Circuit Design Suite (Multisim, Ultiboard)

[Huby]

I need to develop some dc/dc comverter using 3525 and UC3789. None of them are in multisim database so i was planning to create them. Can i use the standard proccess of adding the new symbol and passing the input/output variables or do i have to do something else ?

How to create/add/download such parts that are missing in database ?.

btw. i do have .asy file of the 3525 but i have no idea how to use it. 

Huby. 

[GeorgJ]

Hi Huby!

You can find a step by step tutorial on how to create a new part in Multisim on the NI website:

Creating a Custom Component in NI Multisim

For the electronic behavior of the part you need an XSpice model describing the internal circuit.

Some manufacturers offer this model on their website as a download option.

As far as could find out the asy file you have is the native file format of the

software suite LTspice from Linear Technologies:

http://www.linear.com/designtools/software/#LTspice

This file format is not compatible with Multisim. However, if you can extract the

Spice model from the file you could use it to create your own part in Multisim

(see link above).

Regards,

  Georg

[Huby]

I saw the first link before few days but i dont think that this can be used for PWM controler ?

[GeorgJ]

This is the standard procedure to add a new part to the user database.

Of course you can also create your own circuit within multisim and save it

as an hierarchical block.

http://www.ni.com/white-paper/3990/en

There is no other way to create new parts in Multisim.

Regards,

  Georg

[Huby]

OK. I came to the part 6 of 8.

In this part i have to implement spice model.

Of course i dont have it and i can't find it on the net.

What now ?

[_user32]

Huby,

The Linear Tech SMPS models are not PSPICE or standard Berkeley SPICE (SPICE3F5) models as they have specialized model elements that are only available in the LT SPICE program and thus cannot be run on any other SPICE platform directly.   It may be possible (with some additional work) to follow the example models for SMPS circuit controllers in Multisim that were done by Christophe Basso (they are standard parametric SPICE3f5 models and you can adjust the values to go along with the datasheet as close as possible to give you an approximate level of behavior/performance to the device).   There are some similar examples that are of the step up current mode variety.  They also follow his book and can get you results as discussed.   These are available in Multisim PowerPro edition. 

Regards,

Pat Noonan