Low voltage BICMOS logic switching circuit

The present invention involves a BICMOS logic switching circuit biased between upper and lower supply voltages. This circuit includes a CMOS logic circuit driven by a plurality of logic input signals. This logic switching circuit also has a driving circuit coupled to the CMOS logic switching circuit and includes an output node, a first bipolar transistor, and a second bipolar transistor. The first bipolar transistor is coupled in series with the second bipolar transistor with the output node therebetween for providing an output signal on the output node, wherein the second bipolar transistor has a base directly coupled to a field effect transistor switch coupled to the upper supply voltage. The field effect transistor switch is controlled by logic input signals. The circuit also includes a switching circuit coupled to the upper supply voltage, the lower supply voltage, and the output node for causing the output signal on the output node to swing fully between the upper and the lower supply voltages in response to changes in the logic input signals.