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UCD90120A: I shortcut 3.3V and 1.8V to GND, the power_good signal is still there?

Sam Tao
Prodigy 20 points
Part Number: UCD90120A

I am using UCD90120A to manage my power sequence and monitor my power supply status, I set the lowvoltage threshold for monitoring.

I did a test, I shortcut the 3.3V and 1.8V to GND, I expect it  de-assert power good signal, but I did not see it happen. The power good signal is still there.

I attached the UCD90120A configure file here.

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/196/UCD90120-switchboard.7z

  • 0
    TI__Guru 66170 points

    Hello

    Which exact signal(pin) do you expect to be de-asserted?

    If you want to deassert POWER_LD or UCD_LATE_PG signal, you have to include rail2(3V3) and rail3(1V8) into the logic.

    If you expect short 3V3 and 1V8 to turn off other power, please set the proper fault response.

    Please refer the attached quick guide to configure fault response of a given rail. 3051.UCD90xxx Quick Guide.pptx

    Regards

    Yihe

  • 0 in reply to yihe
    Prodigy 20 points

    Yihe,

    Thanks for answering.

    I want de-assert power good signal when it drops under a threshold, only want a signal, an FPGA will get this signal and take actions. 

    I configured the threshold like belowing, is it enough?  need I do anything else? other configuration or coding needed? If you are in China, Could you give me your phone numer for easier communication?

    B.R.

    Sam Tao

  • 0 in reply to Sam Tao
    TI__Guru 66170 points

    Hello

    No, changing thresholds does not help you. You have to include the rail2/3 into the logic of the POWER_GOOD as shown below

    Please contract Oliver Ou who is your local FAE.

    Regards

    Yihe