| CPC G09G 3/32 (2013.01) [G09G 3/3291 (2013.01); G09G 2310/0275 (2013.01); G09G 2310/0291 (2013.01); G09G 2320/0276 (2013.01); G09G 2330/021 (2013.01); G09G 2330/028 (2013.01)] | 20 Claims |

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1. A data driving circuit comprising:
a reference voltage generator configured to receive a data control signal and to generate a gamma reference voltage and a test reference voltage;
a data driving unit configured to output a data signal for a pixel based on the gamma reference voltage; and
an output circuit configured to output a test data voltage for a dummy pixel based on the test reference voltage,
wherein the reference voltage generator includes:
a first input amplifier configured to receive an upper limit reference voltage;
a second input amplifier configured to receive a lower limit reference voltage;
a resistor string connected between an output terminal of the first input amplifier and an output terminal of the second input amplifier, and configured to output a plurality of voltages that have different voltage levels from each other;
a first output amplifier configured to output one of the plurality of voltages from the resistor string as the gamma reference voltage;
a decoder configured to select one voltage among the plurality of voltages in response to the data control signal; and
a second output amplifier configured to output a voltage selected by the decoder as the test reference voltage.
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