Sandisk Technologies Inc.

Yiwei Song

Xinde Hu

Nian Niles Yang

Zhenlei Shen

Lei Chen

James Fitzpatrick

Gautam Ashok Dusija

Daniel Edward Tuers

Jim Fitzpatrick

Systems, methods and/or devices are used to adjust error metrics for a memory portion of non-volatile memory in a storage device. In one aspect, a first write and a first read are performed on the memory portion. In accordance with results of the first read, a first error metric value for the memory portion is determined. In accordance with a determination that the first error metric value exceeds a first threshold value, an entry for the memory portion is added to a table. After the first write, when a second write to the memory portion is performed, it is determined whether the entry for the memory portion is present in the table. In accordance with a determination that the entry for the memory portion is present in the table, the second write uses a first error adjustment characteristic that is determined in accordance with the first error metric value.

Variable-term error metrics adjustment

Systems and methods for controlling blocks in a memory device using a health indicator (such as the failed bit count) for the blocks are disclosed. However, the health indicator may exhibit noise, thereby resulting in an unreliable indicator of the health of the blocks in the memory device. In order to filter out the noise, a rolling average of the health indicator may be determined, and compared to the current health indicator. The comparison with the rolling average may indicate whether the current health indicator is an outlier, and thus should not be used. The health indicator may also be used to predict a future health indicator for different blocks in the memory device. Using the predicted future health indicator, the use of the blocks may be changed in order to more evenly wear the blocks.

System and method for utilizing history information in a memory device

A non-volatile memory system includes a plurality of groups of connected non-volatile memory cells (e.g., charge trapping memory cells), a select line, and a plurality of select gates connected to the select line. Each select gate is connected at an end (e.g. source end or drain side) of one of the groups of memory cells. The system includes one or more control circuits that are configured to determine whether the select gates are abnormal. If a select gate is determined to be abnormal, then one of the memory cells connected to the select gate is converted to operate as a select gate. The system will then perform memory operations by operating the converted memory cell as a select gate.

Non-volatile memory with supplemental select gates

Systems and methods for metablock relinking may be provided. A first physical block of a first metablock may be determined to have a different health than a second physical block of a second metablock based on health indicators of the first and second physical blocks. Each of the health indicators may indicate an extent to which a respective one of the first and second physical blocks may be written to and/or erased before the respective one of the first and second physical blocks becomes defective. The first physical block of the first metablock may be replaced with the second physical block of the second metablock based on a determination that the health of the first physical block of the first metablock is different than the health of the second physical block of the second metablock.

Metalblock relinking to physical blocks of semiconductor memory in adaptive wear leveling based on health

Systems, apparatuses, and methods are provided that dynamically reassign counters (or other memory monitors) in a memory. A plurality of counters may be assigned to different address ranges within an overall address range of a memory. The value of the counter may be indicative of activity, such as reads, within a respective assigned address range. Depending on the value of the counter, the respective address range of the counter may be dynamically changed. For example, a counter with a high value (indicating higher activity within the address range) may have its respective address range divided, with two counters being assigned to each of the divided address ranges. Likewise, counters with low values (indicating less activity within the address ranges) may have their respective address ranges combined, with a single counter being assigned to the combined address ranges. Thus, in subdividing and combining address ranges, the number of counters assigned may remain the same, while still monitoring the activity with the overall address range.

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Union City, CA, United States of America

Yiwei Song