A novel closed-loop controlled interface IC for differential-capacitive sensor systems

Author

Huang, Xiaozong ; Huang, Wengang ; Zhong, Yingjun ; He, Zhengrong

Author_Institution

Analog IC Design Center, SISC, Chongqing, China

fYear

2010

Firstpage

1447

Lastpage

1449

Abstract

A closed-loop controlled interface IC on the principle of force-balance for differential-capacitive sensor system is presented in this work. Signal buffer immune for the parasitic capacitors is introduced to reduce the signal attenuation. A novel PID compensation block is designed to enhance the stability of the system with extremely high gain for accuracy, which is realized with active feedback Op Amp different from that of the traditional fashions. The circuit is fabricated in the 4μm BiCMOS process with the active area of 2.06mm² (excluding the pads) which is cost-efficient for industrial and commercial applications. The interface circuit operates at ±5V power supply and consumes 23mW of power. It provides typical analog output scale of 100mV/g with full scale of ±30g typically, and total noise of 2.5mgrms through the frequency range of DC-160Hz.

Keywords

BiCMOS integrated circuits; capacitive sensors; closed loop systems; operational amplifiers; stability; three-term control; BiCMOS process; PID compensation block; active feedback OpAmp; closed-loop controlled interface IC; differential-capacitive sensor systems; force-balance; parasitic capacitors; power 23 mW; signal attenuation; size 4 mum; stability; Acceleration; Attenuation; Integrated circuits; Micromechanical devices; Noise; Operational amplifiers; Poles and zeros; Differential-capacitive sensor; Force-balance; Op amp with active feedback; PID compensation;

fLanguage

English

Publisher

ieee

Conference_Titel

Solid-State and Integrated Circuit Technology (ICSICT), 2010 10th IEEE International Conference on

Conference_Location

Shanghai

Print_ISBN

978-1-4244-5797-7

Type

conf

DOI

10.1109/ICSICT.2010.5667570

Filename

5667570