| 摘要 |
PURPOSE:To reduce the power consumption of an unselected column, by switching FETs inserted in series in the power soruce lines of all columns of an S-RAM with a column decoder. CONSTITUTION:The FET6 for power down is inserted into the power source line 5 for a memory cell, a sense amplifier, and a R/W controller at every column, and a column selection signal from the column decoder 4 is applied on the gate electrode of the FET6. Only the FET on a selected column is turned ON, and a sufficient power is supplied to the memory cell, the sense amplifier and the R/W controller. Meanwhile, the FET6 on the unselected column goes to an OFF state, and the power source is disconnected. However, power consumption is limited to a minimum level to prevent the storage of the memory cell from being lost even when the power source is disconnected. |
