Research On Key Technologies Of Readout Integrate Circuit For Large Scale Array Uncooled Infrared Detector

With the continuous improvement of uncooled infrared detector technology,the requirements for its function and performance are also higher and higher.Uncooled infrared focal plane detector is developing in the direction of larger array,smaller pixel,higher speed and higher integration.The pixel size of the array has been developed from1 K,10K to 100 K,1M or even 100 M.The power consumption increases rapidly with the increase of the array size.When the number of pixels increases rapidly,the nonuniformity of the array and interference problems make the image quality of the detector sharply drop,even the image is distorted;and due to the reduction of the pixel area,the physical realization space of the uncooled infrared detector readout circuit is also compressed,how to design a readout integrated circuit with small pixel size and large array becomes a new problem for designers.The performance of ROIC directly affects the imaging quality of uncooled infrared focal plane array(IRFPA).In order to achieve the goal of high-quality imaging of large scale array IRFPA with low cost,this paper studies the key technologies of its dedicated readout circuit,including: high integration digital technology of large scale array,on-chip nonuniformity correction technology of large scale array and low power control technology of large scale array.The main research contents and achievements are summarized as follows:1.High integration digital technology of large scale array ROIC.According to the design index of ROIC of large scale array uncooled infrared detector,the clock scheme of readout circuit system is determined.The main clock cycle of the system is 3ns,the maximum line scan time is 31.5?s,the column selection clock is 42 ns,and the digital output clock is 3ns.A highly integration,low power consumption and low noise digital column level for large area array uncooled microbolometer focal plane is proposed.In addition,a low-power high-speed column level comparator is designed,which uses the tail current enhancement branch of the voltage comparator to only increase the transient power consumption when the comparator is flipped.The delay of the comparator is less than 0.5 ns,and the average current is only 7.26 ?A.2.On-chip nonuniformity correction technology of large scale array ROIC.The source of the non-uniformity and nonuniformity correction technology are studied.The on-chip non-uniformity correction circuit is proposed.The on-chip non-uniformity correction circuit is proposed.The non-uniformity correction of the detector pixel offset and gain is realized by using the DAC adjustment on two chips;the design adopts The simulation results of DNL and INL of 8-bit voltage scaling DAC circuit in "4 + 4" segment mode are-0.3LSB?+0.4 LSB and-0.5 LSB ?+0.6 LSB respectively.In order to better realize that the detector output signal has nothing to do with the substrate temperature,a solution to accurately obtain the detector substrate temperature is proposed,and an onchip high-precision temperature sensor circuit is designed.When the temperature changes from-40 ? to 125 ?,the output voltage of the temperature sensor circuit changes from0.90105 V to 3.16808 V,the temperature response rate is 13.74 m V/K,and its linearity is99.99%.3.Low power control technology of large scale array ROIC.In order to shorten the design cycle and cost,improve the intelligence and reliability of the readout circuit,the semi custom design method of digital control circuit based on digital unit standard library is adopted,and the intelligent digital control circuit of readout circuit is designed and optimized for low power consumption.The high-speed input of off chip signal,on-chip pixel by pixel nonuniformity correction and digital signal output are realized.4.The simulation results show that the average response rate of the ROIC is 55.99 code / K when the target temperature changes 100 K,the power consumption of the single channel column level ROIC is 99.96 ?W at room temperature,and the total power consumption is 272.89 mW for the 1280 × 1024 array large-scale IRFPA ROIC system.