Driving method of memory controller and nonvolatile memory device controlled by memory controller
A method is for driving a memory controller which is configured to control a nonvolatile memory device. The method includes counting a number of error bits of read data provided from the nonvolatile memory device, determining a running average value using the number of error bits; and performing a wear leveling on the nonvolatile memory device using the running average value as a wear leveling index.
1. A method of driving a memory controller which is configured to control a nonvolatile memory device, the method comprising:
counting a number of error bits of read data provided from the nonvolatile memory device;
determining a running average value using a number of error bits and a noise parameter; and
performing wear leveling on the nonvolatile memory device using the running average value as a wear leveling index, wherein:
a noise of the running average value is decreased, as the noise parameter is increased, and
wherein the noise parameter is increased according to an increase in a program/erase cycle of the nonvolatile memory device.
2. The method of claim 1 , wherein when the running average value is less than a reference value, a wear leveling operation on the nonvolatile memory device is performed such that a program or erase frequency is increased.
3. The method of claim 1 , wherein when the running average value is greater than a reference value, a wear leveling operation on the nonvolatile memory device is performed such that a program or erase frequency is decreased.
4. The method of claim 1 , wherein the memory controller comprises an ECC decoder configured to count the number of error bits.
5. The method of claim 4 , wherein:
the memory controller further comprises a wear leveling index former,
the ECC decoder counts the number of error bits and provides the number of error bits to the wear leveling index former, and
the wear leveling index former determines the running average value using the number of error bits.
6. A nonvolatile memory device comprising:
a memory cell array including a plurality of memory blocks storing data;
a page buffer circuit connected to the memory cell array through bit lines and including a sense latch to sense and store data read from the memory cell array; and
a control logic configured to control the page buffer circuit, wherein:
the control logic comprises:
a wear leveling index former which counts a number of error bits of read data based on a result of a comparison between the read data stored in the sense latch and original data, determines a running average value using the number of error bits and a noise parameter, and forms wear leveling indexes of the plurality of memory blocks,
a noise of the running average value is decreased, as the noise parameter is increased, and
the noise parameter is increased according to an increase in a program/erase cycle of the nonvolatile memory device.
7. The nonvolatile memory device of claim 6 , wherein when the running average value is less than a reference value, a program or erase frequency of a memory block corresponding to the running average value is decreased.
8. The nonvolatile memory device of claim 6 , wherein when the running average value is greater than a reference value, a program or erase frequency of a memory block corresponding to the running average value is increased.
9. The nonvolatile memory device of claim 6 , wherein the page buffer circuit further comprises at least one data latch configured to store the original data.
10. The nonvolatile memory device of claim 9 , wherein the page buffer circuit performs an XOR operation using the at least one data latch and the sense latch, and provides the result of the XOR operation to the wear leveling index former.
11. The nonvolatile memory device of claim 10 , wherein the wear leveling index former determines a number of error bits by counting a number of one-bits in the result of the XOR operation.
12. A memory controller comprising:
a microprocessor configured to control and interpret a program or read command to be provided to a nonvolatile memory device;
an ECC decoder configured to count a number of error bits of data read from the nonvolatile memory device under a control of the microprocessor; and
a wear leveling control unit configured to determine a running average value using a number of error bits and a noise parameter, and to perform wear leveling of the nonvolatile memory device according to the running average value, wherein:
a noise of the running average value is decreased, as the noise parameter is increased, and
the noise parameter is increased according to an increase in a program/erase cycle of the nonvolatile memory device.
13. The memory controller of claim 12 , wherein the wear leveling control unit determines a number of program/erase cycles of the nonvolatile memory device using the running average value as a wear leveling index.
14. The memory controller of claim 12 , wherein when the running average value is less than a reference value, a wear leveling frequency of a memory block corresponding to the running average value is decreased.
15. The memory controller of claim 12 , wherein when the running average value is greater than a reference value, a wear leveling frequency of a memory block corresponding to the running average value is increased.
16. The memory controller of claim 12 , wherein the wear leveling control unit is configured to perform an operation under control of the microprocessor.
17. The memory controller of claim 12 , further comprising an ECC encoder configured to encode data to be provided to the nonvolatile memory device.