Patent ID: 7920413
Filing Date: 2011-04-05
Classification: G11C

Abstract:
1. An apparatus for writing data to a phase-change random access memory (PRAM) by using writing power calculation and data inversion functions, the apparatus comprising: a receiving unit which receives original data to be written to a memory cell of the PRAM; a reading unit which reads data existing in the memory cell; an original data writing power calculating unit which compares the received original data with the read existing data by the bit and calculates a total power consumption value for writing bits of the original data which are different from those of the existing data, based on a first number of bits of the original data which are different from those of the existing data and have a bit type of SET, a second number of bits of the original data which are different from those of the existing data and have a bit type of RESET, and a power consumption value corresponding to each bit type of the PRAM; an inverted data writing power calculating unit which inverts the received original data by the bit, compares the inverted data with the existing data by the bit, and calculates a total power consumption value for writing bits of the inverted data which are different from those of the existing data based on a third number of bits of the inverted data which are different from those of the existing data and have a bit type of SET, a fourth number of bits of the inverted data which are different from those of the existing data and have a bit type of RESET, and the power consumption value corresponding to each bit type of the PRAM; and a writing unit which compares the total power consumption value for the original data with the total power consumption value for the inverted data and chooses the data which has a smaller power consumption value between the original data and the inverted data, and stores the chosen data in the memory cell.