Research And Design Of High Speed Isolated Driver Circuit

In recent years,as the process of market demand diversification has accelerated,traditional drive circuits have been unable to meet market demand.Isolation drive circuits have attracted much attention due to their fast transmission speed,strong CMTI resistance,and full electrical isolation.The research in this paper focuses on the problem of highspeed and high-performance transmission of magnetically coupled isolation drive circuits.First,by analyzing and modeling the magnetically coupled isolators,a fast transmission speed,strong CMTI capability,small process mismatch,and small area are proposed.Features such as Cross-Over differential output magnetic coupling isolation structure.This article compares and analyzes the two traditional magnetically coupled isolation structures and Cross-Over differential output magnetically coupled isolation structures in terms of transmission efficiency,CMTI capability,process mismatch,and area,and elaborates the superiority of the new structure.At typical frequencies,the S(1,1)of the Cross-Over differential output coil proposed in this article is-23 dB,which is equivalent to the-22 dB of the traditional single-coil magnetically isolated structure,which is better than that of the traditional dual-coil magnetically isolated structure(-15dB);At the same time,S(1,3)of Cross-Over structure is-29 dB,which is equivalent to-25 dB of traditional dual-coil differential magnetic coupling isolation structure,which is better than-65 dB of traditional single-coil magnetic coupling isolation structure.Under the same process mismatch gradient,the CMTI capability of the Cross-Over differential output coil is better than the other two traditional structures,and the Cross-Over differential output structure is guided and optimized.At the same time,the new structure is verified by tape-out,and the Cross-Over is tested.The function and performance of the over-differential output magnetic-coupling isolation structure.The transmission frequency tested can reach MHz,which meets the design requirements.Secondly,based on the Cross-Over differential output magnetic coupling isolation structure,an alternative narrow pulse signal transmission method suitable for the structure is proposed,and the basic circuit for implementing this transmission method is also set up,including a narrow pulse generation circuit,magnetic coupling isolation circuit and a signal recovery circuit based on the Cross-Over differential output magnetic coupling isolation structure,and the function of the circuit is verified by simulation.Then,the joint simulation of HFSS and Cadence is used to combine the Cross-Over structure modeled in HFSS with the alternating narrow pulse signal transmission circuit in Cadence.This alternate narrow pulse signal transmission method is based on the original signal transmission method.Improved,the improved transmission method has smaller transmission delay,and can also perfectly match the Cross-Over differential output magnetic coupling structure to form a high-speed isolated drive circuit,build an overall high-speed magnetically isolated drive circuit,and perform simulation verification.The high-side input and the low-side input are respectively applied with a 10-MHz square wave excitation signal to obtain the high-side and low-side output signals.Simulation results show that the high-side and low-side on-state delays are 26.8ns and 31.6ns,respectively.Finally,circuit protection modules are added to this circuit,including over-current protection,over-temperature protection and under-voltage protection,to ensure the reliability of the circuit work.