Re: Allegro 3977

Mariss,

Ahhh, I didn't realize he was comparing it to a LR drive. I was
picturing the L298 w/ those 2 Watt sense resistor.

Any thoughts on a good sense resistor for the 3977? The closest I've
found are these non-inductive "wire element" resistors. But they are
overkill at 3 Watts. Tried looking at "normal" resistors in
paralell, etc. but the available values just don't seem to work out...

- Tom S.

--- In CAD_CAM_EDM_DRO@y..., "mariss92705" <mariss92705@y...> wrote:
> That is not a problem. The purpose of a "sense" resistor is so that
> the drive circuit has feedback or knowledge of what current is
> flowing in the winding. The drive needs this info to adjust the
> winding currents to the required values.
> The "current sense" resistors are power resistors, but not like the
> enourmous current limiting resistors needed in an R/L drive.
> The chip is rated at 2.5A and the sense voltage is 0.5V, so using W
> I times V you get 1.25 Watts of dissipation. That's not a lot.