Reg: UCC28070 PSPICE SIMULATION

 

Dear Friends,

I'm trying to do simulation of PFC in OrCAD. I've downloaded the PSPICE library file from TI website; also I've downloaded one PFC simulation circuit with UCC28070 controller from same TI website. While I'm running this simulation file it is working fine, even if I'm changing the values in the schematic it is working fine. But, I tried to make separate PFC simulation circuit as per my requirement I'm facing a problem with the PSPICE library, because "IRIPA, IRIPB and F_KHZ" are the terms which I'm not able to find it from datasheet. So please help me to solve this issue.

 

Thanks & Regards,

A.Arun

  • Hi Arun,

    Since the average model is averaging the switching waveform (there is no switching waveform in an Average Model), it requires additional information which is available only from the switching waveform. In this case it is the switching frequency and the ripple current. F_KHZ represents the switching freq in KHz and IRIPA, IRIPB represent the ripple currents. In a pure transient model this information is inherently available, whereas in an average model it has to be mathematically computed. That is why these extra pins are required in the average model. This is not present in the actual part (only required for the average model simulation).

    The average model is topology dependent and is only applicable to the EVM configuration. However, you can change component values within this topology to match your circuit.

    Best regards,

    Nikhil 

    Nikhil Gupta | Product Folder Modeling Manager | Online Design Tools                                                                                                                                                    

    All TI Spice Models can be found here | All WEBENCH supported devices can be found here

     

  • In reply to Arun Arockiasamy:

    Hi Nikhil,

    , This is the feedback I have from Arun on your inputs --

    I tried to use this PFC less than 100V input, output voltage is not getting boosted.

    If you can guide me how to give IRIPA, IRIPB and F_KHz values in pspice, or can you tell me how to create a PSPICE library in for the same that can be helpful for me to complete my requirement.

     

    Can you please help us further on this?

     

  • In reply to GJ:

    Hi Gaurav,

    For the schematic configuration, you do not have to make any changes to the topology. F_KHZ is automatically calculated based on the RT resistor that you connect. Similarly, IRIPA and IRIPB are calculated automatically as long as you leave the configuration unchanged (F_KHZ, IRIPA and IRIPB connected from UCC28070 to the BOOST_AVG Blocks).

    The working range of the EVM is from 85VRMS to 265VRMS. The model has also been verified in this range (>110V peak).

    Best regards,

    Nikhil

    Nikhil Gupta | Product Folder Modeling Manager | Online Design Tools                                                                                                                                                    

    All TI Spice Models can be found here | All WEBENCH supported devices can be found here

     

  • In reply to Nikhil Gupta (1):

    I am using transient model in my simulation. So shall I leave these 3 pins open? What about the ground pin? I have not completed my design entry but OrCad does not work without ground connection. Can you help with this. Thanks.
  • In reply to Nikhil Gupta (1):

    Hello Nikhil,

    Could you please let me know how to use these pins if I use the same UCC28070 block on a boost circuit that is designed by me? It would be helpful if you could give me a pin description for these pins