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TPS2121: Help, TPS2121 Output Current Issue

CELESTE GONZALEZ CANTERO
Prodigy 70 points
Part Number: TPS2121

Hello, good morning. I need help; I set up this configuration for an input power supply of 5V and an auxiliary supply (btvcc) of 5V. Initially, it worked perfectly for 8 hours, and suddenly, it stopped delivering the required current to power the device and remained at 40mA-300mA (depending on the power source I used). I want to know if the values I used are correct for a dual 5V power supply for an output of 5V up to 3A. The TPS2121 can handle up to 4.5A. Thank you in advance. Regards

  • 0
    TI__Mastermind 28300 points

    Hi Celeste,

    The schematic in the picture you sent looks good.

    When you see the current limited to 40mA-300mA, what are the voltages on the inputs? Currently, since PR1 and CP2 are tied to ground, the device is determining which VIN to use as VOUT by comparing VIN1 and VIN2. It's possible that when VIN1 and VIN2 are very close, the device is constantly switching between the two inputs, which can cause unintended operation including voltage droop/current limiting.

    If this is happening, then the issue you are seeing can be addressed by operating the device in the VREF mode connecting PR1 to VIN1 through a resistor divider.

    Please take the above measurements and we can continue based on the results.

    Thanks,

    Patrick