SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE

PURPOSE:To improve the trackability of a power source voltage and to reduce power consumption by supplying a negative voltage formed by a capacitor through an FET controlled by a negative voltage generated complementary to the former voltage. CONSTITUTION:An inverter formed with P-type complementary FETs Q1 and Q2 and that formed with N-type complementary FETs Q3 and Q4 operate complementarily. When one electrode of the capacitor C1 connected to the FETs Q3 and Q4 with their outputs at L comes to L, a diode connection FET Q5 is turned off, and the other electrode C comes to a negative potential. An FET Q7 is turned on by the inverters Q1 and Q2 operating complementary to the inverter, the capacitor C2 connected to the inverter and the level L of a diode connection FET Q6, and the low potential of the electrode C is outputted as the back bias voltage of a substrate. With this constitution using the capacitor, the trackability of the power source voltage is improved, and the FET for controlling a negative voltage can transmit a negative potential back bias without loss. And power consumption can be reduced by making an oscillation frequency and capacitor capacity smaller.