DYNAMIC READ BASED ON READ STATISTICS

• US 20200133570A1
• Filed: 05/15/2019
• Published: 04/30/2020
• Est. Priority Date: 10/30/2018
• Status: Active Grant

• Current Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: Shadmi, Eyall, Fainzilber, Omer
• Granted Patent: US 10,866,763 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 13/1668 Details of memory controller
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

Apparatuses, systems, and methods are disclosed for dynamic read operations. A controller monitors one or more read statistics during a read operation for data of a non-volatile memory die. The controller determines whether one or more read statistics satisfy a threshold for a read operation. The controller dynamically modifies a read operation based on determining that one or more read statistics fail to satisfy a threshold.

Claims

1. A method comprising:

at a controller for a non-volatile memory element, the controller being coupled to the non-volatile memory via a memory bus;

initiating a read operation for data of the non-volatile memory element, the data stored subject to a data transformation that balances ones and zeros for the data.

determining whether an ongoing balance between ones and zeroes for the data during the read operation meets exception criteria;

in response to a determination that the ongoing balance between ones and zeroes for the data during the read operation does not meet exception criteria;

decoding data of the non-volatile memory element;

in response to a determination that the ongoing balance between ones and zeroes for the data during the read operation meets exception criteria;

performing at least one of;

dynamically adjusting the read operation based on the tracked ongoing balance, and

aborting decoding on the non-volatile memory element without performing error code correction and without transferring the data from the non-volatile memory to a host controller.

2. The method of claim 1, wherein the exception criteria include a criterion that is met when the tracked ongoing balance does not exceed a first threshold.

3. The method of claim 2, wherein the exception criteria are not met when the tracked ongoing balance exceeds the first threshold but is less than a second threshold;

and further comprising;

in response to a determination that that the ongoing balance between ones and zeroes for the data during the read operation exceeds the first threshold but is less than a second threshold;

dynamically adjusting the read operation based on the tracked ongoing balance.

4. The method of claim 3, wherein the exception criteria is not met when the tracked ongoing balance exceeds the first threshold but is less than the second threshold;

and further comprising;

in response to a determination that that the ongoing balance between ones and zeroes for the data during the read operation exceeds the first threshold and the second threshold;

aborting decoding on the non-volatile memory element without performing error code correction and without transferring the data from the non-volatile memory to a host controller

5. The method of claim 1, wherein dynamically adjusting the read operation comprises changing one or more read parameters during the read operation, prior to transferring the data to a host controller.

6. The method of claim 5, wherein changing one or more read parameters comprises one or more of:

changing one or more read thresholds; and

obtaining soft bits indicating a reliability of the data.

7. The method of claim 1, further comprising:

at the controller;

before determining an ongoing balance between ones and zeroes for the data during the read operation, de-interleaving the data into respective data portions having a known physical order

for each of the respective data portions, performing the determining step of claim 1,

wherein in response to a determination that ongoing balance between ones and zeroes for the respective data portion meets exception criteria;

identifying that the respective data portion has a possible physical defect and transmitting possible physical defect information for the respective data portion to the device controller.

8. The method of claim 1, wherein determining whether an ongoing balance between ones and zeroes for the data during the read operation meets exception criteria includes comparing the ongoing balance to one or more data statistics to verify and validate the shaped data.

9. The method of claim 1, further comprising:

at the controller;

reading a block data header associated with the data indicated in the read operation to determine an expected balance between ones and zeroes for the data during the read operation;

wherein determining whether an ongoing balance between ones and zeroes for the data during the read operation meets exception criteria includes comparing the ongoing balance to the expected balance, and

wherein the exception criteria includes a criterion that is met when the tracked ongoing balance is greater than the expected balance, and

wherein in response to a determination that the tracked ongoing balance is greater than the expected balance;

dynamically adjusting the read operation based on the tracked ongoing balance.

16. The system of claim 10, wherein the controller is further configured to perform the steps of:

before determining an ongoing balance between ones and zeroes for the data during the read operation, de-interleaving the data into respective data portions having a known physical order

for each of the respective data portions, performing the determining step of claim 1,

wherein in response to a determination that ongoing balance between ones and zeroes for the respective data portion meets exception criteria;

identifying that the respective data portion has a possible physical defect and transmitting possible physical defect information for the respective data portion to the device controller.

10. A system comprising:

a non-volatile memory element;

a memory bus; and

a controller for the non-volatile memory element, the controller being coupled to the non-volatile memory via the memory bus, the controller configured to perform the steps of;

initiating a read operation for data of the non-volatile memory element, the data stored subject to a data transformation that balances ones and zeros for the data.

determining whether an ongoing balance between ones and zeroes for the data during the read operation meets exception criteria;

in response to a determination that the ongoing balance between ones and zeroes for the data during the read operation does not meet exception criteria;

decoding data of the non-volatile memory element;

in response to a determination that the ongoing balance between ones and zeroes for the data during the read operation meets exception criteria;

performing at least one of;

dynamically adjusting the read operation based on the tracked ongoing balance, and

aborting decoding on the non-volatile memory element without performing error code correction and without transferring the data from the non-volatile memory to a host controller.

11. The system of claim 10, wherein the exception criteria include a criterion that is met when the tracked ongoing balance does not exceed a first threshold.

12. The system of claim 11, wherein the exception criteria are not met when the tracked ongoing balance exceeds the first threshold but is less than a second threshold;

and further comprising;

in response to a determination that that the ongoing balance between ones and zeroes for the data during the read operation exceeds the first threshold but is less than a second threshold;

dynamically adjusting the read operation based on the tracked ongoing balance.

13. The system of claim 12, wherein the exception criteria are not met when the tracked ongoing balance exceeds the first threshold but is less than the second threshold;

and further comprising;

in response to a determination that that the ongoing balance between ones and zeroes for the data during the read operation exceeds the first threshold and the second threshold;

aborting decoding on the non-volatile memory element without performing error code correction and without transferring the data from the non-volatile memory to a host controller

14. The system of claim 10, wherein dynamically adjusting the read operation comprises changing one or more read parameters during the read operation, prior to transferring the data to a host controller.

15. The system of claim 14, wherein changing one or more read parameters comprises one or more of:

changing one or more read thresholds; and

obtaining soft bits indicating a reliability of the data.

17. The system of claim 10, wherein determining whether an ongoing balance between ones and zeroes for the data during the read operation meets exception criteria includes comparing the ongoing balance to one or more data statistics to verify and validate the shaped data.

18. The system of claim 10, wherein the controller is further configured to perform the steps of:

reading a block data header associated with the data indicated in the read operation to determine an expected balance between ones and zeroes for the data during the read operation;

wherein determining whether an ongoing balance between ones and zeroes for the data during the read operation meets exception criteria includes comparing the ongoing balance to the expected balance, and

wherein the exception criteria include a criterion that is met when the tracked ongoing balance is greater than the expected balance, and

wherein in response to a determination that the tracked ongoing balance is greater than the expected balance;

dynamically adjusting the read operation based on the tracked ongoing balance.