Notification 628 -Feedback pin current too low

CATEGORY

ISSUE / RESULT

FIX / REFERENCE(S)

Warning

Feedback current is too low.

  • Use smaller device or force optimization with higher value of VOR.

 

In order to maximize the allowable output voltage variation and give the smallest output current variation a value of 150 μA is ideal allowing an LED string voltage variation of up to 2:1, (VO(MAX):VO(MIN)).  

Because most designs have a smaller output variation, IFB is allowed to be between 100 μA and 205 μA.