US 9,870,830 B1Granted

Optimal multilevel sensing for reading data from a storage medium

AssigneeSanDisk Technologies LLC

InventorSeungjune Jeon

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Abstract

Systems, methods and/or devices that enhance the reliability with which data can be stored in and read from a memory utilize an error indicator, obtained from using one reading threshold voltage for decoding, to adaptively determine the reading threshold voltage(s) used for subsequent decoding attempts. For example, in some implementations, the method includes initiating performance of a first read operation, using a first reading threshold voltage, to obtain a first error indicator, and further includes initiating performance of a second set of additional read operations using two or more second reading threshold voltages, the second reading threshold voltages determined in accordance with the first error indicator, to obtain a second error indicator. In some embodiments, when the first error indicator is greater than a first threshold, a difference between two of the second reading threshold voltages is greater than when the first error indicator is less than a first threshold.

Claims16

Dependent claims

A method of reading from a storage medium, the method comprising:

receiving a host read command specifying an address or location in the storage medium from which to read data;
in response to receiving the host read command specifying the address or location in the storage medium from which to read the data:
initiating performance of a first read operation in accordance with the address or location, using a first reading threshold voltage, to obtain a first error indicator value for the first read operation by decoding data obtained from the first read operation;
in accordance with a determination that the first read operation is successful, returning, as a response to the host read command, decoded data produced by said decoding;
and
in accordance with a determination that the first read operation is unsuccessful:
determining, in accordance with the first error indicator value for the first read operation, second reading threshold voltages, wherein when the first error indicator value for the first read operation is greater than a first threshold, a difference between two of the second reading threshold voltages is greater than a difference between the two second reading threshold voltages that is determined when the first error indicator value for the first read operation is less than the first threshold;
and
initiating performance of a second set of additional read operations in accordance with the address or location using the two second reading threshold voltages to obtain a second error indicator value for the second set of additional read operations by decoding data obtained from the second set of additional read operations using the two second reading threshold voltages.

6 more elements

A device operable to read from a storage medium, comprising:

a storage medium interface for coupling the device to the storage medium;
and
one or more modules, including a memory management module that includes one or more processors and memory storing one or more programs configured for execution by the one or more processors, the one or more modules coupled to the storage medium interface and configured to:
receive a host read command specifying an address or location in the storage medium from which to read data;
in response to receiving the host read command, specify the address or location in the storage medium from which to read the data;
initiate performance of a first read operation in accordance with the address or location, using a first reading threshold voltage, to obtain a first error indicator value for the first read operation by decoding data obtained from the first read operation;
in accordance with a determination that the first read operation is successful, returning, as a response to the host read command, decoded data produced by said decoding;
and
in accordance with a determination that the first read operation is unsuccessful:
determine, in accordance with the first error indicator value for the first read operation, second reading threshold voltages, wherein when the first error indicator value for the first read operation is greater than a first threshold, a difference between two of the second reading threshold voltages is greater than a difference between the two second reading threshold voltages that is determined when the first error indicator value for the first read operation is less than the first threshold;
and
initiate performance of a second set of additional read operations in accordance with the address or location, using the two second reading threshold voltages to obtain a second error indicator value for the second set of additional read operations by decoding data obtained from the second set of additional read operations using the two second reading threshold voltages.

9 more elements

Dependencies are inferred from the claim text.