Patent ID: 8860767
Filing Date: 2014-10-14
Classification: G09G

Abstract:
1. A gamma reference voltage generation circuit comprising: a red (R) gamma reference voltage generator including a plurality of digital-to-analog converters (DACs), each of which generates an R gamma reference voltage corresponding to R gamma data; a green (G) gamma reference voltage generator including a plurality of DACs, each of which generates a G gamma reference voltage corresponding to G gamma data; and a blue (B) gamma reference voltage generator including a plurality of DACs, each of which generates a B gamma reference voltage corresponding to B gamma data, wherein in the DACs of each of the R, G and B gamma reference voltage generators that receive respective R, G and B gamma data, a high potential bias voltage input terminal of an uppermost DAC used to generate a gamma reference voltage of a maximum gray level is connected to a high potential voltage source, and wherein an output of the uppermost DAC is connected to a high potential bias voltage input terminal of a next DAC such that a high potential bias voltage input terminal of each of remaining DACs except the uppermost DAC is cascade-connected to an output terminal of an upper DAC next to each of the remaining DACs, and wherein the high potential bias voltage input terminal of each of the DACs is connected to an internal resistance string included in each of the DACs, wherein the high potential bias voltage input terminal of the uppermost DAC is connected to the high potential voltage source through a temperature compensator, wherein the temperature compensator includes: a temperature sensor that is connected to the high potential voltage source to lower an output voltage of the temperature sensor when an ambient temperature is higher than a normal temperature and to increase the output voltage of the temperature sensor when the ambient temperature is lower than the normal temperature; and a comparator that differentially amplifies the output voltage of the temperature sensor and a predetermined reference voltage and supplies the amplified voltages to the high potential bias input terminal of the uppermost DAC.