Research On Key Technology Of DAC Chip For Fiber Optic Gyroscope

As the core device of the inertial navigation system,the fiber optic gyroscope is a low-cost,all-solid-state,high-precision angular velocity sensor,which has a wide range of applications in the fields of national defense and civil use.At present,due to the deterioration of relations between China and the United States,the IC industry has been severely hit,and most of China's chips have been severely restricted.Especially for fiber optic gyroscopes that are widely used in the military field,the localization of its chips is imminent.This article mainly focuses on the localization of DAC chips in fiber optic gyroscopes,theoretically analyzes the influence of DAC on fiber optic gyroscopes,and designs DAC chips that meet the working requirements of fiber optic gyroscopes.The specific research contents are as follows:1.The basic working principle of the fiber optic gyroscope is studied,the structure of the fiber optic gyroscope is analyzed,and the modulation and demodulation technology of the fiber optic gyroscope is analyzed;2.The fiber optic gyroscope simulation model was built in Simulink to realize the system-level modeling of the fiber optic gyroscope,and by analyzing the model,the design indicators suitable for the fiber optic gyroscope DAC were obtained,and the requirements for subsequent DAC design were clarified;3.On the basis of the DAC design index,the common structure of the existing DAC is compared,the current type structure is selected,the best segmentation is "5+5+6" through model simulation,and the behavior-level modeling of the DAC in Simulink And error analysis,focusing on the impact of random error,gradient error and current source finite output impedance caused by mismatch on the INL,DNL,SFDR and SNDR of the DAC;4.The DAC module is designed under the TSMC 0.18 ?m 1P6 M process,including bandgap reference,amplifier,calibration circuit,temperature coefficient compensation circuit,decoding circuit,current source switch tube and delay synchronization circuit.Carry out circuit simulation on the designed DAC circuit module,and obtain that the DAC circuit jumps from all “0” to all “1”.The setup time is 13.5 ns,20 MHz sine wave is input,and the SFDR is 83.9 d B when the sampling clock frequency is 50 MHz.The simulation results show that the DAC designed in this paper can meet the requirements of the fiber optic gyroscope.