MEMORY HEALTH MONITORING

• US 20160378400A1
• Filed: 10/27/2015
• Published: 12/29/2016
• Est. Priority Date: 06/25/2015
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Inventors: YANG, NIAN NILES, ALROD, IDAN
• Granted Patent: US 9,996,299 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G11C 16/3495 Circuits or methods to detect or delay wearout of nonvolatile EPROM or EEPROM memory devices, e.g. by counting numbers of erase or reprogram cycles, by using multiple memory areas serially or cyclically
• CPC Class Codes: G11C 2211/5647 Multilevel memory with bit inversion arrangement
• CPC Class Codes: G11C 7/1006 Data managing, e.g. manipulating data before writing or reading out, data bus switches or control circuits therefor

Abstract

A data storage device may be configured to write first data to a first set of storage elements of a non-volatile memory and to write second data to a second set of storage elements of the non-volatile memory. The first data may be processed by a data shaping operation, and the second data may not be processed by the data shaping operation. The data storage device may be further configured to read a representation of the second data from the second set of storage cells and to determine a block health metric of a portion of the non-volatile memory based on the representation of the second data. The portion may include the first set of storage elements and the second set of storage elements. As an illustrative, non-limiting example, the first portion may be a first block of the non-volatile memory.

Claims

1. A data storage device comprising:

a non-volatile memory; and

a controller coupled to the non-volatile memory, the controller configured to;

write first data to a first set of storage elements accessible via a first word line of the non-volatile memory, the first data processed by a data shaping operation;

write second data to a second set of storage elements accessible via a second word line of the non-volatile memory, wherein the second data is not processed by the data shaping operation;

read a representation of the second data from the second set of storage elements; and

determine a block health metric of a portion of the non-volatile memory based on the representation of the second data, the portion including the first set of storage elements and the second set of storage elements.

2. The data storage device of claim 1, wherein the block health metric is determined based on a bit error rate of the representation of the second data and based on a count of program and erase cycles corresponding to the portion of the non-volatile memory.

3. The data storage device of claim 2, wherein the block health metric is determined based on a comparison of the bit error rate of the representation of the second data to one or more bit error rate thresholds.

4. The data storage device of claim 1, wherein the data shaping operation is configured to generate shaped data having a larger number of bits having a first value than bits having a second value.

5. The data storage device of claim 1, wherein the controller is configured to store a table that identifies a group of word lines associated with data that is not shaped by the shaping operation, and wherein the group of word lines includes the second word line.

6. The data storage device of claim 5, wherein the table further identifies a second group of word lines that is associated with data that is not shaped by the data shaping operation, wherein the controller is further configured to write data that is not shaped to storage elements accessible via the group of word lines prior to a first polling cycle, and wherein the controller is further configured to write data that is not shaped to storage elements accessible via the second group of word lines prior to a second polling cycle.

7. The data storage device of claim 5, wherein the non-volatile memory is divided into multiple portions, and wherein each of the multiple portions is associated with a corresponding entry in the table.

8. The data storage device of claim 7, wherein the multiple portions include multiple blocks of the non-volatile memory.

9. The data storage device of claim 5, wherein the controller is further configured to write data that is not processed by the data shaping operation to each of one or more sets of storage elements of the portion of the non-volatile memory during a polling cycle of the portion of the non-volatile memory, and wherein the one or more sets of storage elements are selected based on the group of word lines.

10. A method comprising:

writing first data to a first set of storage elements accessible via a first word line of a non-volatile memory, the first data processed by a data shaping operation;

writing second data to a second set of storage elements accessible via a second word line of the non-volatile memory, wherein the second data is not processed by the data shaping operation;

reading a representation of the second data from the second set of storage elements; and

determining a block health metric of a portion of the non-volatile memory based on the representation of the second data, the portion including the first set of storage elements and the second set of storage elements.

11. The method of claim 10, wherein the second data is written to the second set of storage elements during a program and erase cycle prior to a polling cycle of the portion of the non-volatile memory.

12. The method of claim 10, further comprising maintaining a count of program and erase cycles corresponding to the portion of the non-volatile memory, and wherein the second data is written to the second set of storage elements during a program and erase cycle when the count has a value is a multiple of a particular count value.

13. The method of claim 12, further comprising:

writing third data to the first set of storage elements, the third data processed by the data shaping operation; and

writing fourth data to the second set of storage elements, the fourth data processed by the data shaping operation, wherein the third data and the fourth data are written during a program and erase cycle when the count has a value that is not a multiple of the particular count value.

14. The method of claim 10, further comprising:

writing data that is not processed by the data shaping operation to storage elements accessible via a particular group of word lines prior to a first polling cycle; and

writing data that is not processed by the data shaping operation to storage elements accessible via a second group of word lines prior to a second polling cycle.

15. The method of claim 10, further comprising:

writing third data to the first set of storage elements, the third data processed by the data shaping operation;

writing fourth data to the second set of storage elements, wherein the fourth data is processed by a data preprocessing operation prior to being processed by the data shaping operation;

reading a representation of the fourth data from the second set of storage elements; and

determining a second block health metric of the portion of the non-volatile memory during a second polling cycle based on the representation of the fourth data.

16. A data storage device comprising:

a controller; and

a non-volatile memory coupled to the controller and including storage elements configured to store data, wherein the storage elements are organized into multiple portions, and wherein at least one of the multiple portions stores de-shaped data and shaped data.

17. The data storage device of claim 16, wherein the de-shaped data is interspersed with the shaped data within the at least one of the multiple portions according to a periodic pattern.

18. The data storage device of claim 17, wherein the non-volatile memory is further configured to store a table identifying a set of word lines, and wherein the periodic pattern is based on the set of word lines.

19. The data storage device of claim 16, wherein the multiple portions include multiple blocks, wherein the at least one portion includes a first block of the non-volatile memory, and wherein the at least one portion further includes erased storage elements.

20. The data storage device of claim 16, wherein the controller is configured to read a representation of the de-shaped data from the at least one portion, and wherein the controller is further configured to determine a block health metric of the at least one portion based on the representation of the de-shaped data.