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Old Dec 04, 2003, 07:22 PM
jeffs555 is offline
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"Simplify, then add lightness"
Raleigh,NC
Joined Nov 2000
2,701 Posts
Billy,
I didn't notice that it didn't have separate emf sense inputs. It doesn't look like you could add Mosfets easily to it. The capacitor values for startup would have to be tuned to the motor you are using. That would be another problem with using this chip. They say to use a value of 220nF if the damping is high, but I doubt there is much if any damping for these little motors, so you would need to know the torque constant, pole-pairs, and inertia for the motor you were running and if you changed motors you would have to change the capacitor. Probably not very practical for a general purpose controller.

Another thing you need to watch for is the maximum power disipation of 1.38watts. If you run VMOT and VP from the same voltage, then you could only pull a current of around 0.7 amps before you exceeded the power rating. Another reason for running a voltage booster for the VP pin.

Jeff
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