[Ragnarok]

Hi everyone, I need a little help with this, i have just finish the beta version of a pic controller for ster motors, please tell me your point of view, it works!!!, I'm planning to upgrate the sensing part for a high side current sensor, and the pic for an avr for the speed.
I have tested this with a little stepper with 46v at 300 rpm, i'm not currently testing the bigger ones 'cause i want to considerate everything, specially the chopper On and Off times (can some one help me with this).
I been checking datasheets like sla7260, it says Toff 12us and Ton 1.8us <- should i leave this??
I been thinking use a pull up resistor to activete the IRLZ44 with 10v, to avoid heat.
And what about using a ADC instead of a DAC to measure the voltage given by the high side sensor, is DAC better and comparator better?
The schematic is is the Stepper.zip, and the source code is in the Motortest.zip (feel free to use and modify them), i hope someone can help me to improve the design i'm convensed this can be done and the components are very cheap.

Just one more thing, who many rpm have you reach and with which one driver, thanks!!!!!

I almost forget explain how it works, the is a 0.1ohms resistor at the end of the A/A and B/B phase, those are for current sensing as Ex: 0.1ohm*1A, this give us 0.1v, the the Op amp inversor are to ajust the gain depends on the ampers you want, the Vref of the dac are 3V, so if you want 1A to pass ajust the gain to 30 -> 0.1v * 30gain -> 3v, so with 0.1v in Rsense you have 1A throung it!!!, you compare the two voltages in the pic comparators and then make the chopper thing!!!, and so if you want 3A throung Rsense, you have to ajust the gain to 10 (10K+10K+10K/10K POT to regulate), so when you have 0.3v*10gain -> 3v, and let the pic chopp!!!you ajust the dac voltajes in the pic for microstepping, the second op amp inversor is for reverse the voltaje for - to + the gain is 1, i want to fix this with a high side sense.

hi pminmo!!!, i have get my maxim samples and build an isolator (after get a job for pay everything (chair) ), and my jrgo is very close!!!. see you!!!

[pminmo]

Hey Ragnarok,
A passive pullup actually may not help. The capacitance of the gate really needs an active drive. You would be better off to use a 74AC08 to drive, or a true mosfet driver.