| 摘要 |
PURPOSE:To prevent a malfunction due to a noise generated in a GND line or a VDD line for a semiconductor integrated circuit device constituted of a MOS transistor which has been made minute and whose threshold value is low. CONSTITUTION:In an ordinary operation, a MOS transistor 110 which has been formed at a high threshold voltage is changed into a low threshold voltage by a substrate bias 106, and it is operated at high speed. The application of the substrate bias is suspended by a noise-level identification circuit 101 which detects a noise or a sudden change in a power supply voltage, at the same time, a circuit is changed to a standby state, the generation of a malfunction is prevented, the application of the substrate bias is resumed when a change in the noise or the sudden change in the level of the power supply voltage is stopped, the standby state is released, so that the circuit operation continues operating. |
