Patent ID: 7733257

Claim:
A digital-to-analog converter comprising: a gamma voltage generator for generating a plurality of gamma voltages; and a decoder for receiving an M-bit digital value to select one of the gamma voltages, the decoder comprising: a first thermometer encoder for receiving N bits of the digital value to generate a first thermometer code with 2 N bits, wherein N is smaller than M, and M and N are positive integers; a second thermometer encoder for receiving K bits of the (M−N) bits of the digital value except the N bits inputted into the first thermometer encoder to generate a second thermometer code with 2 K bits, wherein K is smaller than or equal to (M−N), and is a positive integer; a first selector having a plurality of selecting groups, each selecting group having 2 N switches being controlled by the first thermometer code to output one gamma voltage; and a second selector comprising a plurality of selecting groups, each selecting group has 2 K switches controlled by the second thermometer code to receive gamma voltages outputted from the first selector and output one gamma voltage selected from the received gamma voltages according to the second thermometer code.