A buffer circuit includes first and second current generators, a comparator, a differential driver, and an inverter. The first current generator outputs a first current corresponding to a reference voltage. The second current generator generates a limit current corresponding to an input limit voltage, and outputs a second current having a size equal to about half of the limit current. The sizes of the first current and the limit current are controlled by the feedback voltage. The comparator generates the feedback voltage by comparing the first and second currents. The differential driver generates an internal current, and controls the internal current based on the feedback voltage. The magnitudes of an upper limit value and a lower limit value of the internal current are substantially equal to each other with respect to a reference value. The inverter generates an output current by inverting the internal current based on supply voltage.