Re: [CAD_CAM_EDM_DRO] Re: Current and the L298 & IRF530/IRF540

When I finish proving / improving my current 10A driver, I plan on
publishing it in
the files area. PC board layout and schematics. But I'm moving it over to a
16F628
PIC instead of an L297 and I'll probably offer preprogrammed parts instead
of
releasing the .hex file. That's just to keep someone from going into
production and
selling my design instead of doing the work themselves.

In a rush of get it to the board shop before I go in vacation, I forgot to
include a way
to drop the current in idle mode. So when your steppers are stationary in
idle mode
it's chopping away at full current. I'm piggybacking a 16F84 PIC with an R2R
DAC
to provide an idle current step down on the boards I have. Then I'll mod the
board
for the 16F627 or 16F628 and have that feature included.

That version is what should end up in the files area. That is if the on chip
comparitors
work as well as I hope they will for a chopper drive.

I still don't think it could compete with a Gecko drive, but some folks just
want to build it themselves.

Myself, I like to be able to fix it myself when it breaks. So I do a lot of
things myself
just so I'll have the schematics and source code when something does go
wrong.

later,
Larry E.

----- Original Message -----
From: "Ross Overstreet" <ross-o@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Sunday, August 19, 2001 3:04 PM
Subject: RE: [CAD_CAM_EDM_DRO] Re: Current and the L298 & IRF530/IRF540


> Hi Guys,
> I'm having a hard time finding a source for L297's.
> Where do you guys buy these things?
>
> Dave - thanks for asking this one! I'm in the same
> boat and was searching the web for homebrew ~10A
> stepper driver circuits!
>
> Cheers,
> Ross-O
> http://users.better.org/roverstreet/
>
> -----Original Message-----
> From: daque@... [mailto:daque@...]
> Sent: Sunday, August 19, 2001 9:41 AM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] Re: Current and the L298 & IRF530/IRF540
>
>
> Thanks for the replies. Seems simple enough. I once used IRF530's in
> a 36vdc h bridege motor circuit. They were held to the heatsinks with
> plastic push rivets. You could find the blown one easy. It would melt
> the push rivet, the solder around its legs, and then slide down about
> a quarter inch.
>
> One thing for people new to MOSFETS, use a high enough voltage rated
> part. Inductive pulses were killing those 100v fets protected by a
> 68v znr. The problem was the peak clamping volatage of the znr was
> over 100v by a little. Live and learn. IRF540's were rock solid.
>
> Dave
>
>
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