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UC2903: UC2903 line/switch sense input

user3864010
Prodigy 40 points

Part Number: UC2903

Hello, I am preparing a power supply circuit for an inverter and i need a power monitoring, I was thinking in the UC2903, because it´s for 40V supply and has 4 channels. I wanted to use the power ok output, but it is sensing the line input, which i don´t have connected.

What should i do with that pin so i don´g get a fault?

  • 0
    TI__Genius 12630 points

    The POWER OK output monitors the LINE/SWITCHER SENSE input. You must connect LINE/SWITCHER SENSE input to a voltage rail above the LINE/SWITCHER SENSE voltage threshold or else you will get a fault on POWER OK output. Is this the operation you desire?

    -Michael

  • 0 in reply to Michael_DeSando
    Prodigy 40 points

    Hello!

    Yes, I think so. Because I am just monitoring DC voltages in a board.

    Thanks!!

    -Luis

  • 0 in reply to user3864010
    TI__Genius 12630 points
    Luis,

    If you provide me with your "must-have" requirements, I can help you find the best device. Thanks!

    -Michael
  • 0 in reply to Michael_DeSando
    Prodigy 40 points

    Hi Michael,

    Thanks a lot for the help. I am designing a power supply board for complex system in which i have different supply voltages, for example 24, 5, 3.3 and 2.5V, and I want to check that all are working fine but I just have only 1 pin in the FPGA.

    So the idea was to use this quad supply monitoring and using the POWER OK out to give a warning if something is not working fine.

    I am still working on the design as for me this datasheet is a bit complex and it doesn´t provide a lot of information. By the way, which is the threshold voltage: 2,5V or 1,8V?

    Thank you very much,

    -Luis

  • 0 in reply to user3864010
    TI__Genius 12630 points

    Luis

    The best quad supply monitor we have is TPS386000. This have 4 independent monitor inputs each with independent programmable delay. This device also features a Watchdog for MCU monitoring and also a "Manual reset" feature for an external reset button or system shut down.

    A little less intense device might be TPS3307 which is a simple 3- input monitor device.

    To answer your question, the input sense threshold reference is 2.5V so this is what will be checked for at the device pin. Using external resistor divider, you can change the sense threshold. Please let me know if any additional support is needed or if you have any other questions!

    -Michael

  • 0 in reply to Michael_DeSando
    Prodigy 40 points

    Thank you very much. I am checking the option of the TPS386000 and I have a further question:

    What if the WDI is not used? To avoid the WDO from reseting, can I leave it open?

    Thanks a lot!

    BR,

    Luis