The device for generating three mode signals includes: a voltage setting block including an input terminal receiving three input signals of driving voltage, open, and ground and setting three voltages according to the three input signals; and an output block including two output terminals and a second node B receiving the three voltages from the voltage setting block, and outputting three combined signals by comparing an input voltage with a reference voltage, whereby only a small number of resistors and amplifiers generates three mode signals to further reduce the chip size than the related art and the external power source is not required to solve the problems of the related art due to noise.