Simpler PC PS master/slave controller

Thread Starter

Zod

Joined Jul 3, 2011
12
There is a very simple way of doing it with a generic NPN transistor, and a 10K resistor. Base current is insignificant, and that's all the master supply sees.

Basic diagram is basic; slave PS/on to the collector, grounds from both supplies to the emitter, and +5v from the master through the 10K resistor to the base.

If you want the LED, put the 5Vsb from the slave to the positive on the LED, and the other side to the grounds through a 1.5K resistor. If you want it only lit when the PS is operating, put the negative side (with the resistor) to the collector with the PS/on; when the transistor turns on, it gets ground along with.

I'm running this sans LED right now, and with up to 800mA available, I could easily stack several supplies.

Grounds MUST be commoned when paralleling supplies.
 
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Wendy

Joined Mar 24, 2008
22,236
Try posting a schematic of your efforts to date? It might make the text more intelligable (nothing wrong with your english, but trying to describe a circuit without a schematic is like speaking a foriegn language).
 

CDRIVE

Joined Jul 1, 2008
2,219
Bill, the problem with his post is it doesn't appear to be a question. It reads more like a reply to a question that was never asked. Possibly there's a current thread with this topic but Zod started a new thread instead of hitting reply?
Chris
 

Wendy

Joined Mar 24, 2008
22,236
Perhaps. It could be something spit out of a Google translator, we'll just have to wait and see if the OP makes a reply.
 

SgtWookie

Joined Jul 17, 2007
22,221
It certainly does seem to be a mis-placed reply. Easy to do for a forum newbie; the "Post Reply" and "New Thread" buttons are pretty close together.

Our OP is talking about how to turn on, for example, an ATX-form-factor PC power supply as a slave. In the 20-pin (v1) or 24-pin (v2, ATXPLUS12) mobo connector, there is a green wire on pins 14 or 16 respectively that's pulled up to +5v standby via a 10k resistor. That wire is pulled to ground to turn on the supply.
So, what the OP is saying makes sense.


There's a pinout of the ATX and ATXPLUS12 supplies on this page:
http://www.smpspowersupply.com/connectors-pinouts.html
 

Thread Starter

Zod

Joined Jul 3, 2011
12
It was a reply to a very old post, which used an optoisolator in the design.


Here is the schematic:
 
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