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TPS758: What conditions lead to TPS75801KTTR output nothing ?

Went Cao
Genius 5550 points
Part Number: TPS758

Dear all

      What conditions lead to TPS75801KTTR output nothing ?

      The input is 5V, the output is set to 3.75V, and the output have link to 3.7V battery. When there is not input, the battery would reverse to input, and power up, TPS75801KTTR would be not output .

  • 0
    TI__Guru 55940 points

    Hi Went,

    TPS758 has an internal active discharge circuit which will engage when the LDO is disabled or Vin is below UVLO.  

    If you do not want to discharge your battery, you will need to make sure that Vin is above UVLO and Ven is above the on threshold (2 V).  This could be achieved by shorting EN to IN and placing a Schottky diode from OUT to IN.  This diode will be in parallel with the internal body diode and will provide a robust path for the reverse current.  If you wish to block current from flowing past the LDO you could place a blocking diode before the input capacitor of the LDO.

    Very Respectfully,

    Ryan

  • 0 in reply to Ryan Eslinger
    Genius 5550 points

    Dear Ryan

           Thanks your help.

           In your opinion, the conditions which will lead to TPS75801KTTR output nothing that are below :

           1.  Vin is under UVLO

           2.  Ven is under the on threshold (2 V). 

           Right ?

          

  • 0 in reply to Went Cao
    TI__Guru 55940 points
    Hi Went,

    Correct, if Vin is under the UVLO threshold and/or Ven is under the on threshold, the pass FET for the LDO will be off and the active discharge circuit will be engaged.

    Very Respectfully,
    Ryan