Read Voltage Calibration for Memory Copyback Operations
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Solution Overview
Problem
In memory systems used for autonomous vehicles and IoT devices, the gap between total bytes written and user capacity has increased, leading to inefficiencies in data transfer and energy consumption during copyback operations, where errors can be propagated without error correction, causing data corruption.
Innovation Solution
A memory sub-system that performs read voltage calibration on a sample data set to determine a calibrated read voltage for copyback operations, reducing the need for additional calibrations and minimizing errors during data transfer from a buffer memory portion to a snapshot memory portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If read voltage calibration is performed on every data set during copyback operations, then data accuracy is improved, but energy consumption and operation time increase
Solution Approach 1:
The patent performs read voltage calibration on a sample data set before the copyback operation to establish a calibrated read voltage. This preliminary calibration action allows the system to use the same calibrated voltage for subsequent data transfers without repeating the calibration process, thereby reducing energy consumption while maintaining data accuracy.
Solution Approach 2:
The calibrated read voltage determined from the sample data set is applied universally to multiple data sets during the copyback operation. This multi-functional application of a single calibration result eliminates the need for separate calibrations on each data set, reducing both energy consumption and operation time while preserving measurement precision.
2Measurement precision
If read voltage calibration is performed on every data set during copyback operations, then data accuracy is improved, but operation time increases
Solution Approach 1:
The system performs the read voltage calibration action in advance on a sample data set before initiating the copyback operation. This preliminary calibration establishes a reference voltage that can be reused, eliminating the need for time-consuming recalibration on each subsequent data set and thereby reducing total operation time.
Solution Approach 2:
The patent copies the calibrated read voltage parameter from the sample data set calibration to multiple subsequent data sets. This parameter copying approach avoids repeating the calibration process on each data set, significantly reducing operation time while maintaining data accuracy through the reused calibration.
3Use of energy by moving object
If error correction is not performed during copyback operations, then energy consumption is reduced, but data reliability deteriorates
Solution Approach 1:
The patent performs error detection on the sample data set before the copyback operation to identify potential errors. This preliminary error detection allows the system to focus error correction resources only on data sets that actually contain errors, rather than performing unnecessary error correction on all data sets, thereby reducing energy consumption while maintaining data reliability.
Data Source
AI summary
A system includes a memory device having a plurality of groups of memory cells and a processing device communicatively coupled to the memory device. The processing device is be configured to read a first group of memory cells of the plurality to determine a calibrated read voltage associated with the group of memory cells. The processing device is further configured to determine, using the calibrated read voltage associated with the first group of memory cells, a bit error rate (BER) of a second group of memory cells of the plurality. Prior to causing the memory device to perform a copyback operation on the plurality of groups of memory cells, the processing device is further configured to determine whether to perform a subsequent read voltage calibration on at least the second group of the plurality based, at least partially, on a comparison between the determined BER and a threshold BER.