非制冷红外探测器的低噪声成像电路研究

发布时间：2019-07-07 19:43

【摘要】：作为红外成像技术的一部分,随着红外成像技术的发展,非制冷红外成像技术也快速的发展。由于非制冷红外成像系统有着许多制冷型不能实现的功能特性,在各行各业获得了广泛的需求。然而,非制冷探测器在噪声等效温差和响应时间等性能方面远不如制冷型红外探测器。为了提高非制冷红外成像系统的整机性能,本文从硬件电路的角度出发,研究和设计低噪声成像电路,以使探测器发挥出其最佳性能为目的。本文从探测器偏置电压、探测器数字时序驱动信号、探测器模拟输出等方面说明了设计低噪声成像电路的重要性。作为红外成像系统电子学部分,成像电路包括了电源模块、偏置电压模块、AD转换模块、FPGA时序驱动模块、数据采集模块和TEC温控模块。电源模块采用了噪声较低的LDO电源管理芯片;偏置电压模块采用基准电压源和运算放大器的组合;AD转换模块采用了14位的模数转换芯片AD9240;时序驱动模块由Cyclone IV FPGA实现;数据采集模块由FPGA配合USB2.0控制芯片实现了基于USB2.0的数据传输和采集;TEC温控电路以单片TEC控制芯片为核心。完成了FPGA中探测器时序驱动和USB数据采集的逻辑开发。在电路中的关键位置设计了低通滤波电路,滤除高频噪声;对电路板中噪声做了一定的分析,在PCB设计中考虑到了噪声的控制。成像电路设计为三块电路板,实现了电路的小型化。另外,电路设计考虑到了成本控制。最后,通过仿真和实验验证了设计的可行性。
[Abstract]:As a part of infrared imaging technology, with the development of infrared imaging technology, uncooled infrared imaging technology is also developing rapidly. Because the uncooled infrared imaging system has many functional characteristics which can not be realized by refrigerating type, it has obtained a wide range of requirements in various industries. However, the performance of uncooled detector is much worse than that of refrigerated infrared detector in noise equivalent temperature difference and response time. In order to improve the performance of uncooled infrared imaging system, this paper studies and designs the low noise imaging circuit from the point of view of hardware circuit, in order to make the detector give full play to its best performance. In this paper, the importance of designing low noise imaging circuit is explained from the aspects of detector bias voltage, detector digital timing driving signal, detector analog output and so on. As the electronic part of infrared imaging system, the imaging circuit includes power supply module, bias voltage module, AD conversion module, FPGA timing drive module, data acquisition module and TEC temperature control module. The power module adopts LDO power management chip with low noise; the bias voltage module adopts the combination of reference voltage source and operational amplifier; the AD conversion module adopts 14-bit analog-to-digital conversion chip AD9240; timing drive module realized by Cyclone IV FPGA; the data acquisition module realizes data transmission and acquisition based on USB2.0 by FPGA and USB2.0 control chip; and the TEC temperature control circuit is based on a single TEC control chip. The logic development of detector timing drive and USB data acquisition in FPGA is completed. In the key position of the circuit, a low-pass filter circuit is designed to filter out the high frequency noise, and the noise in the circuit board is analyzed, and the noise control is taken into account in the PCB design. The imaging circuit is designed as three circuit boards, which realizes the miniaturization of the circuit. In addition, the circuit design takes into account cost control. Finally, the feasibility of the design is verified by simulation and experiment.
【学位授予单位】：中国科学院研究生院(西安光学精密机械研究所)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN215

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