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TPS62130: Apply voltage at the output pins - will it damage the chip?

Michael Weston
Prodigy 120 points
Part Number: TPS62130

Tool/software:

Hello,

I have an application where the input to the TPS62130 is provided by a regulated, high voltage source and isn't practical for office testing and programming.  I was wondering if I would be able to add header pins at the output of this chip in order to provide the same voltage that would normally be created here.

The idea is that this chip provides a regulated voltage of 6V that is distributed to the rest of the board, and regulated even lower, where necessary.  I would like to tap into this output to provide a safe, bench supply based 6V that would be distributed through the copper on the board.  There would be no voltage source applied to PVIN at all.  Would this destroy anything inside the TPS62130?  This chip does have an output that is connected to its input by FETs with body diodes.  Those diodes would probably conduct back to PVIN where the EN pin is connected through a 0.5x voltage divider that would put ~3V into the EN pin and maybe turn it on.

I've got an old board using this chip running in this configuration, just to see what happens.  It works but I don't know if it is damaging the part which could shorten its life on customer products.  Please provide me with some feedback on whether this is an acceptable thing to do or if there is a different IC that is made to handle this better.

Thanks so much!

Michael

  • 0
    TI__Mastermind 21361 points

    Hi Michael,

    Any block diagram of this?

    From your description, did you want to apply power to  TPS62130 output and get a voltage at input?

    Thanks

    Colin

  • 0 in reply to Colin Chen
    Prodigy 120 points

    Hi Colin,

    I don't have anything simple to draw but the idea is to have a two pin header at the output of this supply that can be used to power the board when the input is not applied to the TPS62130.  There is no requirement for any voltage to make it back to the input.  It's like a bypass but without wiring in a physical switch.  This chip would normally put out 6V but the jumper would be used to bring in 6V.

    I guess my main question is that since this chip's output is not directly wired through to the input (other than body diodes on the internal FETs), would it damage the chip in any way to see 6V on the output when nothing is being driven on the input?

    Thanks!

    Michael

  • 0 in reply to Michael Weston
    TI__Mastermind 27626 points

    Hi Michael

    Colin will check and reply to you later.

    Thanks and best regards.

  • 0 in reply to Michael Weston
    TI__Mastermind 21361 points

    Hi Michael,

    Understood your point. We suggest you seriating a diode in output or make TPS62130 enable by outside power to prevent device having potential to enable and work.

    Thanks

    Colin

     

  • 0 in reply to Colin Chen
    Prodigy 120 points

    Hello,

    I guess you are telling me that the answer is NO?  If not, this doesn't really help.  Adding a diode causes losses and lower efficiency for the entire design.  If I were to find a way to maintain the enable pin low on the input side, would that then make this safe to apply voltage on the output side of this chip? Is this the primary/only concern that I must worry about?

    Thanks,

    Michael

  • 0 in reply to Michael Weston
    TI__Mastermind 21361 points

    Hi Michael,

    Yes, you are right. 

    Maintaining the enable pin low on the input side is a good way to prevent device was enabled by applying voltage on Vout.

    Hope this can help you.

    Thanks

    Colin