To fulfill the demands of achieving low-noise and high-precision detection of capacitive MEMS gyroscopes

this paper presents a fully differential sensing circuit based on a switched capacitor structure. The design consists of two parts: capacitance detection and digital quantization processing. The discrete-time capacitor to voltage (C/V) conversion scheme is used for capacitance detection. The method of combining high frequency carrier modulation and correlated double sampling technique is proposed to reduce the low frequency noise. The quantization circuit adopts a bandpass ΔΣ modulator with a 4th-order

4-bit single-loop feedforward structure. The input signal feedforward pathway is introduced to improve the stability of the system. The internal multi-bit quantizer is used to improve the signal-to-noise ratio. The system achieves high precision with low power consumption. Based on the 0.18 μm BCD process

the overall circuit is simulated and verified under a 5 V power supply. The simulation results demonstrate that the sensitivity of the detection circuit can reach 10 mV/fF

and the equivalent input capacitive noise is 0.062 aF/Hz at 5 kHz. The quantization accuracy of the readout signal can be up to 15 bits in the bandwidth range of 100 Hz. Compared with the traditional MEMS gyroscope sensing circuit

this circuit has lower noise and higher quantization accuracy. It is suitable for high-precision detection.