Memory device for performing read operation and program verification operation
A memory device includes a memory cell array including memory cells; a row control circuit coupled to the memory cells through word lines and configured to apply, to a selected word line during read operations, respective read voltages having different levels; a page buffer circuit coupled to the memory cells through bit lines and configured to adjust, according to a sensing control signal during each of the read operations, an amount of current flowing through the bit lines to sense the adjusted amount; and a read control circuit configured to adjust, during a second read operation subsequent to a first read operation among the read operations, a voltage level of the sensing control signal when a voltage level of a second read voltage corresponding to the second read operation is different from a level of a first read voltage corresponding to the first read operation.
1. A memory device comprising:
a memory cell array including a plurality of memory cells;
a row control circuit coupled to the memory cells through a plurality of word lines and configured to apply, to a selected word line during read operations, respective read voltages having different levels;
a page buffer circuit coupled to the memory cells through a plurality of bit lines and configured to adjust, according to a sensing control signal during each of the read operations, an amount of current flowing through the bit lines to sense the adjusted amount; and
a read control circuit configured to adjust, during a second read operation subsequent to a first read operation among the read operations, a voltage level of the sensing control signal when a voltage level of a second read voltage corresponding to the second read operation is different from a level of a first read voltage corresponding to the first read operation.
2. The memory device of claim 1 , wherein the read control circuit is configured to decrease the voltage level of the sensing control signal when the level of the second read voltage is greater than the level of the first read voltage.
3. The memory device of claim 1 , wherein the read control circuit is configured to increase the voltage level of the sensing control signal when the level of the second read voltage is lower than the level of the first read voltage.
4. The memory device of claim 1 , wherein the memory cells include cells each configured to store therein two or more bits of data.
5. The memory device of claim 1 , wherein the memory cells are programmed into a plurality of program states, and the read operations are performed a number of times for determining the program states.
6. A memory device comprising:
a memory cell array including a plurality of memory cells programmed into a plurality of program states;
a peripheral circuit coupled to the memory cell array through a plurality of word lines and a plurality of bit lines, and configured to perform a plurality of read operations on selected memory cells among the memory cells; and
a control logic configured to control the peripheral circuit to adjust, during a current read operation of the read operations, a voltage level of the bit lines when a level of a read voltage applied to a selected word line during the current read operation is different from a level of a read voltage during a previous read operation.
7. The memory device of claim 6 , wherein the peripheral circuit includes:
a row control circuit coupled to the memory cells through the word lines and configured to apply, to a selected word line during the read operations, respective read voltages having different levels; and
a page buffer circuit coupled to the memory cells through the bit lines, and configured to adjust, according to a sensing control signal during each of the read operations, an amount of current flowing through the bit lines to sense the adjusted amount.
8. The memory device of claim 7 , wherein the control logic is configured to decrease a voltage level of the sensing control signal when the level of the read voltage applied during the current read operation is greater than the level of the read voltage applied during the previous read operation.
9. The memory device of claim 7 , wherein the control logic is configured to increase a voltage level of the sensing control signal when the level of the read voltage applied during the current read operation is lower than the level of the read voltage applied during the previous read operation.
10. The memory device of claim 6 , wherein the memory cells include cells each configured to store therein two or more bits of data.
11. The memory device of claim 6 , wherein the read operations are performed a number of times for determining the program states.
12. An operating method of a memory device, the operating method comprising:
performing a first read operation including:
applying a first read voltage to a word line selected from a plurality of word lines; and
sensing an amount of current flowing through a plurality of bit lines according to a sensing control signal; and
performing a second read operation including:
applying a second read voltage to the selected word line;
adjusting a voltage level of the sensing control signal when a level of the second read voltage is different from a level of the first read voltage; and
sensing the amount of current flowing through the bit lines according to the sensing control signal.
13. The operating method of claim 12 , wherein the adjusting the voltage level of the sensing control signal includes decreasing the voltage level of the sensing control signal when the level of the second read voltage is greater than the level of the first read voltage.
14. The operating method of claim 12 , wherein the adjusting the voltage level of the sensing control signal includes increasing the voltage level of the sensing control signal when the level of the second read voltage is lower than the level of the first read voltage.