Partially programmed block read operations
Apparatuses and methods for determining performing read operations on a partially programmed block are provided. One example apparatus can include a controller configured to apply a read voltage to a word line in an array of memory cells during a read operation on the word line, apply a first pass voltage to a number of programmed word lines in the array of memory cells during the read operation, and apply a second pass voltage to a number of unprogrammed word lines in the array of memory cells during the read operation.
1 . An apparatus, comprising:
an array of memory cells;
a controller coupled to the array of memory cells and the controller is configured to:
apply a read voltage to a word line in the array of memory cells during a read operation on the word line;
apply a first pass voltage to a number of programmed word lines in the array of memory cells during the read operation;
apply a second pass voltage to a number of unprogrammed word lines in the array of memory cells during the read operation; and
apply a third pass voltage to a programmed word line adjacent to the word line being read and a fourth pass voltage to an unprogrammed word line adjacent to the word line being read, wherein a magnitude of the third pass voltage is greater than a magnitude of the fourth pass voltage, wherein the second pass voltage is restored to an initial value after completion of the read operation.
2 . The apparatus of claim 1 , wherein the apparatus contains a partially programmed block comprising the number of programmed word lines and the number of unprogrammed word lines.
3 . The apparatus of claim 2 , wherein the word line being read is located in the partially programmed block.
4 . The apparatus of claim 1 , wherein a magnitude of the second pass voltage is less than a magnitude of the first pass voltage.
5 . The apparatus of claim 1 , further including obtaining a location of the last programmed word line in the array.
6 . The apparatus of claim 1 , wherein the first pass voltage and second pass voltage are based on the location of the last programmed word line in a partially programmed block.
7 . The apparatus of claim 1 , further including performing the read operation on a boundary word line of a partially programmed block.
8 . An apparatus, comprising:
an array of memory cells;
a controller coupled to the array of memory cells and the controller is configured to:
apply a read voltage to a word line in the array of memory cells during a read operation on the word line;
apply a first pass voltage to a number of programmed word lines in the array of memory cells during the read operation;
apply a second pass voltage to a number of unprogrammed word lines in the array of memory cells during the read operation;
apply a third pass voltage to a programmed word line adjacent to the word line being read and a fourth pass voltage to an unprogrammed word line adjacent to the word line being read;
wherein a magnitude of the third pass voltage is greater than a magnitude of the fourth pass voltage, and
wherein the third pass voltage is based upon a distance between the number of unprogrammed word lines and the word line being read, and
wherein the second pass voltage is restored to an initial value after completion of the read operation.
9 . The apparatus of claim 8 , wherein the second pass voltage is applied to a number of unprogrammed memory cells that are not adjacent to the word line being read.
10 . The apparatus of claim 8 , wherein the controller is configured to use a look up table to determine a value of the second pass voltage.
11 . The apparatus of claim 10 , wherein the look up table includes values for the second pass voltage based upon a quantity of unprogrammed word lines comprising the number of unprogrammed word lines.
12 . The apparatus of claim 8 , wherein the controller is configured to calculate a value of the second pass voltage based on a location of the word line being read in a partially programmed block.
13 . The apparatus of claim 8 , wherein the apparatus calculates a change from the first pass voltage for the second pass voltage applied to the unprogrammed word lines based on a quantity of unprogrammed word lines in a partially programmed block.
14 . A method, comprising:
performing a read operation on a word line in a memory array,
wherein performing the read operation includes:
applying a read voltage to the word line in the array of memory cells during the read operation on the word line;
applying a first pass voltage to a number of programmed word lines in the array of memory cells;
applying a second pass voltage to a number of unprogrammed word lines in the array of memory cells; and
applying a third pass voltage to a programmed word line adjacent to the word line being read and a fourth pass voltage to an unprogrammed word line adjacent to the word line being read, wherein a magnitude of the third pass voltage is greater than a magnitude of the fourth pass voltage; and
restoring the second pass voltage to an initial value after completing performing the read operation.
15 . The method of claim 14 , further including performing the read operation on a partially programmed block.
16 . The method of claim 14 , further including obtaining a location of the last programmed word line in the array.
17 . The method of claim 16 , further including calculating the first pass voltage and second pass voltage values based on the location of the last programmed word line and last unprogrammed word line.
18 . The method of claim 14 , further including performing the read operation on a boundary word line of a partially programmed block.