Noise of a JFET Charge Amplifier for Piezoelectric Sensors
Noise of a JFET Charge Amplifier for Piezoelectric Sensors
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DOI：
10.1109/jsen.2017.2759000
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发表时间：
2017-11-15
影响因子：
4.3
通讯作者：
Hoft, Michael
中科院分区：
文献类型：
--
作者：
Durdaut, Phillip;Penner, Veronika;Hoft, Michael
提出了一种适用于压电传感器的结栅场效应晶体管（JFET）电荷放大器的综合噪声模型。基于此放大器结构，噪声等效电路的推导和讨论。给出了12个噪声源的通用噪声增益表达式。通过对电荷放大器噪声特性的分析描述，可以大大简化各种电容式微机电传感器系统中前置放大器的设计和优化。本底噪声的计算进行比较与测量与一个MEMS型磁电传感器和迄今为止常用的基本电荷放大器的性能。利用JFET电荷放大器，在所利用的传感器的7.45 kHz的谐振频率附近实现了约22 dB的噪声降低。报道的放大器是第一个没有负面影响的谐振磁电传感器系统的总噪声水平。
A comprehensive noise model of a junction gate field-effect transistor (JFET) charge amplifier is presented for applications with piezoelectric sensors. Based on this previously reported amplifier structure, a noise equivalent circuit is derived and discussed. Universal noise gain expressions for each of the twelve considered noise sources are given. By means of an analytical description of the charge amplifier's noise behavior, the design and optimization of such preamplifiers for various capacitive microelectromechanical sensor systems will be distinctly simplified. Calculations of the noise floor are compared with measurements with a cantilever-type magnetoelectric sensor and with the performance of a so far commonly utilized basic charge amplifier. With the JFET charge amplifier a noise reduction of approximately 22 dB is achieved in the vicinity of the utilized sensor's resonance frequency of 7.45 kHz. The reported amplifier is the first which has no negative influence on the total noise level of a resonant magnetoelectric sensor system.