Research And Design Of Delta-Sigma Modulator Using High Precision Feedback DAC

In today’s signal processing technology,to process the signal,the analog signal needs to enter the analog-to-digital converter through the input,convert it into a digital signal,and then pass through the digital-to-analog converter and the actuator to convert it into a digital signal after a special digital signal processing process.The analog signal required in the real world,in which the performance of the analog-to-digital converter will directly affect the accuracy of signal processing.Among them,the application of high-precision analog-to-digital converters in the fields of bio-medicine,high-precision audio equipment,and application interfaces has become more and more extensive.The design of highprecision Delta-Sigma ADC has also become one of the mainstream direction in the design of analog-to-digital converters.For the application of high-precision broadband Delta-Sigma ADC,Based on Cadence software under the 0.188μmCMOS integration process,this thesis designed a DeltaSigma modulator using high-precision DAC feedback.Based on the precision DAC feedback,try to improve the precision to a higher level.This thesis analyzes the advantages and disadvantages of Delta-Sigma modulators with different architectures,and finally chooses the 4th order 4bit CRFF structure for modeling simulation and circuit design.In the Matlab modeling and simulation,we simulated several main non-ideal effects of the Delta-Sigma modulator,and calculated the coefficients to obtain the final modeling results.According to the parameters of the model,we then carried out circuit design,module Validation and overall simulation validation.In the schematic simulation,the input signal is 28.07 KHz and the amplitude is-0.6d B,then the signal-to-noise-distortion ratio reach to 111.15 d B.The total circuit bandwidth is 100 KHz,and the clock frequency is 10 MHz.Eventually,the Schreier figure of merit of is 172.05 d B,which meets the designed performance.