Multiple grounds in Switching power supply course

[giga_temp]

I am following your switching power supply videos and I am enjoying them. I have one question. My question is that in the data sheet of the switching IC, i see that there is more than one ground however when you are designing both the schematic and the PCB I can see that you're only placing one ground. why is that so?

Thank you!

[robertferanec]

This is a very tricky question Theoretically, you may really want to design power supply layout the way you keep grounds separated. However I tested it in multiple designs, that if you have multiple solid grounds in your stackup you can simply use a one GND net, but be careful and do not mix high power components with sensitive components. Many times, I have the High current components placed on one side of PCB and the sensitive components on the other side of PCB ... or they are placed in different areas, so the currents flowing in the high power areas will not influence currents in the noise sensitive areas.

If you are not sure, you should follow the recommended layout and split the grounds. If you think you may guess how the currents flow and you are confident they will not influence each other, you can use one common GND.