A MEMS gyroscope readout circuit with temperature compensation

This paper presents a high precision integrated circuit for readout of a bulk micro-machined vibratory gyroscope. The fully differential circuit has adopted the chopper technique, combined with the differential-common duo-opamp structure, which has been proved excellent capability for low frequency noise cancellation. As the readout sensitivity is proportional with both the amplitude of the chopper modulation signal and the gain of the charge sensing amplifier, we have designed an on-chip modulation signal generator, of which the temperature coefficient is adjusted right opposite against the amplifier, so that temperature compensation is accomplished. The chip measures 2.1×2.1mm
²
in a standard 0.35μm CMOS process. The simulation shows that with a single 5V supply, the readout circuit achieves 0.11aF/rtHz resolution, and 0.85mV/fF sensitivity with 30ppm/°C temperature drift.