• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 538 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.

LP2985: Short Circuit Protection

Allan Fan
Expert 5730 points
Part Number: LP2985

Hi Expert,

Customer used LP2985 with fuse(0451002) at output and expect to have brown out 2nd protection to the fuse in short circuit event. The fuse spec is 250mA(test and see blown out at 350mA) however when they test with LP2985 and make the output short by wire, they observe ~360mA constant current(refer to below waveform) but the fuse didn't blow out. Checked LP2985 datasheet in figure 4, it shows ~230mA in short circuit event instead. Why their result didn't match datasheet? 

Could you please have a look and provide any possible reasons?  Thank you.

  • 0
    TI__Mastermind 29150 points

    Hi Allan,

    I will need additional data to troubleshoot this issue.
    What I need is:

    4 channel oscilloscope with the following waveforms being monitored during a short circuit event.

    1. Output current through the fuse (in series with the fuse)
    2. Input voltage with respect to GND of the linear regulator
    3. Pin 5 of the linear regulator with respect to GND of the linear regulator
    4. The voltage across C62 or C63 with respect to GND of the linear regulator

    Thanks,

    - Stephen