Need help figuring out Chinglesh schematic and a PoE module

[HPS USA]

If your red wire connects to the positive terminal of your power supply then you have them reversed. The more positive terminal of your power supply should connect to the GND connection of that little green PCB.
Adam

So like this? with power positive going to 'IN-' and power negative going to 'IN+'

Seems crazy, if so...

 

[Arouse1973]

Yeah I know it seems strange but thats what the supplier is saying

 

[HPS USA]

Yeah I know it seems strange but thats what the supplier is saying

I just hooked it up like described in most recent photo, and my bench top power supply immediately shut down when I turned it on...

 

[Arouse1973]

If you disconnect what is plugged into the RJ45 connector does the power supply still shut down?

 

[Arouse1973]

Where is the LAN transformer? The power to the RJ45 goes to a transformer and then splits off to 4 pins. Check you have the right pins connected. It looks like you are connecting it up differently to the circuit diagram. I am not familiar with POE so not sure why you would do that.
Adam

 

[HPS USA]

If you disconnect what is plugged into the RJ45 connector does the power supply still shut down?

That device is a PoE tester. It will light up when PoE is present.

Yes, power supply shuts down with it unplugged.

 

[HPS USA]

Where is the LAN transformer? The power to the RJ45 goes to a transformer and then splits off to 4 pins. Check you have the right pins connected. It looks like you are connecting it up differently to the circuit diagram. I am not familiar with POE so not sure why you would do that.
Adam

The transormer is integrated into the RJ45. It is called a mag jack.

 

[Arouse1973]

The little PCB with you show in the picture, what is the purpose of this PCB. Do you have a circuit diagram for it?
Adam

 

[Arouse1973]

I need to have a look at POE, I have never looked at it before.
Adam

 

[HPS USA]

The little PCB with you show in the picture, what is the purpose of this PCB. Do you have a circuit diagram for it?
Adam

It is a PoE control module. It was provided to me by my customer, via their supplier. The only info I have been given is the schematic I uploaded on the very first post of this thread. I wish I had more info, but I do not, and I don't think I will get more info, either... frustrating. We are at the tail end of a much larger R&D and prototyping process, and this little bugger (PoE module) is the last thing to figure out before I can submit the final prototype and begin production.

I will say that we are not committed to this particular PoE module. It is within my authority to source something else if it makes sense, but this one is made by my clients existing supplier, so there are economies of scale that are attractive.

 

[Arouse1973]

Ok so without any additional info being available from the supplier I would be looking at changing parts. I have been doing a little digging and -48 Volts is commonly used in telecoms because in the olden day they used negative voltages with respect to GND to stop electroplating taking copper from the wires when the outer insulation got damp.

RJ45 part of the diagram looks correct from what I have seen. But without a circuit diagram for the other part I am stuck. Here is a link to a Lineartech part which shows indeed a minus voltage output.
http://www.linear.com/product/LTC4265

Thanks
Adam