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ISOW7841: Using a few ISOW7841 with DCDC output (Viso) connected in parallel

Part Number: ISOW7841
Other Parts Discussed in Thread: ISO7741, SN6505B, SN6501, ISO7841

I'm interested if I'm able to use five ISOW7841 connected in parallel. They are supplied with 5V from the primary side and outputs of their DCDCs are tied together (5Viso) and they are supplying a load. 
My concern is if the DCDCs will fight with each other if they are paralleled. Is that true?
Please take a look at the schematic for exact circuit.

  • Hi Milos:

    Thanks for posting on E2E.

    Unfortunately, multiple ISOW7841 outputs cannot be tied together. Please look into the below E2E for additional details.

    Regards,

    Dushmantha

  • Hi Milos,

    Thank you for posting, and welcome to E2E! Connecting the Viso pins of multiple ISOW devices in parallel should not be done as Dushmantha mentioned above. These outputs will fight each other and some devices may start to undesirably sink current or stop generating isolated power. For more information on this, please refer to the threads linked below:





    TI's SN6501 or SN6505B can be used to develop discrete isolated power supplies for needs up to 5W, and multiple digital isolators (like ISO7841 and ISO7741) can be used instead in configurations like the one shown in Figure 22 of the ISO7741 datasheet copied below. For this case, multiple digital isolators could be powered by a single SN6501 (up to ~1.75W) or SN6505B (up to ~5W) system:



    Please let us know if this is a solution you are interested in pursuing!


    Respectfully,
    Manuel Chavez