Dynamic Sense Current Adjustment for Memory Leakage Compensation
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Solution Overview
Problem
Resistance variable memory cells in high-density memory arrays face errors due to leakage current from degraded cells, leading to incorrect data state sensing, especially in cross-point architectures with increased memory cell density.
Innovation Solution
Implement a dynamic adjustment of the sense current magnitude based on pre-read operations to compensate for leakage current, increasing the reference current only when necessary to accurately distinguish between data states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory cell density is increased in cross-point architecture, then memory capacity is improved, but leakage current from degraded cells increases causing sensing errors
Solution Approach 1:
The patent applies dynamics by making the sense current magnitude adjustable rather than fixed. The sense current is dynamically increased when leakage current is detected during pre-read operations, allowing the system to adapt to degraded cell conditions while maintaining high memory cell density.
Solution Approach 2:
The patent changes the parameter of sense current magnitude based on detected leakage current levels. By varying the sense current parameter in response to pre-read measurements, the system compensates for leakage effects and maintains reliable data state sensing despite increased cell density.
2Measurement precision
If sense current magnitude is increased to compensate for leakage current, then data state sensing accuracy is improved, but power consumption increases
Solution Approach 1:
The patent applies partial action by increasing the sense current magnitude only partially and only when necessary, rather than always using maximum current. The pre-read operation determines the actual need for increased sense current, avoiding unnecessary power consumption while maintaining sensing accuracy when required.
Solution Approach 2:
The patent uses preliminary action through pre-read operations that detect leakage current before actual data sensing. This preliminary detection allows the system to prepare appropriate sense current levels in advance, ensuring accurate sensing while minimizing power consumption by avoiding unnecessary high current when leakage is not present.
3Reliability
If pre-read operations are performed to detect leakage current, then sensing reliability is improved, but access time increases
Solution Approach 1:
The patent applies periodic action by performing pre-read operations at regular intervals or selectively rather than continuously. The system periodically assesses leakage current levels and adjusts sense current accordingly, maintaining reliability while minimizing the time overhead associated with pre-read operations.
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 enhances the accuracy of data state sensing, improves memory performance, and extends the lifetime of memory devices by preventing erroneous readings caused by leakage current, while allowing for increased memory cell density.
Implementation Method 1
determine whether an amount of current on the access line in response to the applied voltage meets or exceeds a threshold amount of current
Implementation Method 2
The sensed current, which varies based on the resistance level of the cell, can indicate the state of the cell
Data Source
AI summary
The present disclosure includes apparatuses, methods, and systems for increase of a sense current in memory. An embodiment includes a memory having a plurality of memory cells, and circuitry configured to apply, prior to sensing a data state of a memory cell of the plurality of memory cells, a voltage to an access line to which the memory cell is coupled, determine whether an amount of current on the access line in response to the applied voltage meets or exceeds a threshold amount of current, and determine whether to increase a magnitude of a current used to sense the data state of the memory cell based on whether the amount of current on the access line in response to the applied voltage meets or exceeds the threshold amount of current.