Where I connected my fan...

Any technical questions about the Epiphany chip and Parallella HW Platform.

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Where I connected my fan...

Postby hamster » Sat May 17, 2014 9:35 am

Rather than using the clustering jumper I paralleled the fan over the barrel jack. Seemed to work fine even though I used my leaded solder...
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parallella_fan.jpg
My fan connections
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Re: Where I connected my fan...

Postby FHuettig » Sun May 18, 2014 6:54 pm

Hamster, that's an excellent place to make the connection! Those through-hole pins are big & sturdy and it's got good clearance from other signals apart from that one big cap. I'm going to link to this posting from the "Where can I draw 5V for a fan?" topic.
-- Fred -- Hardware Guy --
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Re: Where I connected my fan...

Postby doddy1985 » Sat May 31, 2014 9:14 pm

Quick question concerning the 5V fan. I was just curious what is the power limit I should consider for the fan. Should it be under .5W? I was under the impression that I didn't need that much air being pushed to cool the board/zynq chip. I grabbed a cheapo thing on digikey but it's only .2W and I couldn't even feel the air moving when I put my hand near the fan powered on. I figured I should move up a size but didn't want to draw too much power. I figure I've got about 5 watts to work from though?? Board takes up about 5 perhaps? Extra 5 to work with (5V*2Amps = 10Watts total input)..

Any suggestions?

Thanks!
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Re: Where I connected my fan...

Postby 9600 » Sun Jun 01, 2014 8:42 pm

The board could consume >1A with heavy loads and I'd probably want to budget 1.5A for it just to be on the safe side, leaving 0.5A for peripherals. You really don't need to move much air, and the little fans I use and which seem to work great take <0.1A.

Cheers,

Andrew
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Re: Where I connected my fan...

Postby shodruk » Mon Jun 02, 2014 4:51 am

If the power consumption of the devices is 2A, we should use 4A PSU.
Because it means the maximum value.
It doesn't guarantee sustained use.
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Re: Where I connected my fan...

Postby 9600 » Mon Jun 02, 2014 8:27 am

shodruk wrote:If the power consumption of the devices is 2A, we should use 4A PSU.
Because it means the maximum value.
It doesn't guarantee sustained use.


I think that would be overkill in all but fairly exceptional cases, and if you are drawing up to 4A I'd probably start to worry about power traces and connectors. Not sure offhand what the most you could feed into the barrel connector and draw via the board itself, USB and PEC_POWER is, but it can't be far off that.

Cheers,

Andrew
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Re: Where I connected my fan...

Postby doddy1985 » Mon Jun 02, 2014 5:49 pm

9600 wrote:The board could consume >1A with heavy loads and I'd probably want to budget 1.5A for it just to be on the safe side, leaving 0.5A for peripherals. You really don't need to move much air, and the little fans I use and which seem to work great take <0.1A.

Cheers,

Andrew


Great I'll that this into consideration. So when I booted my board (everything looked great btw!!! ) I had hdmi out to display and opened a browser just to try stuff out. I noticed a bit of lag effect just moving the cursor around with the browser window. I figured this is probably just in the nature of an embedded OS and hardware used on the board and clock speed. I guess I just became over cautious and worried that my board could be running hot. I figure I'll just be on the safe side and get a slightly bigger fan to push air through those side slots of the case. Anyways, thanks again for the quick reply, good to know what type of power budget to work with.
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Re: Where I connected my fan...

Postby shodruk » Tue Jun 03, 2014 4:16 am

9600 wrote:
shodruk wrote:If the power consumption of the devices is 2A, we should use 4A PSU.
Because it means the maximum value.
It doesn't guarantee sustained use.


I think that would be overkill in all but fairly exceptional cases, and if you are drawing up to 4A I'd probably start to worry about power traces and connectors. Not sure offhand what the most you could feed into the barrel connector and draw via the board itself, USB and PEC_POWER is, but it can't be far off that.

Cheers,

Andrew


Sorry, 2A is just an example.
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Re: Where I connected my fan...

Postby imwmh » Tue Jun 24, 2014 2:05 am

My solution shown in the pics, which is binding a fan to the heatsink. Due to the both sizes of the hehe atsink and the fan, it's have to be running without the lid on.The power supply for the fan is a standalnoe one, it steps the input voltage of 5v down to 3.3v to drive the fan.
Attachments
QQ截图20140624095801.png
A standalone power supply and step-down board.
QQ截图20140624095801.png (394 KiB) Viewed 14227 times
QQ截图20140624095729.png
A fan bound to the heatsink.
QQ截图20140624095729.png (752.33 KiB) Viewed 14227 times
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Re: Where I connected my fan...

Postby svartalf » Tue Jul 01, 2014 11:34 pm

9600 wrote:I think that would be overkill in all but fairly exceptional cases, and if you are drawing up to 4A I'd probably start to worry about power traces and connectors. Not sure offhand what the most you could feed into the barrel connector and draw via the board itself, USB and PEC_POWER is, but it can't be far off that.


Actually, knowing what I know about switching supplies in general, he's a lot closer to the truth than many would like to own.

If you're using a basic, minimally regulated wall-wart, you'd be right- 2.5A is probably what you want to aim for. If you're using a switching supply (Which I would be using for power stability...why break my toy prematurely?) you would want one made from a reputable supplier- or double the total available power because the supplies tend to cook themselves if you're exceeding 75% the rated value, and the cheapies tend to be worse and need 200% of the desired draw to be stable and not roast themselves over time. A Laptop supply would be a class of switcher, mind.
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