• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 884 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.

TL431: Negative voltage of Ref pin

Eric Lai
Expert 4940 points
Part Number: TL431

Hi Expert,

The customer used TL431 for power supply applicant.

The input to the Ref pin is from the +12V and -12V resistors divider.

In certain case,will have negative voltage of Ref pin.

May we know whether Ref pin can support the -12V.

Best regards,

Eric Lai

 

Field Application Engineer

Texas Instruments Taiwan Limited

O: +886-2-2175-2582

M: +886-909-262-582

E-Mail:Eric.Lai @ti.com

  • 0
    TI__Mastermind 19470 points

    Hi Eric,

    The TL431 cannot support -12V on the Ref pin if the cathode has a positive voltage. As soon as the voltage drops below -1V the current consumption will exceed the absolute max current of the device because internally it will see a short with GND. The Ref pin will be sourcing current and the limit on current sourcing is -0.05 mA which will be exceeded very fast.

    -Marcoo Zamora