• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 63 subscribers
  • Views 249 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

UCC256402: simulation model

paul brooking
Prodigy 20 points
Part Number: UCC256402
Other Parts Discussed in Thread: UCC25600, UCC25660

Tool/software:

Hi, is there a simulation model for UCC256402  that i can use on LTspice ot LTPspice ?

The only moel I see says simplis, presumably intended to run on this.

I have only just downloaded Pspice not familiar with it yet.

I am particularly concerned about the multiplexed function pins I think there may be problems doing what I require.

Paul

  • 0
    TI__Guru 50190 points

    HI Paul,

    Unfortunately the LLC topology is too complex for a spice model to support. If we were to create one, it would take a very long time to simulate even  few switching cycles. This is why we only have a Simplis model or the EVM.

    Also note, we can not support any models for LTspice. We do have Pspice for TI, but the LLC model is not in there for the above reason. 

    We do have a newer LLC controller which might be easier to bring up if you are not familiar with the LLC topology. The UCC256602 is the newest controller in this family of products. 

    I hope this answers your question.

    Regards,

    John

  • 0 in reply to JCHK
    Prodigy 20 points

    Many thanks John,

    that does answer my question. I have used the UCC25600 before (which I see now does have a model). I am familiar with the basic operation of a variable frequency LLC PSU, but it is the functionality of the chip that I would like to get a clearer understanding of than I feel I have got from the datasheet. An example is the LL/SS pin and interaction of multiple functions.

    I feel I cant use the UCC25660X series chip because the version without X cap discharge does not seem to be widely available. In the current situation of component supply I feel it is only safe to design in things that seem to be widely used. In my application where there is an unusual front end the X cap discharge would be a problem, I would not be able to supply it with AC.

    There do seem to have been a sucession of controllers after the UCC25600, the 25630x, 25640x, 25660x, is there anything in particular about the 25640x series that has been resolved in the 25660x and I may find a problem? My application is not very demanding, although there is only limited time available for start up.

    Best wishes Paul

  • 0 in reply to paul brooking
    TI__Guru 50190 points

    Hi Paul,

    The UCC256602 is in preview on TI.com and will be fully released before the end of the year. Some of the key improvements the UCC256602 has over the UCC256402 are:

    1. HIgher resonant frequency - so far the UCC25660 series is the fastest LLC on the market which can resonate up to 750kHz. During startup, the switching frequency can get as high as 1.6MHz to quickly get into resonance

    2. Wide VIN/VOUT support - The UCC25660 series introduce IPPC (Input Power Proportional Control) which makes it much easier to maintain burst mode and over-load power limit thresholds with varying input and output voltages

    3 Improved Soft start - With the UCC25660 series, even with a compromised layout, it is far less sensitive to external noise fooling it to prematurely exiting soft-start. 

    I hope this answers your questions.

    Regards,

    John