Driving voltage generator and digital to analog converter

Abstract

A digital to analog converter is disclosed. The invention provides a digital to analog converter (DAC) including a plurality of voltage transmitting switches and a selecting signal decoder. The voltage transmitting switches respectively receive a plurality of input voltages, and output terminals of the voltage transmitting switches are commonly coupled to an output terminal of the digital to analog converter. The selecting signal decoder receives a plurality of selecting signals, and generates a plurality of transmitting enable signals to control the voltage transmitting switches. Wherein only one of the voltage transmitting switches is connected between each of the input voltages and the output terminal of the digital to analog converter.

What is claimed is: 
     
         1 . A digital to analog converter, comprising:
 a plurality of voltage transmitting switches, respectively receiving a plurality of input voltages, and output terminals of the voltage transmitting switches being commonly coupled to an output terminal of the digital to analog converter; and   a selecting signal decoder, receiving a plurality of selecting signals, and generating a plurality of transmitting enable signals to control the voltage transmitting switches,   wherein only one of the voltage transmitting switches is connected between each of the input voltages and the output terminal of the digital to analog converter.   
     
     
         2 . The digital to analog converter as claimed in  claim 1 , wherein at most one of the voltage transmitting switches is turned on according to the transmitting enable signals. 
     
     
         3 . The digital to analog converter as claimed in  claim 1 , wherein the voltage transmitting switches are respectively formed by a plurality of transistors. 
     
     
         4 . The digital to analog converter as claimed in  claim 3 , wherein types of the transistors are the same. 
     
     
         5 . A driving voltage generator, adapted to a display device, and comprising:
 a first digital to analog converter, comprising:
 a plurality of first voltage transmitting switches, respectively receiving a plurality of first input voltages, and output terminals of the first voltage transmitting switches being commonly coupled to an output terminal of the first digital to analog converter; and 
 a first selecting signal decoder, receiving a plurality of first selecting signals, and generating a plurality of first transmitting enable signals to control the first voltage transmitting switches, 
   wherein only one of the first voltage transmitting switches is connected between each of the first input voltages and the output terminal of the first digital to analog converter.   
     
     
         6 . The driving voltage generator as claimed in  claim 5 , further comprising:
 a second digital to analog converter, comprising:
 a plurality of second voltage transmitting switches, respectively receiving a plurality of second input voltages, and output terminals of the second voltage transmitting switches being commonly coupled to an output terminal of the second digital to analog converter; and 
 a second selecting signal decoder, receiving a plurality of second selecting signals, and generating a plurality of second transmitting enable signals to control the second voltage transmitting switches, 
   wherein only one of the second voltage transmitting switches is connected between each of the second input voltages and the output terminal of the second digital to analog converter.   
     
     
         7 . The driving voltage generator as claimed in  claim 6 , further comprising:
 a gamma input voltage generator, coupled to the first digital to analog converter and the second digital to analog converter, and generating the first and the second gamma input voltages.   
     
     
         8 . The driving voltage generator as claimed in  claim 6 , further comprising:
 a driving voltage output buffer, coupled to the first and the second output terminals, and selecting a voltage on the first output terminal or the second output terminal according to a polarity selecting signal to generate a driving output voltage.   
     
     
         9 . The driving voltage generator as claimed in  claim 6 , wherein at most one of the first voltage transmitting switches is turned on according to the first transmitting enable signals, and at most one of the second voltage transmitting switches is turned on according to the second transmitting enable signals. 
     
     
         10 . The driving voltage generator as claimed in  claim 6 , wherein the first and second voltage transmitting switches are respectively formed by a plurality of transistors. 
     
     
         11 . The driving voltage generator as claimed in  claim 10 , wherein types of the transistors are the same.