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From: firstname.lastname@example.org (Nico Coesel)
Subject: Re: Recommend a flyback IC?
Date: Fri, 20 Sep 2002 09:05:21 GMT
References: <3D8A2BFD.email@example.com> <firstname.lastname@example.org>
NNTP-Posting-Date: Fri, 20 Sep 2002 08:55:37 +0000 (UTC)
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email@example.com (Bob Wilson) wrote:
>In article <firstname.lastname@example.org>, email@example.com
>>"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
Depends on what you want. If you need to convert one stabilized
voltage into another, you can do with a fixed pulse-width ratio
converter. Using an NE555 was just easier in that particular case.
Reply to nico@nctdevpuntnl (punt=.)
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