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TPS2363: How to handle the fault signal if one of the main slot or both the main slots are not used through TPS2363 for 3.3V

Padmesh M L
Prodigy 40 points
Part Number: TPS2363

Hi,

In our new design, we are not controlling the PCIe main voltage (3.3V) through TPS2363.We are using only 12v main and 3.3v aux through TPS2363

We would like to know that will it create any issues with the fault signal and the device will trip. currently the pins 3VGATEA, 3VGATEB, 3VOUTA and 3VOUTB are floating.

Is there any recommendation for these pins to avoid tripping.

Regards,

Padmesh

  • 0
    TI__Guru 57737 points

    Hi Padmesh,

    I don't see any issue in leaving the 3VGATEA, 3VGATEB, 3VOUTA and 3VOUTB pins floating. The Fault shouldn't assert as long as there is 3.3SH33A/B on SH33A/B pins.

  • 0 in reply to Praveen GD
    TI__Guru 57737 points

    Hi Padmesh,

    Hope your question is answered. In case you do not have further questions, can we close this thread ?

  • 0 in reply to Praveen GD
    Prodigy 40 points

    Hi Praveen,

    Thanks for your answer. I just want to clarify few things which I am mentioning below:

    1. You mentioned that "The Fault shouldn't assert as long as there is 3.3SH33A/B on SH33A/B pins." which means there should be a sense resistor connected to 3.3V and both the sides of the resistor should be connected to the pins SH33A/B and SL33A/B of TPS2363. Correct me if I am wrong.

    2. Our implementation is shown below:

       

    3. Since we are connecting 3.3V, UVLO will not be there but we should maintain minimum current threshold of 45mV. How can we manage it since the load current is 0 and according to the below formula

    Threshold Voltage = Rsense * Isense the threshold value will always be zero. Is there any internal logic to mitigate this scenarion ? Will this condition create any issues ?

    Thanks in advance

    Regards,

    Padmesh

  • 0 in reply to Padmesh M L
    TI__Guru 57737 points

    Hi Padmesh,

    Looks like there was a typo in my previous message. I meant, 'The Fault shouldn't assert as long as there is 3.3V on SH33A/B pins.'

    It should be okay if you connect SH33A/B and SL33A/b to 3.3V directly as shown below.