Forward-looking determination of read voltage using memory cell patterns
AssigneeMicron Technology, Inc.
InventorsUmberto di Vincenzo, Ferdinando Bedeschi, Christian Marc Benoit Caillat
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Abstract
Systems, methods, and apparatus for a memory device that uses multiple groups of pattern cells to select a voltage for reading memory cells. In one approach, a controller applies different magnitude levels of voltages to each of the groups of pattern cells. The controller determines which of the groups have pattern cells that first switch (e.g., switch at the lowest magnitude of applied voltage). Based on identifying the first group to switch, the controller selects a read voltage. The selected read voltage is used to read data cells (e.g., corresponding to a codeword).
Claims22
A system comprising:
- a memory array comprising pattern cells and data cells, wherein the pattern cells are configured to store a first logic state, and the data cells are configured to store the first logic state or a second logic state;
- and
- a controller configured to:
- apply first voltages to the pattern cells;
- determine a portion of the pattern cells switch;
- determine that a number of the data cells that switch due to applying a second voltage is below a threshold;
- in response to determining that the number is below the threshold, determine a third voltage by incrementing the second voltage;
- and
- apply, using bias circuitry, the third voltage to the data cells.
A method comprising:
- programming pattern cells to store only a first logic state;
- applying respective first voltages to groups of the pattern cells;
- identifying those of the groups that switch due to applying the first voltages;
- and
- selecting, based on the identified groups that switch, a second voltage for reading a logic state of data cells.
A system comprising:
- first memory cells configured to store only a first logic state;
- and
- a controller configured to:
- determine at least one characteristic of the first memory cells;
- and
- read second memory cells using at least one voltage selected based on the at least one characteristic.
Dependencies are inferred from the claim text.