Memory device and operating method thereof
There are provided a memory device for improving performance by decreasing a time at which a program operation is completed while decreasing a peak current flowing through a bit line, and an operating method of the memory device.
1. A memory device comprising:
a memory cell coupled to a bit line and a word line;
a page buffer coupled to the bit line, and configured to output a bit line voltage to the bit line in response to a page buffer sensing signal; and
control logic configured to:
output, to the page buffer, a signal increased from a first voltage level at a first time of a precharge period to a second voltage level at a second time of the precharge period, as the page buffer sensing signal,
in response to the second voltage level being less than a target voltage level, output, to the page buffer, a pulse signal having the target voltage level at a third time of the precharge period, as the page buffer sensing signal, and
output a control signal to provide a program voltage to the word line after the precharge period.
2. The memory device of claim 1 , wherein a voltage level of the program voltage increases according to a count in which the program voltage is applied to the word line.
3. The memory device of claim 2 , wherein a voltage level of the signal increases according to a slope value corresponding to the count among a plurality of slope values during a time period from the first time to the second time.
4. The memory device of claim 3 , wherein the plurality of gradient values include:
a first gradient value corresponding to a count that is less than or equal to a first reference count;
a second slope value corresponding to a count that is greater than the first reference count, and is less than or equal to a second reference count greater than the first reference count; and
a third slope value corresponding to a count that is greater than the second reference count, and
wherein each of the first slope value and the third slope value is greater than the second slope value.
5. The memory device of claim 3 , wherein the voltage level of the signal continuously increases according to the slope value during the time period, or increases by once per a unit time according to the slope value during the time period.
6. The memory device of claim 1 , wherein the control logic is configured to output, to the page buffer, as the page buffer sensing signal, a signal increased from a voltage level of a ground voltage to the first voltage level before the first time of the precharge period.
7. The memory device of claim 6 , wherein the control logic is configured to output a control signal to provide a precharge voltage to the word line, while a signal having the voltage level of the ground voltage is output as the page buffer sensing signal before the first time of the precharge period.
8. The memory device of claim 1 , wherein the control logic is configured to output a control signal to provide a ground voltage to the word line during a time period from the first time to the third time of the precharge period.
9. The memory device of claim 1 , wherein the control logic is configured to output, to the page buffer, a ground voltage as the page buffer sensing signal while the program voltage is applied to the word line.
10. The memory device of claim 1 , wherein the page buffer includes a page buffer sensing transistor configured to connect the bit line and a common sensing node in response to the page buffer sensing signal, and
wherein the second voltage level is a voltage level to turn on the page buffer sensing transistor.
11. The memory device of claim 1 , wherein the bit line voltage is one of a program allow voltage and a program inhibit voltage.
12. A method of a memory device comprising a memory cell and a page buffer, the method comprising:
providing the page buffer with a signal increased from a first voltage level in a first time of the precharge period to a second voltage level in a second time of the precharge period;
in response to the second voltage level being less than a target voltage level, providing the page buffer with a pulse signal having the target voltage level at a third time of the precharge period; and
applying a program voltage to a word line connected to the memory cell after the precharge period.