Maybe you clarified earlier but I missed it: I still don't know what you're doing. What is "12V_in_a" and "12V_in_b"? I assume "Ramp_out" from the AD5227 is going to the ECU but what is the ECU input? What is this all doing?
I see "Servo Eliminator" in the title block: Is this for a motorcycle exhaust valve or ... ?