Design And Implementation Of Refrigeration CCD Circuit With High Sensitivity

Charge-coupled device(CCD),as an important image sensor,has been widely used in various photoelectric imaging detection systems.With the deepening of various applications,higher requirements have been put forward for the performance parameters of CCD image sensor.Especially in the application of weak light signal detection,how to reduce the noise of CCD and improve the signal-to-noise ratio of its output signal has become an important issue in the application of CCD image sensor.This paper aims to improve the weak light detection performance of optical fiber spectrometer.Based on a large number of relevant literatures at home and abroad and the relevant products on the market,by studying the EMVA1288 standard for the performance parameters of the image sensor developed by the European Machine Vision Association,a high sensitivity refrigeration CCD image sensor is selected.The driving sequence,power supply,refrigerator control,output signal digitization and transmission circuit are designed,and the corresponding software program is written.In the hardware circuit,the main control unit uses the complex programmable logic device CPLD to provide driving signals for CCD,and controls the analog-to-digital conversion chip to convert the output signals of CCD,and uses the USB2.0 chip to carry out data transmission and communication with the upper computer.Refrigeration circuit by the MCU control circuit drive the CCD built-in thermo electric cooler(TEC)to achieve.In the aspect of software program,the CPLD program was written using hardware description language(Verilog HDL),and the USB chip firmware program and single-chip temperature control program were written using C language.Finally,an experimental test device was built in the laboratory,and the refrigeration effect and performance parameters of the designed CCD circuit were tested and analyzed.The CCD temperature was lowered and stabilized at-30?at room temperature in only 32s.When the temperature is-10?,the dark current noise is 7.5e~-/(pixel·s),and the dynamic range is up to61.44d B,the results show that the refrigeration CCD circuit designed in this paper can work stably,has good refrigeration effect,can effectively reduce the dark current noise,and improve the weak light detection performance of the optical fiber spectrometer.