Storage Controller Read Voltage Tuning for Soft-Decision Decoding
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Solution Overview
Problem
As the number of bits stored in each memory cell increases, the probability of errors occurring in data stored in non-volatile memory devices also increases, necessitating improved methods to recover original data and ensure data integrity.
Innovation Solution
A storage controller generates read voltage for soft decision decoding based on read information and decoding information, utilizing an OVS management module, exponent calculator, and read level calculator to determine adaptive read voltage levels for accurate data recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of bits stored in each memory cell increases, then the storage capacity increases, but the probability of errors in stored data increases
Solution Approach 1:
The patent performs preliminary actions by conducting multiple read operations at different voltage levels before final data recovery. The controller reads data at various voltage points (e.g., first read voltage, second read voltage) and uses these preliminary readings to calculate probability values and determine the most likely original data, thereby compensating for errors introduced by higher storage density
Solution Approach 2:
The patent implements feedback mechanisms where the controller uses read data and probability values from preliminary reads to adjust and determine final data values. The decoding process receives feedback from multiple read operations and iteratively refines the data recovery by comparing probability values against thresholds and adjusting voltage levels for subsequent reads
2Reliability
If multiple read operations are performed to recover original data, then data reliability improves, but read latency increases
Solution Approach 1:
The patent applies partial action by performing a limited number of targeted read operations at specific voltage levels rather than exhaustive reads. The controller strategically selects which voltage levels to read based on preliminary information and probability calculations, performing only the necessary reads to achieve confident data recovery without unnecessary additional operations
Solution Approach 2:
The patent implements dynamic voltage level adjustment where the controller adapts read voltage levels based on preliminary read results and probability values. The system dynamically determines optimal voltage levels for subsequent reads based on the state of memory cells and error patterns observed in preliminary operations, rather than using fixed voltage sequences
Data Source
AI summary
Disclosed is a method of operating a storage controller which is configured to communicate with a non-volatile memory device. The method includes receiving count data from the non-volatile memory device, determining a pre-read voltage based on the count data, sending a pre-read request using the pre-read voltage to the non-volatile memory device, receiving pre-read data from the non-volatile memory device responsive to sending the pre-read request, calculating a decoding value corresponding to the pre-read data, and generating read voltage information based on the count data and the decoding value, and the decoding value predicts an error voltage of the pre-read data.