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TPS22992SEVM: power on sequence

Tommy Tzeng
Genius 5215 points
Part Number: TPS22992SEVM

Hi Sir,

customer use EVM testing issue as below, may we know why?

since there is delay of 57m/s from input to output when EN is high( 5V Vin red frame), why is the IC unable to output immediately? but 3.3v vin won't.

In addition, when Vin is always on, when testing the EN trigger, the phenomenon of the red frame will also occur.

  • 0
    TI__Mastermind 22620 points

    Hi Tommy,

    My thought is that there is a very high capacitance or some component that sinks a lot of current during startup on the output. It looks like the output voltage is below VSC (0.45V) during this condition, and the load current is limited to roughly 1-1.5A. Also, the only condition where this issue doesn't occur is when VIN is turning on to 3.3V, and in this case VIN = 1.25V when EN goes high - in all the other cases, VIN is higher when EN goes high and we see this issue.

    Can you ask the customer for a schematic or list of components after the load switch, especially ones that can sink a lot of current when voltage is first applied or that can mimic a short circuit?

    Thanks,

    Patrick

  • 0 in reply to Patrick Shalton
    Genius 5215 points

    Hi Patrick,

    ok~will ask customer and reply us.

  • 0 in reply to Tommy Tzeng
    TI__Mastermind 22620 points

    Hi Tommy,

    Thank you, I will be waiting for your update.

    Thanks,

    Patrick