Invention Grant
- Patent Title: Read retry operations with estimation of written data based on syndrome weights
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Application No.: US15205654Application Date: 2016-07-08
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Publication No.: US10276247B2Publication Date: 2019-04-30
- Inventor: AbdelHakim S. Alhussien , Sundararajan Sankaranarayanan , Thuy Van Nguyen , Ludovic Danjean , Erich F. Haratsch
- Applicant: Seagate Technology LLC
- Applicant Address: US CA Cupertino
- Assignee: Seagate Technology LLC
- Current Assignee: Seagate Technology LLC
- Current Assignee Address: US CA Cupertino
- Agency: Ryan, Mason & Lewis, LLP
- Main IPC: G11C16/28
- IPC: G11C16/28 ; G11C29/52 ; G06F11/10 ; G11C11/56 ; H03M13/11 ; H03M13/37 ; H03M13/00

Abstract:
Methods and apparatus are provided for read retry operations that estimate written data based on syndrome weights. One method comprises reading a codeword from a memory multiple times using multiple read reference voltages; obtaining a syndrome weight for each of the readings of the codeword; identifying a given reading of the codeword having a substantially minimum syndrome weight; and estimating a written value of the codeword based on the given reading. Two cell voltage probability distributions of cell voltages are optionally calculated for each possible cell state of the memory, based on the estimated written value and plurality of readings of the codeword. The cell voltage probability distributions are used to (i) dynamically select log likelihood ratio values for a failing page, (ii) determine a read reference voltage that gives a desired log likelihood ratio value, or (iii) dynamically select log likelihood ratio values for the page populations associated with the distributions.
Public/Granted literature
- US20170125114A1 READ RETRY OPERATIONS WITH ESTIMATION OF WRITTEN DATA BASED ON SYNDROME WEIGHTS Public/Granted day:2017-05-04
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