Storage System and Method for Balanced Quad-Level Cell (QLC) Coding with Margin for an Internal Data Load (IDL) Read

摘要

A storage system and method for balanced quad-level cell (QLC) coding with margin for an internal data load (IDL) read are provided. In one example, an MLC-Fine programming approach uses a balanced 3-4-4-4 coding, where the data is encoded by assigning a unique binary sequence per state. The IDL read is supported by using a unique 3-4-4-4 coding that provides at least a three-state gap between the MLC states, while using the same ECC redundancy per page. This allows for a reduced write buffer by supporting the IDL read and provides a balanced bit error rate (BER) due to the balanced mapping.