Re: [CAD_CAM_EDM_DRO] re: comments on driver circuits

On Thu, 20 Nov 2003 17:17:22 -0000, you wrote:

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>Hi Harvey,
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>can you elaborate on the filters ?

The problem is that the control chip can lock in on a sub-harmonic of
the chopping frequency, causing the motor to "sing". This is often
caused by spikes in the current waveform, or noise, or sometimes
perhaps cross coupling.

I added an RC filter, about 0.001 ufd to ground from the sense
inputs, and about 10K or so to the current sense resistors. It's
detailed in the application sheets, and also on Hans' site. He didn't
need it, but with futzing around with the layout, I did.

Harvey

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>Dave
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