• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 63 subscribers
  • Views 822 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.

LM5088 regulation issue

Agusto Labao
Prodigy 20 points
Other Parts Discussed in Thread: LM5088

HI All,

I am hoping I can get some help with the following issue in regards to the LM5088 device.  Here is the design, which was generated using WEBENCH.  Vin= 55V, Vout=12V, max Iout= 2.2A.

The problem I am seeing is that at low load (130mA), LM5088 is regulating giving the proper Vout.  When the current load is increased to 500mA to 1.1 A.  Vout starts to drop to about 8.5V.  Any recommendation on what could be causing this unregulated voltage issue.

Thanks,

Gus

  • 0
    TI__Mastermind 46081 points

    Hi 

    Please check your SW node waveform first. If there is no oscillation at 1.1A load, the output voltage drop might be caused by false current limiting. 

    Generally, false current limiting is caused by;

    - Poor current sense (kelvin-connection from CSG-CS to Rsense is required)

    - Excessive switching noise

    - Wrong component 

    Regards,

  • 0 in reply to EricLee
    Prodigy 20 points

    Hi Eric,

    Thanks for the feedback.  It appears to be Rsense routing on the board does use the kelvin connection.  After re-routing the Rsense close to the device between the pins, then the supply regulated properly.  I needed to add extra 47uF output cap to reduce the ripple.

    thanks again.

    Gus