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公开(公告)号：US09633740B1
公开(公告)日：2017-04-25
申请号：US15041501
申请日：2016-02-11
Applicant: Seagate Technology LLC
Inventor： AbdelHakim S. Alhussien , Sundararajan Sankaranarayanan , Thuy Van Nguyen , Ludovic Danjean , Erich F. Haratsch
CPC classification number: G11C16/26 , G11C7/1006 , G11C11/5642 , G11C16/16 , G11C16/28 , G11C16/3418 , G11C16/3431 , H03M13/1111 , H03M13/1125 , H03M13/3746 , H03M13/6325
Abstract: Read retry operations in a memory employ likelihood value assignments that change sign at different read voltages for a plurality of read retry operations. A method for multiple read retries of a memory comprises reading a codeword using a first read voltage to obtain a first read value; mapping the first read value to first likelihood values based on a first likelihood value assignment that changes sign substantially at the first read voltage; reading the codeword using a second read voltage to obtain a second read value, wherein the second read voltage is shifted from the first read voltage to compensate for an expected change in analog voltages; and mapping the second read value to second likelihood values based on a second likelihood value assignment, wherein the second likelihood value assignment changes sign substantially at the second read voltage. Read data is optionally generated using iterative decoding of the codeword based on the first likelihood values and/or the second likelihood values.
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公开(公告)号：US10276247B2
公开(公告)日：2019-04-30
申请号：US15205654
申请日：2016-07-08
Applicant: Seagate Technology LLC
Inventor： AbdelHakim S. Alhussien , Sundararajan Sankaranarayanan , Thuy Van Nguyen , Ludovic Danjean , Erich F. Haratsch
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.
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公开(公告)号：US20170125114A1
公开(公告)日：2017-05-04
申请号：US15205654
申请日：2016-07-08
Applicant: Seagate Technology LLC
Inventor： AbdelHakim S. Alhussien , Sundararajan Sankaranarayanan , Thuy Van Nguyen , Ludovic Danjean , Erich F. Haratsch
CPC classification number: G11C16/28 , G06F11/1012 , G11C11/5642 , H03M13/1108 , H03M13/1111 , H03M13/3707 , H03M13/3723 , H03M13/612 , H03M13/6325
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.
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4.发明授权Read retry operations with read reference voltages ranked for different page populations of a memory 有权读取重试操作，读取的参考电压按不同页面的内存数量排列公开(公告)号：US09563502B1
公开(公告)日：2017-02-07
申请号：US15205616
申请日：2016-07-08
Applicant: Seagate Technology LLC
Inventor： AbdelHakim S. Alhussien , Sundararajan Sankaranarayanan , Thuy Van Nguyen , Ludovic Danjean , Erich F. Haratsch
IPC: G06F11/10 , G11C16/28 , G11C29/42 , G11C29/52 , H03M13/11 , G11C16/16 , G11C11/56 , G11C16/26 , G11C16/04 , G11C16/34 , G06F12/02 , H03M13/05 , G06F11/00
CPC classification number: G06F11/1048 , G06F11/00 , G06F11/10 , G06F11/1012 , G06F11/1072 , G06F12/02 , G11C11/56 , G11C11/5642 , G11C16/04 , G11C16/16 , G11C16/26 , G11C16/28 , G11C16/3431 , G11C29/021 , G11C29/028 , G11C29/42 , G11C29/52 , H03M13/05 , H03M13/1102
Abstract: Methods and apparatus are provided for read retry operations with read reference voltages ranked for different page populations of a memory. One method comprises obtaining a plurality of rankings of a plurality of read reference voltages for a plurality of page populations, wherein the rankings are based on a predefined performance metric; and reading a codeword from the memory a plurality of times, wherein each of the read operations uses a different one of the plurality of read reference voltages selected based on the rankings of the plurality of read reference voltages. The performance metric comprises, for example, a bit error rate, a bit polarity disparity, a substantially minimal syndrome weight and/or measures of an average system latency or a tail latency. The ranking is optionally based on a size of the page populations that had each of the ranked read reference voltages. Channel estimation is performed separately for each of the plurality of page populations.
Abstract translation: 提供了用于读取重试操作的方法和装置，其具有针对存储器的不同页面种群排列的读取参考电压。 一种方法包括为多个页面群体获得多个读取参考电压的多个排名，其中所述排名基于预定义的性能度量; 以及多次从存储器读取码字，其中每个读取操作使用基于多个读取参考电压的等级选择的多个读取参考电压中的不同的一个。 性能度量包括例如误码率，位极性差异，基本上最小的综合征权重和/或平均系统等待时间或尾部延迟的度量。 排名可选地基于具有每个排名的读取参考电压的页面群体的大小。 针对多个页面群体中的每一个分别进行信道估计。
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