System to control a width of a programming threshold voltage distribution width when writing hot-read data

• US 9,218,885 B2
• Filed: 02/26/2014
• Issued: 12/22/2015
• Est. Priority Date: 02/17/2014
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Cai, Yu, Wu, Yunxiang, Haratsch, Erich F.
• Primary Examiner(s): Lappas, Jason
• Application Number:
  US14/191,263
• Publication Number:
  US 20150235705A1
• Time in Patent Office: 664 Days
• Field of Search: 365/185.2, 365/189.14, 365/185.15, 365/185.16
• US Class Current: 1/1
• CPC Class Codes: G11C 11/5628 Programming or writing circuits; Data input circuits
• CPC Class Codes: G11C 11/5642 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 16/10 Programming or data input circuits
• CPC Class Codes: G11C 16/28 using differential sensing or reference cells, e.g. dummy cells
• CPC Class Codes: G11C 2211/5634 Reference cells

Abstract

An apparatus comprising a memory and a controller. The memory is configured to process a plurality of read/write operations. The memory comprises a plurality of memory modules. Each memory module has a size less than a total size of the memory. The controller is configured to write user data using a plurality of threshold voltages. The data considered hot-read data is written using a first voltage threshold. The data not considered hot-read data is written using a second voltage threshold. The first voltage threshold reduces an impact on endurance of the memory.

Claims

1. An apparatus comprising:

a memory configured to store data, the memory comprising a plurality of memory modules each having a size less than a total size of the memory; and

a controller configured to (A) process a plurality of read/write operations and (B) write the data using a plurality of threshold voltages, wherein (i) data considered hot-read data is written using a first voltage threshold, (ii) data not considered hot-read data is written using a second voltage threshold, and (iii) the first voltage threshold reduces an impact on endurance of the memory.

2. The apparatus according to claim 1, wherein the first voltage threshold results in faster reads, fewer read retries, less recycling of hot-read data, and saves power when reading from the memory.

3. The apparatus according to claim 1, wherein the threshold voltages are implemented using incremental step pulse programming.

4. The apparatus according to claim 1, wherein a voltage pulse width distribution of the first voltage threshold is narrower than a voltage pulse width distribution of the second voltage threshold.

5. The apparatus according to claim 1, wherein the first voltage threshold is generated using slow programming.

6. The apparatus according to claim 5, wherein the slow programming of the memory occurs during an idle time.

7. The apparatus according to claim 5, wherein the slow programming of the memory occurs during a garbage collection state.

8. The apparatus according to claim 5, wherein the slow programming of the memory occurs during a data recycling state.

9. The apparatus according to claim 5, wherein the slow programming does not affect the performance of the apparatus.

10. The apparatus according to claim 5, wherein the data is read from an original location if the hot-read data is read during the slow programming.

11. The apparatus according to claim 1, wherein the controller calculates the hot-read data by keeping track of a number of read operations on the memory during data reading operations and determines if the number of read operations is above a threshold value.

12. The apparatus according to claim 11, wherein the data is classified as hot-read data if the number of read operations is above the threshold value and is classified as non hot-read data if the number of read operations is not above the threshold value.

13. The apparatus according to claim 11, wherein the controller selects the hottest subset of hot-read data for recycling with distribution width control when hot-read data is above a predetermined amount.

14. A method for controlling a solid state drive, comprising the steps of:

configuring a memory to store data, the memory comprising a plurality of memory modules each having a size less than a total size of the memory;

processing a plurality of read/write operations; and

writing the data using a plurality of threshold voltages, wherein (i) data considered hot-read data is written using a first voltage threshold, (ii) data not considered hot-read data is written using a second voltage threshold, and (iii) the first voltage threshold reduces an impact on endurance of the memory.

15. An apparatus comprising:

a memory configured to store data, the memory comprising a plurality of memory modules each having a size less than a total size of the memory; and

means for (A) processing a plurality of read/write operations and (B) writing the data using a plurality of threshold voltages, wherein (i) data considered hot-read data is written using a first voltage threshold, (ii) data not considered hot-read data is written using a second voltage threshold, and (iii) the first voltage threshold reduces an impact on endurance of the memory.