Research And Design Of Microchannel Board CMOS Readout Circuit

With the advancement of modern technology,laser radar has many important applications in many aspects such as laser measurement such as industrial,medical and military.As an important branch of laser radar,laser radar 3D imaging technology has received more and more attention in military vehicles,aircraft and aerospace.At present,the three-dimensional imaging technology of MCP laser radar is mainly limited by the shortcomings of flight time error,low resolution and long dead time.According to these problems,some solutions are proposed and implemented in this paper.This design mainly introduces the design of the analog front-end circuit and the auxiliary digital circuit of the pixel based on time-of-flight measurement imaging technology.In this paper,the background and research progress of MCP lidar system are briefly analyzed.The working principle of the system is introduced and several imaging methods are analyzed.Finally,the imaging method of time-of-flight measurement method is selected and the design index is proposed.Secondly,the pixel structure and imaging principle of the CMOS readout circuit are introduced,and the source of flight time error is analyzed in detail.The method of error correction using constant ratio timing is proposed.In addition,several structures of the charge amplifier are compared,and a current-sensitive charge amplifier is selected according to the requirements of dead time and impedance matching.A high speed and high gain cross-zero comparator has been designed then.The interface,timing,and principle of each part of the SPI circuit are introduced.Finally,the circuit is physically implemented by smic 0.18?m CMOS process.The pixel array has a scale of 10×10 and an area of 4.25 mm×4.35 mm.The dead time of analog link is 15 ns,the time walk under each process corner is less than 50ps,the input charge range is 4×10~5 to 1.25×10~7electrons,the input equivalent noise are 7322 electrons,and the single pixel area is 363?m×358?m.