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 TI494 part and transformer modeling 

Last post Mon, Nov 5 2012 2:30 PM by oldmouldy. 1 replies.
Started by Joel2012 05 Nov 2012 01:01 PM. Topic has 1 replies and 998 views
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  • Mon, Nov 5 2012 1:01 PM

    • Joel2012
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    • Joined on Mon, Nov 5 2012
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    • Points 40
    TI494 part and transformer modeling Reply

    My group and I are trying to build a transformized h-bridge dc-dc converter. I was hoping to model this on spice, but have had no luck so far. First I am trying to use an ideal transformer but do not see how you enter the turns ratio to make it step up at the right ratio. Also I was hoping to try to simulate the PWM using the ti494 pwm chip. I know that this chip is still produced by TI, but cannot seem to find the model in Pspice. I am using Orcad Capture CIS. Can this be found in one of the libraries on p-spice. If so what is it called. If this part is not able to be used on this software is there any other parts that would work for my h-bridge simulation. Thanks in advance for any help. Don't know if this is needed but the mosfets on the primary side are MbreakN and all the diodes used are D1N3940. 

    • Post Points: 20
  • Mon, Nov 5 2012 2:30 PM

    • oldmouldy
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    • Woking, Surrey
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    Re: TI494 part and transformer modeling Reply

    Ideal, linear transformers in SPICE use a ratio of Inductance, not turns. You could go the linear route, or use the default Kbreak from the Breakout library to couple with a turns ration, the default parameters will require some considerable drive to saturate so, to all intents, this will behave as a linear transformer for smaller loads.

    There is a TL493 in the PSpice swit_reg library, this is a close relative of the TL494, the Current Amplifier of the TL493 would need to be tweaked to match the Error1 Amplifier to provide the Error2 Amplifier function for the TL494. Probably best to copy the swit_reg.lib to your own location and rename the LIB file and TL493 model within to ensure that your defintion gets used, the Implementation will need to be changed for the Capture part to pick up your model name for the modified model, also rename a copy of the Capture part to avoid confusion between the models.

    • Post Points: 5
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Started by Joel2012 at 05 Nov 2012 01:01 PM. Topic has 1 replies.