RE: Would Snubbers Kill Ignition Coil Output? (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Thu, 18 Dec 2003 02:16:21 -0600
From: Daniel Barrett <dbarrett1@xxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: RE: Would Snubbers Kill Ignition Coil Output? (fwd)

	Yes, but it's really the *turn-off* that gets you. You want the fastest
turnoff you can get, which will yield the highest-voltage secondary pulse,
but also causes a high voltage pulse on the primary. In theory, you would
turn the IGBT on as fast as possible to minimize switching losses, wait
until you had accumulated the amount of charge you want, then turn the IGBT
off (causing the output spike) at a rate that (here's the tradeoff:) A) is
as fast as possible and B)doesn't overvolt the IGBT...
db


-----Original Message-----
From: High Voltage list [mailto:hvlist@xxxxxxxxxx]
Sent: Wednesday, December 17, 2003 11:09 PM
To: hvlist@xxxxxxxxxx
Subject: Re: Would Snubbers Kill Ignition Coil Output? (fwd)


Original poster: Steven Roys <sroys@xxxxxxxx>



---------- Forwarded message ----------
Date: Tue, 16 Dec 2003 12:11:45 -0700
From: Gomez <gomez@xxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Would Snubbers Kill Ignition Coil Output? (fwd)


On Monday, December 15, 2003, at 07:40  PM, High Voltage list wrote:

> Original poster: Steven Roys <sroys@xxxxxxxx>
>
>
>
> ---------- Forwarded message ----------
> Date: Mon, 15 Dec 2003 11:38:10 -0600
> From: Daniel Barrett <dbarrett1@xxxxxxxxxxxxx>
> To: High Voltage list <hvlist@xxxxxxxxxx>
> Subject: RE: Would Snubbers Kill Ignition Coil Output? (fwd)
>
> 	I've been playing with this a bit lately. Unfortunately, the snubber
> will
> kill the output by about the same amount that it allows the MOSFET to
> live.
> Even a 600V IGBT will die quickly without a snubber.

  Isn't the whole point of IGBT's (as opposed to SCR's) that you can
turn it on
at whatever rate you wish, thus obviating the need for snubbers and
chokes?