I WELL understand, Jim!! I've been at this game for some 30+ years.
I know the SMPS designers don't line resistances or small inductors
inserted in series with the gate drive of the final switching FETs, but
those measures sure quiet them down. They might loose 2 or 3 % in
efficiency, but if they are no present, they learn how to decouple the RF
energy from radiating!!!! True, the components add a very small amount of
cost and contribute nothing to the performance of the system, but they sure
quiet them doen in the RF world. The game is to minimize the FETs on-time
during the ON/OFF and OFF/ON transitions. Why scream that at the limit of
the silicon process??
Dave - WØLEV
On Thu, Dec 16, 2021 at 9:03 PM Jim Brown <jim@audiosystemsgroup.com> wrote:
> Exactly my point, David. And switching speed is critical for EFFICIENCY
> in power systems -- it is unrelated to the "speed" of Si. Those
> switching devices would "fry" if slowed down, because power is burned
> during that switching time, in addition that burned when the device is
> in the "On" state.
>
> I think Ed's reading is solid.
>
> 73, Jim K9YC
>
> On 12/16/2021 12:49 PM, David Eckhardt wrote:
> > Yes, they have to generate RF energy when multi-amperes are rapidly
> > switched. BUT,.......they should be constructed such that they do not
> > RADIATE that energy. There are two sides to the RFI/EMC "solution": 1)
> > attempt to not generate RF energy - about impossible with the high
> > speeds of silicon today, and, 2) if they must generate RF energy,
> > prevent it from being radiated (or conducted).
> >
> > So, according to Ed Hare, ARRL, solar power systems might fall under
> > Part 15, Subpart B, as unintentional radiators as an "appliance". This
> > would require passing both radiated emissions (minimum 30 MHz through at
> > least 1 GHz as an entire system - including simulated house wiring!!)
> > and conducted emissions (150 kHz through 30 MHz on the AC side).
> > Clearly, they do not. Even the Part 15, Subpart B, unintentional
> > radiator limits, would get under the skin of most amateurs operating HF.
> >
> > So, are single-family home solar power installations considered an
> > "appliance". Personally, I have trouble with that, but let's _not_
> > involve the lawyers as we'll get something we really don't want!!!😖😫😕
> >
>
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--
*Dave - WØLEV*
*Just Let Darwin Work*
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