System Structure Analysis And Layout Design Of CMOS Image Sensor

With the rapid progress of integrated circuit technology,the integration of chips has gone through the development of flying style.The number of transistors in a single chip increases dramatically,and the development of computer aided technology provides more convenient conditions for chip design.With the continuous improvement of CMOS technology,the application of CMOS image sensor is more and more extensive.This paper reviews the development of integrated circuit and compares it with CCD related image sensors,which shows the advantages of low voltage,simple system and low cost of CMOS image sensor.The CMOS image sensor focuses on a single silicon chip by using an amplifier,a photosensitive sensor array,a A/D converter,a row array driver,a digital signal processor,a DATA bus output interface,a sequence control logic unit,and a control interface.The main circuit of pixel circuit is designed and simulated.The structure selection and charge integral mode selection of the photodiode are mainly accomplished.At the same time,the pixel array is designed.Conditional reset and improved method are used to reduce the output voltage error,and the correlated double sampling circuit is used to remove the fixed mode noise.The design and Realization of the analog to digital converter mainly completes the design and Simulation of the sampling and holding circuit and the multiplicative analog conversion circuit,and pays attention to the effect of the amplifier gain,the parasitic capacitance and the amplifier's gain bandwidth.After completing the design of the comparator and the operational amplifier,the relevant simulation needs to be verified.When the bandgap reference circuit is designed,the temperature of the circuit is simulated.The temperature curve of the voltage is obtained.The temperature is processed by the curve,and the temperature parameters are finally obtained.The chip is based on the 0.11-M process and is used for layout design through Cadence software.The simulation part mainly adopts the full custom design method,the digital part is automatically generated by the system,then the function and timing distribution of the system are completed,and the correctness of the function and timing is confirmed by the system simulation.The analog part is integrated with the digital part,and then the layout and routing are carried out.After completion of the design,check the design rules and check the consistency rules of the circuit to form the layout of the whole chip.Finally,by optimizing the standard cell library,the layout symmetry can be improved,the layout planning is more scientific to improve the performance of the chip,and the area of the layout is reduced to reduce the production cost.