• State
  • +1 person also asked this people also asked this
  • Locked Locked
  • Replies 2 replies
  • Subscribers 64 subscribers
  • Views 64 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.

UCC256402: Unable to set correct burst mode limit for 270V/0.5A

Michal Sitta1
Intellectual 290 points
Part Number: UCC256402

Tool/software:

Hi,

I am trying to correctly set SMPS, but I am unable to correctly set burst mode threshold.

Burst mode is turned off with load of 600 mA and more. With lower load is SMPS always in burst mode.

SMPS is possible to regulate it, but for now I am using it on 235 V output setting.

100mA load

300mA load

600 mA load

Power on condition with 1kOhm load

I will by glad for any hint.

  • 0
    TI__Guru* 85656 points

    Hello,

    I am reviewing this and will get back to  you shortly.

    Regards,

  • 0 in reply to Mike O'
    TI__Guru* 85656 points

    Hello,

     

    The voltage diver on the BW pin set the burst mode levels BMTH and BMTL during power up.  The

    FBreplica voltage is generated based on the FB.

     

    If your design is not tripping at your desired load voltage more than likely your BMTH and BMTL thresholds are not set correctly.  The following link will bring you to an excel design tool that will calculate the resistor divider on the BW pin to set your burst mode thresholds.   This should help you resolve your issue.

    https://www.ti.com/tool/download/SLUC675

     

    Regards,