Video display driver with gamma control

Abstract

Voltage generator circuitry for providing a plurality of voltages for use in gamma compensation of a video signal.

1 . An apparatus including voltage generator circuitry for providing a plurality of voltages for use in gamma compensation of a video signal, comprising:
 first and second input electrodes to convey first and second input voltages;   input voltage division circuitry coupled between said first and second input electrodes and responsive to said first and second input voltages by providing a plurality of divided input voltages;   input voltage selection circuitry coupled to said input voltage division circuitry and responsive to said plurality of divided input voltages and a plurality of input control signals by providing a plurality of selected input voltages each of which is related, in accordance with said plurality of input control signals, to a respective one of a selected portion of said plurality of divided input voltages;   output voltage division circuitry coupled to said input voltage selection circuitry and responsive to at least a portion of said plurality of selected input voltages by providing a plurality of divided output voltages; and   output voltage selection circuitry coupled to said output voltage division circuitry and responsive to said plurality of divided output voltages and a plurality of output control signals by providing a plurality of selected output voltages each of which is related, in accordance with said plurality of output control signals, to a respective one of a selected portion of said plurality of divided output voltages.   
   
   
       2 . The apparatus of  claim 1 , wherein:
 said first and second input voltages have maximum and minimum input magnitudes, respectively;   maximum and minimum ones of said plurality of divided input voltages have maximum and minimum divided input magnitudes no greater than said maximum input magnitude and no less than said minimum input magnitude, respectively;   each remaining one of said plurality of divided input voltages has a respective magnitude intermediate said maximum and minimum divided input magnitudes;   maximum and minimum ones of said plurality of divided output voltages have maximum and minimum divided output magnitudes no greater than said maximum divided input magnitude and no less than said minimum divided input magnitude, respectively; and   each remaining one of said plurality of divided output voltages has a respective magnitude intermediate said maximum and minimum divided output magnitudes.   
   
   
       3 . The apparatus of  claim 1 , wherein said input voltage division circuitry comprises a resistive voltage divider circuit. 
   
   
       4 . The apparatus of  claim 1 , wherein:
 said input voltage selection circuitry comprises digital-to-analog conversion circuitry;   said plurality of divided input voltages comprises a plurality of analog reference voltages;   said plurality of input control signals comprises a plurality of digital signals; and   said plurality of selected input voltages comprises a plurality of selected analog voltages related to a selected portion of said plurality of analog reference voltages in accordance with said plurality of digital signals.   
   
   
       5 . The apparatus of  claim 1 , wherein:
 said input voltage selection circuitry comprises analog signal multiplexor circuitry;   said plurality of divided input voltages comprises a plurality of analog input voltages;   said plurality of input control signals comprises a plurality of digital signals; and   said plurality of selected input voltages comprises a plurality of multiplexed analog voltages corresponding to a selected portion of said plurality of analog input voltages in accordance with said plurality of digital signals.   
   
   
       6 . An apparatus including voltage generator circuitry for providing a plurality of voltages for use in gamma compensation of a video signal, comprising:
 first and second input electrodes to convey first and second input voltages;   input voltage division circuitry coupled between said first and second input electrodes and responsive to said first and second input voltages by providing a plurality of divided input voltages;   input voltage selection circuitry coupled to said input voltage division circuitry and responsive to said plurality of divided input voltages and a plurality of input control signals by providing a plurality of selected input voltages each of which is related, in accordance with said plurality of input control signals, to a respective one of a selected portion of said plurality of divided input voltages, wherein said plurality of selected input voltages includes
 maximum and minimum selected input voltages having maximum and minimum selected input magnitudes, and 
 one or more intermediate selected input voltages having respective magnitudes intermediate said maximum and minimum selected input magnitudes; and 
   output voltage division circuitry coupled to said input voltage selection circuitry and responsive to said plurality of selected input voltages by providing a plurality of divided output voltages.   
   
   
       7 . An apparatus including voltage generator circuitry for providing multiple pluralities of voltages for use in gamma compensation of a video signal with multiple color depths, comprising:
 first and second input electrodes to convey first and second input voltages;   input voltage division circuitry coupled between said first and second input electrodes and responsive to said first and second input voltages by providing a plurality of divided input voltages;   input voltage selection circuitry coupled to said input voltage division circuitry and responsive to said plurality of divided input voltages and a plurality of input control signals by providing, mutually exclusively in accordance with said plurality of input control signals, first and second pluralities of selected input voltages each of which is related to respective ones of first and second selected portions of said plurality of divided input voltages, respectively, wherein
 said first plurality of selected input voltages includes maximum and minimum selected input voltages having maximum and minimum selected input magnitudes, respectively, and one or more intermediate selected input voltages having respective magnitudes intermediate said maximum and minimum selected input magnitudes, and 
 said second plurality of selected input voltages includes first and second ones of said maximum, minimum and one or more intermediate selected input voltages; and 
   output voltage division circuitry coupled to said input voltage selection circuitry and responsive to said first and second pluralities of selected input voltages by providing first and second pluralities of divided output voltages, respectively.