Storage control system with data management mechanism and method of operation thereof

• US 9,123,445 B2
• Filed: 01/22/2013
• Issued: 09/01/2015
• Est. Priority Date: 01/22/2013
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Smart Storage Systems Incorporated (Western Digital Corporation)
• Inventors: Ellis, Robert W., Fitzpatrick, James, Dancho, Mark, Martin, Michelle
• Primary Examiner(s): Blair, April Y
• Assistant Examiner(s): GANDHI, DIPAKKUMAR B
• Application Number:
  US13/746,542
• Publication Number:
  US 20140208174A1
• Time in Patent Office: 952 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1048 using arrangements adapted for a specific error detection or correction feature
• CPC Class Codes: G11C 16/04 using variable threshold transistors, e.g. FAMOS
• CPC Class Codes: G11C 16/26 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 29/48 Arrangements in static stores specially adapted for testing by means external to the store, e.g. using direct memory access [DMA] or using auxiliary access paths
• CPC Class Codes: G11C 29/50 Marginal testing, e.g. race, voltage or current testing
• CPC Class Codes: G11C 29/50004 of threshold voltage
• CPC Class Codes: G11C 29/56 External testing equipment for static stores, e.g. automatic test equipment [ATE]; Interfaces therefor

Abstract

A method of operation of a storage control system includes: determining a bit error rate of a page; calculating a slope based on the bit error rate; and adjusting a threshold voltage for the page based on the slope for reading a memory device.

Claims

1. A method of operation of a storage control system comprising:

determining a bit error rate of a page in an erase block;

calculating a slope based on the bit error rate of one or more pages of the erase block; and

adjusting a threshold voltage for reading the page of the erase block based on the slope.

2. The method as claimed in claim 1 wherein adjusting the threshold voltage includes adjusting the threshold voltage with a threshold change value based on the slope and an age of the erase block.

3. The method as claimed in claim 1 further comprising estimating a target bit error rate for adjustment of the threshold voltage.

4. The method as claimed in claim 1 wherein adjusting the threshold voltage includes adjusting the threshold voltage based on where the page is located within the erase block.

5. The method as claimed in claim 1 wherein:

determining the bit error rate includes determining bit error rates for the slope based on a beginning page and an ending page of the erase block; and

further comprising;

estimating an age of the erase block based on a change of a difference in the bit error rates.

6. The method as claimed in claim 1 further comprising estimating a target bit error rate by sampling a mid-point page of the erase block for adjustment of the threshold voltage.

7. The method as claimed in claim 1 wherein adjusting the threshold voltage includes increasing the threshold voltage by a threshold change value when reading a beginning page of the erase block and decreasing the threshold voltage by the threshold change value when reading an ending page of the erase block.

8. The method as claimed in claim 1 wherein:

determining the bit error rate includes determining bit error rates for calculating the slope based on a beginning page and an ending page of the erase block; and

further comprising;

estimating an age of the erase block based on a change of a difference in the bit error rates and a change in the threshold voltage.

9. A storage system comprising:

a controller, coupled to non-volatile storage, the controller including one or more processors for executing software instructions stored in memory of the storage system;

a measurement module for determining a bit error rate of a page in an erase block of the non-volatile storage;

a calculation module, coupled to the measurement module, for calculating a slope based on the bit error rate of one or more pages of the erase block; and

an adjustment module, coupled to the calculation module, for adjusting a threshold voltage for reading the page of the erase block based on the slope.

10. The system as claimed in claim 9 wherein the adjustment module is for adjusting the threshold voltage with a threshold change value based on the slope and an age of the erase block.

11. The system as claimed in claim 9 further comprising a rate estimation module, coupled to the calculation module, for estimating a target bit error rate for adjustment of the threshold voltage.

12. The system as claimed in claim 9 wherein the adjustment module is for adjusting the threshold voltage based on where the page is located within the erase block.

13. The system as claimed in claim 9 wherein:

the measurement module is for determining bit error rates for the slope based on a beginning page and an ending page of the erase block; and

further comprising;

an age estimation module, coupled to the measurement module, for estimating an age of the erase block based on a change of a difference in the bit error rates.

14. The system as claimed in claim 9, wherein the adjustment module is for adjusting the threshold voltage with a threshold change value based on the slope, and an age of the erase block.

15. The system as claimed in claim 9, further comprising a rate estimation module, coupled to the calculation module, for estimating a target bit error rate by sampling a mid-point page of the erase block for adjustment of the threshold voltage.

16. The system as claimed in claim 9, wherein the adjustment module is for increasing the threshold voltage by a threshold change value when reading a beginning page and decreasing the threshold voltage by the threshold change value when reading an ending page.

17. The system as claimed in claim 9, wherein:

the measurement module is for determining bit error rates for calculating the slope based on a beginning page and an ending page of the erase block; and

further comprising;

an age estimation module, coupled to the measurement module, for estimating an age of the erase block based on a change of a difference in the bit error rates and a change in the threshold voltage.

18. The system as claimed in claim 9, further comprising said non-volatile storage.

19. The system as claimed in claim 9, further comprising:

a retention estimation module for determining an amount of correct data after a predetermined period of time.