Re: [CAD_CAM_EDM_DRO] Re: Microstepping - Constant freq. vs constant off-time.

Mariss,
Thanks!
I thought L297 & L6506 were constant frequency controllers but I've used the
L297 and noise is pretty painfull :-(
Doesn't make sense to me......
So, using the L6506 for microstepping should work AND be silent?

You've been most helpful! Thanks again!
/Henrik Olsson. Sweden.

----- Original Message -----
> Hi,
>
> Constant off-time:
>
> + Very simple, effective circuit.
> + Stable operation.
> - Frequency varies with current.
> - Annoying hissing and squealing because of phase-locking.
> - Asymmetrical current slopes cause "tailing" distortion.
>
> Constant frequency:
>
> + Silent; no hissing, squealing, etc.
> + Lower distortion, no current "tailing".
> + Electrical noise is synchronous and is easily rejected.
> - More complex circuit.
> - Overconstrained current loop; requires feed-forward compensation.
>
> Most people don't like the audible noise, so my choice is constant
> frequency. I'm also a fanatic about accuracy, so again, same choice.
> Finally, it's a lot of fun to design "difficult" circuits.
>
> Mariss