Enhanced data write for multi-level cell (MLC) memory using moving baseline data encoding

摘要

A method and apparatus are provided for implementing enhanced performance for multi-level cell (MLC) memory using threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding. A voltage baseline of a prior write is identified, and a data write uses the threshold-voltage-drift or resistance-drift tolerant moving baseline memory data encoding for data being written to the MLC memory responsive to the identified voltage baseline. The identification of the baseline may include reading MLC memory cells before performing the data write or may include a predefined parameter information on the MLC memory cells. Performing the data write may also include using a run-length limited (RLL code). The method may also involve periodically writing reference cells at specific voltage levels. Also the invention includes apparatus 100 for implementing data write for a multi-level cell (MLC) including a controller 106, a moving baseline memory data encoding controller 112, and memory MLC devices 114 which may be Phase Change Memory (PCM) devices or Multi-level (MLC) NAND Flash memory devices 114.