Research And Design Of Digital Isolator Chip

The safety and stability are important performance index needing to be taken into consideration when electronic product is being designed.With the uncertainty of working environment such as working under humidity or high temperature,and in industial application in IGBT and the driving circuit,there is huge voltage gap between the low voltage logic control circuit and high voltage working circuit,so isolation between the two parts is needed to ensure safety.The isolation chip could implement the isolation between high voltage working circuit and low voltage control circuit and ensure the safety of the low voltage side,which has great meaning to engineering application and scientific research.This thsis focus on the research of digital isolator chip based on silicon-embedded transformer.With four solutions to digital isolator,which are set/reset modulation,amplitude modulation,pulse count modulation and pulse polarity modulation,pulse count and polarity modulation will be further analyzed and taken research for there advantages in transmission speed and signal delay.In pulse count modulation,only one port in the primary side of the silicon-embedded transformer is used,and the posedge and negedge signal is curved by double short and single pulse.While the both ports of the transformer are used in pulse polarity modulation,and the posedge and negedge signal is curved by positive and negative single pulse.Based on the two different working mode of the modulation solution,this thsis implements the transmitter and receiver module of the two solutions.And careful design and analysis has been done for submodule,which includes the filter module and monostate module to deal with the outter interference signal and inside giltch,the modulation and decode module in pulse count modulation,as well as the pulse detecting module,the high-speed comparator,the hysteresis comparator in pulse polarity modulation.In the meantime,based on the simulation flow of silicon-embedded transformer and the quivalent model of transformer,simulation and verification are done for the transformer.And the whole silicon-embedded digital isolator is emplemented in the thsis.With the process of Xfab 0.18?m,careful simulation and verification of submodule for pulse count and pulse polarity modulation have been implemented,and the function and performance indicators are well satisfied.For the two different solutions to modulation,system verification has been done with the equvalent silicon-embedded transformer,and the signal transmission has been done under the condition of 5V working voltage,-20? ~ 100? and 100 MHz input signal.The encoded signal delay is 14.55 ns under the condition defore,which is consistent with performance of the series of digital iaolator product ADuM128 X of ADI.