Design Of Mix-mode Driving Circuit In The Interface Circuit Of Quartz Gyroscope

QRS is a kind of MEMS gyroscope which is tiny and lowcost. It has manyadditional advantages due to its piezoelectric property. QRS has a much simplerstructure and is easier to manufacture. Besides, leakage of electricity is not likely tohappen in it. That is why QRS is becoming more and more popular in society. WhenQRS is driven by a voltage it starts to oscillate. With the help of its piezoelectricproperty and coriolis force QRS is able to achieve the rotation rate. Apparently, thedriving voltage is the key to the proper functioning of QRS. Traditional drivingmethods include sine wave driving and square wave driving, each of which hasunavoidable shortcomings. Square wave driving circuit is likely to be influenced byhigher harmonic waves and sine wave driving circuit is stabilized too slowly. Thisarticle is about designing a new mix-mode driving circuit that uses both drivingmethods to adopt their good points and avoid their shortcomings.First, the working principle of QRS is analyzed. The structure and electrodeconfiguration of the tuning fork is illustrated. The dynamic equation and the electricequivalent model are derived and simulated separately which lays a foundation ofthe circuit design.According to the analyzing result, driving method is analyzed and chosen.Then the whole structure, digital control module, switch circuit, square wavegenerating circuit and sine wave driving circuit are designed separately. Eachmodule is tested and simulated.At last, the whole mix-mode driving circuit is simulated. The simulation resultshows that the oscillation is stabilized within8ms and the range of frequency is11.68kHz~11.69kHz. The distortion factor of the driving circuit is3.22%whichmakes the circuit much more satisfying.Finally, in order to judge the pros and cons of the mix-mode driving circuit,square wave and sine wave driving circuit are going to be analyzed and simulated.The simulation results will be compared to that of the mix-mode driving circuit.Comparison result indicates that the mix-mode driving circuit can be stabilized in amuch shorter time than the sine wave driving circuit and its signal quality is betterthan of the square wave driving circuit. Besides, their frequency performances arenearly the same. As a conclusion, the mix-mode driving circuit is a better choice forQRS driving.