Patent ID: 8665650
Filing Date: 2014-03-04
Classification: G06F,G11C

Abstract:
1. A method for reading a target memory sector of a memory, the method comprising: based on read data corresponding to a plurality of memory sectors of the memory, estimating (i) first one or more reference voltages, and (ii) a first set of log-likelihood ratios (LLRs) corresponding to the first one or more reference voltages, wherein an LLR is an indication of a confidence for each data bit read from a memory cell for a given range of reference voltages; using the first one or more reference voltages, performing a first read operation on the target memory sector; determining an error correcting code (ECC) decoding failure of the first read operation while ECC decoding results of the first read operation using the first set of LLRs; in response to determining the ECC decoding failure of the first read operation and based on read data corresponding to the target memory sector, (i) updating the estimate of the first one or more reference voltages to generate second one or more reference voltages, and (ii) updating the estimate of the first set of LLRs to generate a second set of LLRs; and using the second one or more reference voltages, performing a second read operation on the target memory sector, wherein performing the second read operation further comprises ECC decoding the results of the second read operation using the second set of LLRs.