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WEBENCH® Tools/LM5085: continuous operation LM5085

user4803443
Prodigy 120 points
Part Number: LM5085

Tool/software: WEBENCH® Design Tools

Hi,

I want to use DC / DC to provide 40W and I follow the topology LM5085 (Webench) but I have some problem with the temperature when I have a full charge because I exceed 100ºC. Is it normal or is this topology not designed to work in continuous mode?

Thanks

  • 0
    TI__Mastermind 40020 points
    Hello,

    The Device should work perfectly fine in continuous mode of operation. You need to first ensure the design is stable when you load the output. If so, the main dissipators will be the top FET and the diode.

    If the top FET is hot look at the RDS on and the gate charge, improve the figure of merit on these two, lower RDS on and lower gate charge. You can also reduce the switching frequency to minimize the losses associated with the gate charge that impacts transitional losses.

    For the Diode, look at the VFWD and the Reverse recovery, a good choice of diode is a schottky with a low VFwd.

    Make sure the packages is large enough for the two components mentioned above, enough to dissipate the heat.

    Hope this helps?