REFRESH METHOD FOR MEMORY DEVICE

PROBLEM TO BE SOLVED: To provide a refresh method with little power consumption in the refreshing operation which can be applied to a semiconductor memory device using a piled refresh system. SOLUTION: In the refresh method for the memory device having N pieces of banks, the refresh operation is executed by the piled refresh system, in which the N pieces of the banks are sequentially refreshed, in a self refreshment mode when all the N pieces of the banks are refreshed. The refreshment operation is executed by a PASR system when an i (1≤i≤N-1) pieces of the banks is refreshed among the N pieces of the banks. The refresh operation is executed by the piled refresh system in an auto refresh mode. COPYRIGHT: (C)2006,JPO&NCIPI