Rotor Micro Gyro ASIC Interface Detects Circuit Design

With the development of inertial devices, gyroscopes in various fields, especially in the field of military and civilian areas play an increasingly important role, and therefore drive the various research institutions to improve gyro performance improvements and research and development to meet the gyroscope adaptability to different environments. HIT MEMS Center presents a new type of ball rotor disc gyroscope structure, the basic principle is with the outside world through the differential capacitance change detecting changes in order to determine the angular velocity and other physical performance detection circuit determines the accuracy of the final output, so that the detector circuit the importance of the whole system is self-evident.In this thesis, the principles of gyro systems were reviewed in detail the working principle of the detection circuit, focusing on the overall system module division, insight Ball Singles- rotor gyroscope drive works with the design requirements of the circuit and the detection circuit of each module, specific complete ball Singles-designed rotor gyroscope detection circuit of each module. Detection circuit comprises a sine generator, high-frequency modulator, active low-pass filter switch phase sensitive demodulation circuit with amplification function, passive low-pass filter. The specific design ideas for high-frequency carrier generated by the carrier-frequency generator gyro is driven through a charge amplifier into a voltage signal, and the signal to prevent secondary amplification effect of noise on the signal. After inverting amplifier output signal obtained by inverting the ratio of the differential signal, using a switching phase sensitive demodulator demodulates the signal, and then demodulated signal low-pass filter to filter out the noise and get the output potential of the high-frequency carrier. According to the indicator of the basic structure of the circuit design, circuit determines the basic structure of the use of simulation software for parameter index Candence circuit configuration to verify various indicators integrated circuits required to achieve the basic function of each module. Capacitance can be obtained by resolution of the detection circuit output signal and the overall system performance requirements. The output signal of the linear fit and the data can be processed and non-linear scale factor factor. High frequency carrier output Fourier spectrum analysis obtained harmonic distortion metrics. Analysis of the scale factor of the circuit at different temperatures to obtain the temperature coefficient. Each module to optimize overall 0.35μm CMOS process and after completion of the overall system layout drawing, and simulation-based verification system analysis and improvement.Through the circuit design and improve the frequency of the final design of a high frequency carrier wave generator for 200 kHz, start-up time of 8.77 ms, amplitude 7.36 V, harmonic distortion of-110 dB, a multi-stage high-gain op amp gain 115.29 dB, phase margin is 80.93°,bandwidty is 3.3MHz, capacitive relative resolution 4.5×10-9pf, linear factor of 5×10-5, the detection capacitance range 4.5×10-8pf to 5×10-2pf, temperature coefficient of 67 ppm / ℃, each module parameters to meet performance targets.