A depth sensing apparatus for acquiring a depth image of a target object, comprising: a calculator to calculate a difference voltage between a first floating diffusion node and a second floating diffusion node based on a sub-integration period, said calculator being configured to calculate the difference voltage based on a voltage of a photodiode stored in the first floating diffusion node in a first phase interval and a voltage of the photodiode stored in the second floating diffusion node in a second phase interval, wherein the first phase interval indicates an interval in which charge is stored in the first floating diffusion node according to the application of a signal having a first phase relative to light that is emitted toward the object, and wherein the second phase interval indicates an interval in which charge is stored in the second floating diffusion node according to the application of a signal having a second phase relative to light that is emitted toward the object; a feedback unit to feed back the difference voltage to one of the first floating diffusion node and the second floating diffusion node to be stored in the one of the first floating diffusion node and the second floating diffusion node; a resetting unit to reset, to a reference voltage, a remaining floating diffusion node to which the difference voltage is not fed back between the first floating diffusion node and the second floating diffusion node; and a controller to calculate a depth value of a pixel based on an accumulation of a plurality of said difference voltages, wherein the difference voltages have been accumulated during an integration period comprising a plurality of said sub-integration periods, said controller comprising a comparator to compare a voltage of the first floating diffusion node to a voltage of the second floating diffusion node; characterized in that the feedback unit feeds back the difference voltage to the second floating diffusion node when the voltage of the first floating diffusion node is greater than the voltage of the second floating diffusion node, based on the comparison result, and feeds back the difference voltage to the first floating diffusion node when the voltage of the first floating diffusion node is less than or equal to the voltage of the second floating diffusion node based on the comparison result. a calculator to calculate a difference voltage between a first floating diffusion node and a second floating diffusion node based on a sub-integration period, said calculator being configured to calculate the difference voltage based on a voltage of a photodiode stored in the first floating diffusion node in a first phase interval and a voltage of the photodiode stored in the second floating diffusion node in a second phase interval, wherein the first phase interval indicates an interval in which charge is stored in the first floating diffusion node according to the application of a signal having a first phase relative to light that is emitted toward the object, and wherein the second phase interval indicates an interval in which charge is stored in the second floating diffusion node according to the application of a signal having a second phase relative to light that is emitted toward the object; a feedback unit to feed back the difference voltage to one of the first floating diffusion node and the second floating diffusion node to be stored in the one of the first floating diffusion node and the second floating diffusion node; a resetting unit to reset, to a reference voltage, a remaining floating diffusion node to which the difference voltage is not fed back between the first floating diffusion node and the second floating diffusion node; and a controller to calculate a depth value of a pixel based on an accumulation of a plurality of said difference voltages, wherein the difference voltages have been accumulated during an integration period comprising a plurality of said sub-integration periods, said controller comprising a comparator to compare a voltage of the first floating diffusion node to a voltage of the second floating diffusion node; characterized in that the feedback unit feeds back the difference voltage to the second floating diffusion node when the voltage of the first floating diffusion node is greater than the voltage of the second floating diffusion node, based on the comparison result, and feeds back the difference voltage to the first floating diffusion node when the voltage of the first floating diffusion node is less than or equal to the voltage of the second floating diffusion node based on the comparison result.