• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 64 subscribers
  • Views 759 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.

TPS5430

abdelkader majaiti
Prodigy 30 points
Other Parts Discussed in Thread: TPS5430

Hello,

I want to use the TPS5430 (24VDC input to 5V output) parallel to a second power supply 24VDC input to 5V output. in some applications the TPS5430 has to be disabled, in this case I will have 24VDC @ the input of TPS5430, ENA pin below 0.5V and 5V at the output of TPS5430 from the second power supply.

my question: is it allowed to use the TPS5430 under the above conditions?

 

  • 0
    TI__Guru**** 191445 points

    The TPS5430 is a voltage mode converter.  It is not intended to be operated in parallel with other converters.  You may possibly do that, but when both converters are enabled, there is no provision to share current.  One will probably operate at max current and the other at minimal current.  You may also see control stablity issues.  You could possibly isolate teh two outputs using or'ing diodes.

  • 0 in reply to JohnTucker
    Prodigy 30 points

    Hi John,

    Thanks for your quick response.

    But what about the other condition, when one TPS5430 is disable. in this case the disabled device will have 24VDC on the input pin and 5V on the output pin from the second power supply. is it allowed? or the disabled device will be broken?

    Best regards

  • 0 in reply to abdelkader majaiti
    Prodigy 30 points

    can some one help me. I have to make a decision in my design. my question is:

    what will be the behaviour of the TPS5430 under the following conditions: VIN=24VDC, ENA pin <= 0.5V (device is disabled), but at the output of TPS5430, a 5V  from an external power supply will be applied. can the device survive under these conditions? should I take some countermeasures?

    best regards

  • 0 in reply to abdelkader majaiti
    TI__Guru**** 150650 points

    You can order the EVM here, http://focus.ti.com/docs/toolsw/folders/print/tps5430evm-173.html, and test this under your conditions.

    But yes, since the device is off/disabled, it should be ok.

    Note that if Vin were not present, then the output voltage would power Vin through the body diode of the high side FET.  The current through this diode would be uncontrolled and possibly an issue.  But since you have a Vin and it is larger than Vout, this diode is off.