• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 280 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.

LM2623 true output disconnect

Jose FELIX
Prodigy 10 points
Other Parts Discussed in Thread: LM2623

Hi all,

I drive the lm2623 Enable pin but unfortunatly this chip is not true shutdown.

I need 1A at 3.3V output, which parts and schematics would you recommend to built a simple output disconnection when driving Enable pin?

Many thanks in advance,

Felix

  • 0
    TI__Genius 10115 points

    Hi Jose,

     

    There are a couple of options, but the one we pick will depend on your input voltage.  Can you tell me the range of your input voltage? Also what voltage would you be using to drive the enable pin?

     

    The first option is to use the part as a sepic converter.  The sepic has a blocking capacitor which will give you true shutdown when the part is disable.

     

    The second option is to ac couple the switchnode through a capacitor to a pair of rectifier diodes.

     

    The third option is a PFET to shut off, but this has problems when the input voltage is close to the output voltage, and can also exhibit overshoot on startup.

     

    Regards,

    Marc