[Milsurplus] [ARC5] If You Need a Regulated Low B+ Supply

[J. Forster]

One solution to the EMI problem from switchers is to use a low frequency
square waves, of the order of 60 Hz, rather than 10s of KHz. This enables
you to use much slower rise/fall switching times and conventional filament
transformers run backwards. They are bigger and require bigger HV caps,
but are a lot quieter.

Best,
-John

================





> While the diagram says "new" this part and the associated circuit dates to
> 1991 when it went into the early GM airbags.  I know because my work group
> designed it.  However, it is still sold along with a plethora of other
> "Simple Switchers" which have gone through five generations now.  If you
> go
> to the National Semiconductor website you will a cluster of easy-to-use
> design tools that allow virtually anyone to design the switching reg they
> need right on-line.  All the popular configurations are covered.  You can
> then order the components along with the PCB from the distributor link or
> just roll your own by buying the chip from DigiKey.
>
> BTW, you can still stack "common-ground" DC/DC converters by feeding them
> raw DC from independent windings on the transformer.
>
> Remember that most switcher circuits are not designed to have low enough
> EMI
> to guarantee happiness in our radios.  Pay close attention to short lead
> dress, good grounding and use shielded inductors vs the cheap solenoid
> types.  For best results, extra input & output filtering and a metal box
> may
> be needed.
>
>
> Dennis AE6C
>
> On Sat, Feb 13, 2010 at 11:50 AM, David Stinson <arc5 at ix.netcom.com>
> wrote:
>
>> This cute little circuit is an example of the kind of DC/DC
>> converter you cannot stack, since in and out have a
>> common ground:
>>
>> http://www.nbglin.com/dc.htm
>>
>> Still a neat circuit, though.  I'm gonna get me a
>> couple to use as "Borg Implants."
>>
>> 73 Dave S.
>>
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