| Related citation: | TAN Xiao-yun,SUN-Ming,WANG Jia-qi,YIN Liang,LIU Xiao-wei.New low noise interface circuit for detecting weak current of micro-sensors[J].Journal of Harbin Institute Of Technology(New Series),2011,18(4):9-12.DOI:10.11916/j.issn.1005-9113.2011.04.003. |
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| Author Name | Affiliation | | TAN Xiao-yun | MEMS Centre,Harbin Institute of Technology,Harbin 150001,China | | SUN-Ming | MEMS Centre,Harbin Institute of Technology,Harbin 150001,China | | WANG Jia-qi | MEMS Centre,Harbin Institute of Technology,Harbin 150001,China | | YIN Liang | MEMS Centre,Harbin Institute of Technology,Harbin 150001,China | | LIU Xiao-wei | MEMS Centre,Harbin Institute of Technology,Harbin 150001,China
Key Laboratory of Micro-Systems and Micro-Structures Manufacturing,Ministry of Education,Harbin 150001,China |
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| Abstract: |
| A new low noise interface circuit for detecting weak current of micro-sensors is designed.By using the transimpedance amplifier to substitute the charge amplifier,the closed-loop circuit can avoid the phase error of the charge amplifier.Therefore,the phase compensation devices will be cancelled,because there is no phase transformation through the transimpedance amplifier.As well as,by using CCCII devices to implement the high value feedback resistor of the impedance amplifier,the noise of the I-V transformation devices is reduced,comparing with the passive resistor.The floating resistor is easy to be integrated into chips,making the integration of the interface circuit of the intelligent sensors increase.Through the simulation,the phase error of the charge amplifier is almost 9°at 2 kHz and it changes with the working frequency of the micro-sensors making the phase compensation not easy.The value of the floating resistor is 250 kΩ where the bias current is 50 μA.The noise of the active resistor is 0.037 fV2/Hz,comparing with the noise of the passive resistor,which is 4.14 fV2/Hz. |
| Key words: micro-sensor weak signal detection phase error low noise |
| DOI：10.11916/j.issn.1005-9113.2011.04.003 |
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