A gamma correction circuit for AMOLED display driver chip

Based on the UMC80nm process, this paper uses a non-linear data transformation combined with a linear DAC structure to design a gamma correction circuit for 1080 p resolution AMOLED display drive. Among them, the non-linear transformation circuit is designed by piecewise linear fitting method, which is simple and flexible, and easy to implement; in order to meet the high-precision requirements of gray-scale voltage, the DAC bit width is designed to be 11 bit, and the "6 + 5" two-stage structure is adopted; The stage DAC is designed as a class-AB output interpolation op amp structure, not only as part of the 11 bit DAC, but also used to drive R, G, B pixel circuits, saving chip area. Spectre simulation of the circuit, the non-linear data conversion error is 0.77%, the maximum INL of the 11 bit DAC is + 0.33LSB / -0.51LSB, the maximum DNL is + 0.24LSB / -0.16LSB, and the error of the overall gamma correction circuit is 0.96 %, Meeting the needs of AMOLED driver chips with 1080 p resolution, which has certain application value.