JP2869791B

There are provided a bipolar-MOS IC device smaller than half-micron scale, and a combination of such IC device and external circuits. The IC device has an internal voltage generating circuit for generating an internal power source by using an external power source, the voltage of the internal power source being lower than that of the external power source. The internal voltage generating circuit includes an NPN transistor formed in an N-type region or N-type island within a P-type semiconductor substrate of the IC device, and a PMOS transistor formed in the N-type island. The collector of the NPN transistor and the source of the PMOS transistor are used as external power source terminals. The drain of the PMOS transistor is connected to the base of the NPN transistor. The gate is used as a control signal terminal. The emitter of the NPN transistor is used as an internal power source output terminal. A current path from the external power source input terminal and the internal power source output terminal is accordingly formed within the N-type island isolated from the P-type substrate.