Abstract: A digital to analog converter circuit applied to a source driving apparatus is disclosed. The digital to analog converter circuit includes P-type transistors coupled in series, N-type transistors coupled in series and a substrate voltage control unit. The substrate voltage control unit is coupled to substrates of the P-type transistors and substrates of the N-type transistors respectively and used for controlling the substrates of the P-type transistors to have a first substrate voltage and controlling the substrates of the N-type transistors to have a second substrate voltage. The first substrate voltage is an operating voltage substituted by a specific voltage difference and the second substrate voltage is a ground voltage added by the specific voltage difference, and the operating voltage is higher than the ground voltage.