RE: [CAD_CAM_EDM_DRO] Getting 4.2V from a 5V PSU for a Stepper Motor Driver Board

Hi Kev
Just put a hi power silicon diode in series with the supply. This'll drop
the voltage by a good 0.6volts. That should keep the motors happy and forget
the series resistor and especially forget the voltage divider.. In fact the
diode and the motor become a voltage divider system.
Good luck



-----Original Message-----
From: CAD_CAM_EDM_DRO@yahoogroups.com
[mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Kev Pearce (kevp.com)
Sent: Monday, 13 June 2005 10:36 AM
To: cad_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Getting 4.2V from a 5V PSU for a Stepper Motor
Driver Board

Hi all,

I'm trying to put together a stepper motor driver board using L297/8's.

The stepper motors I'm using are rated bipolar 4.2V/phase at 1.2A/phase.

I wanted to use an old PC power supply, as it can nicely do 5V at upto 22A
ready done.

But what's the best way to get 4.2V from 5V at about 3A per driver board and
be able to run it with a L298???
I've tried looking up voltage regs at 4.2V with no luck, or zeners...
Would a simple series resistor or voltage divider do the job... but at 15W
could they handle it???

Anyone any ideas...


Cheers all

Kev/.

[Non-text portions of this message have been removed]



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