• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 173 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.

LM5146-Q1: Not working!

M.A Amir
Prodigy 140 points
Part Number: LM5146-Q1
Other Parts Discussed in Thread: LM5146, LM5164-Q1

Hi everyone!

I've designed a buck converter based on LM5146 IC using webench design. Also I checked the design with the quick start calculator. Input voltage is 15v < Vin < 95v and Vout =12V and it is designed for Iout=1A.

But LM5146 is not working at all. EN/UVLO pin is about 2.5V at 27V input. A 2.2uF cap is connected to VCC pin. VCC pin is presented below. it seems that it is kind of restarting! Is any protection activated?

Vout in this situation is about 2.5V and there is no gate pulses for the mosfets. I've checked the design with the circuits presented by TI. The only difference is in the AGND that i forgot to consider. I mean in my circuit, GND and AGND is the same like typical application example in the datasheet.

Looking forward for any comment.

Thanks.

  • 0
    TI__Guru 56762 points

    Hello,

    Please send the schematic and a completed quickstart file for review. It seems that VCC is hitting its current limit - perhaps the FETs are oversized or the Fsw is set too high.

    Note we generally recommend a converter (with integrated FETs) for a 1A application - see the LM5164-Q1 100V/1A converter for example.

    Regards,

    Tim