COLUMN SELECTING CIRCUIT

摘要

PURPOSE: A column selecting circuit is provided to minimize a layout area and to prevent a generation of an unwanted current flowing by sharing a read bus line and write bus line with a single bus line. CONSTITUTION: An equalizer part(37) makes a bit line to equalize to a bit bar line. A bit line sensing amplifier(33) compensates for a level of signal voltage of the bit line and bit bar line as a word line is selected. An enable signal output part(35a) gives an output of enable signal for operating a bit line sensing amplifier. Data bus line and data bar bus line transfer data of a memory cell from the bit line and bit bar line into the sensing amplifier and output data of main sensing amplifier into the bit line and bit bar line. A data transferring part(39) alternatively transfers data of each lines each other according to a column selecting signal and read/write signal between the data bus line and the data bar bus line and bit line and bit bar line. A precharge lever adjusting part(41) performs an adjustment of the precharge level of the data bus line and the data bar bus line.