Hi All,

I have been thinking about a power supply for a personal project and I am wondering if it already exists (doesn't everything!)

I want to combine POE, 24v DC & USB C

Most of the time I will use 24v DC from an external power supply 5-48v could be useful though.

USB C AND POE will be useful 2nd & 3rd priority options respectively.

I only want about A @ 3.3v

I have had a look through a few reference designs but they all seem massively over engineered for such low power.

Any suggestions?
Cheers

 

Welcome to AAC!! Interesting goal! And certainly rather ambitious. I mention that because I see nothing simple in the POE communications scheme. In addition, providing the efficient sourcing of those voltages from a 24 volt external source will require a switching type circuit, which will certainly need to be VERY WELL ENGINEERED. so whatever you saw was probably not "Over engineered" but rather ADEQUATELY ENGINEERED!! That is because designing a cost effective efficient and reliable switching power supply is really a serious challenge.

 

Well, 3 weeks on and my research is getting me close to a ‘final’ circuit (not a chance it’ll be final )

I want to get it made so I can test it in isolation from tge rest of the board probably at JLCPCB etc but I also want to avoid lots of components not related to the PS.

I got to thinking will the POE bit work with just the 8742A but without a MAC? Or even without the Phy

I dont know, but if not I will need to add all the data gubbins for the power test board and that adds a chunk of change!

Any thoughts?

Cheers