Build a Switching Regulator

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tmort
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Build a Switching Regulator

Post by tmort » Wed Mar 04, 2009 11:13 am

I have a question regarding the building a switching regulator article that discusses using the National Semiconductor LM2576. My application will be regulating voltage down from 48 volts to 12. Using the datasheet this calls for a 330uh inductor and the datasheet also gives some suppliers and model numbers.

I see that these inductors are rated at 3 amps as is the LM2576. I'm only looking to draw less than 500 mA. Can I use a lower rated inductor?

Thanks

Bigglez
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Re: Build a Switching Regulator

Post by Bigglez » Wed Mar 04, 2009 4:07 pm

tmort wrote:I see that these inductors are rated at 3 amps as is the LM2576. I'm only looking to draw less than 500 mA. Can I use a lower rated inductor?
Take care doing this mod. The current in the inductor is
proportional to the load current, but not the same.
In a flyback converter the energy transferred on each cycle
is first stored in the inductor (actually in the gap in the core).
There is also DC current flowing in the inductor, which
will cause saturation unless the inductor is design ed for
that service. Skimping on the inductor is the usual downfall
of SMPS designs.

Are you following the manufacturer's design guide? You
didn't cite what 'article' you are referring too.

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Michael Kaudze
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Re: Build a Switching Regulator

Post by Michael Kaudze » Thu Mar 05, 2009 9:01 am

Hi Bigglez, I belive tmort is talking about the NV article: Build a Switching Regulator
http://www.nutsvolts.com/index.php?/mag ... _regulator
Intelligence is the ability to adapt to change. Stephen William Hawking.

Bigglez
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Re: Build a Switching Regulator

Post by Bigglez » Thu Mar 05, 2009 9:28 am

Michael Kaudze wrote:Hi Bigglez, I belive tmort is talking about the NV article: Build a Switching Regulator
Got it! Should be all the OP needs to read and then build their project.

jeffbirkle
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Re: Build a Switching Regulator

Post by jeffbirkle » Fri Oct 23, 2009 7:19 am

Hi All,
Can this be used to charge a 12V battery from a 48V DC source?
Thanx

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