Patent 11170869 was granted and assigned to Western Digital on November, 2021 by the United States Patent and Trademark Office.
The present disclosure generally relates to storage devices, such as solid state drives. A storage device comprises a controller comprising a controller error correction code (ECC) engine and a storage unit comprising a plurality of dies. Each of the dies comprise a die ECC engine. When user data is received, the controller ECC engine generates first ECC/error detection code (EDC) data. The user data and the first ECC/EDC data is sent to a die for storage as a code word. The die ECC engine generates second ECC/EDC data for the code word in granular portions. The second ECC/EDC data is used to correct bit errors in one or more code words up to a threshold value. When the number of bit errors exceeds the threshold value, the failed code words are sent to the controller ECC engine for correction.