Research On Low Noise Imaging Circuitry Of Uncooled Infrared Detector

As part of infrared imaging technology, the uncooled infrared imaging technology has been developing rapidly with the development of the infrared imaging technology. Because the uncooled infrared detectors have many features which cooled detectors are not able to reach, uncooled infrared imaging system has been required in all kinds of field. However, uncooled detectors in performance aspects such as the NETD and response time are much worse than the cooled infrared detectors. In order to improve the machine performance of uncooled infrared imaging system, this dissertation carries on the research and design of low noise imaging circuit from the perspective of hardware circuit, so that the detectors are able to exert its best performance.Analysing the bias voltage、digital timing driver signal and analog output of uncooled infrared detectors, this dissertation illustrates the importance of low noise imaging circuit design. As electronics parts of infrared imaging system, imaging circuit including power supply module, the bias voltage module, AD conversion module, FPGA timing driver module, data acquisition module and TEC temperature control module. Power supply module adopts lower noise power management chip, LDO. The AD conversion module adopts 14 bits AD conversion chip, AD9240. Timing driver module is implemented by Cyclone IV FPGA. Based on USB2.0, data acquisition module is realized the data transmission and collection by FPGA with USB2.0 controller chip. TEC temperature control circuit use the single chip TEC control chip. The FPGA logic development of detector timing driver and USB data acquisition is completed. In order to filter out the high frequency noise, low pass filter circuits are designed at the key points of circuitry. With some analyses, the noise of PCB is reduced by some means. The total imaging circuitry is divided to three parts, so that it satisfies the requirement of miniaturized design. Beside, the design of reducing the cost is also taken into account. At last, through the simulation and experiment, we verify the feasibility of the design.