摘要
射极耦合差分放大电路可以在保证差模信号放大倍数的前提下,有效地抑制共模信号。射极耦合差分放大电路主要有两种负反馈形式:电阻负反馈和恒流源负反馈。文中从Multisim仿真结果和实验结果两个方面对比分析了这两种不同负反馈电路对射极耦合差分放大电路性能的影响。从Multisim仿真结果可以得出:电阻负反馈射极耦合差分放大电路的单端输出共模抑制比受负反馈电阻值约束,电阻值越大,共模抑制比越高,但该电阻值的大小也会影响静态工作点的设置;恒流源负反馈射极耦合差分放大电路的恒流源负反馈电路的等效电阻趋于无穷大,因此其单端输出共模抑制比趋于无穷大。实验结果进一步证实了上述结论。
The emitter-coupled differential amplifier circuits, which suppress the common-mode sig- nal effectively, can amplify the differential mode signal well. There are two kinds of negative feedback in the emitter-coupled amplifier circuits, which are resistance negative feedback and constant-current source negative feedback respectively. In this article, both of Muhisim simulation and actual experi- ment results are used to compare the performance of these two kinds of negative feedback. The Multisim simulation results indicated that the common mode rejection ratio （CMRR） of the resistance negative feedback emitter-coupled differential amplifier circuit is constrained by the feedback resistance value. The larger the resistance value is, the larger the CMRR will be. But the resistance value will also affect the setting of the static operating point. In the constant-current source negative feedback emitter-cou- pled differential amplifier circuit, the equivalent resistance of the feedback circuit is very infinite, so its CMRR tends to infinity. The experimental results confirmed the conclusions further.
出处
《实验室科学》
2017年第2期36-39,共4页
Laboratory Science
基金
中央高校基本科研业务费专项资金资助项目(项目编号:DUT16QY32)
大连理工大学教育教学改革基金项目(项目编号:YB2016012)
大连理工大学教材建设出版基金项目(项目编号:JC2016055
JC2016059)
