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From: firstname.lastname@example.org (Bob Wilson)
Subject: Re: Recommend a flyback IC?
Date: Fri, 20 Sep 2002 04:01:14 -0000
Organization: Your Organization
X-Newsreader: WinVN 0.99.9 (Released Version) (x86 32bit)
References: <3D8A2BFD.email@example.com> <firstname.lastname@example.org>
In article <email@example.com>, firstname.lastname@example.org
>"Christopher R. Carlen" wrote:
>>Since there are 1000s of switcher controller ICs out there, I figured
>>there'd be a good chance you folks could narrow down my choices a bit if
>>I ask here first.
>>I want to make a supply that will produce an adjustable 100-300VDC at up
>>to 25mA. If it's too out of the ordinary to make an adjustable supply
>>with typical chips, then maybe I could reduce the range to about
>>150-250VDC. Worst case I need a constant 200VDC. The input power will
>>be raw rectified and capacitively filtered DC from about 12-24V.
>>Efficiency doesn't have to be stellar, >75% would be great, but I could
>>tolerate a little less. Output ripple and regulation don't have to be
>>lab-grade either, about 1% all around would be great.
>A good old NE555 + IRF730 and a 200uH inductor should get you going.
>I've made a step-up converter from these components to turn a
>stabilized -48V into +160V. Regulation may be hard to do with the
>NE555, an LM3525 or TL494 (these are really old parts, but cheap and
>easy to obtain) probably fit better.
Using a 555 when there are REAL SMPS controllers easily available? You must
be kidding! You can also use a wrench as a hammer, but....WHY?? The 3525
(voltage mode controller), or the 384x series (current more controllers) are
more like it!
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