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TPS2553: TPS2553 - REVERSE-VOLTAGE PROTECTION

Dice-K
Mastermind 7470 points
Part Number: TPS2553

Hello,
I have two questions about TPS2553.

(1)
The condition of REVERSE-VOLTAGE PROTECTION.

I think that the condition of REVERSE-VOLTAGE PROTECTION is as follows.
(Vout-Vin)>135mV
Is the setting of the EN-terminal the condition of the REVERSE-VOLTAGE PROTECTION?

I cannot observe the protection behavior under the condition as follows.

VIN=5V
EN=VIN=5V
VOUT=5.5V

expectation: VIN=5V, VOUT=5.5V, FAULT=LOW
actual:VIN=5.5V, VOUT=5.5V, FAULT=HIGH

It becomes the expectation behavior when I make EN-terminal H ⇒ L ⇒ H.

When EN-terminal is Hgh fixation, does it not become the protection behavior?

Or it becomes the expectation behavior when I spend 1.2A on VIN by electronic load.
Is this behavior correct?

(2)
About Figure-10 of Page-9 of SLVS841F.


Does an electric current more than 1A flow till REVERSE-VOLTAGE PROTECTION acts?

Regards,
Dice-K

  • 0
    TI__Expert 8420 points

    Hi Dice,

    To my understand, the reverse protection need two condition :

    1) Vout higher than Vin more than 130mV.

    2) The time period of Vout higher than Vin need more than 4mS.

    3) En able pin is avtice.

    Mihcael Tan(PI)

  • 0 in reply to Michael Tan
    Mastermind 7470 points

    Hello Michael,
    Thank you for your reply.

    But your answer is only what is written in the data sheet.

    Can you answer my questions?

    Best regards,
    Dice-K

  • 0 in reply to Dice-K
    TI__Expert 8420 points
    Hello Dice,
    For question 1: Could you help to capture the Faul, vin, vout enable pin waveform for analysis ? I suspect of the time not longer than 4mS .
    For question 2: The reverse current needn't larger than 1A for reverse protection act .

    Michael Tan(PI)
    Best regards!
  • 0 in reply to Michael Tan
    Mastermind 7470 points

    Hello Michael,
    Thank you for your reply.

    Q1
    I ask my customer waveform. Please wait a little.

    Q2
    Does the red circle not express 1A?


    Best regards,
    Dice-K

  • 0 in reply to Dice-K
    TI__Expert 8420 points
    Hello Dice,
    Q2 base on the waveform the reverse current have exceed 1A , but this is not the necessary condition for reverse protection act . It just a example ,the revese protection act condition is Vout>Vin 135mV and time need long than 4mS.
    Michael Tan(PI)
    Best regards!
  • 0 in reply to Michael Tan
    Mastermind 7470 points

    Hello Michael,
    Thank you for your reply about Q2.

    Does the value of Reverse-Current depend on the difference between VIN and VOUT?
    If difference between VIN and VOUT is small, is the value of Reverse-Current small?

    Of course on this condition " Vout-Vin>135mV ".

    Best regards,
    Dice-K

  • 0 in reply to Dice-K
    TI__Expert 8420 points

    Hello Dice,

    Yes,the reverse current depend on Vin Cap and delta V( between Vin and Vout) .

    You can refer to the formula I=C*dV/dt , enlarge Vin cap and delta V then the revserse current wil increase accordingly .

    Mihcael Tan (PI)

    Best regards 

  • 0 in reply to Michael Tan
    TI__Expert 8420 points

    Hello Dice,

    You can chek with my test waveform, Vout>Vin=160mV and Time is about 4.2mS then Fault signal assert . Pls. refer below waveform (Yellow: Vin Blue: Vout Pink: Fault ) . I think your customer haven't keep Vout >Vin  during the reverse period. you can pararell an resistor with Vin to discharge to  avoid this situation(keep Vin <Vout).

    Michael Tan(PI)

    Best regards!