Research And Design Of Pixel Circuit In CMOS Pixel Sensor

The CMOS pixel sensor is a key technology for detecting particle existence,detecting particle track,and studying particle properties in high-energy physics experiments,space physics detection,and intelligent digital medical fields.These basic scientific questions will help us understand the mysteries of the existence of the universe and influence the development of science in the coming decades.In this paper,the pixel array in CMOS pixel sensor is deeply studied,and the pixel array circuit and layout are designed.The models and simulations of charge sensitive device for commercial 180nm CIS?CMOS Image Sensor?process have been done.Considering the effects of key process parameters on charge collection efficiency,time and equivalent capacitance,the optimal structure and bias voltage of charge sensitive device have been determined.The simulations of the collected charge range with ¹²C⁶⁺different hit positions provide input current for the pixel circuit design.The pixel circuit is designed with low-power and high-sensitivity structure.The analog front-end circuit has the functions of amplification and comparison.The threshold charge is 325e-,and it is externally adjustable.The power consumption?current?is 100nA/pixel,and the output duration is 1-3?s.The fill factor can reach 100%.The digital storage circuit is used to store the hit state in order to output the hit pixel address,which can be configured as normal,mask and pulse mode.The single pixel layout area is 25.76?m×24.76?m.In order to correctly output the hit pixel address,a low-power fast address readout circuit is designed using a priority encoder structure.The advantage of this structure is that the address of the hit pixel is read-only and the missed pixel is ignored.Thereby greatly improving readout speed and reducing power consumption.It can reach that a single clock cycle?25ns?outputs a single hit pixel original address.The RTL design and the back-end implementation of the peripheral readout control module are used to configure the different working modes of the pixel,and control and output the complete address information of the hit pixel.Finally,the pixel circuit,the address readout circuit and the peripheral readout control module are simulated.The overall layout of the pixel array is designed,and the size is2609.76?m×3391.97?m.