A data driving circuit for driving a pixel of a light emitting display based on externally supplied data for the pixel, the pixel being electrically connectable to the data driving circuit via a data line, the data driving circuit comprising: a current supply unit including a current sink configured to sink a predetermined current flowing through the pixel via the data line for generating a compensation voltage using the predetermined current; a voltage generator configured to generate and set values for a plurality of gray scale voltages (V 0-2 k-1) based on the compensation voltage generated by the pixel when the predetermined current flows through the pixel, wherein the voltage generator comprises a plurality of voltage dividing resistors (R1-R1) provided between a first terminal for receiving a reference power source (Vref) and a second terminal for receiving the compensation voltage to set the gray scale voltages; a digital-analog converter for selecting, as a data signal for the pixel, one of the plurality of set gray scale voltages based on a bit value of a portion of the externally supplied data associated with the pixel; and at least one switching unit for supplying the selected data signal to the data line, wherein a value of the predetermined current being equal to or higher than a value of a minimum current employable by the pixel to emit light of maximum brightness, and the maximum brightness corresponds to a brightness of the pixel when a highest one of the plurality of set gray scale voltages is applied to the pixel; wherein the current sink comprises: a current source (Imaxj) configured to receive the predetermined current, wherein the current sink is arranged to receive the predetermined current from the pixel during a first partial period of one complete period for driving the pixel based on the selected gray scale voltage, the first partial period occurring before a second partial period in the one complete period for driving the pixel based on the selected gray scale voltage; a first transistor (M12j) provided between the data line and the voltage generator, the first transistor being arranged to be turned on during the first partial period; a second transistor (M13j) provided between the data line and the current source (Imaxj), the second transistor being arranged to be turned on during the first partial period; and a capacitor (C3j) for charging the compensation voltage. a current supply unit including a current sink configured to sink a predetermined current flowing through the pixel via the data line for generating a compensation voltage using the predetermined current; a voltage generator configured to generate and set values for a plurality of gray scale voltages (V 0-2 k-1) based on the compensation voltage generated by the pixel when the predetermined current flows through the pixel, wherein the voltage generator comprises a plurality of voltage dividing resistors (R1-R1) provided between a first terminal for receiving a reference power source (Vref) and a second terminal for receiving the compensation voltage to set the gray scale voltages; a digital-analog converter for selecting, as a data signal for the pixel, one of the plurality of set gray scale voltages based on a bit value of a portion of the externally supplied data associated with the pixel; and at least one switching unit for supplying the selected data signal to the data line, wherein a value of the predetermined current being equal to or higher than a value of a minimum current employable by the pixel to emit light of maximum brightness, and the maximum brightness corresponds to a brightness of the pixel when a highest one of the plurality of set gray scale voltages is applied to the pixel; wherein the current sink comprises: a current source (Imaxj) configured to receive the predetermined current, wherein the current sink is arranged to receive the predetermined current from the pixel during a first partial period of one complete period for driving the pixel based on the selected gray scale voltage, the first partial period occurring before a second partial period in the one complete period for driving the pixel based on the selected gray scale voltage; a first transistor (M12j) provided between the data line and the voltage generator, the first transistor being arranged to be turned on during the first partial period; a second transistor (M13j) provided between the data line and the current source (Imaxj), the second transistor being arranged to be turned on during the first partial period; and a capacitor (C3j) for charging the compensation voltage. a current source (Imaxj) configured to receive the predetermined current, wherein the current sink is arranged to receive the predetermined current from the pixel during a first partial period of one complete period for driving the pixel based on the selected gray scale voltage, the first partial period occurring before a second partial period in the one complete period for driving the pixel based on the selected gray scale voltage; a first transistor (M12j) provided between the data line and the voltage generator, the first transistor being arranged to be turned on during the first partial period; a second transistor (M13j) provided between the data line and the current source (Imaxj), the second transistor being arranged to be turned on during the first partial period; and a capacitor (C3j) for charging the compensation voltage.