• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 62 subscribers
  • Views 805 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.

LM3481 boost malfunction output voltage same as input voltage

Brian Han
Intellectual 330 points
Other Parts Discussed in Thread: TPA3110D2, LM3481

Hello all,

I have struggled with this for 2days, but I couldn't figure it out.

i have used LM3481 EVM board with Vi = 5V and Vout = 12V settings in the early experimental stage. It worked fine and fired up my TPA3110D2 AMP nicely.

But When I put the boards together by myself on an universal board, the output voltage didn't go up to 12V.

I checked the nodes with DMM but it's only giving me 5V(input voltage) whereever I measure it.

I failed soldering LM3481 couple times, could this be the root cause damaging the IC?

 

  • 0
    TI__Intellectual 2225 points

    Hi Brian,

    It's hard to tell what's happening here, so i think we will need to do a little more debugging.

    1. I think the first thing to check would be to see if the switch node (drain of Q1) to makes sure that the LM3481 is switching.  You need to measure with an oscilloscope and should see a square wave waveform at about 300kHz (exact frequency depends on your circuit).  If there is no switching, then check the voltage on the UVLO pin to make sure it is high enough to enable the LM3481.

    2. You should also try disconnecting the output of the LM3481 from the TPA amplifier to see if the output comes up.  THis will rule out some interaction with the load.

    Perry

  • 0 in reply to Perry Tsao96839
    Intellectual 330 points

    Dear Perry,

    Thanks for checking.

    As you said, I checked the voltage at the UVLO pin and the pin was measured ~1.2V, which should run the converter.

    I'm currently not able to reach out to oscilloscope. Is it possible to measure square wave with a DMM?

    It will take me couple of days to find avavlilable oscilloscope.

    Thank You