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TPS25923: TPS259231: the behavior when VIN is cut off

Dice-K
Mastermind 7470 points
Part Number: TPS25923

Hello,
I have questions about TPS259231.

I connect a power supply of 5V to VIN terminal of TPS259231.
A different power supply (possible even if a battery) is connected to OUT terminal.
Please teach me the behavior when the power supply of the VIN terminal was cut off.

(1)
If FET was turned off, does the VIN terminal observe the voltage of the OUT terminal via the diode of the internal FET?

(2)
If (1) is "Yes", how much does the electric current flow?
Does the resistance value between the VIN ~ EN/UVLO terminal ~ GND determine it?

(3)
If (1) is "Yes", depending on the voltage observed at VIN, is EN/UVLO terminal recognized as High, and does the FET become ON again?

(4)
If (3) is "Yes", how does TPS259231 behave?

Regards,
Dice-K

  • 0
    TI__Mastermind 42795 points
    This has been moved to the load switch forum
  • 0
    TI__Guru** 105361 points
    Hi Dice,

    Thanks for reaching out!. Please see my response below.

    (1) If FET was turned off, does the VIN terminal observe the voltage of the OUT terminal via the diode of the internal FET?
    (A) Yes. Body diode of the internal FET provides the path.

    (2) If (1) is "Yes", how much does the electric current flow? Does the resistance value between the VIN ~ EN/UVLO terminal ~ GND determine it?
    (A) The magnitude of the electric current depends on the load at VIN. If there is no other loads, the resistance value between the VIN ~ EN/UVLO terminal ~ GND determine the current.

    (3) If (1) is "Yes", depending on the voltage observed at VIN, is EN/UVLO terminal recognized as High, and does the FET become ON again?
    (A) Yes, FET turns ON again

    (4) If (3) is "Yes", how does TPS259231 behave?
    (A) As long as Vout is higher than Vin, the device remains in idle state with FET in fully enhanced position. Please note the device does not provide current limit in reverse direction. So, you have to ensure that there is not overload or short at the VIN terminal.

    Best Regards,
    Rakesh