| mbcouple |
I have a 12vdc source that fluctuates, and i need a clean +/-15v dc power supply from it. Does anyone have any ideas?
Thanks
Hans |
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| imix500 |
| How much current? Maybe a dc-dc convertor? |
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| mbcouple |
Sorry, good point. I dont need very much current. Less than an amp, maybe between 250 and 500mA, more is ok though. I am looking for something i can build, instead of an off the shelf product. I am hoping to keep the cost of the circuit beloew $30 if i can.
Thanks
Hans |
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| richie00boy |
| You're looking at a DC-DC converter and you'll need a transformer. I'll be putting a simple design on my website soon, but you need to be able to wind your own little transformer. I'm thinking of getting some made up if there is enough demand. |
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| richie00boy |
| That looks like a good solution. |
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| pinkmouse |
| For $30, surely it would be easier just to build a proper one from scratch? |
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| Mike Gergen |
| Go to the national Semi web site. You put in the requirements and the site designs the supply you need. |
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| DigitalJunkie |
Maybe something like:
http://www.users.qwest.net/~ptaylor...-Neg-supply.jpg
It's a small dc-dc from older Fluke DMM's.
The input is +5V and the output is +/- 15V (theres a 78/7915,thats not in the schematic,along with the + output diodes,and filtering caps.I modified one a bit for another project-only needed a Neg output.)
I'm not sure of the current available,but it's pretty decent.. Maybe 500ma? |
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| richie00boy |
| quote: | Originally posted by pinkmouse
For $30, surely it would be easier just to build a proper one from scratch? |
US$30 is around £16.50, consider that you have to source a transformer or parts then wind your own, I think that's cheap not to mention a compact solution. A custom transformer will be easily £15 on it's own. |
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| pinkmouse |
Not in the states, dollar and pound prices are just about equivalent, so 30$ will buy about the same as £30 over here.
So how much are those dc-dc converters to do 500mA anyway.
? :) |
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| paulb |
Somebody suggested National. Here's a schematic from their LM2585 datasheet. Looks like the transformer may be available from Coilcraft.
A word of warning: switching power supplies are notorious for being difficult to build. Chances are you'll probably face a few problems while building. |
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| jacco vermeulen |
| is a voltage doubler followed by a voltage regulator not easier ? |
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| richie00boy |
| quote: | Originally posted by pinkmouse
Not in the states, dollar and pound prices are just about equivalent, so 30$ will buy about the same as £30 over here.
So how much are those dc-dc converters to do 500mA anyway.
? :) |
Check your facts ;) I did with today's exchange rate before I made that post. US$30 = £16.44 if you want to be picky :D |
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| pinkmouse |
| Richie, you misunderstand. An item that costs £30 in the UK will usually cost around 30$ in the US. |
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| paulb |
| quote: | Originally posted by jacco vermeulen
is a voltage doubler followed by a voltage regulator not easier ? |
Not for that much current (0.25+ amp).
| quote: | Originally posted by pinkmouse
Richie, you misunderstand. An item that costs £30 in the UK will usually cost around 30$ in the US. |
Yup, dollars for pounds. Also works in Canada. |
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