Temperature-Adaptive Read Voltage Circuit for MLC Memory
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Solution Overview
Problem
Non-volatile memory devices face errors in data reading due to temperature-dependent threshold voltage changes, especially in multi-level cell systems where the increased number of threshold voltage distributions narrows the margin for accurate data retrieval.
Innovation Solution
An apparatus is developed to generate a read voltage that adjusts in accordance with ambient temperature, comprising a first voltage outputting circuit, a buffer circuit, and a second voltage outputting circuit with a sub-voltage outputting circuit and controlling circuit, which divides a driving voltage based on resistance ratios to provide an operation voltage for reading data without limiting the voltage level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multi-level cell MLC is used to store plural bits in one memory cell, then storage capacity is increased, but threshold voltage distributions become complex and programming time increases
Solution Approach 1:
The patent applies dynamics by making the read voltage adjustable and temperature-dependent. The voltage generating circuit dynamically adjusts the read voltage based on temperature conditions to match the shifted threshold voltage distributions, enabling accurate reading without increasing programming time or requiring fixed voltage levels
Solution Approach 2:
The patent changes the voltage parameter by generating temperature-dependent read voltages. The voltage generating circuit produces different read voltage levels corresponding to different temperature conditions, allowing the system to adapt to temperature-induced threshold voltage shifts in MLC memory cells
2Reliability
If threshold voltage of memory cell changes with temperature, then data reading accuracy deteriorates at different temperatures, but using fixed read voltage simplifies the circuit
Solution Approach 1:
The patent implements feedback by using the temperature signal to control the voltage generating circuit. The circuit receives temperature information and automatically adjusts the read voltage accordingly, creating a closed-loop system that maintains reading accuracy across temperature variations without requiring complex external control
Solution Approach 2:
The patent introduces an intermediary element - the voltage generating circuit - that mediates between the temperature conditions and the memory cell reading operation. This intermediary converts temperature variations into appropriate voltage adjustments, isolating the memory cell array from direct temperature effects while maintaining accurate data retrieval
3Adaptability or versatility
If read voltage level is limited by conventional circuits, then circuit design is simplified, but voltage level adaptability to temperature changes is reduced
Solution Approach 1:
The patent makes the voltage output dynamic by designing the voltage generating circuit to produce temperature-dependent read voltages. The circuit transitions from static fixed voltage levels to dynamic adjustable levels that adapt to temperature conditions, enabling versatile voltage output while managing complexity through integrated design
Solution Approach 2:
The voltage generating circuit serves multiple functions: it generates read voltages for different temperature conditions, compensates for threshold voltage shifts, and adapts to various reading scenarios. This multi-functional design achieves voltage level adaptability while consolidating what could have been separate circuits into a single versatile unit
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 solution ensures accurate data reading by adjusting the read voltage in response to temperature changes, reducing errors and maintaining a desired voltage level without limitations, even as the number of bits stored in memory cells increases.
Implementation Method 1
a first voltage outputting circuit configured to receive an input voltage and adjust and output a first voltage in accordance with a temperature
Implementation Method 2
a second voltage outputting circuit configured to receive the second voltage at an input terminal and output a third voltage by dividing a driving voltage in accordance with a resistance ratio
Implementation Method 3
a controlling circuit configured to adjust a voltage level of the third voltage through a feedback of the third voltage to the input terminal
Data Source
AI summary
An apparatus for generating a voltage includes a first voltage outputting circuit configured to receive an input voltage and adjust and output a first voltage in accordance with a temperature, a buffer circuit configured to receive the first voltage and output the received first voltage as a second voltage at an output node of the buffer circuit, and a second voltage outputting circuit configured to receive the second voltage at an input terminal and output a third voltage by dividing a driving voltage in accordance with a resistance ratio, wherein the second voltage outputting circuit includes a sub-voltage outputting circuit and a controlling circuit configured to adjust a voltage level of the third voltage through a feedback of the third voltage to the input terminal.