Trying to do 5V and 12V input on same solder pad of Chinese PCB circuit using computer PSU.

Thread Starter

chuttney1

Joined Nov 12, 2014
4
My electrical engineering experience is minimal and in the general section as the background.

I have one of those Chinese PCB boards that can take a 5V and 12V input on the same solder pad to run the whole device and also have a Type-C input. The maximum input on that device is 24V. I'm using an old PSU for the 5VSB and 12V along with an Arduino. The 5VSB is for running the Arduino when the PSU is off when I don't need the PSU to be on. I am not using the Type-C input.

The reason I want to use 12V on the same solder pad is that 5VSB maxes at 3 amps for my PSU. The Chinese PCB board works well at 12V versus 5V. Due to the design of the PCB, I am required to use a Schottky diode on the 5VSB and a 1N4001 diode on the 12V. Prior to this. I did fry my project board when I had the 5VSB and 12V connected for power without diodes.

What I am looking for is a circuit or device that will allow me to stop the current flow of 5VSB once the 12V line is active. I've been Google searching if a relay exists for this but I do not know which one.
 

Thread Starter

chuttney1

Joined Nov 12, 2014
4
Thank you for the input. I would like to give specific details, but I plan to make my results of the project open source because of how useful it is. It's for a PC case modification. No PC case maker has it available for sale so I have to make my own. Once the project is done, everything gets released at the same time as the video about how I wired it all up.
 

Jon Chandler

Joined Jun 12, 2008
1,029
"Help me, but I won't share the details of the parts that make questionable sense at best, and I may not properly understand."

Ok, got it. Good luck with the magic smoke.
 

Thread Starter

chuttney1

Joined Nov 12, 2014
4
"Help me, but I won't share the details of the parts that make questionable sense at best, and I may not properly understand."

Ok, got it. Good luck with the magic smoke.
I did fry my AMD x370 motherboard without using the diode doing this... Your question has been answered.
 
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