中圖分類號： TN721
文獻標識碼： A
DOI：10.16157/j.issn.0258-7998.200601
中文引用格式： 劉松，吳先梅，孔超. 一種具有高動態范圍的前置放大電路設計及實現[J].電子技術應用，2020，46(11)：114-121.
英文引用格式： Liu Song，Wu Xianmei，Kong Chao. Design and implementation of a preamplifier circuit with high dynamic range[J]. Application of Electronic Technique，2020，46(11)：114-121.

Design and implementation of a preamplifier circuit with high dynamic range

Abstract： 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.

Key words : piezoelectric sensor; preamplifier circuit