Re: L297/L298 And a "correction"

Phil,

Snips, inserts follow...

>In CCED, "Phil Mattison" <mattison20@...> wrote:
>I've looked at the IR2101 but it's fairly expensive and drives up the
>component count since you need 4 for a bipolar stepper driver (or 2
>of the dual version).

Well, you asked for a solution to driving FET's easily and
inexpensively; and that one is IMO one of the best...

FWIW (since others will be reading these messages), Mariss has posted
a circuit for FET driving that he says works well, and while it does
have higher component count, it IS buildable by folks who don't want
to use the IR210x chip(s). AIRC, it's in the files section here at
CCED or in my DIY-CNC group.

>Sure the IRFL MOSFETs have a 5-volt gate but that's relative
>to the source terminal so you still have the same translation
>problem for the high-side switches (and the low side as well if you
>have a sense resistor in series.)

As mentioned there are more than a few circuits on the web showing
their use. (If you need examples of how to implement them.) You asked
for a FET that could be driven by logic levels (Well, actually you
asked for one with a built-in driver<G>), so again, since others will
be reading htese responses, I made a suggestion of how one
might "solve" such a problem...

>I understood what Wayne meant by "bipolar" (as opposed to MOS).

I am sure that YOU did. But I'll bet that literally hundreds of folks
here did not; the distinction between bipolar JUNCTION transistors
and BIPOLAR stepper drive topology is non-obvious to someone new to
all this. And "bipolar" to most of these CNC folks will refer to
drives, NOT transistor type. Which IMO makes it reasonable to let
THEM know the difference...

Ballendo