The present invention describes a circuit and driving method for a digital-to-analog converter to convert an (m+n) bits digital signal to an analog signal. First, the (m+n) bits digital signal is separated into a first set of m first bits and a second set of n second bits. Then, according to the first set of m first bits, a reference voltage range is determined from a plurality of reference voltages. Finally, according to the second set of n second bits, a voltage is determined from the reference voltage range.