红外探测器中一种电容式反馈跨阻放大器的设计

A New Method For Designing Capacitive Feedback Transresistance Amplifier for Infrared Detector

放大器电路对提高红外成像技术中红外探测器的读出精度,是至关重要的。针对电容式反馈跨阻放大器的设计进行了研究,提出了一种在反馈回路中用晶体管代替反馈电阻的新的拓扑结构。对于所提出的拓扑结构,提出并分析了与系统稳定性相关的诸如截止频率和衰减比等的总体频率响应和设计参数,从而获得高直流输入动态范围。此外,还讨论了在直流反馈回路中加入额外的电容以确保系统的稳定性。分析、仿真和实验结果的良好一致性验证了所提出的CF-TIA方案的有效性,而且所提出的电路设计在正常或低直流输入下的整体噪声性能方面相比于传统的CF-TIA方案更具优势。尽管本文中的电路采用分立元件实现,但提出的频率响应模型和稳定性分析适用于所有CF-TIA应用和CMOS芯片设计。

In order to improve the readout accuracy of infrared detector in infrared imaging technology,where the amplifier circuit is very important.The design of capacitive feedback transimpedance amplifier(CF-TIA)is studied,and a new topology that replaces feedback resistance with the transistor in the feedback loop is proposed.For the proposed topology,the overall frequency response and design pa-rameters such as cutoff frequency and attenuation ratio related to the system stability are proposed and analyzed to obtain the high direct current input dynamic range.Moreover,the addition of additional capacitors to the direct current feedback loop for ensuring system sta-bility is discussed.The excellent agreement between the analyses,simulation and experimental results verify the effectiveness of the pro-posed CF-TIA scheme,and the proposed circuit design has more advantages than the traditional CF-TIA scheme in terms of overall noise performance under normal or low direct current input.Although the circuit is implemented with discrete components,the proposed fre-quency response model and stability analysis are applicable to all CF-TIA applications and CMOS chip designs.