There is no difference between your bipolar and unipolar circuits.
bipolar transistor is current operated device while unipolar is voltage operated device. the way to bias these is quite different.
I mean by "bipolar and unipolar circuits" means "bipolar stepper motor driver circuit and unipolar stepper motor driver circuit "
I have used Mosfet which is Voltage activated device unlike transistor which is current driven as you said
The main idea behind making this project is to keep same bridge for Bipolar as well as Unipolar motor. I have studied the step sequence for both types of motor and bias these the way it will full feel the step sequence requirement of motors.
Incase of unipolar motor (5,6 wire) normally common pin is tied to Vcc then you need to pull rest of the pins to GND in proper step i have testing it in two coil activate mode ie in each step 2 coils are always activated to give more torque.
Incase of Bi-polar motor (4 wire) each pin is tied to Vcc / GND alternatively as per step sequence. I have full filled this basic requirment of both of this type of motor and hence i think protesu is in position to simulate it properly.
Also if you see block diagran of L293D,L298 and ignore safty circuit you will find my design much similar. Also L293d also used dual H bridge and some articles shows that it can drive both types of motor.
Awaiting for your comment on thisPosted on: May 22, 2012, 09:11:27 09:11 - Automerged
I am alternatively evaluating the Allegro A4989 and LS8292 too and actually best for stepper driver with microstepping