| 摘要 |
PURPOSE:To reduce power consumption of a substrate generation circuit by switching between the operation with large current supply capability and the operation with small current supply capability by a charge pump circuit and reducing the current supply capability of the substrate generation circuit at the stand-by time of a DRAM. CONSTITUTION:When the interruption service, etc., of an external power source occurs, a voltage VINT is lowered from the voltage VEXT to VBT gradually. For instance, when the voltage becomes lower than VBC1, the fact that an operation condition becomes from a normal state to an information preservation state is informed by a circuit 100. By the circuit 2, the operation is switched to the information preservation state, and minimum power consumption required for the preservation of information is reduced. At this time, the voltage VINT is stopped at the time of arriving at the voltage VBT, and thereafter, the information preservation operation is performed by the voltage. Then, when the voltage VINT is raised and becomes higher than the voltage VBC2 by either the restoration of interruption service or the throw-in of the external power source, signals such as PHIBC, -PHIBC, etc., are restored to the normal operation condition. Thus, the circuit 2 is made to be the original normal state. |
