Iīm building a direct drive device for a machine using a powerful stepper
Bipolar, rated 8.4 amps/Phase, Torque 9.2NM fullstep bipolar drive.
I allready designed/engineered a bunch of unipolar drivers (e.g. "Alexanderīs 3 axis pic" at open source boards/Pminmo.com), but all for unipolar steppers.
Having tried these om the motor (8 wire) i just discovered that the fetīs blew due to inductive kickback from the coils. Tried to make a workaround, but unsuccessfull.
Canīt use them for bipolar steppers, so i have to buils something much more powerful... A dual H-bridge design!
I made a diagram attaches to this post (PDF).
I have no test/build option at the moment, being tied to bed after a back operation last week.
But i made this diagram.
The step/dir X-lator itself is nothing new, but the bridge-design is made using only N-channel fetīs i have in stock allready.
So my questions are regarding the dual h-bridge design.
Will the fetīs (FZīs) turn on as expected? I use a 9 volt supply with optocupler circuitry to get from 5V ttl level to 9V cmos inputs.
Using FZ and NOT LZ the required gate voltage (RdsON) must be quite higher, but i consider the demands met regarding the datasheet info.
Note: The Cmos S/D circuit will be replaced with my own PIC design if the H-bridge circuit is delivering as expected.
Sorry for the poor schematic... Quickly clamped together from my bed!
Regards from Denmark!