Apparatus for supplying voltage free noise and method of operation the same

摘要

A voltage supply apparatus includes a power noise sensing unit, a voltage selecting unit, a first power voltage supply unit and a second power voltage supply unit. The power noise sensing unit senses noise from first and second powers and outputs a power noise sensing signal. The voltage selecting unit outputs first and second driving signals in response to a voltage-supply-enable-signal and the power noise sensing signal. The first power voltage supply unit applies a voltage of the first power in response to the first and second driving signals. The second power voltage supply unit applies a voltage of the second power in response to the first and second driving signals.