• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 255 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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: If INy is not selected during tSETy, can't we switch to IN2 anymore?

Emil Zacharia George
Intellectual 570 points
Part Number: TPS2121

Hi Team,

What does the highlighted text mean?

If we don't select IN2 using CP2 during tSETy, can't we power our system from INY anyome, or is it that the soft start function won't be valid?

Thanks.

Emil

  • 0
    TI__Genius 13760 points

    Hi Emil,

    Welcome to E2E!

    The TPS2121 is configured to soft start when the first power source that becomes valid (INx > UV and INx<OV). The TPS2121 will then wait for the input to finish setting before starting tSETy. During tSETy, the TPS2121 will internally check al the voltages on the pins(IN1, IN2, CP2, PR1) to know in which configuration mode it is set up in. After tSETy, the TPS2121 control logic will have finished its assessment and will then either stay with INx or depending on the configuration it will switch to INy still using soft start. After the TPS2121 has decided to stay with INx or has finished setting INy the soft start feature will not be used again until one of the sources becomes invalid (INx,y <UV or INx,y >OV).

    This doesn't mean that you won't be able to power the system with INy anymore. Everything mentioned in the last paragraph happens when the device is first turned ON. Once it reaches steady state and you select IN2 by using CP2 the device will still be able to switch over to the new source. If IN2 was already valid (INy>UV and INy<OV) at the time CP2 is toggled then the device won't use soft start during switchover. The device will still switch over, but it will either use normal switchover or fast switchover depending on the configuration mode of the TPS2121.

    Let me know if you have any questions!

    Andy Robles