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Accelerometer circuit design

Discussion in 'Sensors and Actuators' started by dimV, Jun 20, 2020.

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  1. dimV


    Jun 20, 2020
    Hello people ,
    I dont know if my question is under the correct category but anyway
    I need to design a very basic accelerometer circuit . The point is to take the voltage measuerement that a capacitive accelerometer provides and after proccessing it to output it .
    The circuit will probably only consist of a few capacitors and resistors , an A/D converter ,an amp and integrators.
    I have searched a lot online and have found very few info about such a topic , most are about the construction of the accelerometer. I have a some knowledge about op-amps(integrator,differentiator) and signals.
    So if anyone can explain how and why things happen i would be very happy.

    P.S i am talking about a diagram not any actual sensors , its more about understanding the concept
  2. bertus

    bertus Moderator

    Nov 8, 2019
  3. Nanren888


    Nov 8, 2015
    bertus likes this.
  4. dimV


    Jun 20, 2020
  5. dimV


    Jun 20, 2020
    Thank you very much for your answers , i am really happy that i can find some assistance and i will try to clarify the best i can.
    The accelerometer will be designed from the start. Only the capacitors are available and their output
    The method is referred as differential capacitive sensing.
    The output of the capacitors needs to get into a differential op-amp or a transimpedence amplifier so we can get the difference. After getting this measumerement, we need to make it as linear as possible and nullify any parasitic capacitance(miller theorem?)
    I guess :
    The linearity will be achieved with some sort of feedback loop
    The parasitic capacities will be nullified by a cascode
    As an output , we need the g force measurement in digital form(A/D converter)
    Any kind of filter and op amp can also be used .
    I am trying to form the question as clearly as possible but since i do not understand it very well it is somewhat diffucult to do so.
    P.S By the way , this was a question for better understanding sensors in my class of microelectronics and i have started studying it again because i finally got into my sector.. but while i can get the grasp of it , i cant form a whole answer.
    Characteristics: the accelerometer needs to measure up to 50g for an airbag
    inside a car that constanly produces up to 2g . Frequency range of the sensor
    should be 400Hz .
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