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TPS54232: Damaging with a +15V Input voltage

Eduardo Pino
Prodigy 60 points
Part Number: TPS54232

Hi,

I am designing a project that uses a TPS54232 to convert a 12V to 24V input to 5V output

My circuit(first image) was based on a TI SwitchPro circuit. 

The problem is that TPS54232 is not handling voltages over 15V. I have destroyed 3 ICs by now.

At first I thought it was due to an input voltage spike coming out of my bench power supply.

However, I tried increasing my input voltage gradually, starting at 12V, while keeping an eye on the IC output. 

Up to 14V the converter worked fine but when the input reached 15V the IC died (This happened twice!).

Maybe the problem is in my PCB design, but I am not sure where I went wrong. (see image below)

(OBS1: I omitted the ground plane to make it easier to see.)

(OBS2: Q1, and R1 are not populated. J1 is a jumper linking the input to TPS)

Is there something I am missing? The TPS54232 should work with Inputs going from 3.5V to 28V,

and circuit is exactly like the one I got from SwitchPro Desktop.

I am pretty sure I made some silly mistake here, I just cannot see where.

  • 0
    TI__Genius 10070 points

    Hi,

    What is the load? Did you see the issue at different load? Could you please share the waveform (VIN,VOUT,SW,IOUT)? 

    The layout is not good, very thin trace is used for the power stage. Please refer to the user's guide to design the layout.

    www.ti.com/.../slvu277.pdf

    Shawn

  • 0 in reply to Shawn Nie
    Prodigy 60 points
    Hi Shawn,

    I tested the buck converter without any load attached to the output. But it is supposed to power a raspberry pi computer.

    About the layout, I used a pcb trace widith calculator to find the appropriate width, in this case I used 0.7mm, but you are probably right, I will rethink this in future designs . However, since there was no load during my tests, I dont see how the trace would be a problem.
    But I'am guessing that since the schematics looks about right, then the problem must be in the pcb.

    (I will post the waveforms as soon as possible!)

    Best regards,

    Ed