
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 design improves write performance by allowing simultaneous writing to multiple memory cells at higher speeds, reducing the time required to write data and overcoming limitations of internal voltage generators, resulting in faster data writing operations.
Implementation Method 1
the material changes from a crystalline state to an amorphous state or vice-versa depending on the change in temperature
Implementation Method 2
the phase change memory device applies a set pulse or a reset pulse to the phase change material to generate heat
Data Source
AI summary
A non-volatile memory device using a variable resistive element is provided. The non-volatile memory device includes a memory cell array having a plurality of non-volatile memory cells, a first voltage generator configured to generate a first voltage, a voltage pad configured to receive an external voltage that has a level higher than the first voltage, a write driver configured to be supplied with the external voltage and configured to write data to the plurality of non-volatile memory cells selected from the memory cell array; a sense amplifier configured to be supplied with the external voltage and configured to read data from the plurality of non-volatile memory cells selected from the memory cell array, and a row decoder and a column decoder configured to select the plurality of non-volatile memory cells included in the memory cell array, the row decoder being supplied with the first voltage and the column decoder being supplied with the external voltage.