Re: solid state coil problem
From: RODERICK MAXWELL [SMTP:tank-at-mail.magnolia-dot-net]
Sent: Thursday, November 13, 1997 5:56 PM
To: Tesla List
Subject: Re: solid state coil problem
> Subject: Re: solid state coil problem
> On Sun, 9 Nov 1997, Tesla List wrote:
> > 222khz. The inductance from each leg to the center tap is 135uH. The
> > signal generator is a SG3525A pulse width modulator. And the driver is
> > an SG3626R dual high speed driver.
> > Does any one know how to limit the current to the output transformer?
> > I was thinking that maybe you could use another inductor of much higher
> > value in series with the transformer to limit current?
> Sounds like a saturating transformer. Check/add pulse-by-pulse current
> limiting shutting the conducting fet off immediately as the current is
> too high. A push-pull system *will* saturate without proper current
> balancing system!
> The transformer magnetizing inductance of 135uH would mean
> XL=170ohms at 200kHz. Too heavy magnetizing current is therefore
> certainly out.
Thanks! That is probably the solution to my problem! I don't have pin
#10 connected at all, which happens to be the shut down pin. I think
what I,ll do is use a 555 to shut down the both outputs at about 300hz
or lower. I may have to play around with the freq. and or the duty cycle
of the 555 for best results. Thanks!