MEMORY CIRCUIT

摘要

PURPOSE:To accelerate both the reading speed and precharging speed by setting the precharging potential of a bit line at a high sensitivity area of a sense amplifier in case the simultaneous reading of two ports is designated to the same memory cell of a two-port RAM. CONSTITUTION:Bit lines 5 and 5' are set at the power supply voltage; while bit lines 6 and 6' are set at the ground potential respectively. Then a charge redistribution is produced between lines 5 and 6 as well as 5' and 6' when FET25-28 are turned on. In this case, the potentials of lines 5 and 6 set after the redistribution are equal to the mean value of the value at which both terminals are previously precharged and set at levels where the sensitivity of a sense amplifier is highest. The same value of potential is also obtained between lines 5' and 6'. Then the lines 5 and 6 are charged at the potential of a point (a); while lines 5' and 6' are charged at the potential of a point (b) respectively. Thus the sense amplifier can decide correctly ''1'' and ''0''.