US Patent 7580278 Variable resistance memory device

A variable resistance memory device includes a memory cell array having a plurality of memory cells, a write driver which supplies a step-down set current to the memory cells, where the step-down set current includes a plurality of successive steps of decreasing current magnitude, and a set program control circuit which controls a duration of the step-down set current supplied by the write driver. The set program control circuit controls the duration of the step-down set current in accordance with at least one of data contained in an mode register set (MRS) and a conductive state of a fuse element.