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Questions tagged [ltspice]

Anything related to LTSpice. LTspice is a SPICE simulation, schematic capture and waveform viewer program from Linear Technology. LTspice is freeware with very liberal license, it is lightweight and isn't crippled in any way.

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30 views

High Voltage Cascode with MOSFET LT Spice Simulation

I'm an electronics engineering student and want to develop a high voltage switch with normal Si N-MOSFETs. After some research, I discovered cascode switches for this application. Most of these ...
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37 views

Problem simulating LMP8645 current sense amplfiier in LTspice

Basically the problem i am getting is that the output offset voltage is extremely large (58mv) here is the datasheet for the amp: http://www.ti.com/lit/ds/symlink/lmp8645hv.pdf on page 9 it shows ...
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176 views

What's wrong with my input circuit? LTspice

I am designing my first power electronics board in LTspice to convert single phase AC to DC. This DC is fed to asymmetric bridge to drive an SR motor which is connected to a flywheel. This flywheel ...
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160 views

Nodal Analysis - solving 2 variables with 3 equations

There are three conditions: before the switch is closed (opened) while the switch is closed (closed) after the switch is closed (opened) I think I need to solve them sequentially, because the system ...
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2k views

LTspice, how to model a TLine

I am trying to do a simulation for a transmission line, I can draw below example circuit but got below two questions. How to do this step: .model TLine LTRA(...) ...
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361 views

Using SPICE to model dV/dt filter for inverter motor drives

I am starting to learn LTSPICE to create model where I can test various passive filter topologies for inverter drives where the output PWM has very short rise times and high switching frequency. I ...
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5k views

LTSpice Solar / photovoltaic simulation

I've been trying to simulate a solar cell with LTSpice to generate an I-V curve. The model I've been using is the simplified equivalent circuit model with a current source in parallel with a diode. ...
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62 views

In LTspice can I convert the units of an FFT which by default seem to be shown in dBV to dBµV?

In LTspice can I convert the units of an FFT which by default seem to be shown in dBV to dBµV? Cause of reason: The reason for this is that I've a modeled a LISN in LTspice where I want to simulate ...
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252 views

3-Phase Inverter simulation

I'm trying to simulate a 3-phase inverter for BLDC(PMSM) in LTSpice. The problem is that drain current is way too high and also phase voltage isn't right. **New image *One leg If I put one source(...
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117 views

LTspice simulation of AD8421 instrumentation amplifier giving incorrect output voltages

I am trying to run a simple simulation of an instrumentation amplifier (AD8421, model from here) running on a single supply, but the output does not seem to be correct. The screenshot below shows the ...
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91 views

Importing transistor spice model to LTSpice not working

Using LTSpice XVII. I want to import the Diodes Incorporated ZXTP19020DG model. The SPICE model from their web site is: ...
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64 views

Improve mosfet spice model for LT spice solver

I have a SI7460DP spice model that I would like to use in a DC DC buck\boost converter (LT8390). I'm using the standard LT spice file generated by LT powercad (boost converter going from 12 to 15V). ...
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152 views

Can the directory/path on the schematics be disabled for the print in LTspice?

When you print preview from LTspice schematics the program automatically adds path/directory of the file to the bottom of the pdf. Not really a question directly related to an electrical engineering ...
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59 views

LTspice Hung Up For Certain Voltages?

I am running a transient model of a Type-E PFN circuit (probably not an important detail) and my processing time jumps from about 1 minute for one DC source voltage to roughly 475 years for another. ...
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243 views

How's this for an SSR LTspice model?

I probably need to use an SSR for a design. I have never used SSRs, I just know things that have read on data sheets and the internet. I am planning on using the following spice circuit for a model... ...
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51 views

irritation in LTspice

I have written some measurement commands in LTSpice to calculate the weighted harmonic distortion (PWHD) .meas a1n INTEG (I(Lgra)*cos(2*n*180*fg*time)) .meas an PARAM a1n*2*fg .... (if somebody ...
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887 views

LTspice unicode trouble with micro symbol

I am having a pretty simple issue with LTspice, I built my circuit and it works fine, but the units for the capacitors don't display properly and I get the that "fE" unicode error I guess instead of ...
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1k views

Use variable in SPICE parameter list

I'm using LTSpice XVII to try and simulate a circuit. I've created a schematic which uses a Pulse voltage source to simulate a rotary encoder as follows: As you can see in the PULSE component, I'm ...
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102 views

Modelling a LED Array for SPICE simualtion

I am currently looking to model a whole LED array within LTSPICE. I am working on all of hte logistics right now. I currently have a LED array with about 300 LEDs on the array. Instead of modelling ...
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185 views

Simulating varicap diode in LTSpice

I have been looking into making a voltage controlled oscillator using varicap diodes, however I have had hard time simulating the diodes in spice. Would anyone here have an idea how this would be ...
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78 views

Problem with Simulation Results VS Tested Results for a signal

For the circuit shown i am having some trouble wondering why my tested signal looks like this (i understand that it could be clipping) but when i measure my circuit in the simulation it is correct? ...
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97 views

How to interpret LTspice simulation outputs for improving dual channel boost converter design using LTC3788

I am working on a boost converter design using the LTC3788. I would like to take advantage of the dual output capabilities of this chip to produce 24 VDC at 4 amps on one output and 48 VDC at 2 amps ...
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1k views

MOSFET Parameters LTSpice

This is the LTSpice model of the Fairchild 2N7002 NMOS transistor. ...
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140 views

Best way to model noise in Current-to-Voltage Signal Amplifier Circuit

I'm working on a photomultiplier circuit shown below. When the photomultipliers are active, they produce a current signal, and the amplifier circuit converts that current signal into a voltage signal. ...
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139 views

LTSpice simulation :Unable to check the output values

I am new in LTSpice simulation .I have prepared the schematic of the following DC to DC buck converter design in folder i.e. C:\Program Files\LTC\LTspiceIV\Rough\ . My aim is to make a charger for a ...
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843 views

LTSpice: How to save output from multiple .op runs

So this is a somewhat complicated question... I am trying to run a .op simulation (DC operating point), using the .step command to iterate through a bunch of component values. I would like to save the ...
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66 views

Modelling transformer voltage drop in LTspice

I read that a transformer has a rated secondary voltage at a rated load current. So open-circuit voltage and any secondary voltage at different loads will be different. When modelling this in ...
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2k views

Diode emission coefficient and saturation current

I have created a Zener diode model in LTSpice, and now I am trying to simulate it with different values of the saturation current (IS), emission coefficient (N) and breakdown voltage (BV) using Spice. ...
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244 views

modelling of solar cell: offset in short-circuit current

I am trying to simulate the IV curve of a solar cell in reverse and forward bias. I have used bishop equation that you can see in the following picture. The mathermatical model is in good accordance ...
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251 views

Simple Interconnect circuit to simulate crosstalk in ltspice

I want to implement a very simple interconnect circuit to simulate crosstalk in ltspice because I am new to this area of crosstalk. Where can I find such a design? I have searched in the net but all ...
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1k views

Importing a verilog-a compact model in ltspice

I have a Verilog-A compact model, and would like to import it in LTSpice. I tried to google this, but to no avail unfortunately. Can anyone tell me how to do this if possible? By the way, in spectre ...
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555 views

Resonant circuit using LTSpice

I'm a college student and I was supposed to draw the Bode-plot of the following resonant circuit. I obtained this. My questions are: shouldn't I have obtained a bell-shaped curve? How can I find the ...
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130 views

What is wrong with this LTspiceIV model of a Deliyannis bandpass filter

I'm trying to analyze a Deliyannis bandpass filter at fc=7.15Mhz. I have constructed the following in LTspiceIV: which results in the following net list: ...
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127 views

boost and flyback converter

I am currently analysing this circuit But I ran into some problem since the boost component standalone raises the voltage to 40v the flyback is suppose to bring up the voltage to a further 540v ...
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329 views

Convergence problem in pspice but not in ltspice

I am trying to simulate a circuit in LTSPICE and it simulates without any convergence problems. However when I copy the netlist into pspice and try it simulate it I get strange results. It keeps ...
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700 views

LTSpice missing an SSR Component?

I want to simulate some circuits with SSR component but LTSpice does not provide this. From Eagle and KiCad I learned I can create my own component diagram. I'm not sure if I can do this also with a ...
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353 views

Spice code for uplim and dnlim?

Does anyone know where I can get sources for LTspice's uplim and dnlim? I'm trying to port a netlist from LTspice to ngspice. ...
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How can I force LTspice to redraw a plot during a long simulation?

Sometimes during long simulations, the LTspice plot window will display a yellow "broken" icon, and/or simply not render parts or all of the data. Sometimes the axis are missing, sometimes it only ...
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21 views

How to simulate memristor crossbar array in spice properly?

I am trying to simulate a memristor crossbar array. But I found the readout voltage is constant for 3x3 and 5x5. Theoretically, the readout voltage should decrease with crossbar size. I check the ...
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32 views

Instrumentation Amplifier Output Voltage Questions

Ok, so I am currently trying to build a temperature sensor based Instrumentation Amplifier circuit using the AD8429 (data sheet link here). The schematic for my circuit so far is below: A very basic ...
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18 views

Singular Matrix: Check node warning

I'm trying to design a regulated power supply. When I try running the following circuit in LTSpice, I get the following error message: ...
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33 views

How do you adequate select correct number of data points and binomial smoothing for correct FFT in LTspice?

I'm trying to simulate what a spectrum analyzer (SA) would see from a LISN, to get a rough know how. Previously solved: In LTspice can I convert the units of an FFT which by default seem to be shown ...
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37 views

Auto-numbering components in LTspice

I'd like to re-number the components of my LTspice simulation from left to right and top to bottom to make the schematic more presentable. For example, in the circuit below, I'd like R44 to be R1, R50 ...
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47 views

Zener Controlled transistor series voltage regulator using LTSpice

I have been designing a Zener Controlled transistor series voltage regulator circuit using LTSpiceXVII. MMSZ5232BT1G is the zener diode (5.1V). For various DC voltages (6V, 8V, 12V, 16V, 20V, 24V and ...
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21 views

Bandpass filter severely attenuating input signal in passband

I've designed a 3rd order chebyshev passive bandpass filter with 10% BW and center frequency of 10kHz. However, when I feed it a 10kHz sine wave to the input, it immediately gets severely attenuated, ...
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35 views

LTspice simulate

I try to do simulation with a saturating inductor of flux model. And when the flux function is simple such as k*x etc, the simulation can run correctly. When this function becomes more complicated, ...
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64 views

Open loop Flyback simulation LTSpice

I am designing a flyback converter with an input voltage of 220Vrms and a 600V output with a current of 0.1A. To begin with, I am considering a 310V DC voltage input, and simulating the open loop ...
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41 views

Infinite Negative Magnitude in LTSpice

I am trying to make a current Dependent current source LTspice and I finally got it to compile, only to get a magnitude of -1.#INFdB on my readout. The dependent sources on this program are very ...
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68 views

Low output voltage on buck converter

I am making use of the LM2678 adjustable version switching regulator in the design of a 5.5V buck converter. I made use of the design equations detailed here: lm2678 datasheet For the following ...
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129 views

Simulation of 3-phase inverter and bootstrap capacitor in LTSpice

I'm trying to simulate three phase inverter for BLDC. Because of floating potential of high side MOSFETs I need to use bootstrap capacitors. After looking at some datasheets/forums I thought that I ...