Photovoltaic apparatus comprising an auxiliary power supply arrangement which is adapted to feed an electric load of the photovoltaic apparatus itself and comprises: first electronic means connected with a DC power source and comprising a first electronic unit adapted to receive a first feeding voltage and provide a first output voltage of DC type; second electronic means connected with an AC power source and comprising a second electronic unit adapted to receive a second feeding voltage and provide a second output voltage of DC type; and third electronic means connected with the first and second electronic means and adapted to reversibly switch among different operation states based on the status of the electric power sources.