| 摘要 |
PURPOSE:To realize a variety of circuit operation controls for a semiconductor integrated circuit when the power is supplied by generating a control signal which discriminates the period until the predetermined substrate bias is generated and the succeeding period when the power is supplied. CONSTITUTION:A control signal generating circuit is provided for discriminating the period until the predetermined substrate bias is generated and the succeeding period when the power is supplied. For example, when the power is supplied, a substrate bias VBB to be applied to a semiconductor substrate is easily gradually lowered to a predetermined negative voltage from 0V by operating a substrate bias generating circuit having a large drive capability when the power is supplied. When the substrate bias VBB becomes lower than a certain voltage, the transistors 21, 22...2n turn ON. Thereby, voltage of the one end of capacitor 1 namely at the point N1 is gradually lowered and finally discharged up to a negative voltage. Thereby, a control signal VOUT in the output side of inverter 3 turns to high level and only the substrate bias generating circuit having small drive capability is operated so long as the integrated circuit is the standby condition. |
