FIELD

This disclosure relates to multi-level cell block-based non-volatile memory and in particular to improving write bandwidth of block-based multi-level cell non-volatile memory.

BACKGROUND

Non-volatile memory refers to memory whose state is determinate even if power is interrupted to the device. Storage devices that include non-volatile memory include a secure digital card, a multimedia card, a flash drive (for example, a Universal Serial Bus (USB) flash drive also known as a “USB thumb drive” or “USB memory stick” that includes non-volatile memory with an integrated USB interface), and a solid-state drive.

A solid-state drive includes non-volatile memory to store data. The non-volatile memory can comprise a block addressable memory device, such as NAND, or more specifically, multi-threshold level NAND flash memory (for example, Single-Level Cell (“SLC”), Multi-Level Cell (“MLC”), Quad-Level Cell (“QLC”), Tri-Level Cell (“TLC”), or some other NAND).

The NAND flash cell uses the threshold voltage of a floating-gate transistor to represent the data stored in the cell. In a SLC NAND flash memory, each memory cell has two voltage levels corresponding to two states (0, 1) to represent one bit. In a MLC, TLC and QLC NAND flash memory, each memory cell stores more than one bit. Each cell in a MLC NAND Flash memory uses four voltage levels corresponding to four states (00, 01, 10, 11) to represent 2 bits of binary data. Each cell in a TLC NAND Flash memory uses eight voltage levels corresponding to eight states (000 to 111) to represent 3 bits of binary data. Each cell in a QLC NAND Flash memory uses sixteen voltage levels corresponding to sixteen states (0000 to 1111) to represent 4 bits of binary data.

