Patent application number | Description | Published |
20140160590 | DETECTING TRACK INFORMATION FROM OVERLAPPING SIGNALS READ FROM A DATA STORAGE MEDIUM - Detecting track information involves receiving first and second overlapping track signals from first and second read elements that read first and second tracks from a data storage medium. Information of the first and second tracks is estimated using the respective first and second track signals. An improved information estimate of the first track is obtained using the first track signal and the estimated information of the second track, and an improved information estimate of the second track is obtained using the second track signal and the estimated information of the first track. First and second track data are decoded using the respective improved information estimates of the first and second tracks. | 06-12-2014 |
20150092489 | FLASH MEMORY REFERENCE VOLTAGE DETECTION WITH TRACKING OF CROSS-POINTS OF CELL VOLTAGE DISTRIBUTIONS USING HISTOGRAMS - Cross-points of flash memory cell voltage distributions are determined by reading data from a portion of the flash memory two or more times using two or more different candidate reference voltages and determining corresponding decision patterns. The frequency of occurrence of the decision patterns in the data read from the flash memory is used to conceptually construct a histogram. The histogram is used to estimate the cross-points. Employing decision patterns enables multiple cross-point voltages to be determined with a minimum of read operations. | 04-02-2015 |
20150127883 | REDUCTION OR ELIMINATION OF A LATENCY PENALTY ASSOCIATED WITH ADJUSTING READ THRESHOLDS FOR NON-VOLATILE MEMORY - Channel information and channel conditions that are determined by an Offline Tracking process are used to determine whether or not an adjustment to the read reference voltage can be avoided altogether without detrimentally affecting performance, or, alternatively, to determine a precision with which a read reference voltage adjustment should be made. If it is determined based on the channel conditions that a read reference voltage adjustment can be avoided altogether, read performance is improved by reducing the probability that a read reference voltage adjustment needs to be made during normal read operations. If it is determined based on the channel conditions that a read reference voltage adjustment needs to be made with a particular precision, the read reference voltage is adjusted with that precision. This latter approach is advantageous in that a determination that the precision with which the adjustments can be made is relatively low leads to fewer adjustments having to be made during normal read operations. | 05-07-2015 |
20150162057 | MULTIPLE RETRY READS IN A READ CHANNEL OF A MEMORY - An apparatus having a circuit and a decoder is disclosed. The circuit is configured to (i) adjust an initial one of a plurality of reference voltages in a read channel of a memory by shifting the initial reference voltage an amount toward a center of a window and (ii) read a codeword from the memory a number of times. The window bounds a sweep of the reference voltages. Each retry of the reads uses a respective reference voltage from a pattern of the reference voltages. The pattern is symmetrically spaced about the initial reference voltage. The pattern fits in the window. The decoder is configured to generate read data by performing an iterative decoding procedure on the codeword based on the reads. | 06-11-2015 |
20150199149 | FRAMEWORK FOR BALANCING ROBUSTNESS AND LATENCY DURING COLLECTION OF STATISTICS FROM SOFT READS - An apparatus includes a plurality of memory devices and a controller. The controller is coupled to the plurality of memory devices and configured to store data in the plurality of memory devices using units of super-blocks. Each super-block comprises a block from each of the plurality of memory devices and the controller balances time efficiency and robustness during collection of statistics from soft reads of each super-block. | 07-16-2015 |
20150243363 | ADJUSTING LOG LIKELIHOOD RATIO VALUES TO COMPENSATE MISPLACEMENT OF READ VOLTAGES - An apparatus having a circuit and an interface to a nonvolatile memory is disclosed. The circuit is configured to (i) perform one or more attempts of a soft-decision decode of data stored in the nonvolatile memory, where soft-decision decode uses a plurality of log likelihood ratio values stored in a table, (ii) generate one or more adjusted log likelihood ratio values by adding a constant value to one or more of the log likelihood ratio values in response to a failure to decode the data using the log likelihood ratio values and (iii) re-decode the data using the adjusted log likelihood ratio values. | 08-27-2015 |
20150355838 | ESTIMATING READ REFERENCE VOLTAGE BASED ON DISPARITY AND DERIVATIVE METRICS - An adaptive channel tracking algorithm performed by a flash memory system obtains disparity metrics and derivative metrics and uses a combination of the disparity and derivative metrics to estimate an optimal read reference voltage. The estimation of the optimal read reference voltage does not rely on assumptions about the underlying cell voltage distributions and results in a good estimate of the read reference voltage even if the standard deviations of the cell voltage distributions are different. In addition, the algorithm is relatively simple and less computationally intensive to perform than the known tracking algorithms. | 12-10-2015 |
20160118093 | MULTIPLE RETRY READS IN A READ CHANNEL OF A MEMORY - An apparatus having a circuit and a decoder is disclosed. The circuit is configured to adjust an initial one of a plurality of reference voltages in a read channel of a memory by shifting the initial reference voltage an amount toward a center of a window and read a codeword from the memory a number of times. The window bounds a sweep of the reference voltages. Each retry of the reads uses a respective reference voltage from a pattern of the reference voltages. The pattern is symmetrically spaced about the initial reference voltage. The pattern fits in the window. The decoder is configured to generate read data by performing an iterative decoding procedure on the codeword based on the reads. | 04-28-2016 |