A device can be used for refreshing memory contents of first and second memory cells. The memory contents of the first memory cells are refreshed in a first period of time and the memory contents of the second memory cells are refreshed in a second period of time. A pre-charge circuit is provided for bit lines for the first memory cells and the second memory cells. A controller may be coupled to the pre-charge circuit to control the pre-charge circuit such that a pre-charge voltage may be applied to the bit lines of the first memory cells during the first period of time and not during the second period of time and that the pre-charge voltage may be applied to the bit lines of the second memory cells during the second period of time and not during the first period of time.