Nathan House wrote:
> I'm kind of confused; Isn't a Schottky diode a fast recovery diode?
> Could you give an example as to what diodes you would have used for
> this?

Yes, Schottky diodes have very fast recovery times, usually so fast as to b=
e
ignorable.  The only drawback to Schottkys in this case is that they may
have excessive reverse leakage.  That is usually a function of their voltag=
e
rating and your operating temperature.  Check the datasheet, and if the
leakage is acceptable then go with them.

As for which silicon diodes I would use, I would start with Schottky and us=
e
silicon if the Schottkys weren't good enough.  Recovery time is a serious
issue and slow recovery can really beat the crap out of both the diode and
the switch.  There are various silicon diodes labeled as "fast" and
"ultrafast".  However, that's often a load of marketing.  You have to check
the datasheets carefully.  I've seen cases of a ultra fast diode being
slower than a fast one.  All the labels tell you is that recovery time was
probably at least some consideration in the design of the diode.

> My mistake, I thought they were brushless.

Wait a minute!  How can you make a driving circuit without knowing what kin=
d
of motor you are driving.  The two are driven quite differently.

> I'm not sure if I connected the flyback diodes correctly in my
> circuit. Here's the schematic:
>
http://www.roboticsguy.com/images/misc/balancing_robot/balancing-robot-boar=
d-schematic-r8.png.
> Is that the right way to do it?

That looks right.  Next time don't be so lazy and rotate the part
designators properly before asking anyone else to look at the schematic.

I see some other potential issues, but I will wait to comment until your
schematic shows you are taking this project seriously.  If you don't care,
why should I?


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