Memory data detecting apparatus and method for controlling reference voltage based on error in stored data

• US 7,929,346 B2
• Filed: 07/10/2008
• Issued: 04/19/2011
• Est. Priority Date: 02/15/2008
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Cho, Kyoung Lae, Kong, Jun Jin, Kim, Jae Hong, Yu, Dong Hun, Song, Seung-Hwan, Chae, Dong Hyuk
• Primary Examiner(s): HUR, JUNG H
• Application Number:
  US12/216,745
• Publication Number:
  US 20090207671A1
• Time in Patent Office: 1,013 Days
• Field of Search: 365/185.02, 365/185.09, 365/185.03, 365/185.21, 365/185.22, 365/185.2, 365/200
• US Class Current: 365/185.09
• CPC Class Codes: G11C 11/5642 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 2211/5634 Reference cells
• CPC Class Codes: G11C 29/00 Checking stores for correct operation ; Subsequent repair; Testing stores during standby or offline operation
• CPC Class Codes: G11C 29/028 with adaption or trimming of parameters
• CPC Class Codes: G11C 29/42 using error correcting codes [ECC] or parity check
• CPC Class Codes: G11C 29/50 Marginal testing, e.g. race, voltage or current testing
• CPC Class Codes: G11C 7/1006 Data managing, e.g. manipulating data before writing or reading out, data bus switches or control circuits therefor
• CPC Class Codes: G11C 7/14 Dummy cell management; Sense reference voltage generators

Abstract

Example embodiments may relate to a method and an apparatus for reading data stored in a memory, for example, providing a method and an apparatus for controlling a reference voltage based on an error of the stored data. Example embodiments may provide a memory data detecting apparatus including a first voltage comparator to compare a threshold voltage of a memory cell with a first reference voltage, a first data determiner to determine a value of at least one data bit stored in the memory cell according to a result of the comparison, an error verifier to verify whether an error occurs in the determined value, a reference voltage determiner to determine a second reference voltage that is lower than the first reference voltage based on a result of the verification, and a second data determiner to re-determine the value of the data based on the determined second reference voltage.

Claims

1. A method for detecting memory data, comprising:

comparing a threshold voltage of a memory cell with a first reference voltage;

determining a value of at least one data bit stored in the memory cell according to the comparing;

verifying whether an error occurs in the at least one data bit based on the determining a value;

determining a second reference voltage that is lower than the first reference voltage based on the verifying; and

re-determining the value of the at least one data bit based on the determining the second reference voltage, wherein

the determining of the second reference voltage includes identifying an error-bit location where an error occurs among the data bits and determining the second reference voltage according to the identified error-bit location.

2. The method of claim 1, wherein the determining of the second reference voltage further includes,

determining the second reference voltage so that a difference between the first and the second reference voltage is reduced.

3. The method of claim 2, wherein the determining of the second reference voltage further includes,

determining the second reference voltage so that an error is eliminated from error-bit data in the at least one data bit.

4. The method of claim 1, wherein the determining of the second reference voltage includes,

determining the second reference voltage so that a difference between the first and the second reference voltage is reduced.

5. The method of claim 1, wherein the determining of the second reference voltage includes,

determining the second reference voltage so that an error is eliminated from error-bit data in the at least one data bit.

6. The method of claim 1, wherein the determining of the second reference voltage includes,

determining the second reference voltage based on an error of a lower bit of the at least one data bit;

re-determining the value of the at least one data bit based on the determining the second reference voltage; and

updating the second reference voltage according to whether an error occurs in an upper data bit of the at least one data bit among the re-determined data.

7. The method of claim 1, wherein the verifying of whether an error occurs includes,

verifying whether an error occurs in the determined data using at least one of a block code and a convolutional code.

8. A non-transitory computer readable medium storing a computer program for implementing the method of claim 1.

9. An apparatus for detecting memory data, comprising:

a first voltage comparator to compare a threshold voltage of a memory cell with a first reference voltage;

a first data determiner to determine a value of at least one data bit stored in the memory cell according to a result of the comparator;

an error verifier to verify whether an error occurs in the determined value;

a reference voltage determiner to determine a second reference voltage that is lower than the first reference voltage based on a result of the verifier; and

a second data determiner to re-determine the value of the data based on the determined second reference voltage, wherein

the reference voltage determiner identifies an error-bit location where an error occurs among the data bits and determines the second reference voltage according to the identified error-bit location.

10. The apparatus of claim 9, wherein the reference voltage determiner determines the second reference voltage so that a difference between the first and the second reference voltage is reduced.

11. The apparatus of claim 10, wherein the reference voltage determiner determines the second reference voltage to eliminate an error from error-bit data in the at least one data bit.

12. The apparatus of claim 9, wherein the reference voltage determiner determines the second reference voltage so that a difference between the first and the second reference voltage is reduced.

13. The apparatus of claim 9, wherein the reference voltage determiner determines the second reference voltage to eliminate an error from error-bit data in the at least one data bit.

14. The apparatus of claim 9, wherein, the reference voltage determiner determines the second reference voltage based on an error of a lower data bit of the at least one data bit, re-determines the value of the at least one data bit based on the determined second reference voltage, and updates the second reference voltage according to whether an error occurs in an upper data bit of the at least one data bit among the re-determined data.

15. The apparatus of claim 9, wherein the error verifier verifies whether an error occurs in the determined data using at least one of a block code and a convolutional code.