Re: Pushing a TL494

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Shad Henderson <shenderson@xxxxxxxxxxxxxxxx>

I've run them up to around 500-600khz without any ill effects.  So long
as the outputs (or output, if running it single-ended) is lightly
loaded, it shouldn't be a problem.  And since you won't be loading down
the output, it should be okay.  Ensure that you stiffen the VCC at the
chip with an electrolytic and a small mylar cap to make sure it's
getting clean power.

One thing you'll want to do is use a *quality* capacitor for the
oscillator of the TL494.  Little ceramics drift, so use a tantalum or
dipped mica cap.

Hope it helps!

Shad H.


On Wed, 2007-04-04 at 23:04 -0600, Tesla list wrote:
> Original poster: "Joshua Johnson" <jjohnson98@xxxxxxxxx>
>
> I am trying to throw together a audio modulated SSTC. The
> secondary/topload I am going to use looks like 400 to 500 kHz for a
> resonant frequency. I was wondering if I could stick with the TL494
> controller even though the spec sheet says it's only good to 300 kHz.
> The Plasmasonic II setup,
> 
<http://www.easternvoltageresearch.com/designfiles/plasma02_presentation.pdf>http://www.easternvoltageresearch.com/designfiles/plasma02_presentation.pdf
> is tested to 400 kHz with the TL494. Can I push it a bit farther?
> Anyone run at higher frequencies with this controller?
>
> I skimmed through Texas Instruments' SMPS controllers that handle
> higher frequencies but they don't have the handy Dead-Time Controller
> pin like the TL494 where you can just feed in the audio for modulation.
>
> Any ideas much appreciated.
>
> Thanks,
> JJ
>
>