Design Of Switched Capacitor Detection Circuit Of Rotational Gyroscope

With the micro-electromechanical systems(MEMS) develop,as a major product of microelectromechanical systems branch-gyroscope gradually is being known to everyone. Since the gyroscope can be widely used in military civilian areas,its people are increasingly demanding accuracy requirements.Traditional magnetic suspension rotor micro gyro,electrostatic suspended gyroscope its accuracy is not high enough to generate eddy currents heat problems,high processing costs,the electrostatic voltage is too high to support the required shortcomings rather than mainstream.Harbin Institute of Technology MEMS Center presents a whole new ball-singles micro gyroscope rotor structure,can effectively avoid the above problems.The complete system is composed of micro-mechanical gyroscopes and electrical composed of two parts.In this paper,HIT MEMS Center based on the new structure gyroscope.In this paper,the ball-singles rotor micro gyro working principle, the principle of detection, detection method were analyzed.By comparing a variety of detection methods,select the appropriate design of the circuit topology.The detecting circuit is designed mainly consisted of two parts,pre-switching capacitance detection circuit and analog to digital conversion circuit.Previous stage capacitance detection circuit switch module part of this design include a charge sensitive amplifier, the secondary amplifier, correlated double sampling circuit, a low-pass filter circuit.The simulation can be a relative permittivity resolution 5.12x10-8,nonlinear around at 100 ppm, the scale factor is 39.86 m V / ff, scale factor temperature coefficient 92.08 ppm.And the use of a third-order modulator single loop a quantization analog output stage before detection circuit digitize.Modulator is fully differential switched capacitor circuits manner.Sampling clock frequency is 100 KHz. Analysis and design each module modulator.The main module integrator operational amplifier, a latch, a comparator, a clock generation circuit.Modulator input signal bandwidth is 30 Hz, the input signal frequency is 16 Hz, amplitude-8d BFS, SNR is 99 d B, 1Hz dynamic range of approximately 120 d B, power consumption of the whole circuit 11.856 m W.Then adjust the overall switch capacitance detection circuit layout drawing and post-simulation.This paper can get the scale factor temperature coefficient 95.12 ppm, nonlinear can reach 200 ppm, a relative permittivity resolution 5.89x10-8.Modulator simulation with the same conditions as before, SNR is 95 d B, 1Hz dynamic range of 120 dB.