Power supply for GCA-PI06

RocNet(RaspberryPi), mergCBUS and LocoNet based hardware developed by Peter Giling. (GCA)
Documentation: http://wiki.rocrail.net/doku.php?id=english#hardware
Order information: http://wiki.rocrail.net/doku.php?id=gca:gca-index-en/

Power supply for GCA-PI06

Postby DIYglenn » 26.05.2015, 15:03

Hi!
I have a AC/DC power supply for laptops. It can supply 12V 5A DC, is this sufficient for the GCA-PI06? Would it be better with lower or higher voltage?

I also have several with 12V 2-3A, which I was hoping to use instead, but maybe they are to small?
DIYglenn
 

Re: Power supply for GCA-PI06

Postby rjversluis » 26.05.2015, 17:06

Best Regards, Rob.
:!: PS: Do not forget to attach the usual files.
:!: PS: Nicht vergessen die übliche Dateien an zu hängen.
[ macOS - Linux] - [ N: CBus - CAN-GCA ] - [ 0: RocNetNode - GCA-Pi ]
rjversluis
Site Admin
 

Re: Power supply for GCA-PI06

Postby DIYglenn » 27.05.2015, 06:56

rjversluis wrote:Hi,

just read the manual:
http://wiki.rocrail.net/doku.php?id=gca ... hieve_that


It was a bit confusing for me.
Do I need VAC or VDC?
How do I know if it is linear or not?
What has to be 22V?
How do I get 16VA?

I would want to use the 12V PSU with SPROG, as it can be switched to deliver 15V 4A.
I have a lot of 19V 90W HP Laptop PSU's, can one of these be used with GCA-PI06?
DIYglenn
 

Re: Power supply for GCA-PI06

Postby rjversluis » 27.05.2015, 07:08

Hi,

It only needs a 8-20 Vac or 12-24 Vdc input line, minimum 16 VA, for the full load of 3 Amp.


8V to 20V AC
or
12V to 24V DC
Best Regards, Rob.
:!: PS: Do not forget to attach the usual files.
:!: PS: Nicht vergessen die übliche Dateien an zu hängen.
[ macOS - Linux] - [ N: CBus - CAN-GCA ] - [ 0: RocNetNode - GCA-Pi ]
rjversluis
Site Admin
 

Re: Power supply for GCA-PI06

Postby DIYglenn » 29.05.2015, 12:31

rjversluis wrote:Hi,

It only needs a 8-20 Vac or 12-24 Vdc input line, minimum 16 VA, for the full load of 3 Amp.


8V to 20V AC
or
12V to 24V DC


Thanks!

So we're talking 5V 3A load?

16VA at 12V = 1.3A?
In other words if I have a 12V 2A PSU I got more than enough? As 2A*12V=24VA.

I'm not too good at this. So VA is the conversion of ampere between different voltages, without considering the wattage?
DIYglenn
 

Re: Power supply for GCA-PI06

Postby ron&bram » 29.05.2015, 13:52

Hi,

A power upply of 12 V, 2 A is capable of upplying a maximum of 2 A, regardless of voltage.
Best regards, Viele Grüsse, vriendelijke groeten, Ronald :rr_cap:
GCA85/50/93/145/146/153 Loconet, Twincenter+booster for locs, seperate booster for accessory decoders, dedicated laptop with XP and Ubuntu for Rocrail, AndRoc, LGB indoor OTF layout
ron&bram
 

Re: Power supply for GCA-PI06

Postby DIYglenn » 29.05.2015, 13:58

ron&bram wrote:Hi,

A power upply of 12 V, 2 A is capable of upplying a maximum of 2 A, regardless of voltage.


But it would be VA24 right?

In other words with a step down to 5V (GCA-PI06), it could provide 4.8A?
DIYglenn
 

Re: Power supply for GCA-PI06

Postby RainerK » 29.05.2015, 14:20

Hi Glenn ? or what ever ...

You need to consider a efficiency of 80% of the switched power supply and additional the loss of the bridge rectifier in the input circuit.
So You will have only 10.6 V with 2 A at the switching unit = near 21 W * 80% = 17 W at the output of the switching unit.
And so You get the result: With 5 V and 17 W You will get a max. current near 3 A.

Thats the difference between the expectation 4.8 A and the reality near 3 A :!:

Because the IC "2576" of the switching unit can provide only 3 A is Your 12 V / 2 A a usable thing to supply it. :wink:

Best Regards
RainerK
Last edited by RainerK on 29.05.2015, 14:45, edited 1 time in total.
Best Regards, es grüßt RainerK

DCC++ with Arduino Uno / Motor shield and LocoNet GCA85, 50, 93 and 136. Special interests: DIY electronic assemblies. http://www.rainermoba.blogspot.com
Planning replace the coincidence by the mistake
RainerK
 

Re: Power supply for GCA-PI06

Postby DIYglenn » 29.05.2015, 14:39

RainerK wrote:Hi Glenn ? or what ever ...

You need to consider a efficiency of 80% of the switched power supply and additional the loss of the bridge rectifier in the input circuit.
So You will have only 10.6 V with 2 A at the switching unit = near 21 W * 80% = 17 W at the output of the switching unit.
And so You get the result: With 5 V and 17 W You will get a max. current near 3 A.

Thats the difference between the expectation 4.8 A and the reality near 3 A :!:

Best Regards
RainerK


Not sure I understand the loss completely, as it does provide an exact 12V out from the PSU.

Anyways; I have several 19V 3-4A laptop power supplies, I guess one of these can be used?
DIYglenn
 

Re: Power supply for GCA-PI06

Postby RainerK » 29.05.2015, 14:55

Hi Glenn,

DIYglenn wrote:...Not sure I understand the loss completely, as it does provide an exact 12V out from the PSU...

my description above I have nothing to add.

DIYglenn wrote:...Anyways; I have several 19V 3-4A laptop power supplies, I guess one of these can be used?...

Use it or leave it.

Best Regards
RainerK
Best Regards, es grüßt RainerK

DCC++ with Arduino Uno / Motor shield and LocoNet GCA85, 50, 93 and 136. Special interests: DIY electronic assemblies. http://www.rainermoba.blogspot.com
Planning replace the coincidence by the mistake
RainerK
 

Re: Power supply for GCA-PI06

Postby DIYglenn » 29.05.2015, 15:06

RainerK wrote:Hi Glenn,

DIYglenn wrote:...Not sure I understand the loss completely, as it does provide an exact 12V out from the PSU...

my description above I have nothing to add.

DIYglenn wrote:...Anyways; I have several 19V 3-4A laptop power supplies, I guess one of these can be used?...

Use it or leave it.

Best Regards
RainerK


I mean, where does it go down from 12V to 10.6V? Is that the GCA-PI06? If so I guess the 12V is too small.

What do you mean "Use it or leave it"?
Would it be a bad choice to use this PSU?

Edit:
Sorry, for some reason this didn't show in my browser:
Because the IC "2576" of the switching unit can provide only 3 A is Your 12 V / 2 A a usable thing to supply it.


I got it.

But my 19V supply would probably make the GCA-PI06 generate more heat?
DIYglenn
 

Re: Power supply for GCA-PI06

Postby RainerK » 29.05.2015, 16:05

Hi Glenn,

DIYglenn wrote:...my 19V supply would probably make the GCA-PI06 generate more heat?

no, than there is the fundamental difference between linear and switched power supply.
Linear:
Increase the input voltage and You get higher losses = increasing heat.

Switched:
Increase the input voltage in limited ranges and You get NOT higher losses in the switching unit = NOT increasing heat.
In this case is the mentioned limited range about 12 V to 24 V.
The switching unit will only some time parts take current from the input (on) and other time parts not (off).
There are ca. 57.000 periods / sec with the "2576"
The relations between the on and off phases are variable controlled and so the losses will be regulated to the same value.
So, as wrote above, the heat doesn't increase.

If You need even more description, please use google, wikipedia or what ever You want.

Only a note to the difference 12 V to 10.6 V:
Look in the circuit scheme of the Pi06. There You will find a bridge rectifier GR1 which the reason is of the 1.4 V voltage loss.

Best Regards
RainerK
Best Regards, es grüßt RainerK

DCC++ with Arduino Uno / Motor shield and LocoNet GCA85, 50, 93 and 136. Special interests: DIY electronic assemblies. http://www.rainermoba.blogspot.com
Planning replace the coincidence by the mistake
RainerK
 

Re: Power supply for GCA-PI06

Postby DIYglenn » 29.05.2015, 18:22

RainerK wrote:Hi Glenn,

DIYglenn wrote:...my 19V supply would probably make the GCA-PI06 generate more heat?

no, than there is the fundamental difference between linear and switched power supply.
Linear:
Increase the input voltage and You get higher losses = increasing heat.

Switched:
Increase the input voltage in limited ranges and You get NOT higher losses in the switching unit = NOT increasing heat.
In this case is the mentioned limited range about 12 V to 24 V.
The switching unit will only some time parts take current from the input (on) and other time parts not (off).
There are ca. 57.000 periods / sec with the "2576"
The relations between the on and off phases are variable controlled and so the losses will be regulated to the same value.
So, as wrote above, the heat doesn't increase.

If You need even more description, please use google, wikipedia or what ever You want.

Only a note to the difference 12 V to 10.6 V:
Look in the circuit scheme of the Pi06. There You will find a bridge rectifier GR1 which the reason is of the 1.4 V voltage loss.

Best Regards
RainerK


Aha, got it! This is all new to me, thanks for helping!
Well then I've got no reason not to use one of my 19V laptop PSU's, got plenty of them, both 65W and 90W.
Just wanted to know so I don't fry anything.

Again, thanks!
DIYglenn
 


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