Stephan Frei

Computer simulation of ESD from voluminous objects compared to transient fields of humans

Computer simulation of electrostatic discharge (ESD) for simplified objects is described and compared to measured transient fields of human/metal ESD. The simulation algorithm uses the method of moments in time domain, coupled with nonlinear arc resistance model. Transient currents and fields are analyzed from the electromagnetic compatibility (EMC) point of view. Validation of the numerical simulation is done by comparison to experimental data. The simulated structure models the human/metal ESD in its peak current and field values and their derivatives reasonably well.

Fields on the horizontal coupling plane excited by direct ESD and discharges to the vertical coupling plane

Abstract Field levels in indirect electrostatic discharge (ESD) test setups are hardly known yet. It has been proposed to ANSI and IEC to use a horizontal simulator position instead of a vertical position in indirect ESD testing. This paper shows the field values on the horizontal coupling plane for different excitations and grounding topologies and questions if the goal of the change – a reduction of the simulator influence – will be achieved. Also, investigations dealing with the sensitivity of digital devices to impulsive fields are presented.

Complex approaches for the calculation of EMC problems of large systems

Large and complex systems from the EMC point of view are objects that contain different structures requiring individually composed methods for modeling as well as calculation. Automobiles, aircraft, or PCBs with devices are large and complex systems. The paper describes activities that were done to handle automotive EMC problems with computer simulations. A set of methods was compiled to allow, in a first stage, a fast calculation model generation, and, to apply in a second stage with minimum user interaction, accurate and fast multi step hybrid methods. The paper focuses less on the methods themselves, but more on the completeness of the process chain that is required to do successful simulations of automobiles or other large systems.

A failure levels study of non-snapback ESD devices for automotive applications

Snapback ESD devices suffer from increasing danger when the protected ICs experience ESD events in powered up states. To ensure more reliable ESD protections, non-snapback ESD structures are gaining more importance in the field of automotive ESD design. Two types of on-chip non-snapback ESD devices, pn-diodes and active FET structures are investigated in this work regarding their failure levels. Characteristics of the ESD devices as well as electrical SOA of an nLDMOS are evaluated and discussed in detail with TCAD electro-thermal simulation, SPICE circuit simulation and mainly TLP measurements. Comparison of the efficiency of different ESD protections considering ESD window is also given, delivering the basic idea of choosing the right ESD devices in automotive applications.

Estimating Accuracy of MoM Solutions On Arbitrary Triangulated 3-D Geometries Based On Examination of Boundary Conditions Performance And Accurate Derivation of Scattered Fields

A new error metric is applied for estimating accuracy of MoM solutions on purely 3-D geometries using triangle doublet basis functions. This error metric is based on checking boundary conditions performance (BCP) on scatterer surface and shown to be suited for arbitrary 3-D geometries including open ones. First, accurate expressions for the scattered field are derived to be valid at any observation points including those on the surface of triangles. Further, BCP error metric is examined for estimating accuracy of the scattering problem solution on open cube geometry, and to find the correlation of BCP error with that for near-field characteristics. Finally, BCP error metric is applied to estimate accuracy of MoM solutions on realistic car model, and to find the contributions of its elements to the total error.

Comparing Cable Discharge Events to IEC 61000-4-2 or ISO 10605 Discharges

Cable Model (CM) discharge events can cause serious ESD damages. Especially during the automotive production process, when numerous cables are connected to electronic devices. Here exists a potential risk for electronic devices. Typical cable discharges occurring in the automotive production environment are investigated and characterized. Possible charging effects of the wiring harness were identified. Discharge shapes depending on automotive wiring harness configurations were classified. Modelling of the cable parameters was done and cable discharge events were simulated. The simulation results were verified with measurements. Possible impacts on affected electronic control units were identified and a comparison between ISO/IEC electrostatic discharges and cable discharges was drawn.

Modeling of the automotive power supply network with VHDL-AMS

Considering the ongoing increase of the amount of electronic components in vehicles the optimization of the power network is essential. To optimize the cable harness the ampacity, the voltage drop and the temperature of every cable have to be determined. In this paper stationary and transient ways of modeling cables are presented and compared. All simulation models are created in VHDL-AMS and validated with several measurements. The benefit of exact cable models is the possibility to analyze and optimize the cable harness in an early stage of development. A method to generate a simulation model of a power supply system is presented. The complete benefit of the method is illustrated with a simplified model of a typical automotive supply cable harness. The simulation results of the model are compared to vehicle measurements.

Modeling of Frequency Dependent Losses of Transmission Lines with VHDL-AMS in Time Domain

A time domain model of a three conductor transmission line considering frequency depended losses, e.g. skin-effect, for the modeling language VHDL-AMS was developed. The calculation features of VHDL-AMS were considered and flexible and efficient approximations for the frequency dependent propagation and admittance functions could be implemented. The model can be used for linear and non-linear time and frequency domain simulations. It forms a basis for EMC extensions that can be implemented using the developed approximation techniques. Modern standardized modeling languages like VHDL-AMS (Very High Speed Integrated Circuit Hardware Description Language - Analog and Mixed Signal) have the important advantage that growing model libraries permit fast creation of complex simulation models. Exchange and extension of models is easily possible. After a short introduction and presentation of the theory used for modeling, application examples are shown. The developed model is compared to measurement results and to a lossless multiconductor transmission line model. The validity of the implemented VHDL-AMS model is proved.

Computer simulation of ESD from cone

The paper is devoted to a computer simulation of the electrostatic discharge (ESD) from cone. The numerical model is based on the electrodynamical consideration of the problem. The method of moments (MoM) in the time domain, coupled with a nonlinear model of the arc, is used to develop an efficient algorithm of the ESD simulation. The transient currents and fields are analysed from an EMC point of view. The results of numerical simulation are shown to be in a good agreement with experimental data.

Enhanced MoM scheme with incorporation of general N-port networks in application to automotive EMC problems

An enhanced MoM scheme is suggested to effectively handle EM and EMC problems with including general N-port networks. This scheme is based on incorporation of network equations for voltages and currents into the standard MoM scheme. Application of this scheme to handle complicated automotive EMC problems is considered. Potential of integrated MoM-network scheme to solve complicated automotive and other vehicle EMC problems is outlined.