MPQ4572 no output Voltage

DC-DC Power Converters
1

Hi,

We have designed a DC-DC Buck based on the MPQ4572. However, we don’t manage to get any output voltage. We have tried the following:

  • Check issues in the design
  • Check shorts, assembly issues
  • Removed R4
  • Replaced R7 with 20k to see if there was any difference
  • Check the online design tool you have to verify everything makes sense.
  • Check the SW node with the oscilloscope; there is some switching but at lower freq and really low duty cycle (also the signal looks bad).

Here I attach the schematics. Is there anything we are missing?

image
image2226×1280 275 KB

2

Removing R1 fixed it. A capacitor on the SW node is not such a good idea. I added R1 as a 0ohm resistor just for the footprint for a potential snubber but I shouldn’t have plugged it.