Method of Executing Wear Leveling in a Flash Memory Device According to Ambient Temperature Information and Related Flash Memory Device

• US 20140050026A1
• Filed: 08/16/2012
• Published: 02/20/2014
• Est. Priority Date: 08/16/2012
• Status: Active Grant

• Current Assignee: Transcend Information Incorporated
• Original Assignee: Transcend Information Incorporated
• Inventors: Li, Tseng-Ho
• Granted Patent: US 8,873,323 B2
• Time in Patent Office: Days
• US Class Current: 365/185.11
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/1032 Reliability improvement, data loss prevention, degraded operation etc
• CPC Class Codes: G06F 2212/7211 Wear leveling
• 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

Abstract

A method of executing wear leveling in a flash memory device includes determining whether a current temperature is in a normal operating temperature range of the flash memory device, and reprogramming data associated with data blocks to another location in a flash memory array when the current temperature is in the normal operating temperature range of the flash memory device, wherein the data is programmed in a temperature out of the normal operating temperature range of the flash memory device.

Claims

1. A method of executing wear leveling in a flash memory device according to temperature information recorded in the flash memory device, the method comprising:

determining whether a current temperature is in a normal operating temperature range of the flash memory device; and

reprogramming first data associated with first data blocks to another location in a flash memory array when the current temperature is in the normal operating temperature range of the flash memory device, wherein the first data is programmed in a temperature out of the normal operating temperature range of the flash memory device.

2. The method of claim 1, wherein the step of determining whether the current temperature is in the normal operating temperature range of the flash memory device comprises:

measuring the current temperature by a temperature sensor of the flash memory device; and

providing the measured current temperature to a controller of the flash memory device.

3. The method of claim 1, wherein ambient temperature information of the first data is recorded in the flash memory array of the flash memory device when the first data is programmed to the first data blocks.

4. The method of claim 3, wherein the ambient temperature information of the first data is recorded in a spare area of the flash memory array of the flash memory device.

5. The method of claim 3 further comprising:

updating the ambient temperature information of the first data with the current temperature after reprogramming the first data associated with the first data blocks to another location.

6. The method of claim 3 further comprising:

erasing the ambient temperature information of the first data after reprogramming the first data associated with the first data blocks to another location.

7. The method of claim 1 further comprising:

reprogramming second data associated with second data blocks to another location in the flash memory array according to erase counts of data blocks when the current temperature is greater than a maximum of the normal operating temperature range of the flash memory device, wherein the second data is programmed in a temperature which is greater than the maximum of the normal operating temperature range of the flash memory device.

8. The method of claim 7 further comprising:

reprogramming third data associated with third data blocks to another location in the flash memory array according to the erase counts of the data blocks when the current temperature is less than a minimum of the normal operating temperature range of the flash memory device, wherein the third data is programmed in a temperature which is less than the minimum of the normal operating temperature range of the flash memory device.

9. The method of claim 8, wherein the second data and the third data are parts of the first data.

10. A flash memory device, comprising:

a controller for controlling operation of the flash memory device;

a temperature sensor for providing ambient temperature information of the flash memory device to the controller; and

a flash memory array controlled by the controller to be programmed data and recorded temperature information of the data, which is a temperature when the data is programmed to a data block in the flash memory array;

wherein the data is reprogrammed by executing wear leveling in the flash memory device in a normal operating temperature range of the flash memory device if the data is programmed in the temperature which is out of the normal operating temperature range.

11. The flash memory device of claim 10, wherein the temperature information of the data is updated with a current temperature provided by the temperature sensor when the data is reprogrammed by executing wear leveling in the flash memory device.

12. The flash memory device of claim 11, wherein the normal operating temperature range of the flash memory device is greater than −

25°

C. and less than 70°

C.

13. The flash memory device of claim 11, wherein the flash memory array further comprises:

a plurality of data blocks for storing the data; and

a plurality of spare areas for recording the temperature information of the data.

14. A method of executing wear leveling in a flash memory device according to temperature information recorded in the flash memory device, the method comprising:

programming data to data blocks in a flash memory array in a first temperature which is out of a normal operating temperature range of the flash memory device;

recording the first temperature as first temperature information in the flash memory array;

determining whether a current temperature is in the normal operating temperature range of the flash memory device; and

reprogramming the data associated with the data blocks to another location in the flash memory array when the current temperature is in the normal operating temperature range of the flash memory device.

15. The method of claim 14, wherein the step of determining whether the current temperature is in the normal operating temperature range of the flash memory device comprises:

measuring the current temperature as second temperature information provided by a temperature sensor of the flash memory device; and

providing the second temperature information to a controller of the flash memory device.

16. The method of claim 15 further comprising:

updating the first temperature information with the second temperature information when the measured second temperature is in the normal operating temperature range of the flash memory device.

17. The method of claim 14, wherein the first temperature information is recorded in a spare area of the flash memory array.

18. The method of claim 14 further comprising:

erasing the first temperature information of the data.

19. The method of claim 14, wherein when the first temperature is larger than a maximum of the normal operating temperature range of the flash memory device, the method further comprises:

reprogramming the data associated with the data blocks to another location in the flash memory array according to erase counts of the data blocks when the measured current temperature is larger than the maximum of the normal operating temperature range of the flash memory device.

20. The method of claim 19, wherein when the first temperature is less than a minimum of the normal operating temperature range of the flash memory device, the method further comprises:

reprogramming the data associated with the data blocks to another location in the flash memory array according to erase counts of the data blocks when the measured current temperature is less than the minimum of the normal operating temperature range of the flash memory device.