The present invention relates to a liquid crystal display, a driving device thereof, a digital to analog converter, and an output voltage amplifying circuit. The present invention provides a liquid crystal display driving device including a reference gray voltage generator for generating a plurality of reference gray voltages, and a data driver for generating a plurality of gray voltages based on the plurality of reference gray voltages and applying a data signal that is generated by selecting a gray voltage corresponding to m-bit video signals applied from the outside from among the plurality of gray voltages to the pixel The data driver includes: a voltage generator for selecting a first gray voltage and a second gray voltage corresponding to bit values of (m−k) bits from among the video signal from among the plurality of gray voltages, and outputting the first and second gray voltages; an output voltage generator for outputting 2k voltages determined as one of the first and second gray voltages corresponding to bit values of k bits from among the video signal; and an output voltage amplifier for generating the data signal by combining the 2k voltages, and applying the data signal to a plurality of pixels. According to the present invention, a liquid crystal display having a small cost and area can be realized.