Study On The Circuit Of Long Wave Photoconductive Infrared Detector Based On Non-Uniformity Correction

With the development of semiconductor technology,infrared detection technology has been developing rapidly.The development demand of the third generation infrared detector is increasing.In the field of space remote sensing,the long wave detector with wavelengths above 10 microns is still dominated by HgCdTe photoconductive detectors and it plays an important role in infrared detection and imaging.However,the nonuniformity of the current optical infrared detector is prominent,the dynamic range of the conventional readout integrated circuit(ROIC)is too small and even some signals cannot be read out.Therefore,the non-uniformity has become the focus and difficulty of infrared imaging technology.In this thesis,the non-uniformity of long wave photoconductive infrared detector is studied in depth.A digital-analog mixed ROIC with non-uniformity correction for long wave photoconductive infrared detector is designed.After considering various of the input stage structure of ROIC,a feedback comparison ADC and DAC bridge input structure is adopted,and then through a resistive trans-impedance amplifier(RTIA)for uniform and stable output signal.The correction ROIC consists of four modules,including the comparator,the counter,the resistance network module and the adjustable gain resistive trans-impedance amplifier RTIA module.In the first chapter,we introduce the classification and development of infrared detector technology,and the principle and application of the photoconductive detector.Secondly,it describes the development status of the non-uniformity correction of infrared detector,and analyzes various on chip correction methods at present,then we test and analyze the non-uniformity for the long wave HgCdTe photoconductive detector.The purpose and significance of the work of the paper are explained.The second chapter mainly introduces the design method and process of ROIC.In the third chapter,we put forward the detailed scheme and design target of the on-chip readout circuit for the non-uniformity of current detector,and completes the circuit principle design and simulation of the overall circuit frame and four correction modules on the 0.5?m CMOS process platform.In the fourth chapter,we complete the layout design and tapeout.In the fifth chapter,we make simulation and analysis on the result of non-uniformity correction of the circuit,then tests and analyzes the circuit chip after the tapeout processing,and finally puts forward improvements scheme for the correction circuit.In the sixth chapter,we summarize the main contents and conclusions of the paper.The simulation and test show that the correction ROIC can reduce the nonuniformity of long wave photoconductive detector from 19% to less than 0.5% equivalently in resistance,and the non-uniformity of readout signal from more than 50% to less than 10%.It can not only effectively solve the problem of the non-uniformity of the linear long wave photoconductive detector,but also is of great significance to the design of the readout circuit for the high performance long wave infrared photoconductive detector.