AC/DC power modules adding to a existing PCB

Thread Starter

DJ_AA

Joined Aug 6, 2021
206
Hi All

I have an existing PCB, which has a GSM/NB-IOT communication module, microcontroller and back up li-poly batteries and its charger.

At the moment, I am either using a simple AC/DC USB power adaptor when used indoors, and if its kept outdoors, I am using a MEAN WELL HDR-15 Series | DIN Rail Power Supplies | MEAN WELL to connect to available power supply cables and then using wire connection to my PCB.

I am now thinking, about replacing the din rail power supply with IRM-03-MEAN WELL Switching Power Supply Manufacturer , so I can do away with any external wiring etc.

If I am correct the power supply includes all components, so I do not need to add anything additional to it.

But is there any rules which I should keep in mind on the placement of it on my PCB?

This is my PCB

1670058783660.png

I would need to extend either the top or bottom to place the new power supply. I would prefer it on the top left conner away from any other connector.

Any thing else i need to keep in mind?
 

PadMasterson

Joined Jan 19, 2021
42
Can't really tell if that's a 4 layer or more PCB, or just 2 layers, but if it's 4 or more, drilling any holes can potentially cause a short if the internal layers are planes. If you are designing the board then you shouldn't have any issues as long as you get some good ground plane area under the supply which may not be needed, but can't hurt. When you say "extent the top or bottom, I'm not sure what you are referring to there either, Top side or Bottom side of the board? If you extend the board keep in mind adding or moving the mounting holes to ensure your board and the power supply are stable. I can't tell if your current mounting holes are plated or not, but it's best not to plate mounting holes or any hole that will have hardware added. The barrel of the hole can/will crack over time and you lose the connection. It's best to use a non plated hole and add a ring of copper around the hole, (top and bottom) and then add vias outside of the ring with traces connecting them to the rings. That's a standard way of grounding, (connecting) mounting holes. That board looks pretty good from what I can tell from the picture. After looking at the power supply part, you will need to be sure you have the correct separation distance for the high voltage side for isolation. In some cases, you may need a routed slot in the board to provide the isolation needed depending on the voltage, material used, (FR4 with or without soldermask) and copper weight for current capabilities. If you have IPC documents to refer to you can use them or download a copy of the Saturn PCB Calculator, (should be free still) and it will give you spacing for voltage, etc. and lots of other calculations you may need. Working with high voltage or line voltages like this is not hard but you do need to understand the requirements for creepage and isolation. Good luck...
 
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