A non-volatile memory device includes a memory cell array including a plurality of memory cells; a page buffer for performing a plurality of read operations and storing results of the read operations, wherein each of the read operations includes at least one sensing operation for selected memory cells from the plurality of memory cells; a multi-sensing manager for determining a number of sensing operations for each of the plurality of read operations and controlling the page buffer to perform the read operations; and a data identifier for identifying a data state of a bit for the selected memory cells based on the results of the read operations, wherein the multi-sensing manager determines the number of sensing operations for at least one read operation from among the read operations to be different from the number of sensing operations for other read operations from among the read operations.

According to one embodiment, a memory system includes a semiconductor memory and a controller. The semiconductor memory includes first blocks including a memory cell capable of storing data of one bit, a second block including a memory cell capable of storing data of two or more bits. The semiconductor memory stores first data in a first latch circuit, and second data in a second latch circuit, and writes the first data into one of the first blocks in page units, and the second data into one of the first blocks in page units. The semiconductor memory writes data of at least two pages into the second block, using the first data stored in the first latch circuit and the second data stored in the second latch circuit.

According to an embodiment, a control circuitry performing: a first operation of reading data out of a memory cell with a first voltage applied to a word line while changing the first voltage by a first shift amount within a first range, and a second operation of reading data out of the memory cell with a second voltage applied to the word line while changing the second voltage by a second shift amount within a second range, wherein the second shift amount is smaller than the first shift amount, and wherein the control circuitry performs the second operation to apply the second voltage to the word line subsequently to application of the first voltage to the word line in the first operation.

A semiconductor memory device includes a memory cell array, a peripheral circuit, and a control logic. The memory cell array includes a plurality of memory blocks. The peripheral circuit performs a read operation on a selected memory block among the plurality of memory blocks. The control logic controls the read operation of the peripheral circuit. The selected memory block is coupled to a plurality of bit lines, and the plurality of bit lines are grouped into a plurality of bit line groups. The peripheral circuit performs data sensing by applying different reference currents to the plurality of bit line groups, respectively.

A data storage system performs operations including receiving a data read command corresponding to a first memory cell; determining whether the first memory cell is in a first read condition; if the first memory cell is in the first read condition: applying a first voltage level to the first memory cell, the first voltage level being a predetermined voltage level corresponding to a read operation for memory cells in the first read condition; and sensing a first level of current, or lack thereof, through the first memory cell during application of the first voltage level to the first memory cell; and if the first memory cell is not in the first read condition: applying a second voltage level to the first memory cell, the second voltage level being a voltage level corresponding to a read operation for memory cells in a read condition other than the first read condition.

Presented herein is a memory device and a method of operating the memory device. The memory device may include a memory cell, and a page buffer coupled to the memory cell via a bit line and configured to perform a read operation on the memory cell. The page buffer may include a storage unit configured to control a bit line precharge operation during the read operation and to store a result value of a first sensing operation. After the bit line precharge operation, a value stored in the storage unit is inverted before the storage unit stores the result value of the first sensing operation.

Presented herein is a memory device and a method of operating the memory device. The memory device may include a memory cell, and a page buffer coupled to the memory cell via a bit line and configured to perform a read operation on the memory cell. The page buffer may include a storage unit configured to control a bit line precharge operation during the read operation and to store a result value of a first sensing operation. After the bit line precharge operation, a value stored in the storage unit is inverted before the storage unit stores the result value of the first sensing operation.

An apparatus includes a plurality of NAND strings in a block with word lines connected to cells of the NAND strings and select lines connected to select gate transistors of the NAND strings. A control circuit is configured to, after a read operation of memory cells of the block apply substantially zero volts to the global word lines to discharge the word lines to substantially zero volts. The control circuit is further configured to turn off the select gate transistors to isolate channels, turn off the block select transistors to isolate the word lines from the global word lines, and with the block select transistors turned off, apply a low positive voltage on the global word lines.

An apparatus includes a plurality of NAND strings in a block with word lines connected to cells of the NAND strings and select lines connected to select gate transistors of the NAND strings. A control circuit is configured to, after a read operation of memory cells of the block apply substantially zero volts to the global word lines to discharge the word lines to substantially zero volts. The control circuit is further configured to turn off the select gate transistors to isolate channels, turn off the block select transistors to isolate the word lines from the global word lines, and with the block select transistors turned off, apply a low positive voltage on the global word lines.

Presented herein is a memory device and a method of operating the memory device. The memory device may include a memory cell, and a page buffer coupled to the memory cell via a bit line and configured to perform a read operation on the memory cell. The page buffer may include a storage unit configured to control a bit line precharge operation during the read operation and to store a result value of a first sensing operation. After the bit line precharge operation, a value stored in the storage unit is inverted before the storage unit stores the result value of the first sensing operation.