A microelectronic device includes: a photovoltaic module configured to convert a light energy into an electric energy; a converter configured to convert a voltage output from the photovoltaic module into a predetermined voltage; a capacitor configured to store an electric energy transferred from the converter; and a controller configured to predict an available current of a next time slot based on the electric energy stored in the capacitor, and determine a consumed current of a load system of the next time slot based on the predicted available current.