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Indexed by:会议论文

Date of Publication:2019-01-01

Included Journals:EI、CPCI-S

Volume:1187

Issue:2

Abstract:The compensation of zero drift of charge amplifier is of great significance to its application in testing field. In this paper, the zero drift theory of charge amplifier used in an integrated piezoelectric torque dynamometer is studied, which lays a theoretical foundation for the design of high cost-effective zero drift compensation circuit. The charge amplifier is designed based on MOSFET 3N165 and LF356N operational amplifier. The analysis of the charge conversion circuit of this charge amplifier and the establishment of a reasonable equivalent circuit model are the key to design the compensation circuit. In this paper, the equivalent circuit model of charge conversion is established for this charge amplifier, and the theoretical formula of zero drift at 25 degrees C similar to 40 degrees C is derived. By comparing theoretical value of zero drift with measured value, the compensation ratio coefficient epsilon of junction temperature is introduced to modify the formula. Finally, the correctness of the revised formula is verified by experiments. The result shows that the modified formula is applicable to the actual zero drift prediction in the experimental process, which lays a theoretical foundation for the design of zero drift compensation circuit for the integrated piezoelectric torque dynamometer with this charge amplifier.