Storage system and method for balanced quad-level cell (QLC) coding with margin for an internal data load (IDL) read
AssigneeWestern Digital Technologies, Inc.
InventorEran Sharon
Life of this patent
Estimating the term…
Abstract
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.
Claims19
A storage system comprising:
- a memory;
- and
- a controller configured to:
- apply a quad-level cell (QLC) 3-4-4-4 grey code to lower and middle pages of data, which induce a multi-level cell grey coding with a margin of at least a two state difference;
- program the lower and middle pages of data in the memory using a multi-level cell programming operation;
- read the programming of the lower and middle pages of data in the memory;
- and
- program upper and top pages of data in the memory to induce a quad-level cell (QLC) distribution using the read lower and middle pages.
In a storage system comprising a memory and a controller, a method comprising:
- programming lower and middle pages of data in the memory using a multi-level cell programming operation;
- generating an exclusive-or of the lower and middle pages of data in the memory;
- storing the exclusive-or of the lower and middle pages of data in the storage system;
- reading the programming of the lower and middle pages of data in the memory;
- decoding the lower and middle pages of data using the exclusive-or of the lower and middle pages of data;
- and
- programming upper and top pages of data in the memory.
A storage system comprising:
- a memory;
- means for applying a quad-level cell (QLC) 3-4-4-4 grey code to lower and middle pages of data, which induce a multi-level cell grey coding with a margin of at least a two state difference;
- means for programming the lower and middle pages of data in the memory using a multi-level cell programming operation;
- means for reading the programming of the lower and middle pages of data in the memory;
- and
- means for programming upper and top pages of data in the memory to induce a quad-level cell (QLC) distribution.
Dependencies are inferred from the claim text.