• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 505 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.

LM3423 boost application on high input

David Park
Expert 5400 points
Other Parts Discussed in Thread: LM3423

Hi,

input voltage is 13.4V and LED string is 3s so output voltage is 9V on boost application of LM3423.

But LED can be turned on.

Customer wants to disable IC under this condition but LM3423 doesn't have this protection feature.

Could you advise for the issue?

Thanks.

  • 0
    TI__Mastermind 25500 points

    What is your full input voltage range? Is it usually lower than 9V and that is why you are using a boost?

    In any case a boost regulator always has a path from the input to the output through the inductor and diode. The only way to make sure the LEDs do not turn on when the input voltage is high enough (and the switcher is shut down) is to use a disconnect switch at the input or in the LED string. Another option is to use a buck-boost topology that could either regulate at 13.4V input or will isolate the input from the output when it is shut down.