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12v to 5v circuit?

daz

By daz
in DIY Astronomer

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daz

daz

Posted
Posted

Calling you expert electronic chaps :D

I have a 12v to 5v step down transformer for my USB hub, but I would like to incorporate a smaller version so I can place on the side of the mount.

Anyone have a diagram, or link, I can look at?

Ta

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Psychobilly

Psychobilly

Posted
Posted

I guess your 12V is likely to be closer to 13.8V ... so for a linear regulator design you would be lookign to get rid of 8.8W/A which would mean a meaty heatsink and possibly a fan...

There are quite a few readily available swithching regulator modules out there...

DC/DC Converter Regulator 12V/24V Step down to 5V ? 50W | eBay UK

or have a look the other items they have available...

tchwarehouse | eBay UK

this one in particular...

KIM-055L DC-DC 12V Step Down to 5V 5A (Wide I/P 9-35V) | eBay UK

Or this as an "encapsulated" solution... I like the look of this one and may get one myself...

http://cgi.ebay.co.uk/24V-12V-5V-Step-down-5A-25W-DC-DC-Converter-/180642562049?pt=LH_DefaultDomain_0&hash=item2a0f22c001

If you only needed 1A then you could pick up one of the cheap Cigarette lighter plug USB charger adaptors and rip the innards out...

Peter...

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malc-c

malc-c

Posted
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There are switching regulators that can directly replace the 7805 liniar regulators, but most are rated at 1A. Unlike the liniar regulator the switching version tend to run cool. They are however expensive, typically £7 - £10 compared to the 70p for the liniar regulator.

Typical examples:

XP POWER|SR10S05|SWITCHING REGULATOR, 5V, 1A O | Farnell United Kingdom

http://www.robotshop.com/eu/Dimension-Engineering-Switching-Regulato.html?utm_source=google&utm_medium=base&utm_campaign=GoogleUK

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daz

daz

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Thanks chaps!

I will check the ampage tonight, but I like the look of that all-in-one package Billy.

Malc - the SR10S05 looks good as well. The technical sheet shows I would need a couple of capacitors and a coil... Is that right?

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malc-c

malc-c

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Daz, to be honest I've not used one in the field... most regulation recomemnd a couple of capacitors either side of the regulator, so I think that's fairly standard. You could probably get away with out using them coil IMO

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r3i

r3i

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If you only needed 1A then you could pick up one of the cheap Cigarette lighter plug USB charger adaptors and rip the innards out...

That's what I use to power a USB hub attached to my pier. Something like one of these: Micro DC to USB Adaptor : InCar Power Adaptors : Maplin, though you can get them a lot cheaper on ebay.

It just plugs into a cigarette lighter socket that I've got connected to my 12V Bench PSU. I modified an old USB cable and fitted the appropriate power connector for the hub. Seems to work fine.

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r3i

r3i

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Yep those are the ones...

Really depends on what your plugging into the hub... some usb powered cameras like the DSI's are power hungry...

Billy...

I've got a QHY8, Meade DSI 1, EQDir and a Wireless Gamepad dongle all going through mine. So far so good.

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daz

daz

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Indeed....

Thinking of an alternate though...

Making a box with my dew control, FCUSB and USB housed together and just run a 12v power lead and a 5v power lead...

The lead would be about 1.5m long - would this be OK?

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