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DC power adapter splitting for multiple power outputs (controller boards and playstation 2)

nobelium98

Jan 7, 2015
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So basically I have this project going on - https://www.electronicspoint.com/threads/portable-playstation-2-project.272126/

It would be awesome if you could help me about anyting I asked there. Anyway if you are interested in all that, here is one of the things I need to figure out about powering this thing.

I need power for these 3 things

http://ebay.to/1xNGd7s - There isnt said what kind of connector that is (how big, what plug) so Im guessing its just a common 5.5mm plug (correct me if Im incorrect). Anyway it is said that this board needs 5V 2A power.

http://ebay.to/1tQE10R - this is the other board that needs power. Im guessing this has the same size of a plug. This one needs 12V 2A-5A power. Im guessing this will also power the laptop monitor that will be connected via LVDS cable to this board. So if someone could confirm that then that would be helpful.

And the third thing that needs power is the PS2 Slim itself. I dont know what size plug it has and how much power it needs though.

Questin is that is there by any chance possible to connect all 3 things mentioned above all to one power adapter. Maybe the original PS2 power adapter, buy 2 splitter and get 3 plugs and connect all in. Im pretty sure there is the need to control Amps and Voltage somehow too and I basically have no idea if this kind of configuration work but thats why Im asking.
 

Harald Kapp

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A simple splitter won't suffice.
You will need a voltage regulator for each separate voltage, at the current levels involved preferably a switch-mode regulator. You can buy these as off-the-shelf modules or as kits. Even adjustable ones.
It seems the PS2 runs off 8.5V (this may not be the most reliably source, sorry).
The PS2 seems to be rated at 35W max. (depending on the model). This translates into I=35W/8.5V=4.1A.

If that's so, you can start with a 12V power source, step down to 8.5V, then from 8.5V down to 5V.

Note that the input current of a reasonable step down regulator is less than the output current. A rule of thumb is:
Iin= Iout*Vout/Vin / 0.75 assuming an efficiency of 75% for the step-down converter.
Your power budget therefore is:
5V/2A -> 0.8A on the 8.5 V rail from the 5V board
8.5V/(0.8A+4.1A) -> 5A from the 8.5V rail for PS2 and the 5V board.
This 5A are stepped down from 12V, so the input current to the 12V/8.5V step down converter is 5A*8.5V/12V / 0.75 = 4.7A.
Your display controller needs 12V/5A max. In total you have 2*5A from the 12V rail.

Therefore a good starting point is a 12V/10A power source plus two step-down converters for 8.5V and 5V. It may be advantageous to step down the 5V from the 12V directly. This wlil increase efficiency a bit since teh 2A on the 5V rail will not be converted twice.
 

nobelium98

Jan 7, 2015
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A simple splitter won't suffice.

Well now Im embarassed... Its not a most complicated thing in the world but still a bit of thinking and researching.

Anyway I made a scheme of what I think I need to connect to what and how - http://gyazo.com/e32a121cfa0b0422c8d928ad9995f3cd

Should those do the trick for "switch-mode regulators"? - http://ebay.to/1xPdTDo

And these for splitters? - http://ebay.to/1FzbPEL

And these plugs to connect to switch-mode regulators? - http://ebay.to/1AQfrhl

Im also not sure yet if all the connectors for the controller plates and the PS2 are the same size? Im pretty sure it isnt said anywhere in the information about those products on ebay, there was just the Voltage and amps.

Thank you for the help.
 

nobelium98

Jan 7, 2015
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Last edited:

Harald Kapp

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Your "schematic" although somewhat unusual, looks right.
http://ebay.to/1AR4A6B - this one says that the output current is 12V, nothing said about input
It does:
Description
1. Module Properties: non-isolated step-down constant current, constant voltage module (CC CV) charging module
2. Input voltage: DC 7-32V
3. Output voltage:DC 0.8-28V continuously adjustable
4. Output Current: 12A (when power tube\'s temperature exceeds 65 degrees, please add cooling fan)
But you don't have to worry about that high amperage from the step down regulators. The 5V need to supply 2A, the 8.5V need to supply 4.1A (when connected as in your diagram, i.e. 5V directly from 12V, which is good).

I wouldn't care for off-the-shelf splitters. Grab some cable and connectors and solder them to your needs. Take care to vserve the polarity of the contacts.

Im also not sure yet if all the connectors for the controller plates and the PS2 are the same size? Im pretty sure it isnt said anywhere in the information about those products on ebay, there was just the Voltage and amps.
You'll have to find that out for yourself. I don't know. If you are going to buld these components into a single case, you don't need the connectors anyway. You can solder the cables directly to the respective pads on the PCBs.
Whichever way you chose, it won't hurt to include a separate fuse in each positive cable (one fuse for each sub-unit), rated for the max. current required. An inline fuse holder (e.g. similar to this one) is a good choice. DO not put a fuse in the ground (or "-") wires, on the contrary, ensure a good connection of al grounds using rather thick wire to minimize noise on ground (noise on ground can lead to unexpected and hard to debug behaviour).
 

nobelium98

Jan 7, 2015
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Your "schematic" although somewhat unusual, looks right.


I wouldn't care for off-the-shelf splitters

I mean those are cheap and I guess more convenient because techinally I wouldn have to solder a single thing because of the screw-connections (or whatever they´re called) on the step-down modules and 5.5mm plugs also.

But you don't have to worry about that high amperage from the step down regulators

What about the current input? Can they handle the original 10A input. By the way, it is said that the PS2 needs 5.6A on the original power adapter. I guess I have to take that into consideration when choosing a power adapter(Im guessing I will not be able to use the original PS2 power adapter to power all 3 things, yes?).

And more about amp regulations. The step-down conventer lets you adjust the voltages and that automatically changes to current too, yes? But is there no need for the option to change it exactly to 5.6A for example for the PS2.

Found an unit that specifically said that the current is adjustable too, but cant find it at the moment. Most 10A and even 12A units (like this one - http://ebay.to/1IdfXrR) sayd that if dealing with more than 8A, a heatsink should be installed..But there already are heatsinks on those units so where should I install the extra one? Or would a simple little PC fan work too? It is also said that the step-down converters like this can provide up to 8A constant power, and 10A and up would be short-time peak capability or something like that. I guess that doesnt concern me because I need max 5.6A for a ps2. Anyway the main question here is that whether the 10A means max output and the unit can handle input more than that or is there something else to it. Also the current adjustments, how does that work? I also hope that the splitter cables can handle the current and voltages, thats not usually said in the specs of the cables.
Also what are these kind of connection called, where there is a solid piece of metal connecting the 5.5mm plug and the step-down conventer by the screw-connections? That way would that connection be solid, without flimsy wires. I mean the small metal connections
like shown on that picture - http://gyazo.com/6e26b7efc372679e0be65246cf20571c
Are they called something or are they just random pieces of metal?
 

Harald Kapp

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The step-down conventer lets you adjust the voltages and that automatically changes to current too, yes
A load only draws as much current as it requires. Once you provide the correct operating voltage, current follows suit. All you need to consider is that the power supply can deliver at least as much current as the load requires. Otherwise your voltage will break down.

Found an unit that specifically said that the current is adjustable too,
This typically refers to a built-in current limiting function. As long as the current is below the limit, it is a function of the load. Only if a load would try to draw more current than the limit, the regulator will reduce the output voltage to keep the current within limits. The unit you refer to obviously has an adjustable limit.

Anyway the main question here is that whether the 10A means max output and the unit can handle input more than that or is there something else to it
Sorry, I dont fully understand. Input and output are separate issues. All it says is that the unit delivers up to 10A. There is no statement about input current.

Are they called something or are they just random pieces of metal?
It seems that a standard plug for the cable has been abused here. I don't think there's a dedictaed name for these things.
 
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