SUBSTRATE BIAS GENERATING CIRCUIT

摘要

PURPOSE:To decrease the power consumption in a waiting mode of a DRAM by applying the substrate potential detection output to each gate electrode of a control MOS transistor. CONSTITUTION:When a substrate potential is kept at a low level, the output of a substrate potential detecting circuit 7 connected to a power line 6 outputs a potential that can sufficiently turn on the control MOS transistors 11-13. Therefore the high frequency output of a ring oscillator 1 is applied to a driver 2, and the potential of the line 6 is quickly raised up. While the output of the circuit 7 is gradually reduced when the substrate potential is reduced down to a satisfactory level. Then the resistance values of the transistors 11-13 are increased. As a result, the power consumption of the oscillator 1 is reduced and at the same time the power consumption of a driver 2 is also reduced. Then the power consumption can be reduced in a waiting mode of a DRAM.