A power supply multiplexing circuit including a first supply voltage
input. A first pair of cascoded PMOS transistors are in series with the
first supply voltage input. A first native NMOS transistor is in series
with the first pair of cascoded PMOS transistors. Also, a second supply
voltage input and a second pair of cascoded PMOS transistors are in
series with the second supply voltage input; and a second native NMOS
transistor in series with the second pair of cascoded PMOS transistors.
The gates of the first and second native NMOS transistors are driven by
two control signals out of phase with each other, and sources of the
first and second native NMOS transistors are connected together to output
an output voltage.