PREFACE 5 THE AUTHOR 6 INDEX 7 FOREWORD 21 1 LTSPICEIV: INTRODUCTION AND HISTORY 25

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1 INDEX PREFACE 5 THE AUTHOR 6 INDEX 7 FOREWORD 21 1 LTSPICEIV: INTRODUCTION AND HISTORY Circuit simulation with LTspice IV The three basic steps Results analysis The story of LTspice IV CANCER to SPICE to SPICE to SPICE to The birth of LTspice LTspice/SwitcherCADIII LTspice IV version since the end of What are the main benefits of LTspice IV? What can LTspice IV do? What LTspice IV cannot do Conclusion 32 2 FILES SUPPLIED WITH LTSPICE IV Installation of LTspice IV System requirements Downloading LTspice IV How does LTspice IV work? LTspice IV's editors Included files Models, subcircuits, macro models, and component libraries Application examples LTspice IV file extensions 42 3 WORKING WITH LTSPICE IV AND FIRST EXAMPLE First use of LTspice IV Launching LTspice IV in Windows How LTspice IV works LTspice IV start-up phase menus File Menu View Menu

2 3.3.3 Tools Menu Help Menu: This menu is the same in all stages of LTspice IV Start-up page pop-up menu A detailed example, step by step Drawing a schematic Enter the parameters of components Enter simulation parameters First frequency measurements Transient measurements FFT measurements Measures of harmonic distortion Maximum amplitudes before clipping Zooming in on part of the trace to identify a defect To conclude this first approach 86 4 SCHEMATICS EDITOR The commands of LTspice IV Schematics editor File menu Edit menu Hierarchy Menu View Menu Simulate Menu Tools Menu Window Menu Help Menu Schematic editor pop-up menu Components databases Draw a new schematic Open the schematic editor Place the first elements on the schematic Main commands of the schematic editor Connecting elements from the schematic Enter the value or reference of a component Enter the values of a component with the attribute editor Enrich the schematic (optional) Add simulation, source and directives (optional) Save your schematic Launch the simulation Incorporation of a wiring BUS Reminder of the schematic editor use rules You must be very careful about two points: Export a schematic 116 8

3 SYNTAX AND COMPONENTS EDITOR General syntax rules in LTspice IV Component values editor Procedures to access usual or complex component models.. Changing the current values of a component Display of attributes and modification of components' values. Allocation of the attributes editor fields Display of a component's attributes using two models SYMBOL EDITOR AND HIERARCHY Symbol editor menu File Menu Edit Menu Hierarchy Menu Draw Menu View Menu Tools Menu Window Menu (management of the display windows) Help Menu Symbol editor context menu First step: Drawing the symbol Second step: Adding connection terminals Third step: Adding or modifying attributes Possible calls from a symbol Visible attributes connected to the symbol Automatic symbol generation from a section of the schematic Automatic symbol generation from a Netlist Hierarchical links in LTspice IV Hierarchy usage rules A method similar in concept to the Matryoshka dolls Hierarchy structure rules Levels hierarchy Commands of the Hierarchy menu Example: Work flow of a simple two-level hierarchic structure. Screen number 1: Subcircuit model Screen number 2: Secondary schematic Screen number 3: Main schematic Screen 4: Simulation of the main schematic Export of the hierarchy directory Interactivity between the lower and the higher level NETLIST EDITOR The origin of Netlists The Netlist: A mandatory step Structure, syntax and conventions of Netlist,

4 7.4 A Netlist example Netlist editor menus Edit Menu View Menu SimulateMenu Netlist editor context menu Writing a Netlist Syntax of Netlist files.cir,.net or.sp How to open the Netlist editor from a schematic Running a Netlist Exporting the Netlist of a schematic System commands used in Netlists MEASUREMENTS, VIRTUAL OSCILLOSCOPE AND FFT EDITORS LTspice IV waveform viewer Display of the simulation calculation results How to select measurement points on your schematic? How to display a measurement on the virtual oscilloscope? Visualise a ground referenced voltage Visualise a current Visualise a differential voltage (not ground referenced) Erase previous traces Selectively erase one or more traces Display instantaneous power dissipation Display average power and energy integral of power over time displayed Display average voltage or current over the displayed period or effective value (RMS) Use of menus Virtual oscilloscope and FFT analyser editor File menu View menu Plot Settings Menu (Configuration of the virtual oscilloscope) Simulation Menu (Launch simulation) Tools Menu Window Menu Help Menu Virtual oscilloscope context menu Choosing the measurements to display Add a trace or a screen Add a trace Add a screen Zoom functions Mathematical operations in the virtual oscilloscope Request the calculation of an algebraic expression Modify the appearance of a trace User-defined functions

5 8.10 Modify the axes scales Vertical axis scales Horizontal axis scales Use of the virtual oscilloscope in X-Y mode Context menu and scales Other scales configurations Left vertical scale Only display the phase Left vertical scale Display management of several traces on the virtual oscilloscope Information about the virtual oscilloscope traces Other traces customisation in the virtual oscilloscope Control of the virtual oscilloscope's colours Two measurement cursors Placing measurement cursors on traces Display of coordinates in the bottom banner Save the virtual oscilloscope configuration Acceleration of file loading RAM and addressing space SIMULATIONS CONFIGURATION DIRECTIVES Definition of a simulation directive Simulation directives editor Syntax of simulation directives First syntax rule Second syntax rule Third syntax rule Never forget a mandatory parameter Options parameters modifying the execution of a simulation IC Fix initial conditions for transient simulation Savebias Save a DC operating point Loadbias Load a DC operating point Net Calculation of a network parameter with an AC simulation Nodeset Initial conditions for DC analysis THE SIX MAIN SIMULATIONS Presentation of the six main simulations DC simulations (continuous) AC Simulations (frequency) Non-linear circuits simulations Simulations characteristics Choice criteria regarding simulations If the only excitation source of the circuit is a direct voltage source The only excitation source of the circuit is low amplitude alternating voltage

6 The only excitation source of the circuit is a high amplitude alternating voltage source (or any other causing the non-linearity of the components of the circuit) OP - Simulation of a continuous polarisation point DC - DC source sweep analysis (one to three sources) TF -Transfer function simulation (gain, input and output impedance) AC - Simulation of an AC signal around a polarisation point NOISE- - Noise simulation TEMP - Temperature sweep simulation TRAN - Transient simulation (non-linear) Configuration of the transient simulation.tran Be careful with the Maximum Timestep value Parameter:.uic (transient simulation) Parameter: startup (transient simulation) Parameter: steady (transient simulation) Parameter:.nodiscard (transient simulation) Parameter:.step (transientsimulation) FOUR - Edit harmonics as numeric format How does the FFT analysis work? Conditions to fulfil to obtain a representative FFT analysis Influence of Stop Time and Time step parameters on the FFT Monte Carlo statistic simulations First step Second step Third step Comment on the Monte Carlo method Simulations configuration NUMERIC MEASUREMENTS, DOWNLOADS, BACKUP AND MODELS Retrieving measurements as numeric data Retrieving measurement files as numeric data Declaration of variables MEAS - Display measurements values numerically First type of measurement: For only one X-axis point Examples of use of.meas for only one X-axis point Second type of measurement: For an interval between two points on the X-axis Examples of use of parameters rise, fall, last and cross Case of a NOISE simulation Creation of a measurement script: File_name.meas Precision of results obtained with the command.meas PARAM - Variables & Parameters STEP - Configurable intervals The commands. step and select steps, step by step FUNC - User functions Efficiency report of a DC/DC converter: steady FERRET - Download a file online

7 11.8.GLOBAL General declaration SAVE Limitation of the quantity of saved data WAVE -Transform the output signal to.wav Comments for.wav files Configuration of a component value with the command. param MODEL.-Define a SPICE model SUBCKT - Define a subcircuit INCLUDE - include a new library LIB - Models or subcircuits library Encrypted library IMPORT OF COMPONENTS MODELS Does LTspice IV need to download components models? Macromodels and models Macromodels or models file extensions:.model or.mod Subcircuits Libraries and models A component model consists of two elements Symbols to call components Downloading a component model Three extensions for three ways to add components One symbol can call several elements Models libraries How does the compiler detect that one component rather than another is used? Each component has several possible models Models Example: Subcircuit library 74htc.lib Example: Darlington bipolar transistor MJ First step, download Second step, automated symbol creation Third step, symbol adaptation Example: Operational amplifier TL How to create a subcircuit? Creation steps of a new circuit Illustrated example of creating a subcircuit VOLTAGE AND CURRENT SOURCES EDITOR Two types of sources and two editors Two types of sources: dependent or independent All simulations require independent sources Voltage or current sources must be adapted to the requirements of each type of simulation How to place a source on a schematic Three independent sources Nine independent source, 6 linear sources and 3 non-linear sources Two dependent sources (obsolete)

8 13.5 Independent sources V Independent voltage source PULSE tension source SINE voltage source EXP voltage source (exponential) Frequency modulated voltage source (SFFM) Voltage arbitrary source modulated by PWL Voltage source modulated by a. wav file I Independent current source PULSE current source SINE current source (sinusoidal) EXP current source (exponential) Frequency modulated current source (SFFM) Modulated current sources Load Independent active load Independent sources editor Independent source frequency sweep configuration for an AC simulation Configuration of independent sources for a DC simulation (small amplitudes) Configuration of independent sources for an AC simulation (small amplitudes) Configuration of independent sources for transient simulation (high amplitude) Independent sources E Voltage controlled voltage sources First model: The transfer function is a constant value Second model: The transfer function is a table of couples of values Third model: Transfer function is a Laplace transform and is a function of S F Current controlled current source Example G Voltage controlled current source First model Secondmodel Third model H Current controlled voltage source B Non-linear arbitrary voltage source For an arbitrary voltage source B Non-linear arbitrary current sources Epoly Non-linear polynomial voltage source Gpoiy Non-linear polynomial current source Attributes editor for dependent sources PASSIVE COMPONENTS Passive components Preamble to the use of component model parameters R - Resistor (one model) C - Capacitor (two models) First model of standard capacitor

9 Second model of capacitor L. Inductor First inductor model (linear without saturation) Second model (non-linear) Third model: CHAN (non- linear with saturation and hysteresis taken into account) Hysteresis cycle Differences between inductors with and without magnetic circuit Wound inductor without magnetic circuit Wound inductor with magnetic circuit K Transformers (mutual inductance) Mutual inductance with several windings Other ways to make a transformer with saturation and hysteresis SEMI-CONDUCTOR COMPONENTS Semi-conductor components How to choose a component model D Diode (three models) First standard model of diode Second diode model Power parameters common to both models Q Bipolar transistor (three models: Ebers-Moll, Gummel-Poon and VBIC) First (Ebers-Moll) and second (Gummel-Poon) model Third model (VBIC) J JFET transistor (one model) M Monolithic MOSFET (several models) Monolithic MOSFET MOSFET transistor models M Double vertical diffusion MOFSET (one model) Z MESFET transistor (one model) ACCESSORY COMPONENTS Other accessory components Preamble to the use of component model parameters S - Voltage controlled switch (two models) Standard model Level=l Second complete model Level= W Current controlled switch (three models) First standard model Lossy transmission line (one model) T. Lossless transmission line (one model) U RC transmission line (one model) A. Special functions Special functions INV, BUF, AND, OR, XOR Special functions SCHMITT, SCHMTBUF, SCHMTINV, DIFFSCHMITT, DIFFSCHMITTINV and DIFFSCHMITTBUF

10 Special functions DFLOP and SRFLOP Special function PHIDET Special function VARISTOR Special function MODULATE Special function SAMPLE X Calling a subcircuit INDUCTOR, HYSTERESIS CYCLE, TRANSFORMER AND MUTUAL INDUCTANCE Interest in using a magnetic circuit Operation of a magnetic circuit Some useful definitions Paths on the hysteresis cycle First magnetisation curve (dotted line) Path of the hysteresis cycle (full line) Measurements of inductance, magnetic field and induction The CHAN model (saturation and hysteresis) Inductance measurement Measurement of the magnetic induction flux density Three examples of hysteresis cycles Hysteresis cycle with airgap Hysteresis cycle with several values of H Hysteresis cycle with continuous polarisation Presentation of four LTspice IV transformer models First two transformer models without consideration of saturation and hysteresis Four values are necessary for models 1 and Two important values, the coupling coefficient K and the transformation ratio N Two equivalent schematics for models 1 and Transformer model 1, K=1 and explicit leakage inductance Transformer model 2: K different from 1 and implied leakage inductance (calculated by LTspice IV) Case of transformers consisting of several windings Determination of a transformer according to the characteristics of an SMPS Our choice of transformer Calculations of the model's values from measurements or characteristics Models 1 and 2 of the transformer Schematic of the SMPS with transformer n Schematic of the SMPS with transformer n Conclusions about these two methods Case of transformers with multiple windings Saturation problems of the transformer Transformer model n 3 (with saturation and hysteresis) Transformer model No. 3 made with a subcircuit Subcircuits with only one secondary Transformer subcircuit with several secondaries Integration of the subcircuit (transformer model No. 3) in an SMPS

11 17.29 Setting of a snubber (overvoltage clipper) Exceeding a component's characteristics Similitude between simulation results and measurements taken on a wired prototype Conclusions for the similitude between simulation and real measurements CONTROL PANEL AND KEYBOARD SHORTCUTS Presentation of the control panel in nine tabs Compression tab (options related to data compression) Save Default tab (options related to saving) SPICE tab (LTspice IV simulation core operating options) Precautions concerning SPICE configuration Simulation calculation control parameters Integration method control parameters Solver control parameters Drafting options tab (drafting options) Netlist option tab (Netlist syntax or writing options) Waveform tab (waveform viewer or virtual oscilloscope) Operation tab (general LTspice IV configuration) Hacks tab (internal operation of LTspice IV) Precautions regarding Hacks! configuration Hacks! control parameters Web tab (internet connection) Keyboard shortcuts configuration Interactivity of the schematic editor Schematic editor keyboard shortcuts Colours configuration (colour preferences) SOME EXAMPLES Characteristic network trace of a semiconductor component Characteristics of an N-Channel JFET, the 2N Characteristics of an N-Channel bipolar transistor, the 2N Evolution of characteristics with temperature Characteristics of a Zener diode according to temperature Amplifier circuit Amplifier specifications sheet Amplifier assembly Verification of the circuit's component values Yield Average power Harmonic distortion measurements Tracing the FFT curve Intermodulation distortion measurements Response to a square signal Let's trace the Bode diagram Noise generated by the amplifier

12 Transfer function of this amplifier Bode diagram of a regulation loop (SMPS application) Disadvantages of the classic methods Advantages of the new method Gain Bode diagram Impedance Bode diagram A simple wattmeter, application of a source B Parametric analysis of an RLC circuit Incorporation of a wiring BUS DC/DC Converter (SMPS) Use of a non-saturable air inductor Use of an inductor with a saturated magnetic circuit Use of an inductor with a non-saturated magnetic circuit DC/DC converter efficiency report Analysis according to the dispersion of component values according to the Monte Carlo method QUESTIONS AND ANSWERS What is the impact of the computer on the calculation time of a simulation in LTspice IV? Three examples of laptop computers Four examples of desktop computers What are the limits of LTspice IV? Is LTspice IV really helpful? How to retrieve the list of a circuit's components? How to easily toggle between schematic pages? How to copy/paste part of a circuit from one schematic page to another? What are the most common mistakes made when using LTspice IV? What hints and tips can save time? In which situation can LTspice IV freeze? Can LTspice IV be installed on any computer? Which concrete help does LTspice IV provide in terms of electronic circuits simulation? Are many steps required for a simulation using LTspice IV? How helpful is LTspice IV in terms of measurements? Why does LTspice IV allow the testing of more solutions? Is there a risk of becoming addicted to LTspice IV? Is LTspice IV really useful to learn about electronics? You cannot find the indicated menus or their content is different from what you expected? What flags are associated with the launch of LTspice IV? Which actions allow a simulation to be carried out? Are LTspice IV SMPS circuit models compatible with other SPICE software versions? Where can we find reliable information, models and application examples for LTspice IV users? Is there a Linux version of LTspice IV?

13 21 LTSPICE MODELS OF INDUCTORS AND TRANSFORMERS Content of the Online Model Package SMPS design and development tools Presentation of the WE-FLEX and WE-FLEX + transformers range The LTspice CHAN inductor model A sufficient precision with the CHAN model Advantages of the LTspice CHAN model First magnetisation curve Similarities between simulation and measurements on the tabletop prototype Nominal current l N depends on the windings wiring How is saturation visible in LTspice IV? Two modelling methods of inductors Three methods to model transformers WE-FLEX and WE-FLEX* transformer model Modelling methods equivalencies, outside the saturation zone Content of the Online Model Package and method of using these WE-FLEX transformer models To make a transformer or a inductor, configure the value of AG To make a transformer using the WE-FLEX model, the values of PR, PL, SR and SL must also be configured To make a inductor using the WE-FLEX model, the values of IR and IL must also be configured Tables S2 and T2: A precious help to choose the inductor or the transformer for your SMPS A complete and illustrated example of an LTspice IV WE-FLEX model used for a Flyback SMPS Transformers and inductors LTspice models How to obtain the value of the magnetic material losses? Windings wiring of LTspice CHAN WE-FLEX and WE-FLEX+ models Series and/or parallel winding of the WE-FLEX range Limits of the LTspice CHAN model for transformers The value of a inductor made with a magnetic circuit varies according to the current flowing through it Frequently asked questions 713 APPENDICES Values of L m and A to be used in the CHAN model Values of B s, B r and H c to be used in the CHAN model Parameters directly useable for the CHAN model by LTspice IV 724 BIBLIOGRAPHY 733 INDEX