24-03-2016 дата публикации
Номер: US20160086671A1
Принадлежит:
In NAND Flash memory, bit line precharge/discharge times can be a main component in determining program, erase and read performance. In a conventional arrangement bit line levels are set by the sense amps and bit lines are discharged to a source line level is through the sense amplifier path. Under this arrangement, precharge/discharge times are dominated by the far-side (relative to the sense amps) based on the bit lines' RC constant. Reduction of bit line precharge/discharge times, therefore, improves NAND Flash performance and subsequently the overall system performance. To addresses this, an additional path is introduced between bit lines to the common source level through the use of dummy NAND strings. In an exemplary 3D-NAND (BiCS) based embodiment, the dummy NAND strings are taken from dummy blocks, where the dummy blocks can be placed throughout the array to evenly distribute the discharging current. 1. A method of operating a non-volatile memory circuit , the non-volatile memory circuit having a plurality of bit lines by each of which a corresponding plurality of individually selectable NAND strings are connectable to an associated sense amp circuit , the NAND stings each comprising a plurality of memory cells connected in series between the corresponding bit line and a source line , the method comprising: pre-charging each of a set of one or more bits lines by the associated sense amp circuits; and', 'concurrently pre-charging each of the set of bit lines by one or more of the corresponding NAND strings connected thereto from the source line., 'performing a sensing operation including a pre-charge phase, wherein the pre-charge phase comprises2. The method of claim 1 , wherein the NAND strings used to pre-charge the set of bit lines are non-selected for the sensing operation.3. The method claim 2 , wherein the NAND strings used to pre-charge the set of bit lines are not assigned by the memory circuit for the storage of data.4. The method of claim 3 , ...
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