Block read count voltage adjustment
AssigneeMicron Technology, Inc.
InventorsHarish Singidi, Kishore Kumar Muchherla, Gianni Stephen Alsasua, Ashutosh Malshe, Sampath Ratnam, Gary F. Besinga, Michael G. Miller
Life of this patent
Estimating the term…
Abstract
Disclosed in some examples, are methods, systems, and machine readable mediums which compensate for read-disturb effects by shifting the read voltages used to read the value in a NAND cell based upon a read counter. For example, the NAND memory device may have a read counter that corresponds to a group of NAND cells (e.g., a page, a block, a superblock). Anytime a NAND cell in the group is read, the read counter may be incremented. The read voltage, Vread, may be adjusted based on the read counter to account for the read disturb voltage.
Claims21
A memory device comprising:
- a memory array comprising a group of cells;
- and
- a controller operably coupled to the memory array and configured to perform operations comprising:
- receiving a command from a host to read the group of cells;
- determining a first read voltage based on a count of a number of previous reads during a period of time to any cell in the group of cells, the period of time corresponding to time since a most cells;
- applying the first read voltage to a cell of the group of cells to determine at least a first bit of a value of the cell;
- after determining at least the first bit of the value of the cell, updating the count of the number of previous reads;
- and
- in response to the command, providing the value of the cell to the host.
A method comprising:
- receiving, by a controller of a memory array comprising a group of cells, a command from a host to read the group of cells;
- determining a first read voltage based on a count of a number of previous reads during a period of time to any cell in the group of cells, the period of time corresponding to time since a most recent erase event for the group of cells;
- applying the first read voltage to a cell of the group of cells to determine at least a first bit of a value of the cell;
- after determining at least the first bit of the value of the cell, updating the count of the number of previous reads;
- and
- in response to the command, providing the value of the cell to the host.
A machine-readable medium comprising instructions, which, performed by a machine, causes the machine to perform operations comprising:
- receiving, by a controller of a memory array comprising a group of cells, a command from a host to read the group of cells;
- determining a first read voltage based on a count of a number of previous reads during a period of time to any cell in the group of cells, the period of time corresponding to time since a most recent erase event for the group of cells;
- applying the first read voltage to a cell of the group of cells to determine at least a first bit of a value of the cell;
- after determining at least the first bit of the value of the cell, updating the count of the number of previous reads;
- and
- in response to the command, providing the value of the cell to the host.
Dependencies are inferred from the claim text.