Simulation And Experimental Investigation For Electrostatic Discharge In Electronic Equipments

Electrostatic discharge is one of the important sources of electromagnetic interference in electronic equipment.It will produce instantaneous large current and strong electromagnetic field,and cause harm or even damage to electronic equipment through conduction and radiation.For air discharge,due to its unrepeatability,the discharge process cannot be accurately simulated only by circuit level simulation or full-wave simulation.Therefore,this paper explores the air discharge process and its influence on electronic equipment by means of fieldcircuit co-simulation and experimental verification assistance.The Rompe-Weizel nonlinear arc model of air discharge described by SPICE model and the full wave model of electrostatic discharge are combined to establish field-circuit cosimulation model of air discharge.The discharge to ground with different arc length and discharge voltage are investigated,and the relationship between rise time and peak current with the change of arc length and discharge voltage is obtained.The rise time and peak current change with the excitation voltage and arc length index,but in the case of small arc length,they are similar to that of contact discharge.Combining with the characteristics of arc length changing with voltage in the experiment,the quantitative relationship between excitation voltage,peak current and rise time is obtained.The simulation results are consistent with the experimental results in the literature,which proves the validity of the air discharge field-circuit co-simulation model,and lays the foundation for the subsequent study of the influence of air discharge on PCB boards and electronic equipment.Then,this paper uses the field-circuit co-simulation model to study the air discharge of the simple PCB of the self-made frequency division circuit,and explores the influence of the arc length,discharge position,vlotage polarity and its value on the PCB device,and verifies the simulation results through experimental tests.The results show that the induced voltage of the device on the PCB decreases with the increase of the arc length.The magnitude of the induced voltage is related to the discharge path of the PCB.Under the same voltage with different polarity,the current on the PCB and the induced voltage on the device have a good symmetry.At the same time,the experimental results show that the magnitude of the fixed gap and the speed of approaching velocity have consistency to the air discharge.In addition,the problems of hard and soft failures of simple PCB are discussed by experimental test and field-circuit cosimulation.Finally,a complete field-circuit co-simulation model of electronic equipment is constructed to explore the influence of air discharge on the signal transmission of electronic equipment.The effects of different arc lengths,different voltages,different discharge media and different discharge positions on PCB signal transmission are obtained through standard field-circuit co-simulation,and the transient field-circuit co-simulation method is used to obtain the electric field distribution on the front of the PCB during the discharge process.The degree of damage at different positions is estimated through the value of Poynting vector at different positions.The results show that the disturbance of the signal decreases with the increase of arc length,and increases with the increase of excitation voltage.Various factors,such as discharge medium and discharge position,will cause different discharge current and signal disturbance through the superposition of various comprehensive factors,such as its relative position to the detection point,the different discharge path formed by the wiring on PCB board,the different impedance to ground circuit and so on.In this paper,based on the field-circuit co-simulation method,a more practical simulation method for the air discharge research of simple PCB devices and complex electronic equipment is provided.The influence of different factors on electronic equipment is explored,which provides theoretical guidance for reducing electrostatic interference in the process of designing and preparing electronic equipments.