US Patent 7375670 Digital-to-analog converter

A DAC is provided to convert an input word into dual output voltages, and the input word includes a least significant bit and remaining bits. The DAC includes an R-string DAC section and a selecting section. The R-string DAC section is capable of providing an nth and (n+2)th voltage levels according to the remaining bits. The selecting section includes a first multiplexer and a second multiplexer. The first multiplexer is coupled to the R-string DAC section to provide a first output voltage according to a panel polarity signal. The second multiplexer is coupled to the R-string DAC section to provide a second output voltage according to the LSB bit of the N-bit input word. The DAC may further include an operational amplifier to average the dual output voltages for producing an analog output signal.