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WEBENCH® Tools/LM5175: LM5175PWPR 12.0V-15.0V to 12.00V @ 10.0A

Danson Garcia
Prodigy 20 points
Part Number: LM5175

Tool/software: WEBENCH® Design Tools

Hi,

I created a buck/boost converter using your LM5175 controller and the TI Webench Tool. Attached below is the webench report. I copied the design report into my schematic design in the hopes that the design process becomes easier and designed a PCB with it.

When I soldered the required components on the PCB, the circuit turns on, and it produces the required voltage level. But after some time, the circuit doesn't work anymore and produce a level of about 8V. This also happened when the system is under some small load such as powering other ICs (mA).

Are there any errors on the schematic or the webench tool? Is there issues with having additional capacitors downstream (around 100uF in total)? I also tried increasing the SS capacitor to 100nF to increase soft-start duration from the 22nF given by the Webench tool. Basically, I added filter capacitors for multiple external connections from the board.

3377.webench_design_12V_10A.pdf

  • 0
    TI__Guru* 78320 points
    Hi Danson,

    Thank you for choosing the LM5175. I don't find any obvious problem with your schematic. Can you monitor the SW1 and SW2, zoomed in to show a couple of cycles, so we can see if there is switching ringings that may damage the BOOT pins? If you can refer to the LM5175 EVM schematic, you can see there are two 7.8V zener diodes are used to protect the BOOT1 and BOOT2 pins against over charging by the switching ringing at the SW nodes. You can add these Zeners and see the effects.

    Thanks,
    Youhao
  • 0 in reply to Youhao Xi
    Prodigy 20 points

    Hi Youhao,

    I will try adding BZT52C8V2T zener diode to see if there are any improvements.

    Also, is it possible that the switch ringing is exceeding the max reverse voltage of the diode (@30V). I am planning to change the B230A-13-F to another that has a higher VR (@100V).

    Best,

    Danson