Non-volatile memory management system with load leveling and method of operation thereof

• US 9,021,319 B2
• Filed: 08/31/2012
• Issued: 04/28/2015
• Est. Priority Date: 09/02/2011
• Status: Expired due to Fees

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Smart Storage Systems Incorporated (Western Digital Corporation)
• Inventors: Fitzpatrick, James, Rub, Bernardo, Higgins, James, Jones, Ryan, Ellis, Robert W.
• Primary Examiner(s): Merant, Guerrier
• Application Number:
  US13/601,607
• Publication Number:
  US 20130061101A1
• Time in Patent Office: 970 Days
• US Class Current: 714/708
• CPC Class Codes: G11C 16/00 Erasable programmable read-only memories G11C14/00 takes precedence
• CPC Class Codes: G11C 16/349 Arrangements for evaluating degradation, retention or wearout, e.g. by counting erase cycles
• CPC Class Codes: G11C 2029/5002 Characteristic
• CPC Class Codes: G11C 29/50004 of threshold voltage

Abstract

A method of operation of a non-volatile memory system includes: generating a test stimulus for a page in a memory array; measuring a test response from the page in the memory array based on the test stimulus; calculating a measured effective life of the page from the test response; and determining a use plan according to the measured effective life for accessing the page.

Claims

1. A method of operation of a non-volatile memory system comprising:

generating a test stimulus for a page in a memory array;

measuring a test response from the page in the memory array based on the test stimulus, the test response including a programming error rate or an erase-duration;

calculating a measured effective life of the page in accordance with the programming error rate or the erase-duration; and

determining a use plan according to the measured effective life for accessing the page.

2. The method as claimed in claim 1, wherein the method includes:

storing the programming error rate from reading the page in the memory array; and

shifting a read threshold for reading data content from the memory array;

wherein;

generating the test stimulus includes reading the page according to a test-read count;

measuring the test response includes determining a test error rate after reading the page according to the test-read count; and

calculating the measured effective life includes calculating the measured effective life using the programming error rate, the test error rate, or both.

3. The method as claimed in claim 1 further comprising:

storing a pretest sum of data content stored in the memory array;

wherein;

generating the test stimulus includes sending data-setting pulses controlled by a pulse count for setting the data content high in the memory array;

measuring the test response includes;

reading updated data stored in the memory array in response to the data-setting pulses;

calculating a total sum of the updated data; and

calculating the measured effective life includes calculating the measured effective life using the total sum of the updated data stored in the memory array and the pretest sum.

4. The method as claimed in claim 1, wherein the method includes:

determining an initial threshold level minimizing a programming error rate; and

wherein;

generating the test stimulus includes processing a read command after a test-leakage duration;

measuring the test response includes determining a test threshold level minimizing a test error rate; and

calculating the measured effective life includes calculating the measured effective life using the programming error rate, the test error rate, the initial threshold level, the test threshold level, or a combination thereof.

5. The method as claimed in claim 1 wherein:

generating the test stimulus includes processing an erase command;

measuring the test response includes receiving an erase-response having the erase-duration for indicating an amount of time spent by the memory array to erase data content in the memory array; and

calculating the measured effective life includes calculating the measured effective life using the erase-duration.

6. A method of operation of an entertainment system comprising:

generating a test stimulus for a page, an erase block, or a combination thereof in a memory array;

measuring a test response from the page, the erase block, or the combination thereof in the memory array based on the test stimulus, the test response including a programming error rate or an erase-duration;

calculating a measured effective life of the page, the erase block, or the combination thereof in accordance with the programming error rate or the erase-duration;

determining a use plan for balancing usage of the page, the erase block, or a combination thereof according to the measured effective life relative to the memory array; and

managing the usage of the memory array according the use plan for performing wear-leveling.

7. The method as claimed in claim 6 further including:

determining an initial threshold level for yielding a predetermined error rate;

wherein;

generating the test stimulus includes reading the page according to a test-read count;

measuring the test response includes determining a test threshold level for yielding the predetermined error rate after reading the page according to the test-read count; and

calculating the measured effective life includes calculating the measured effective life using the initial threshold level, the test threshold level, or both.

8. The method as claimed in claim 6 further including:

determining the programming error rate from reading the page in the memory array;

determining an initial threshold level for minimizing the programming error rate;

wherein;

generating the test stimulus includes reading the page according to a test-read count;

measuring the test response includes;

determining a test error rate after reading the page according to the test-read count;

determining a test threshold level for minimizing the test error rate; and

calculating the measured effective life includes calculating the measured effective life using the programming error rate, the initial threshold level, the test error rate, the test threshold level, or a combination thereof.

9. The method as claimed in claim 6 further comprising:

determining an initial threshold level yielding a predetermined error rate;

wherein;

generating the test stimulus includes processing a read command after a test-leakage duration;

measuring the test response includes determining a test threshold level corresponding to the test error rate; and

calculating the measured effective life includes calculating the measured effective life using the initial threshold level, the test threshold level, or both.

10. The method as claimed in claim 6 wherein:

generating the test stimulus includes processing a write command to the memory array;

measuring the test response includes receiving a write-response having a program-duration for indicating an amount of time spent by the memory array to write data content in the memory array; and

calculating the measured effective life includes calculating the measured effective life using an execution profile and the program-duration.

11. A non-volatile memory system comprising:

a non-volatile memory array;

a memory controller, coupled to the non-volatile memory array, for managing operation of the non-volatile memory array, the memory controller including;

a stimulus module for generating a test stimulus for a page in a memory array;

a response module, connected to the stimulus module, for measuring a test response from the page in the memory array based on the test stimulus, the test response including a programming error rate or an erase-duration;

a reliability calculation module, connected to the response module, for calculating a measured effective life of the page in accordance with the programming error rate or the erase-duration; and

a balance plan module, connected to the reliability calculation module, for determining a use plan according to the measured effective life for accessing the page.

12. The system as claimed in claim 11 further comprising:

an error tracking module, connected to the response module, for storing the programming error rate from reading the page in the memory array;

a threshold adjustment module, connected to the reliability calculation module, for shifting a read threshold for reading data content from the memory array;

a data read module, connected to the stimulus module, for reading the page according to a test-read count;

an error detection module, connected to the operational command module, for determining a test error rate after reading the page according to the test-read count; and

wherein;

the reliability calculation module is for calculating the measured effective life using the programming error rate, the test error rate, or both.

13. The system as claimed in claim 11 further comprising:

a sum storage module, connected to the reliability calculation module, for storing a pretest sum of data content stored in the memory array;

a pulse module, connected to the response module, for sending data-setting pulses controlled by a pulse count for setting the data content high in the memory array;

a data read module, connected to the pulse module, for reading updated data stored in the memory array in response to the data-setting pulses; and

an updated-sum module, connected to the data read module, for calculating a total sum of the updated data;

wherein;

the reliability calculation module is for calculating the measured effective life using the total sum of the updated data stored in the memory array and the pretest sum.

14. The system as claimed in claim 11 further comprising:

a threshold adjustment module, connected to the reliability calculation module, for determining an initial threshold level minimizing the programming error rate;

an operational command module, connected to the response module, for processing a read command after a test-leakage duration; and

an error detection module, connected to the operational command module, for determining a test threshold level minimizing a test error rate;

wherein;

the reliability calculation module is for calculating the measured effective life using the programming error rate, the test error rate, the initial threshold level, the test threshold level, or a combination thereof.

15. The system as claimed in claim 11 further comprising:

an operational command module, connected to the response module, for processing an erase command; and

a data read module, connected to the operational command module, for receiving an erase-response having the erase-duration for indicating an amount of time spent by the memory array to erase data content in the memory array;

wherein;

the reliability calculation module is for calculating the measured effective life using an execution profile and the erase-duration.

16. The system as claimed in claim 11 wherein:

the stimulus module is for generating a test stimulus for a page, an erase block, or a combination thereof in a memory array;

the response module is for measuring a test response from the page, the erase block, or the combination thereof in the memory array based on the test stimulus;

the reliability calculation module is for calculating a measured effective life of the page, the erase block, or the combination thereof from the test response;

the balance plan module is for determining a use plan for balancing usage of the page, the erase block, or a combination thereof according to the measured effective life relative to the memory array; and

further comprising;

a wear balancing module, connected to the balance plan module, for managing the usage of the memory array according the use plan for performing wear-leveling.

17. The system as claimed in claim 16 further comprising:

a threshold adjustment module, connected to the reliability calculation module, for determining an initial threshold level for yielding a predetermined error rate;

a data read module, connected to the pulse module, for reading the page according to a test-read count; and

an error detection module, connected to the operational command module, for determining a test threshold level for yielding the predetermined error rate after reading the page according to the test-read count;

wherein;

the reliability calculation module is for calculating the measured effective life using the initial threshold level, the test threshold level, or both.

18. The system as claimed in claim 16 further comprising:

an error tracking module, connected to the response module, for determining the programming error rate from reading the page in the memory array;

a threshold adjustment module, connected to the reliability calculation module, for determining an initial threshold level for minimizing the programming error rate;

a data read module, connected to the pulse module, for reading the page according to a test-read count; and

an error detection module, connected to the operational command module, for determining a test error rate after reading the page according to the test-read count;

wherein;

the threshold adjustment module is for determining a test threshold level for minimizing the test error rate; and

the reliability calculation module is for calculating the measured effective life using the programming error rate, the initial threshold level, the test error rate, the test threshold level, or a combination thereof.

19. The system as claimed in claim 16 further comprising:

a threshold adjustment module, connected to the reliability calculation module, for determining an initial threshold level yielding a predetermined error rate;

an operational command module, connected to the response module, for processing a read command after a test-leakage duration; and

an error detection module, connected to the operational command module, for determining a test threshold level corresponding to the test error rate;

wherein;

the reliability calculation module is for calculating the measured effective life using the initial threshold level, the test threshold level, or both.

20. The system as claimed in claim 16 further comprising:

an operational command module, connected to the response module, for processing a write command to the memory array; and

a data read module, connected to the operational command module, for receiving a write-response having a program-duration for indicating an amount of time spent by the memory array to write data content in the memory array;

wherein;

the reliability calculation module is for calculating the measured effective life using an execution profile and the program-duration.