[Gumstix-users] Power Supply Filtering

[Grahame J. <gj...@ge...>]

Hi,

This is an electronics question. I hope someone can help.

I have a problem with my motor controller. 
http://www.pololu.com/products/pololu/0205/

I am not actually using a motor but a resisitive load.  When the PWM really 
starts working I get an increadable amount of noise on my power lines such 
that it locks up the gumstix. More than 4V peak to peak

3.686400 MHz / 375 = 9830.4 Hz - Maximum is 10Khz for VHN3SP30
 
Which just happens to the the frequency of the noise.
The higher the current I draw the more noise.  This is obvious.

I can aleviate the problem greatly by putting a big electrolytic capacitor 
across power to ground 4700uF say. Now the noise is ~ 1V - 0.6V peak to peak 
and the gumstix runs OK.

Is there a better way of filtering this noise

Thanks

-- 
Grahame Jordan
Glass Expansion
15 Batman St
West Melbourne
VIC 3003
PH:  +61 3 9320 1111
FAX: +61 3 9320 1112