| 摘要 |
<p>PURPOSE:To reduce power consumption, voltage of a ROM by providing switch means at a bit line, and shutting OFF a connection of the bit line to a power source when the potential of the bit line is raised to a predetermined potential. CONSTITUTION:A transistor Tr 6 is turned ON in a state that the potential of a bit line 4 connected to a selected memory cell 3 is 'L'. When an 'L' precharging signal PC is input in this state, a Tr 1 is turned ON, and storing charge is stored in the cell 3 from a power source VCC through the Trs 1, 6. When the potential of the line 4 is raised so as to exceed a threshold value near 1/2VCC of an inverter 11d, the output signal of the inverter 11d becomes 'L', the Tr6 is turned OFF, and a current to the cell 3 is blocked. The drain potentials of the Trs 1, 2 are raised even after the Tr 6 is turned OFF, and when it is raised substantially to the VCC, a Tr 7 is turned OFF, a Tr 8 is turned ON, a Tr 3 is turned OFF, and this state is latched by the operations of the Tr 2 and inverters 11f, 11g. Thus, power consumption, voltage are reduced.</p> |
