The Design On Ultra Large CIS Sequential Circuit And Research On Circuit Reliability

Resolution is one of the most important indicators of CMOS image sensors.High-resolution CMOS image sensors have a wide range of applications in astronomical detection,high-definition detection,machine vision and other fields.The higher the resolution,the larger the pixel array,and the larger the lateral size of the pixel array puts higher requirements on the driving ability of the timing-driven circuit.The increase in vertical size also causes the delay to affect the generation of the selection signal.In addition,the instantaneous on-current generated by the large array CMOS image sensor in the global shutter mode,which has an impact on circuit reliability.Based on the theoretical analysis,the pixel structure and timing control driving circuit of the large array CMOS image sensor are studied.In the case of determining the size of the pixel array,the left and right ends are simultaneously driven to improve the driving ability of the control circuit,and the influence of the parasitic effect on the control signal line is analyzed,and the clock tree and the timing control driving circuit are laid out and optimized.In addition,the size of the sensor is large,so the row drive circuit is designed as a repeatable unit and then spliced.Finally,based on the 110 nm CMOS process,the ultra-large array CMOS image sensor timing control drive circuit was designed and tested by 2K×2K sample flow.The pixel size of the chip is 6μm×6μm,the size of the single-side row driver circuit is 2256μm×12288μm,the frame rate is 2fps,the row selection time is 24.36μs,and the left and right ends are simultaneously driven,and the signal difference between the two sides is less than 5 ns.Aiming at the latch-up effect of the timing control driver circuit in the global shutter mode,this paper analyzes and verifies the theory,and designs a circuit structure that can compensate the current that triggers the latch.The simulation results show that for the image sensor with 2048×2048 pixel array,there is a instantaneous on-current of 70 m A in the global shutter mode.The structure proposed in this paper compensates the current by 99.97%,which improves the anti-latch ability of the circuit..