Adaptive targeting of read levels in storage devices

摘要

A storage device may include a controller and a plurality of memory devices logically divided into a plurality of pages. Each page in the plurality of pages may include a plurality of bits. The controller may be configured to: apply a read level to a control gate of a transistor for each respective bit in the plurality of bits; determine, based on an amount of current that flows through the transistor, a respective value for each bit from the respective plurality of bits; determine, based on the respective values for the respective plurality of bits, an error ratio that indicates a number of bits from the plurality of bits that are written as a first bit value but are incorrectly read as a second bit value relative to a number of bits from the plurality of bits that are written as the second bit value but are incorrectly read as the first bit value; and adjust, based on the error ratio, the read level.

主权项

1. A storage device comprising:
a plurality of memory devices logically divided into a plurality of pages, each page of the plurality of pages including a respective plurality of bits; and a controller configured to:
apply a read level to a control gate of a transistor for each respective bit in the plurality of bits;determine, based on an amount of current that flows through the transistor, a respective value for each bit from the respective plurality of bits;determine, based on the respective values for the respective plurality of bits, an error ratio that indicates a number of bits from the plurality of bits that are written as a first bit value but are incorrectly read as a second bit value relative to a number of bits from the plurality of bits that are written as the second bit value but are incorrectly read as the first bit value;responsive to determining that the error ratio satisfies a threshold ratio, determine whether the error ratio satisfies a limit ratio;responsive to determining that the error ratio does not satisfy the limit ratio, adjust, based on the error ratio, the read level; andresponsive to determining that the error ratio satisfies the limit ratio, perform a read calibration.