| Electrostatic discharge is an important part of the electromagnetic interference source problem in the field of electromagnetic compatibility.It refers to the electrostatic phenomenon that the contact separation(friction)between substances in different charged sequence position makes the positive and negative charges on the object lose balance.With the improvement of the integration of high-speed integrated circuit and the speed of pulse signal,the wave effect in the circuit becomes more and more obvious.The simulation design with the circuit analysis method alone will cause large errors.Therefore,the influence of electrostatic discharge on electronic equipment is studied by field-circuit co-simulation.In this paper,the field-circuit co-simulation platform of ESD is established firstly.Through this platform,ESD test simulation can be carried out for electronic devices with protection shell,PCBs and corresponding chip models.The electrostatic discharge generator is verified according to IEC61000-4-2 standard.Taking the model of electrostatic discharge generator as an example,three-dimensional full wave model and fieldcircuit co-simulation model are used to verify each other,which proves the correctness of field-circuit cosimulation method.After considering the chip model on PCB,a complete circuit is constructed together with the Sparameter circuit module corresponding to the three-dimensional electrostatic discharge model obtained by full wave simulation,and then the standard field-circuit co-simulation is carried out.Based on the standard field-circuit co-simulation of ESD,the influence of 6 factors on the transmission of PCB signal,such as discharge voltage,different protection shells,different discharge points,discharge voltage rise time,different signal frequency and TVS tube,is explored.The results show that the different polarity electrostatic discharge voltage has a great interference pulse to the transmission signal waveform in the early stage,and the stable period has a lifting / suppressing effect on the waveform;the peak value of the discharge point current has a positive exponential relationship to the signal transmission voltage,while the addition of TVS has a better inhibition effect on the electrostatic discharge,and the interference voltage can be controlled within 2V.Finally,the transient field-circuit co-simulation is carried out for the model of electrostatic discharge discharging on two kinds of protection shells,i.e.cell phone shell and case shell.The electromagnetic field distribution in the whole simulation area and the specific electromagnetic field data are obtained during the discharging process.The influence of electrostatic discharge on electronic equipment is explored and analyzed from the perspective of electromagnetic field.The results show that the internal PCB of phone shell has a large amplitude electromagnetic field under ESD event due to the lack of good shielding,which makes the signal transmission of signal line greatly affected,while in case model it has a small impact on the signal transmission due to the good shielding effect of the electromagnetic field.In this paper,the research on the field-circuit co-simulation of electronic equipment puts forward a more practical and accurate simulation method for electrostatic discharge.Through the field-circuit co-simulation,the influence of different discharge factors on electronic equipment is analyzed,which provides theoretical guidance for reducing the influence of electrostatic discharge in the process of product design. |
