• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Subscribers 63 subscribers
  • Views 204 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS54160A: Current limit

Oba
Genius 16135 points
Part Number: TPS54160A
Other Parts Discussed in Thread: TPS54160,

Hello,

My customer has a question for TPS54160.

Now TPS54160A VOUT is connected to VIN of another converter IC.
And TPS54160A current limit occurs during the ramp-up of the lower converter IC.
While they are trying to reduce the in-rush current, they would like know how to think about the current limit of TPS54160A. 

When current limit occur, could it cause any problem except for just VOUT drop like control loop instability?
If the voltage drop is not problem for them, is it OK to use current limit ? 

Regards,
Oba

  • 0
    TI__Mastermind 27045 points

    Hi Oba,

    Suggest to use TPS54160 PWRGD signal to enable down stream converter

    the saturation current of inductor used with TPS54160 should be >4A.

    Select proper Fsw of TPS54160 to make sure the inductor current will not run away in Vin-max and output shorted condition

    B R

    Andy

       

  • 0 in reply to Andy Chen
    TI__Genius 16135 points

    Hello Andy,

    Thanks for your reply.
    Unfortunately, they can't change TPS54160A because it is located in other module which has been already released.

    What they want to know is the below. Could you please answer for this question?

    >When current limit occur, could it cause any problem except for just VOUT drop like control loop instability?
    >If the voltage drop is not problem for them, is it OK to use current limit ? 

    Regards,
    Oba

  • 0 in reply to Oba
    TI__Mastermind 27045 points

    Hi Oba,

    You still need to review the circuit design of TPS54160 section on below items even though the circuit can't be changed:  

    • the saturation current of inductor used with TPS54160 should be >4A, or its inductance drop less than 50% at 4A.
    • Select proper Fsw of TPS54160 to make sure the inductor current will not run away in Vin-max and output shorted condition

    You may have to reduce the inrush current of down stream converter as lower as possible if above items not OK.

     >When current limit occur, could it cause any problem except for just VOUT drop like control loop instability----no impact on loop stability, TPS54160 maybe damaged if current run away because of inductor saturation or limited Ton-min.


    >If the voltage drop is not problem for them, is it OK to use current limit ?-------TPS54160 maybe damaged if current run away because of inductor saturation or limited Ton-min.

     

    B R

    Andy

  • 0 in reply to Andy Chen
    TI__Genius 16135 points

    Hello,

    Thank you very much for your support.
    So if the inductance is enough large value for the current limit condition like you mentioned, TPS54160 should not be damaged.
    Is it correct?

    Regards,
    Oba

  • 0 in reply to Oba
    TI__Mastermind 27045 points

    Hi Oba,

    You still need to evaluate the potential damage caused by Ton-min:

    For TPS54160, the minimum controllable on time is typically 130 ns and limits the maximum operating input voltage.

    You can first check out the inrush current Iout_pk by downstream load, then use E-load to sink 1.3*Iout_pk at 50ms duration, check the TPS54160 SW duty cycle if ON time is larger than 200ns. 

    B R

    Andy