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Re: libraries for electronic components
.ummm, the best suggestions starting out is to Google the data sheets and see if those devices
match up any of the circuits that have already been modeled around here. Have you designed and run a MOSFET simulation with LTSPICE yet? Might be a good place to start. Here are some useful URLs: ?? <---MOSFET docs ? <---LTSPICE tutorial ?? <---MOSFET modeling ? <---paper ?? <---youtube instructional video W. Warren |
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Re: Modelling an optoisolator
Helmut,
I tried your suggestion of using an arbitrary behavioral voltage source (Bv) with the table you proposed (V=table(I(D1), 0,0, 1m,1, 10m,4.9, 100m, 4.95), and I got the following error:? <<<>>> B1: The table function requires the ordinate followed by pairs of table points, i.e., it requires the total number of arguments to be odd. <<<>>> Here's a link to a screenshot of the LTSpice model I built:? Her's a link to the actual model:? Skip ? |
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Re: Modelling an optoisolator
Hello,
May I ask a question ? If represent the transfer function in math equation, what would be the variables which is depended to vary the output ? It seems the variable is Iin, but how to represent it in math equation ,do that belong to physical domain ? Is it possible to use the BV or BI with those equations to represent the actual behavior if once someone have got the math equation ? Thanks Best regards. ---In LTspice@..., <skip@...> wrote : I have a requirement to model an optoisolator in LTSpice. The optoisolator has an input LED that shines light on a photovoltaic cell on the output. Current in the LED will cause light to fall on the photovoltaic cell and cause a voltage to be generated on the output. I have measured the input-current-to-output-voltage characteristics of the device - Vout=F(Iin). The transfer function F is somewhat nonlinear. I have created a table of measurements listing the output voltage for a set of specific input currents. Now I am trying to build an LTSpice model that functions similarly to the actual device.? A simple first-order approximation of the device would be a current-controlled voltage source with the transfer function defined as a table. i have tried all kinds of ways to define the table in a LTSpice current-controlled-voltage-source, but no luck. Can anyone show me how to do this? What does the spice directive look like, and where (and how) do you put it in LTSpice? A second-order model will need to take into account that output impedance will also affect the output voltage (at low impedances the output becomes more like ?a current source), but that is for another day. |
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Re: course of HOWTO build models like (sanken) STR-A6100
Hi, eetech00:
Thank you. That's really a good news. I had ran the LLC topology in some simulator (NOT SPICE) for control. But it doesn't care very detail values of those hardware parameters. So far I hope to have one certain LLC controller IC in spice simulator to do some estimation. Your decision just help a lot for those people like me who want to evaluate those circuits. Best regards. ---In LTspice@..., <eetech00@...> wrote : Hi I'm creating a UCC25600 behavorial model, just as a challenge, and have almost completed it. I used switches for the? push pull drivers but I'd like to use mosfets. I've tested part of it?using the TI EVM schematic. Output driver waveform is square with dead time. But the?circuit has trouble converging.?Driver output might be too square... :-) stay tuned... |
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Re: Looking for a IDT74CBTLV3253 model.
Gunoi Nare uploaded a circuit using the built-in "Counter" logic device. Many of the logic devices require parameters, which you must attach or add to the device.? To add a parameter, right-click on the part, then type the desired parameter and its value, in the Value, Value2, SpiceLine, or SpiceLine2 fields. The Counter device was not documented in the LTspice "Help" pages.? It was added somewhat recently to LTspice.? It is "documented" in a webpage about "undocumented LTspice", here: According to that page, you have to provide at least the parameter named "Cycles", to tell the counter how many cycles to count.? Without that, the counter doesn't know what to do. For example, right-click on the counter symbol, then click on the Value line (until you can type there), and type something like this: cycles=4 Then press OK. See the LTspice Help page for A-devices, to see some of the other common parameters for these logic devices (input levels, output levels, prop. delays, etc.).? By default these parts use 0V/1V levels.? You can list more than one parameter on the same line, such as: cycles=4 ?Vhigh=5 ?Trise=10ns Regards, Andy |
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Re: Looking for a IDT74CBTLV3253 model.
Gunoi Nare
Thank you Helmut. When Attempting to open de file the error: "multiple instances of circle." is displayed. In Fact all other file will do the same thing although the word "circle' is replaced by 'Flag" or some other indicator. Is my program corrupt? G.
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Re: Modelling an optoisolator
I am sorry.
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...You must apply through a resistor negative bias... You even specify the type of optocoupler. Bordodynov. 02.08.2016, 08:05, "§¡§Ý§Ö§Ü§ã§Ñ§ß§Õ§â §¢§à§â§Õ§à§Õ§í§ß§à§Ó BordodunovAlex@... [LTspice]" <ltspice@...>: Hey. You are probably accessing the telepaths. I do not know the elementary photodetectors elements having an output value of the line voltage. If the primary receiver is a pn junction, it produces current. Having loaded his resistance, can be obtained linearly varying voltage, before starting a pn junction. Neohodimo through resistor feeding a negative bias. For example, one pin resistor connected to the positive supply. See datasheet optocoupler. |
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Re: Modelling an optoisolator
Hey. You are probably accessing the telepaths. I do not know the elementary photodetectors elements having an output value of the line voltage. If the primary receiver is a pn junction, it produces current. Having loaded his resistance, can be obtained linearly varying voltage, before starting a pn junction. Neohodimo through resistor feeding a negative bias. For example, one pin resistor connected to the positive supply. See datasheet optocoupler.
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Show quoted text
Bordodynov. 02.08.2016, 07:19, "skip@... [LTspice]" <ltspice@...>: I have a requirement to model an optoisolator in LTSpice. The optoisolator has an input LED that shines light on a photovoltaic cell on the output. Current in the LED will cause light to fall on the photovoltaic cell and cause a voltage to be generated on the output. I have measured the input-current-to-output-voltage characteristics of the device - Vout=F(Iin). The transfer function F is somewhat nonlinear. I have created a table of measurements listing the output voltage for a set of specific input currents. Now I am trying to build an LTSpice model that functions similarly to the actual device. |
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Re: Looking for a IDT74CBTLV3253 model.
Gunoi Nare
Ok.... I uploaded it. "From G. .... " G.
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Re: Current Dependent Voltage Source
rmoreno.phone?wrote: ? ?"I've tried to understand how to create a current dependent voltage source but am unable to comprehend how to get my simulation circuit to work.? Is there anything available to describe in detail how to do this?" Yes; there is the LTspice Help page for H-elements (current-dependent voltage sources).? But most of the reference descriptions there are most helpful for SPICE Netlists, and are a little vague about applying the same syntax to schematic symbols. Assuming that you are using a schematic: Voltage sources are our "ammeters".? Put a voltage source (probably set to 0V, but could be non-zero if that fits the rest of your circuit) in the branch where you want to sense the current, that will control your CCVS. Add an H element where you want it.? Then right-click on the H that is by itself.? Edit that field so that it looks something like this: Vxxx yyy.y where Vxxx is the name (reference designator) of the voltage source that is the "ammeter", and yyy.y is the transresistance or gain (in ?volts/amps) that you want. Andy |
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Re: Current Dependent Voltage Source
Hello,
Please take a look to this example from our Files-section.. ? Best regards, Helmut H. Current Dependent Voltage SourceSymbol Name: H Syntax: Hxxx n+ n- <Vnam> <transresistance> This circuit element applies a voltage between nodes n+ and n-. The voltage applied is equal to the value of the transresistance times the current through the voltage source <Vnam>. Syntax: Hxxx n+ n- value={<expression>} This is an alternative syntax of the behavioral source, arbitrary behavioral voltage source, B. Syntax: Hxxx n+ n- POLY(<N>) <V1 V2 ... V3> <c0 c1 c2 c3 c4 ...>
This is an archaic means of arbitrary behavioral modeling with a polynomial. ? |
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Modelling an optoisolator
I have a requirement to model an optoisolator in LTSpice. The optoisolator has an input LED that shines light on a photovoltaic cell on the output. Current in the LED will cause light to fall on the photovoltaic cell and cause a voltage to be generated on the output. I have measured the input-current-to-output-voltage characteristics of the device - Vout=F(Iin). The transfer function F is somewhat nonlinear. I have created a table of measurements listing the output voltage for a set of specific input currents. Now I am trying to build an LTSpice model that functions similarly to the actual device.? A simple first-order approximation of the device would be a current-controlled voltage source with the transfer function defined as a table. i have tried all kinds of ways to define the table in a LTSpice current-controlled-voltage-source, but no luck. Can anyone show me how to do this? What does the spice directive look like, and where (and how) do you put it in LTSpice? A second-order model will need to take into account that output impedance will also affect the output voltage (at low impedances the output becomes more like ?a current source), but that is for another day. |
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Need help to design a transimpedance amplifier
Hello ?guys..
I want to design a trans-impedance amplifier to detect currents of the APD (in the range of 200 nA to 100 micro A). Could some one suggest me the best IC with less bias current, single supply (+5 V only) and how to design a high sensitive TIA..? (typically, for every 100 nA change in the current, 100 mV voltage should be displayed). |
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Re: DanTherm model (SOAtherm)
I just discovered the LT application video on the SOAtherm-NMOS device. ?This looks like a really neat function. ?Searching the archives comes up with a thread from last year about converting datasheet information into SOAtherm models, but it looks like MatLab is needed. ?I'm not MatLab fluent (used it once, 20 years ago), but I'd like to model the FETs I'm using in my designs. ?Does anybody have any hints/tricks/recipes for determining the values of the entries in Dan Eddleman's DanTherm model? ?The library has these elements that determine the thermal model:
? * The following two lines are customized for each DanTherm model *? .param Tambient=85 RthetaJA=50 Cheatsink=0? .param Imult=1.00E+01 Iexponent=3.00E-01 R6=3.18E-02 C6=1.77E-04 R5=1.01E-01 ?C5=2.77E-04 R4=2.74E-01 ?C4=1.60E-03 R3=8.49E-01 ?C3=8.83E-03 R2=7.34E-02 ?C2=3.30E-03 R1=1.05E-03 ?C1=1.82E-03 Do I need to contact Dan to get his modeling information? Thanks, Carl |
Nicholas Jankowski