Re: S.s. MOSFET-driving

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Ken,

You may want to see Marco's discussion of IGBT drive problems and fixes at:

 http://personal.inet.fi/atk/dncmrc/

I found that I needed series resistance (100 ohms) to slow down the IC's
switching speed or they would blow the IGBTs.  The IC designers wanted to force
the gate capacitance to the voltage they want instantly and they did a bit
"too" good of a job ;-))  That is the only trouble I ran into but I don't have
transformers and such (fiber optic).

Cheers,

        Terry


At 01:31 PM 12/30/2001 -0500, you wrote: 
>
> There's been mention made recently of the IR2110-series ICs for driving
> Tesla-coil MOSFETs.  A long while back I had intractable trouble using those
> ICs, seemingly because the very high-impedance voltage-translating circuitry
> within the IC was being affected by the coil's electric field.  I had to get
> rid of the IC-drive scheme and go to discrete-component drivers + isolating
> transformers.  For the latter, I just use readily-available common-mode
> chokes (2 windings on a toroid) connected as 1:1 transformers.
>
> And as to the transformer-drive...I additionally found a problem in that,
> every time drive was cut off at the termination of a spark-event, the
> transformer's flux would have to reset to 0 and that would cause the MOSFETs
> to turn on spuriously.  I had to add additional circuitry to eliminate that
> turn-on.
>
> Ken Herrick