Memory Read Parameter Tuning for Temperature Error Compensation
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Solution Overview
Problem
Non-volatile data storage devices face increased bit error rates due to temperature variations between programming and reading temperatures, causing shifts and widening of cell voltage distributions, which existing technologies have not effectively addressed.
Innovation Solution
A data storage device is configured to perform an iterative memory access parameter search, initializing based on temperature measurements to adjust bit line voltage and sense amplifier integration time, using techniques like valley searches to compensate for temperature-induced effects and reduce bit error rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If storage density is increased by storing multiple bits per cell and reducing device feature dimensions, then storage density is improved, but bit error rate increases
Solution Approach 1:
The patent adjusts memory access parameters (read voltage, sense amplifier integration time, bit line voltage) based on temperature conditions to compensate for the increased bit error rate caused by higher storage density. This dynamic parameter adjustment resolves the contradiction by adapting the reading process to maintain reliability despite the physical constraints of high-density storage.
2Reliability
If memory access parameters are adjusted to compensate for temperature variations, then bit error rate is reduced, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where temperature is measured and used to dynamically adjust memory access parameters. The controller continuously monitors temperature and modifies read operations accordingly, creating a closed-loop system that compensates for temperature-induced errors without requiring fundamental changes to the memory architecture.
Solution Approach 2:
The memory system performs self-compensation by using its own temperature measurements to adjust its operating parameters. The controller autonomously determines the appropriate read operations based on measured temperature conditions, eliminating the need for external intervention or complex additional hardware.
3Measurement precision
If iterative memory access parameter search is performed to optimize reading at different temperatures, then measurement precision is improved, but time consumption increases
Solution Approach 1:
The patent performs preliminary temperature measurements and selects initial memory access parameters based on the measured temperature range before executing the actual read operation. This pre-selection process narrows the search space and reduces the time required for iterative optimization during the actual read operation.
Solution Approach 2:
The patent implements dynamic parameter adjustment where memory access parameters are modified in real-time based on temperature conditions. The system transitions from static parameters to dynamic parameters that adapt to changing thermal conditions, allowing the read operation to maintain precision without exhaustive search.
Data Source
AI summary
A device includes a memory and a controller coupled to the memory. The controller is configured to determine a temperature-based value of a search parameter in response to detecting that an error rate of a codeword read from the memory exceeds a threshold error rate. The controller is further configured to iteratively modify one or more memory access parameters associated with reducing temperature-dependent threshold voltage variation and to re-read the codeword using the modified one or more memory access parameters.