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TPS2113 switching issue ?

chiranjeev n
Prodigy 240 points
Other Parts Discussed in Thread: TPS2113, TPS2105, TPS22912C, TPS22910A

hi,

              I m using TPS2113 for switching 2 inputs and 1 output . In that 2 inputs one is USB powered and other one is Battery.

      Here USB is main powered and battery act as Backup.

1. when USB is removed , the switching power to battery is around some milli seconds so that entire circuit got reset and switching is not immediate and this is the issue or problem i am facing.

2.whereas switching from battery to USB , there is no delay and  in this mode it is fine.

  i would like to know whether the switching from USB to battery there must  be a delay  ?             

       

  • Prodigy 240 points

    hi,

    since TPS2113 is used to switch between 2 inputs and 1 output , mainly  on USB and other battery power as inputs

    the switching will happen when the input voltage either from USB or battery is greater than 2.8V , but mostly when Battery as main power , normally we would like to utilize upto 1.8V . but if we give less than 2.6V the switching is not happenning ,so that 

    nearly 1V trade off is their ,therefore Battery is not been utilised fully.

    Is there any other TI Pin mux IC will switch upto 1.8V?please suggest   

  • in reply to chiranjeev n
    TI__Mastermind 40100 points

    Hi Chiranjeev,

    I believe you are refering to the siwtch over propagation delay. Notice they are significantly different switching from one to the other. Please see page 5 of the datasheet.

    Unfortunately, we do not have another power mux in our portfolio that can operate at 1.8V on it's own. VIN2 must be greater than 2.8V in order to operate VIN1 down to 1.5V as shown on page 2 of the datasheet.

  • in reply to Darwin Fernandez
    Prodigy 240 points

    Thnx Darwin Fernandez!

         Instead of Pinmux , (due to propagation delay, Reset occurs) Is it fine to go with ORing circuit ? or would you suggest any TI IC which matches my above criteria(USB and battery shift without any delay).                    

  • in reply to chiranjeev n
    Prodigy 240 points

    Hi TI,

                     Instead of Pinmux , (due to propagation delay, Reset occurs) Is it fine to go with ORing circuit ? or TPS2105 would you suggest any TI IC which matches my above criteria(USB and battery  operated shift without any delay).       

  • in reply to chiranjeev n
    TI__Mastermind 42795 points

    Hello,

    I moved this thread to the load switch section of the forum because the load switch's can provide the lower operating range.

  • in reply to Eric Wright
    Prodigy 240 points

    Thnx...!     Awaiting for your Response 

  • in reply to chiranjeev n
    TI__Prodigy 290 points

    Hi Chiranjeev,

    You can configure a power MUX circuit with 2 load switches as shown below. In your case, since USB needs to have priority, DC_IN will be connected to USB and uUSB will be connected to backup battery. Will this work for your application? I am not sure when exactly you want to switch from one source to the other.

    Regards
    Ankush

  • in reply to ankushg
    Prodigy 240 points

    Thnx Ankush!

    1)In my Requirement the  Battery is main power and USB is secondary

    2)But whenever USB is there, it should not conduct from Battery,only it has to take from USB power because  i m using non rechargeable lithium  battery .

    3)  since it is battery operated , Quiescent current to be less for long life .

    4)is there any delay when it is switching from USB to battery or vice - verse?(To avoid reset of whole system due to propagation delay when i m using Pinmux Ic TPSS2113).

    please find the attachment of block diagram

    6076.functional_block_diagram.pdf

      

  • in reply to chiranjeev n
    TI__Genius 15710 points

    Hello Chiranjeev N,

    If you would like to have the USB power take priority over the battery power, then you could use the circuit Ankush posted with the USB power as DC_IN and the battery as µUSB.  This way the system will draw battery power when not connected through USB and draw USB power when both are connected.

    Regarding delays in the circuit, when switching from USB to battery, there should be no delay.  At 5V, the turn ON time for the TPS22910A is 2µs while the turn OFF time for the TPS22912C is 6.6µs.  Reverse current protection protects both of these devices during the transition.

    When switching from battery to USB, the transition would take about 835µs (based again on turn ON/OFF times).  If that is too slow, I would recommend the TPS22913B in place of the TPS22912C, which would decrease that transition to about 70µs.

     

    Regards,

    Alek