An Ultra Low Voltage (ULV) digital circuit includes a logic circuit comprising a plurality of logic gates and a plurality of buffered interconnects for connecting between the plurality of logic gates, a temperature sensor configured to detect a temperature of the logic circuit, and a voltage controller configured to control a driving voltage provided to the logic circuit in order to reduce a power consumption of the logic circuit based on the detected temperature. Each of the plurality of logic gates and buffered interconnects reduces a signal delay as a temperature increases.