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LM5015: Change input from 48V to 12V

Yue TANG
Expert 8705 points
Part Number: LM5015

Hi,

        Customer have used LM5015 for a 48V input ,5V2A output flyback design as below. it works fine. they would like to make a small change to support input  12V for another product, but still can support 5V2A. . 

if nothing change with 12V input, the output is only 3.5V.  then they tried to double the coil turns at secondary side, the output is 5V, but load capacity is very weak, the output drop to 4.7V with 600mA. this device is kind

old, WEBENCH doesn't support.  could you please suggest how to make a small  modificaiton to support this case? thanks.  

  • 0
    TI__Guru 73675 points

    Hello

    The best way to design this application is to use the calculator tools found on the product folder for 

    this device on the TI website.

    Also, be sure to follow all of the recommendations in the data sheet for this device.

    Thanks

  • 0 in reply to Frank De Stasi
    TI__Expert 8705 points

    Frank, 

                    This device doesn't have a dedicate calculator tools for this. there are two on the product folder: one for forward topology, one from genernal flybuck persective(just give recommendation for transformer), also not include LM5015.

    BTW, according to the flyback calcuator tools,it only recommend transformer turn ratio, nothing else external components, and customer  did change the turn ratio as mentioned,but problem is that it can't take load upto 2A.  I've checked their schematic, bascilly,  fully follow default design in our datasheet. please kindly further comment your insight. thanks. 

     

     

  • 0 in reply to Yue TANG
    TI__Guru 73675 points

    Hello

    Please try the attached calculator tool.

    Thanks

    LM5015_Isolated_Quickstart.xls