• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 92 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.

TPS2121: could not get the expected input

Jiawei Hu1
Expert 4365 points
Part Number: TPS2121
Other Parts Discussed in Thread: TPS2116

Hi team,

My customer use TPS2121 for input selection, and they want to get the output from the higher input, but get the output from 3.6V, not 3.8V.

Sch is as below figure, could you kindly tell why this happen? Thanks!

B.R.

Jiawei

  • 0
    TI__Mastermind 32650 points

    Hi Jiawei,

    The input voltages are quite close to one another. I think that the IN1 could be seeing a slight drop when used which could result in the device selecting IN2. Please note that IN1 has to be larger than IN2 for VCOMP mode to work with IN1 being selected. If In2 is greater OR equal then IN2 will be selected.

    One option would be to introduce some sort of priority structure so as to force the device to select IN1. 

    Another option could be to switch the inputs and see if the priority is acceptable now.

    Finally, since your voltages are quite small, have you considered using TPS2116? This PowerMUX is like a low voltage version of TPS2121.