Research And Design Of Pre Conversion Circuit For Piezoelectric Accelerometer

The piezoelectric acceleration sensor is weak in the output of the response of the sensitive element to the measured signal,and is a high resistance element.If the sensor is not processed,it can't be collected and measured directly.Charge amplifier is the most commonly used pre conversion circuit for measuring charge signals,but there are generally zero drift errors,clutter and noise interference problems in measurement.In view of the above problems,the research and design work is carried out in this paper.First,by studying the working principle of the piezoelectric acceleration sensor and its pre transform circuit,the corresponding equivalent circuit is established by electrical analysis,and the frequency characteristics and sensitivity are discussed.Secondly,the zero drift is studied and analyzed from the three links of the piezoelectric acceleration sensor itself,the connecting cable and the pre transform circuit.According to the cause of zero drift in different links,the corresponding zero drift suppression technology is given.Again,a low zero drift pre transform circuit is designed,which is composed of integrated chips,and the three key technologies of charge conversion,filter level anti-aliasing and low noise coaxial cable selection in the process of circuit design are studied in depth.At the same time,the noise interference of the circuit is de-noised.Finally,the experimental platform is set up to carry out the corresponding test.The working frequency range of the pre transform circuit is not more than 1dB and the frequency range of the two frequency doubling course is not less than 45 dB.It has good frequency response characteristics and the sensitivity of the circuit.It is about 0.475mV/g,which meets the test requirement.After the noise reduction of the ground loop,the output ripple voltage of the circuit is only about 3m V.The contrast test before and after the design improvement also shows that zero drift is effectively reduced after the zero drift suppression technology is adopted in three links of the piezoelectric acceleration sensor,the connection circuit and the pre transform circuit respectively.