Is there a / tell us about balancing robots.
Inquiring minds want to know ...

> I see one oddity: the motor driver chip is powered from Vdd but the
> positive side of the clamp diodes goes to Vcc. =A0The positive side of
> the clamp diodes should go to the same power supply line as what
> powers the driver chip.

Sort of.
If returned to a fixed supply clamp diodes should be returned to a
supply which is greater than or equal to the  supply being used to
drive the outputs.

1. If Vclamp is less than vdrive then the driver will be shorted to
Vclamp via the relevant diode when driving.

2. Here if Vcc >=3D Vdd then all is well.
Vdd is connected to +5V at top middle.
If Vcc >=3D 5 V it will work OK as long as the drivers are open
collector / open drain and rated for whatever Vcc is.

3. As noted several times  - in the special case of driving a centre
tapped mtor - usually a stepper but not always, you must satisfy:

  Vcc >=3D 2 x Vdd "or else".

4. Vcc could be a resistor to ground, or to a power supply, or a zener
to ground of Vz >=3D Vdd (or >=3D 2 x Vdd for centre tapped motor) or
similar energy dissipation or storage means.

If,  Vcc < Vdd then "there will be problems" [tm].

 Russell

--=20
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