Patent ID: 6346857
Filing Date: 2002-02-12
Classification: G09G,H04N

Abstract:
A gamma conversion circuit having a voltage controlled amplifier, said amplifier comprising:a first differential amplifier responding a gain setting voltage to produce a first control signal; a second differential amplifier responding an input voltage and a region setting voltage to produce a second control signal; and a third differential amplifier responding said first control signal and said second control signal to produce an output signal; and wherein said first differential amplifier includes: a first transistor coupled between a first node and a second node, and having a first control electrode receiving said gain setting voltage; and a second transistor coupled between a third node and said second node, and having a second control electrode receiving a reference voltage; and wherein said second differential amplifier includes: a third transistor coupled between a fourth node and a fifth node, and having a third control electrode receiving said input voltage; and a fourth transistor coupled between a sixth node and said fifth node, and having fourth control electrode receiving said region setting voltage; and wherein said third differential amplifier includes: a fifth transistor coupled between a seventh node and said sixth node, and having a fifth control electrode coupled to said first node; and a sixth transistor coupled between an output node and said sixth node, and having a sixth control electrode coupled to said third node; and wherein said fourth node and said seventh node are coupled to a power source line.