一种具有高动态范围的前置放大电路设计及实现  

Design and implementation of a preamplifier circuit with high dynamic range

作　　者：刘松 吴先梅[1,2] 孔超 Liu Song;Wu Xianmei;Kong Chao(State Key Laboratory on Acoustics,Institute of Acoustics,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院声学研究所声场声信息国家重点实验室,北京100190 [2]中国科学院大学,北京100049

出　　处：《电子技术应用》2020年第11期114-121,共8页Application of Electronic Technique

基　　金：国家自然科学基金资助项目(11674351)。

摘　　要：压电式电容型传感器在工作时能输出正比于被测物理量的电荷量,具有较好线性度的同时也具有较高灵敏度,在许多领域中都得到了广泛应用,但该类传感器在工作时所产生的电荷量通常比较微弱,需要对其适当放大以便后续进行处理。通过分析压电式电容型传感器的等效电路模型,结合电路理论和Multisim仿真,设计了前置放大电路。由于该前放电路主要针对小信号的放大需求进行设计,在大信号输入时输出信号会产生畸变。而在实际工程应用中,常出现输入信号中小信号和大信号并存的情况。为了能够对输入信号动态范围较大时的小信号和大信号都实现无失真放大,改进了之前的前置放大电路设计,对其进行了Multisim仿真和实验电路测试。结果表明改进后的前置放大电路在输入信号频率为10 kHz时,其输入信号电压幅值最高可达600 mV,且小信号和大信号的放大均无失真,放大倍数也基本相同,说明该电路设计实现了高动态范围的输入信号的无失真放大需求。A piezoelectric capacitive sensor can output charges directly proportional to the physical quantity to be measured in work.Due to excellent linearity and high sensitivity,it has been widely used in many fields.However,since the quantity of charges generated by such a sensor in work is relatively weak,it is necessary to amplify the charge signal for subsequent processing properly.A preamplifier circuit is designed by analyzing the equivalent circuit model of the piezoelectric capacitive sensor combined with circuit theory and Multisim simulation.As the circuit is mainly designed for amplifying signals with small amplitudes,the output signal will be distorted once it is used for an input signal with large amplitude.But in practical engineering applications,small and large input signals often appear at different conditions.To realize distortionless amplification for both small and large input signals,the design of the former preamplifier circuit is improved.Then Multisim simulation and experimental circuit testing are also carried out successively.The simulating and experimental results both show that when the input signal frequency is 10 kHz,the input signal with the amplitude up to 600 mV can be distortionless amplified by this improved preamplifier circuit.There is also no distortion when amplifying small signals.The amplification ratio is almost the same for small and large signals.These results prove that the preamplifier circuit design can realize distortionless amplification for an input signal with a high dynamic range.

关 键 词：压电式传感器 前置放大电路 

分 类 号：TN721[电子电信—电路与系统]