Method of refreshing a memory device utilizing PASR and piled refresh schemes

摘要

In a memory device having an N number of banks, a refresh operation according to a piled refresh scheme is performed during a self-refresh mode to refresh the N number of banks in regular sequence when it is necessary to refresh all of the N number of banks. A refresh operation according to a Partial Array Self Refresh (PASR) scheme is performed during a self-refresh mode when it is necessary to refresh only an i number of banks (where 1i≦N−1) from among the N number of banks. During an auto-refresh mode, a refresh operation according to the piled refresh scheme is performed.