A reference voltage generating circuit used for a light-emitting diode (LED) driver circuit and a light-emitting diode (LED) driver circuit are provided. A reference voltage generating circuit used for a light-emitting diode (LED) driver circuit includes a voltage measurer configured to sequentially measure feedback voltages of a plurality of LED arrays, the LED arrays being connected to one another in parallel, a quantizer configured to search for one of the plurality of LED arrays having a lowest feedback voltage of the measured feedback voltages, a comparator configured to compare an output of the voltage measurer with a preset comparison voltage to generate a reference voltage, and a timing controller configured to control the comparator to output the generated reference voltage corresponding to the one of the plurality of LED arrays.