The Study On High Speed Imaging Circuit Technology For Area-CCD

CCD has been widely applied in the field of photoelectric detection and imagingarea, as the low output signal noise, the large dynamic range, the high quantumefficiency and charge transfer efficiency advantages. According to its structure, CCDis divided into linear CCD and area CCD。 Area CCD is divided into full frame CCD,interline CCD and frame transfer CCD. Because the development direction ofaerospace camera is towards high-resolution, high-speed and electronic multiplying inweak light, the area CCD is used more and more widely in aerospace field. In thispaper, the research object is Area CCD. The special timing, the high-speed signalgenerating and driving, the power supplying with wide adjustment range andlow-ripple, the high-speed data integration and transmission and so on are studieddeeply, which provide strong reference for area CCD in aerospace applications.Firstly the special timing of area CCD and digital controlled power supplyingwith wide adjustment range and low ripple are investigated. The full frame, interlineand frame transfer area CCD's characteristics and working principle are introduced.The TDI(Time Delay Integration) working mode of interline CCD and TDI three-lineworking mode are discussed. At the same time, the frame transfer area CCD'sultrashort exposure time control method with no electronic shutter is also included.For the application requirements of the CCD circuit, the digital controlledhigh-voltage analog linear power supply and the flyback DC-DC power supply withwide adjustment range and low ripple are studied.And then the area CCD's high speed signal generating, pre-amplifying andprocessing were studied. After the principles introduction and applications comparingunder high-speed conditions of the five high speed signal generating methods, thehigh-speed operational amplifier self-oscillation model was established and the way toovercome self-oscillation was supplied also. With this the procedure andcharacteristics of high-speed CCD signal processing were introduced. Following were the area CCD high-speed signal driving research. For high-speedimaging applications, the driving methods were studied, which were the verticaltransfer signals especially the three-level vertical transfer signal and horizontaltransfer signals whose clock were up to40MHz. Push-pull MOSFET, high-frequencytransformer resonant, RLC resonant, push-pull MOSFET combining RLC resonantwere studied to realize electronic multiplying signal's driving in order to overcomethe hard of E2V EMCCD's to achieve high speed high voltage. The real-timeexamining and calibration methods were studied to stable the parameters of outputsignals produced by high-frequency transformer resonant and RLC resonant which areeasy to change with the external environment,Next, the methods of integration and transmission of the high-speed area CCDdigital data were discussed. The two channels high-speed image data integrationmethods in line and frame were investigated. For the request of high resolution,multi-tap, high-speed, short blanking in the real-time area CCD digital dataintegration, two refresh mode about SDRAM were proposed. The first one wasconsecutive refresh after multi-line reading and writing operations during in data validstage, and the another one was auto-timing refresh during in data invalid stage. Forthe request of high speed data acquisition and transmission, two methods were studiedand proposed also. The first one is depressing SDRAM's operating frequency andimproving memory resource utilization, and the another one is reducing the outputclock frequency by depressing the data's blanking interval.Finally, the circuit system simulation, building and testing has been achieved.The driving circuit of the interline transfer CCD KAI1010M has been designed, thedriving circuit board has been manufactured, and the TDI and TDI three-line workingmode has been achieved. The high-speed imaging circuit of the interline transfer CCDKAI-0340DM has been designed, the PCB whose clock up to40MHz has beensuccessfully manufactured, and four resolutions work mode has been programmed.The real time image data synthesis system of full frame CCD STA1600output hasbeen designed, programmed and simulated. The imaging circuit of the frame transferEMCCD CCD201has been designed, digital controlled wide adjustment range analoglinear power supply and digital controlled wide adjustment range low ripple, flybackDC-DC power supply based on LT3958chip are manufactured. The electronicmultiplying driving circuit has been manufactured with push-pull MOSFET,high-frequency transformer resonant, and push-pull MOSFET combining RLCresonant methods. Real-time examining circuits has been designed and manufacturedto solve the problems that the parameters of output signals produced byhigh-frequency transformer resonant and RLC resonant are easy to change with theexternal environment.