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TPS2553: About reverse-voltage protection

Masanori Tachibana
Genius 5350 points
Part Number: TPS2553

Hello support team,

I have a question about the “reverse-voltage protection” function of TPS2553.

What is the voltage range of VIN where “reverse-voltage protection” works under the condition of VOUT – VIN> 135 mV?
Could you teach me in point of view whether or not reverse current flows from VOUT to VIN.
I don't care whether the FAULT output works or not.

Looking at "7.5 Electrical Characteristics" on page 7 of the datasheet, IREV : Reverse leakage current is 1 µA (MAX) under conditions of VIN = 0 V and VOUT = 6.5 V.
So I think “reverse-voltage protection” may work even if VIN is 0 V. Is my understanding correct?

Sincerely,
M. Tachibana

  • 0
    TI__Mastermind 18031 points

    Hi Sir,

    1. Yes. Current flows from Vout to Vin.

    2. Yes, it works as VIN=0V.

    For TI's policy, I will first click resolved button.

    If you have any other concern, contact me any time.

    If you think resolved, please help click 'Issue is solved button'.

    Thanks.

  • 0 in reply to Ziv Zhang
    Genius 5350 points

    Hi Zhang-san,

    Thank you for the reply.
    But I did not understand well.

    You answered that reverse current flows in No.1, does that mean that the “reverse-voltage protection” does not work?

    Or is that mean that the reverse is current as small as the leakage current and the “reverse-voltage protection” works when VIN is from 0 V to VOUT - 135mV?

    Sorry to trouble you, but please teach me again.

    Sincerely,
    M. Tachibana

  • 0 in reply to Masanori Tachibana
    TI__Mastermind 18031 points

    Hi,

    It's just two situation:

    1. Vin above zero. The IC works. With Vout-Vin>135mV, after 5ms, will turn off MosFet. During the 5ms, current will flow from Vout to Vin. 

    2. Vin=0V, internal FET will not be open, the current from out to input will be blocking. Only with 1uA leakage current.

    For TI's policy, I will first click resolved button.

    If you have any other concern, contact me any time.

    If you think resolved, please help click 'Issue is solved button'.

    Thanks.

  • 0 in reply to Ziv Zhang
    Genius 5350 points

    Hi Zhang-san,

    Thank you for your reply.
    I’d like to get a better understanding just in case.

    My understanding is as below;
      Where VIN is from 0V to VOUT-135mV,
        the reverse current flows from VOUT to VIN for 5ms,
        and internal MOS-FET turns off after 5ms and only the leakage current flows.
    Is it correct?
    What I want to know is the behavior after 5ms.

    I'm sorry to ask you many times, but please teach me again.

    Sincerely,
    M. Tachibana

  • 0 in reply to Masanori Tachibana
    TI__Mastermind 18031 points

    Hi,

    1. hat's right. As Vout bigger than VIN 135V, current will flow from Out to IN for 5ms. And then turn off internal MOS, only leakage current.

    2. VIN=0V, meaning the internal MOSFET is disabled. So no matter how much the voltage is of Output, OUT current will not flow to input. Only leakage current.

    For TI's policy, I will first click resolved button.

    If you have any other concern, contact me any time.

    If you think resolved, please help click 'Issue is solved button'.

    Thanks.

  • 0 in reply to Ziv Zhang
    Genius 5350 points

    Hi Zhang-san,

    I understood.
    Thank you for your kindness despite my repeated questions.

    Respectfully yours,
    M. Tachibana