A memory sub-system configured to read soft bit data by adjusting the read voltage applied to read hard bit data from memory cells. For example, in response to a read command identifying a group of memory cells, a memory device is to: read the group of memory cells using a first voltage to generate hard bit data indicating statuses of the memory cells subjected to the first voltage; change (e.g., through boosted modulation) the first voltage, currently being applied to the group of memory cells, to a second voltage and then to a third voltage; reading the group of memory cells at the second voltage and at the third voltage to generate soft bit data (e.g., via an exclusive or (XOR) of the results of reading the group of memory cells at the second voltage and at the third voltage).

A nonvolatile memory (NVM) device includes a plurality of memory blocks and a control logic receiving a specific command and an address. The control logic may perform a cell count-based dynamic read (CDR) operation on memory cells connected to one of wordlines of a selected block, among the plurality of memory blocks, in response to the address. The control logic includes a cell count comparator circuit configured to compare: (1) a first cell count value for a highest state among a plurality of states with at least one reference value according to the CDR operation and (2) a second cell count value for an erase state among the plurality of states with the at least one reference value. Additionally, the control logic includes a read level selector configured to select a read level according to a result of the comparison of the cell count comparator circuit.

Methods, systems, and media for decoding data are described. A sequence of read-level voltages for decoding operations may be determined based on a trend of decoding success indicators, including a first decoding success indicator and a second decoding success indicator. The first decoding success indicator is obtained from a more recent successful decoding operation. The first one of the sequence may be set to a read-level voltage of the first decoding success indicator. If the read-level voltage of the first decoding success indicator is less than a read-level voltage of the second decoding success indicator, then the trend is decreasing, and the second one of the sequence may be set to a read-level voltage less than that of the first one of the sequence. After executing one or more decoding operations, the decoding success indicators may be updated based on the read-level voltage of the current successful decoding operation.

For a non-volatile memory that uses hard bit and soft bit data in error correction operations, to reduce the amount of soft bit data that needs to be transferred from a memory to the controller and improve memory system performance, the soft bit data can be compressed before transfer. After the soft bit data is read and stored into the internal data latches associated with the sense amplifiers, it is compressed within these internal data latches. The compressed soft bit data can then be transferred to the transfer data latches of a cache buffer, where the compressed soft bit data can be consolidated and transferred out over an input-output interface. Within the input-output interface, the compressed data can be reshuffled to put into logical user data order if needed.

For a non-volatile memory that uses hard bit and soft bit data in error correction operations, to reduce the amount of soft bit data that needs to be transferred from a memory to the controller and improve memory system performance, the soft bit data can be compressed before transfer. After the soft bit data is read and stored into the internal data latches associated with the sense amplifiers, it is compressed within these internal data latches. The compressed soft bit data can then be transferred to the transfer data latches of a cache buffer, where the compressed soft bit data can be consolidated and transferred out over an input-output interface. Within the input-output interface, the compressed data can be reshuffled to put into logical user data order if needed.

For a non-volatile memory that uses hard bit and a soft bit data in error correction operations, architectures are introduced for the compression of the soft bit data to reduce the amount of data transferred over the memory's input-output interface. For a memory device with multiple planes of memory cells, the internal global data bus is segmented and a data compression circuit associated with each segment. This allows soft bit data from a cache buffer of a plane using one segment to transfer data between the cache buffer and the associated compression circuit concurrently with transferring data from a cache buffer of another plane using another segment, either for compression or transfer to the input-output interface.

A memory sub-system configured to read soft bit data by adjusting the read voltage applied to read hard bit data from memory cells. For example, in response to a read command identifying a group of memory cells, a memory device is to: read the group of memory cells using a first voltage to generate hard bit data indicating statuses of the memory cells subjected to the first voltage; change (e.g., through boosted modulation) the first voltage, currently being applied to the group of memory cells, to a second voltage and then to a third voltage; reading the group of memory cells at the second voltage and at the third voltage to generate soft bit data (e.g., via an exclusive or (XOR) of the results of reading the group of memory cells at the second voltage and at the third voltage).

A scheme for non-parametric optimal read threshold estimation of a memory system. The memory system includes a memory device including pages and a controller including a neural network. The controller performs read operations on a selected page using a read threshold set; obtain the read threshold set, a checksum value and an asymmetric ratio of ones count and zeros count which are associated with decoding of the selected page according to each of the read operations; provide the obtained read threshold set, the checksum value and the asymmetric ratio as input information to the neural network; and estimate, by the neural network, an optimal read threshold voltage based on the input information and weights including a combination of multiple matrices and bias vectors.

In a method of reading data in a nonvolatile memory device including a plurality of memory cells having a plurality of states including a first state and a second state, a first read operation for the first state is performed, and a second read operation for the second state is performed. To perform the first read operation, cell counts for a valley of the first state are obtained by performing a valley cell count operation for the first state, a first read voltage level for the first state is determined based on the cell counts and at least one first reference parameter for the first state, and a first sensing operation for the first state is performed by using the first read voltage level. To perform the second read operation, a second read voltage level for the second state is determined based on the cell counts and at least one second reference parameter for the second state, and a second sensing operation for the second state is performed by using the second read voltage level.

A memory device to estimate a bit error count of data retrievable from a group of memory cells. For example, the memory device has a group of memory cells programmed to store a predetermined number of bits per memory cells to be read at a plurality of first voltages. The memory device determines a plurality of calibrated read voltages corresponding to the plurality of first voltages respectively, based on first signal and noise characteristics of the group of memory cells. The first signal and noise characteristics are used to compute second signal and noise characteristics of the group of memory cells for the calibrated read voltages. The second signal and noise characteristics are used in an empirical formula to compute an estimate of the bit error count of data retrievable from the group of memory cells using the calibrated read voltages.