Study And Design Of Source Driver Circuit In AMOLED Driver Chip

In recent years,OLED(Organic Light-Emitting Diode)has gradually replaced LCD(Liquid Crystal Display)as a new and more popular display technology with a series of remarkable advantages,such as wider perspective,faster response,higher brightness,richer color,higher contrast,wider working temperature range,lighter weight,thinner thickness,flexible structure and low power consumption.With the increase of demand,OLED panels will develop towards higher resolution,lower power consumption,richer colors and flexible panels in the future.The performance of the driver chip directly affects the display effect of the display screen.The source driver circuit is the circuit directly connected with the panel pixel points in the driver chip,and its performance determines the quality of the image display.In this thesis,a source driver circuit suitable for driving AMOLED display panel with 1080*2220 resolution and 16.7 million colors is studied and designed.This thesis introduces the driving principle of AMOLED in detail firstly,clarifies the requirements of AMOLED display panel for driver chip,analyzes the role of each key module in the driver chip,and provides the direction for the design of source driver circuit.By comparing different Gamma correction schemes,the Gamma correction scheme combining nonlinear data with linear DAC was determined,and the slope adjustment unit was inserted to improve the structure of linear DAC to fit the gray-order voltage curve,so as to further improve the gray-order voltage precision.The channel number of the source driver circuit is determined by introducing the sub-pixel arrangement of the display panel.According to these,a reasonable architecture of source driver circuit is designed,including Gamma decoding circuit,data latch,level shifting circuit,gray scale voltage generation circuit and output buffer.The designed source driver circuit can achieve high precision and only occupy a small chip area and power consumption.The design index of the chip system is analyzed,the index of the source driver module system is determined,and formulate the key circuit functions and index requirements according to the top index of the source driver.Based on the UMC 80 nm CMOS process,the circuit of the source driver module is designed and the simulation verification is completed.The simulation results show that the source driver module each key circuit can work properly under the 10k?resistor and 30 pf capacitor equivalent loads of panel,the setting time of the output voltage for source driver circuit is less than 5 us,gray-scale voltage accuracy with in 3 mV,the demand of system design index is satisfied.