• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 219 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.

LM3150: Regulator for Raspberry PI not functioning

Alexander MacDonald
Prodigy 125 points
Part Number: LM3150

Tool/software:

I used this part to design a +12V to +5V regulator. I tested this part with an electronic load, and its performance is very good. It can easily supply 6 A with little dropout. Here is the schematic:

When I connected a Raspberry PI and powered everything on, The Raspberry PI didn't turn on. I probed the 5 V rail with an oscilloscope, and I got this:

2.5 V is clearly too low to power the Raspberry PI, but I have no idea why I am getting this signal at the output.

  • 0
    Prodigy 125 points

    I did a bit more digging. It turns out that the input was also exhibiting a similar waveform. I use a CUI VMS-300A-12-CNF 12 V AC/DC power supply for this project.

    I then connected it to a benchtop power supply. I set the voltage to 12 V and the current limit to 2 A. When I turned it on, the benchtop supply whined like made, and it was voltage limited to about 5.5 V.

    It appears the problem is not with my regulator circuit, but that the RPi is a peculiar load.

  • 0 in reply to Alexander MacDonald
    TI__Genius 9460 points

    Hi,

    It seems like the regulator is working fine in isolation with an e-load and the RPi is causing the problem. Closing this thread as it is not a problem in our device. 

    A few helpful tips: 

    - R14 sets the current limit of device

    -Check if your input supply is current limiting, this may be the fix

    - If you see a weird waveform on SW node, C33 might be able to help.

    Regards,

    Rahil