摘要
文章针对仪表放大器的平衡/不平衡输入模式,提出一种扩展其输入范围一倍的方案,重点以输出前馈的方式解决了不平衡输入的扩展问题,并对其未尽平衡共模误差、扩展电路的稳定性等问题作了深入分析和讨论,结果与实验相吻合。作为应用实例,介绍一种具有±30V动态范围和高/低输入阻抗可选的前端放大器,展示了仪表放大器的平衡/不平衡输入扩展对大动态范围信号测量的综合优势。对于某些低电源系统的场合,或采用低压芯片的放大器,这种输入范围的扩展也具有实际意义。
In this paper, for the balanced/unbalanced input mode of the instrumentation amplifiers, an approach of extending their input range doubly was proposed. The difficult one of them, or the unbalanced input-extension, was solved in a creative way of output-front-feed, in which a balanced difference-mode input was built in the unbalanced mode by the mapping of the output which equals to half input, bringing out potential input range without instability. Where, the common-mode error due to unbalanced input, the stability of the circuit, etc. were analyzed in detail, which is in accordance with our experiments. Simultaneously, a front-end amplifier based on instrumentation amplifier, with dynamic range of ± 30V and optional high/low input impedance, was illustrated, where the advantages of the integrated balanced/unbalanced input-extension has been clearly displayed in measurements with greater dynamic range. For some systems with low-tension supplies or low-tension amplifiers, such an approach is also useful.
出处
《电子测量与仪器学报》
CSCD
2006年第2期80-85,共6页
Journal of Electronic Measurement and Instrumentation
关键词
仪表放大器
平衡/不平衡
输入阻抗
动态范围
前馈
instrumentation amplifier, balanced/unbalanced, input impedance, dynamic range, front-feed.
