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17.0V to 15.0V isolated and non-isolated power supply

Hi all,

From 17.0V DC supply I need to generate 15.0V at 500mA isolated power supply and 15.0V at 500mA non-isolated power supply both. I tried with WEBENCH Designer, but wasn't convinced with designs. Please suggest a TI/National  part number with schematics if possible. Please refer the power supply tree below for clear reference.

Thanks and regards


  • In the future, I would recommend making this two separate posts since you want two very different power supplies.  I moved this to the isolated forum, where they can help you choose a controller for your isolated need.  A flyback would likely be the best option.

    For the non-isolated power supply, an LDO would be simplest.  The TPS7A4801, TPS7A4501, and TPS73801 all look like options.

    Chris Glaser

    Texas Instruments

  • Anand,


    On th eassumption that the 17 volts might drop I would recommend the UCC38C45


    It is a flyback design and should be fairly simple to implement. With a 50% limitation on the duty cycle you should not have to implement slope compensation.

    A resonable app note to review for your design is http://www.ti.com/lit/an/slua274a/slua274a.pdf 

    Since you are powering this from a 17 volt source you should be able to power it through a simple series regulator that results with VDD at 9 volts.




    John Bottrill