• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 239 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.

LM2673 Under performance

Ben Wai
Prodigy 150 points

Via Webench, I got a design proposal with LM2673-adj to output 5V/2.5A from a supply ranged 10~26V.  Webench suggested soft-start and Boost capacitor as 0.01uF, current limit resistor=9.79K, power inductor=33uH

I builded the circuit on a bread board and tested.  The circuit was not performed as expected.  It was 5.2V at no load.  3.5V at 5.6ohm load.  Then the power inductor was changed from suggested 33uH to 10uH and boost cap to 0.02uF.  Then 4.85V at 5.6ohm was achieved.  But further test with 2.2ohm load got 3.02V.   Decreased current limit resistor to 2.7K slightly increased the output to 3.3V at 2.2ohm load.

Please advice where should I look into to improve the circuit performance.  Thanks for attention.

  • 0
    Prodigy 10 points
    Some reasons will result in this situations.1.too small size of output capacitor is used.2.Your feedback wiring is too close to interference source ,like inductor.3.Your inductor core size is not enough.It's saturated.4.Wires connected to load are too thin.Your voltage testing spot is wrong .5.You'd better read the datasheet through instead of using automatic design software.