high amperage 5804 stepper driver

Archiver

Im currently running stepper motors using allegros 5804 driver. The
driver works amazingly but Im not able to run big motors. I was hoping
that someone could show me how to step the current up using transistors
and maybe give me some radio shack transistor numbers. I would like to
be capable of running up to 10 amp @ 24v.


Thanks,
Jim Gorbet

Archiver

Jim:
That 5804 is a neat IC. Some suggestions for higher output:

Rat-Shack selection is very poor. Digi-Key has IRF9Z34N P-channel Mosfets
for $1.82 ea. These devices are rated to 17 amps and 55 volts with 0.1 ohm
Rdon, and could be driven from the 5804 IC. Because the 5804 sinks current,
you need the P-channel device. Each output of the 5804 would be tied to the
gate through 1k ohms, and would also need ~1k pull-up resistors to positive.
The MOSFET source would be tied to positive, and the drain to a motor
winding. The stepper commons would now be grounded instead of positive.
You would need clamp diodes from ground to each MOSFET drain, pointing away
from gnd. They should be rated >the positive voltage, and >= motor current.
Since the Mosfet Vgs is 20 v max, you need 12 v zeners from gate to source
for positive supply > 12v (safety factor). The MOSFETS would need heat
sinks.

It could also be done with 2 bipolar transistors per output, using a 3 amp
PNP and a 10amp NPN where the stepper commons would go to positive as you
now have. You now would have twice as many transistors to heat sink.

If you wrote your own stepper code, all you would need is 4 N-channel
Mosfets, (IRL530N), running directly off the stamp through a resistor.

Another approach is to use an EDE1200 stepper IC, (www.elabinc.com), which
has positive going outputs, so could also directly drive the IRL530N
Mosfets. I believe this IC has the same control options as the 5804.

Keep in mind that all of these circuits need protection diodes on each motor
winding.

Good luck,
Ray McArthur

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Original Message

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From: Jim Gorbet <jgorbet@f...>
To: <basicstamps@egroups.com>
Sent: Tuesday, May 23, 2000 8:39 PM
Subject: [noparse][[/noparse]basicstamps] high amperage 5804 stepper driver


> Im currently running stepper motors using allegros 5804 driver. The
> driver works amazingly but Im not able to run big motors. I was hoping
> that someone could show me how to step the current up using transistors
> and maybe give me some radio shack transistor numbers. I would like to
> be capable of running up to 10 amp @ 24v.
>
>
> Thanks,
> Jim Gorbet