The present disclosure relates to a temperature sensor provided in a display driver circuit and an operating method thereof. Disclosed is a temperature sensor provided in a display driver circuit including: a reference voltage generating unit configured to output a set reference voltage; a proportional voltage generating unit configured to output a proportional voltage proportional to a temperature of the circuit; a comparison unit configured to output a flag voltage by comparing magnitudes of the reference voltage and the proportional voltage; and a sensor control unit configured to control the reference voltage generating unit and the proportional voltage generating unit.