Method for changing read parameter for improving read performance and apparatuses using the same

• US 9,009,390 B2
• Filed: 09/21/2011
• Issued: 04/14/2015
• Est. Priority Date: 10/04/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Seong Hyeog, Son, Hong Rak, Cho, Kyoung Lae, Kong, Jun Jin, Lee, Sang Hoon
• Primary Examiner(s): DUDEK JR, EDWARD J
• Application Number:
  US13/238,749
• Publication Number:
  US 20120084490A1
• Time in Patent Office: 1,301 Days
• Field of Search: 711/103, 711/E12.008, 365/189.011
• US Class Current: 711/103
• CPC Class Codes: G06F 13/00 Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units interface circuits for specific input/output devices G06F3/00 ; multiprogram control therefor G06F9/46; multiprocessor systems G06F15/16
• CPC Class Codes: G11C 11/5642 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 16/00 Erasable programmable read-only memories G11C14/00 takes precedence
• CPC Class Codes: G11C 16/02 electrically programmable
• CPC Class Codes: G11C 16/06 Auxiliary circuits, e.g. for writing into memory
• CPC Class Codes: G11C 16/3418 Disturbance prevention or evaluation; Refreshing of disturbed memory data
• CPC Class Codes: G11C 16/349 Arrangements for evaluating degradation, retention or wearout, e.g. by counting erase cycles
• CPC Class Codes: G11C 29/42 using error correcting codes [ECC] or parity check

Abstract

A memory system including a non-volatile memory device and a memory controller is provided. When a read operation on a first data initially output from the non-volatile memory device during a first read operation is successful, the memory controller may change a read voltage for reading a second data stored in the non-volatile memory device during a second read operation.

Claims

1. A method of operating a memory, the method comprising:

performing a first read operation to read data stored in a region of the memory using a first read voltage;

determining whether reading is successful using a first error correction parameter; and

when reading is successful, changing the first read voltage to a second read voltage and changing the first error correction parameter to a second error correction parameter in accordance with current cell conditions of the region;

transmitting the data read in the first read operation using the first read voltage to a host; and

performing a second read operation to read data stored in the memory using the second read voltage.

2. The method as claimed in claim 1, after transmitting the data, saving the second read voltage and the second error correction parameter.

3. The method as claimed in claim 1, wherein the second read operation is performed to read associated cells.

4. The method as claimed in claim 3, wherein the associated cells are in a same block.

5. The method as claimed in claim 3, wherein the associated cells are in a same page.

6. The method as claimed in claim 3, wherein the associated cells are coupled to a same wordline.

7. The method as claimed in claim 1, wherein determining whether reading is successful includes decoding the data.

8. The method as claimed in claim 7, further comprising, before decoding the data, determining current cell conditions includes counting a number of ones or zeroes in the data.

9. The method as claimed in claim 8, wherein, when the number of ones or zeroes in the data is less than a reference number, changing the first read voltage includes increasing a read voltage.

10. The method as claimed in claim 8, wherein, when the number of ones or zeroes in the data is greater than a reference number, changing the first read voltage includes decreasing a read voltage.

11. The method as claimed in claim 1, wherein determining current cell conditions includes reading predetermined data from a spare area.

12. The method as claimed in claim 11, wherein determining current cell conditions includes counting a number of ones or zeroes in the predetermined data.

13. The method as claimed in claim 12, wherein, when the number of ones or zeroes in the predetermined data differs from a reference number, altering a read voltage.

14. The method as claimed in claim 13, wherein, when the number of ones or zeroes in the data is greater than a reference number, altering the read voltage includes decreasing the read voltage.

15. The method as claimed in claim 13, wherein, when the number of ones or zeroes in the data is less than a reference number, altering the read voltage includes increasing the read voltage.

16. The method as claimed in claim 1, wherein changing the first read voltage includes increasing or decreasing a read voltage.

17. The method as claimed in claim 1, wherein the memory includes non-volatile memory cells.

18. The method as claimed in claim 1, wherein the memory includes a plurality of multi-level cells for storing data, each of the plurality of multi-level cells being programmed to have one of a plurality of states.

19. A method of operating a memory controller, the method comprising:

receiving data output from a memory during a first read operation for reading of a region of the memory using a first read voltage;

determining whether reading is successful using a first error correction parameter;

when reading is successful, changing the first read voltage to a second read voltage and changing the first error correction parameter to a second error correction parameter in accordance with current cell conditions of the region and transmitting the data read using the first read voltage to a host; and

receiving data output from the memory during a second read operation based on the second read voltage.

20. The method as claimed in claim 19, wherein determining whether reading is successful includes error correction decoding the data.

21. The method as claimed in claim 20, further comprising, before error correction decoding, determining current cell conditions including counting a number of ones or zeroes in the data.

22. The method as claimed in claim 21, wherein, when the number of ones or zeroes in the data is less than a reference number, changing the first read voltage includes decreasing a read voltage.

23. The method as claimed in claim 21, wherein, when the number of ones or zeroes in the data is greater than a reference number, changing the first read voltage includes decreasing a read voltage.

24. The method as claimed in claim 20, wherein transmitting includes transmitting the error correction decoded data to the host.

25. The method as claimed in claim 24, after transmitting the error correction decoded data, saving the second read voltage and the second error correction parameter.

26. The method as claimed in claim 19, further comprising

outputting the second read voltage and the second error correction parameter.

27. A method of operating a memory system, the method comprising:

reading data stored in a region of a memory device during a first read operation performed using a first read voltage;

transmitting data read during the first read operation performed using the first read voltage to a memory controller;

determining, by the memory controller, whether reading is successful using a first error correction parameter;

when reading is successful, changing, by the memory controller, the first read voltage to a second read voltage and changing the first error correction parameter to a second error correction parameter in accordance with current cell conditions of the region;

transmitting the data read during the first read operation performed using the first read voltage to a host; and

reading data from the memory device during a second read operation performed based on the second read voltage.

28. The method as claimed in claim 27, further comprising

storing the second read voltage and the second error correction parameter in the memory controller.

29. The method as claimed in claim 27, wherein determining whether reading is successful includes error correction decoding data.

30. The method as claimed in claim 29, comprising, before error correction decoding, determining current cell conditions including counting a number of ones or zeroes in the data.

31. The method as claimed in claim 29, after transmitting the data, saving the second read voltage and the second error correction parameter.

32. The method as claimed in claim 29, after transmitting the data, using the second read voltage in reading of associated cells.

33. The method as claimed in claim 32, wherein the associated cells are one of a same block, a same page, and coupled to a same wordline.

34. The method as claimed in claim 27, further comprising:

transmitting data read during the second read operation performed using the second read voltage to the memory controller.