Design Of High Precision 4Th-order MASH ?-? DAC In Digital Silicon Gyroscope

MEMS gyroscope is an effective angular motion detection device and has a very wide range of applications.The micro-machined gyro sensor system mainly includes two parts: a sensor structure and a sensor interface circuit.Among its interface circuits,the accuracy of the digital-to-analog converter has a significant influence on the output signal drive signal accuracy of the interface circuit,and can achieve closed-loop control of the MEMS gyro.Therefore,designing a high-precision DAC has a very important significance in the design of digital gyro integrated circuits.The Delta-Sigma DAC can obtain higher precision with lower hardware consumption than other DACs.It can be applied not only to digital gyro ICs,but also widely used in audio processing and signal processing.It's now a major hot spot for hybrid integrated circuit research.This article begins with a description of the structure and working principle of the Delta-Sigma DAC.System-level design and circuit-level design are performed for each sub-module.Mainly include: 2-1-1 MASH structure Delta-Sigma modulator,2nd-order DWA algorithm module,improved switched-capacitor DAC and a low-pass filter.The overall design shapes the signal with a Delta-Sigma modulator and cancels the non-linear error encountered by the multi-bit quantization through the 2nd-order DWA algorithm block.It is then passed to the sc-DAC and the analog low-pass filter to restore it to analog signal without quantization noise.After the completion of the overall design,the system was simulated with digital-analog mixed-signals to verify that the overall function meets the requirements of the technical specifications,and the work of the overall layout is completed,and post-simulation is performed.In this paper,the design using HHGrace 0.35?m technology to achieve a high-precision Delta-Sigma DAC can be applied to the MEMS gyro drive circuit part,the signal bandwidth 20 kHz,clock frequency 6.4MHz,the effective number of bits of the digital front-end part reached 24.79.In the end,the achieved dynamic range eventually reached 106 dB.