Patent ID: 7277345
Filing Date: 2007-10-02
Classification: G11C

Abstract:
1. A method of refreshing rows of memory cells in a dynamic random access memory in which at least one memory cell in some of the rows may be unable to retain data bits during refresh, the method comprising: writing predetermined bits to the memory cells in a row of memory cells; refreshing the memory cells in the row during a refresh cycle; reading data bits from the memory cells in the row after the memory cells have been refreshed during the refresh cycle; determining if any of the read data bits differ from the corresponding data bits written to the memory cells in the row; if any of the read data bits differ from the corresponding data bits written to the memory cells in the row, refreshing the row of memory cells at a refresh rate that is faster than the rate that other rows of memory cells are refreshed, the refreshing of the row of memory cells at a refresh rate that is faster than the rate at which other rows of memory cells are refreshed comprising: halting the incrementing of the binary numbers in the event one of the recorded subsets of bits matches corresponding bits of a refresh row address until after the row of memory cells corresponding to the row address from which the matching subset of bits were obtained has been refreshed.