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TPSI3100-Q1: Evaluation board issues

Joss Chandler
Prodigy 20 points
Part Number: TPSI3100-Q1

I am having issues with the TPSI31xx-Q1EVM. When I power the primary side the FLT1 pin goes low and I am not have to drive the mosfet.

  • 0
    TI__Expert 5226 points

    Hello Joss,

    Thanks for joining E2E and reaching out to our team!

    • Can you please share a picture of your board/setup so I can try to replicate the problem?
    • Can you also please confirm power transfer is working during this issue by confirming 5 V on VDDM?
      • If 5 V is on VDDM while nFLT1 is going low, try installing a nF-range (e.g. 1 nF) capacitor to C18. 

    Best regards,
    Tilden Chen

    Solid State Relays | Applications Engineer

  • 0 in reply to Tilden Chen
    Prodigy 20 points

    Hello Tilden,

    Thank you for responding, see the drawing below for my current setup. Note that the jumpers are installed the same as in the picture except J2 which is configured for LDO_OUT. I do not see 5V on VDDM with or with out the load/HV connected and VDRV does not go high either, which I don't expect since the nFLT1 is being triggered. It almost seems to me like power is not transferring over the isolation barrier.

  • 0 in reply to Joss Chandler
    TI__Expert 5226 points

    Hello Joss,

    Thanks for the update and sorry for the inconvenience this is causing. Just realized I did not specify how to measure VDDM in my last message, this should be referenced to VSSS. If VDDM is low, that indicates no power transfer. I'm thinking either:

    1. TPSI3103-Q1 is not powered
    2. TPSI3103-Q1 has low CE signal
    3. TPSI3103-Q1 is broken

    To check these cases, can you please apply 12V to the LDO input terminal and confirm 5V across VDDP-to-VSSP, CE-to-VSSP, and nFLT1-to-VSSP?

    If 5V is across all these, please confirm 5V across VDDM-to-VSSS and 0V across FLT1CMP-to-VSSS.

    Best regards,
    Tilden Chen

    Solid State Relays | Applications Engineer

  • 0
    Prodigy 20 points

    VDDP-VSSP: 5.02V

    CE - VSSP: 5.02V

    nFLT1 - VSSP: 0.05V

  • 0 in reply to Joss Chandler
    TI__Expert 5226 points

    Hello Joss,

    Thanks for the update here. Can you please also provide the VDDM-to-VSSS and PGOOD-to-VSSP measurements? If these are 5V, then somehow the comparators are tripping without a load. If these are 0V, then the device is unpowered or broken. 

    Best regards,
    Tilden Chen

    Solid State Relays | Applications Engineer

  • 0 in reply to Tilden Chen
    Prodigy 20 points

    Yes,

    VDDM - VSSS: 0V

    PGOOD - VSSP: 5V

  • 0 in reply to Joss Chandler
    TI__Expert 5226 points

    Hello Joss,

    Thanks for the update. I tried to recreate this issue in the lab by checking the PGOOD and nFLT1 power sequencing, but was unable to. Was wondering if it was possible to collapse the secondary power and create a condition where PGOOD = high and nFLT1 = low. My only conclusion now is that either something is unexpectedly connected or the device is broken. Connecting with you over private message send a new EVM. 

    Best regards,
    Tilden Chen

    Solid State Relays | Applications Engineer

  • 0 in reply to Joss Chandler
    TI__Expert 5226 points

    Hello Joss,

    Also wanted to gather more information on your application, looks like you were testing overcurrent protection - how much load resistance is in series with the 100V source? Was trying to consider the possibility that the overcurrent event exceeded the MOSFET's SOA curve, damaging the MOSFET, and causing a gate-drain-source short, which could then damage the TPSI3103-Q1. 

    Best regards,
    Tilden Chen

    Solid State Relays | Applications Engineer

  • 0 in reply to Tilden Chen
    Prodigy 20 points

    That is a good point. I was using an electronic load with constant resistance set to 100ohms. Looking at the SOA curve for the UJ4C075033B7S that should be ok.

  • 0 in reply to Joss Chandler
    TI__Expert 5226 points

    Hello Joss,

    Was checking with my team and we were trying to consider whether the electronic load could be causing misbehavior. Saw on the tracking information that the new EVM has been delivered. Please verify that the device is functional (power VDDP, measure 5-V on VDDM) before connecting a load, ideally resistive load. 

    Best regards,
    Tilden Chen

    Solid State Relays | Applications Engineer